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ABSTRACT The aim of the present study was to infer phenotypic responses and genetic parameters of the F1 calf diseases diarrhoea (DIAR) and pneumonia (PNEU) in dependency of the prenatal maternal health status (PMHS) of the dam and of the herd‐calving year. The PMHS considered diagnoses for the cow disease mastitis (MAST) and claw disorders (CD) during gestation of F0 dams. Furthermore, 305‐d milk production traits of F1 offspring from either healthy or diseased dam groups were compared. The study comprised 20,045 female calves (F1 = generation 1) and their corresponding dams (F0 = parental generation 0), kept in 41 large‐scale herds. All F1 calves were from their dams' 2nd parity, implying that all dam (maternal) diseases were recorded during the first lactation and dry period of the dams. The F1 calves were phenotyped for DIAR up to 30 days post‐partum, and for PNEU up to 180 days of age. At least one entry for the respective disease implied a score = 1 = sick, otherwise, a score = 0 = healthy, was assigned. Production records of the 10,129 F1 cows comprised 305‐d records in first lactation for milk yield (MY), protein yield (PY) and fat yield (FY). Linear and generalised linear mixed models were applied to infer phenotypic responses of F1 traits in dependency of the PMHS for CD and MAST. A diagnosis for MAST or CD in F0 cows during gestation was significantly (p ≤ 0.05) associated with an increased prevalence for DIAR and PNEU, with pairwise differences of least‐squares‐means between calves from healthy and diseased cow groups up to 3.61%. The effects of PMHS on 305‐d production traits in offspring were non‐significant (p > 0.05). In bivariate genetic analyses, DIAR and PNEU were defined as different traits according to the PMHS, i.e., DIAR‐MASThealthy and DIAR‐MASTdiseased, DIAR‐CDhealthy and DIAR‐CDdiseased, PNEU‐MASThealthy and PNEU‐MASTdiseased, and PNEU‐CDhealthy and PNEU‐CDdiseased. The direct heritabilities for DIAR and PNEU were quite similar in the healthy and respective diseased dam group. Slightly larger direct heritabilities in the diseased dam groups were due to increased genetic variances. Maternal heritabilities were quite stable and smaller than the direct heritabilities. In random regression models, genetic parameters for DIAR and PNEU were estimated along the continuous herd‐calving‐year prevalence scale, considering a prevalence for MAST and CD (based on the 20,045 dam records plus 16,193 herd contemporary records) in the range from 0% to 30%. Direct heritabilities for PNEU were quite stable along the herd‐calving‐year gradient for MAST and CD. For DIAR, we observed stronger estimate fluctuations, especially increasing direct heritabilities in dependency of the herd‐calving‐year prevalence for MAST from 0.13 (at a MAST prevalence of 0%) to 0.30 (at a MAST prevalence of 30%). Consequently, obvious genotype x herd‐calving‐year PMHS interactions were observed for DIAR on the prenatal MAST scale, with a minimal correlation of 0.48 between direct genetic effects at 0% MAST prevalence and at 30% MAST prevalence. The correlations between direct genetic and maternal genetic effects were antagonistic at all herd‐calving‐year prevalence levels, displaying strongest fluctuations for “DIAR‐MAST.” The genotype x herd‐calving‐year PMHS interactions for DIAR suggest consideration of specific sires according to the herd health status for CD and for MAST. [ABSTRACT FROM AUTHOR]

ABSTRACT Genomic selection (GS) and genome‐wide association studies (GWAS) have not been investigated in Vietnamese dairy cattle, even for basic milk production traits, largely due to the scarcity of individual phenotype recording in smallholder dairy farms (SDFs). This study aimed to estimate heritability (h2) and test the applicability of GS and GWAS for milk production, body conformation and novel heat tolerance traits using single test day phenotypic data. Thirty‐two SDFs located in either the north (a lowland vs. a highland) or the south (a lowland vs. a highland) of Vietnam were each visited for an afternoon and the next morning to collect phenotype data of all lactating cows (n = 345). Tail hair from each cow was sampled for subsequent genotyping with a 50K SNP chip at that same visit. Milk production traits (single‐test day) were milk yield (MILK, kg/cow/day), energy corrected milk yield adjusted for body weight (ECMbw, kg/100 kg BW/day), fat (mFA, %), protein (mPR, %) and dry matter (mDM, %). Conformation traits were body weight (BW, kg) and body condition score (BCS, 1 = thin to 5 = obese). Heat tolerance traits were panting score (PS, 0 = normal to 4.5 = extremely heat‐stressed) and infrared temperatures (IRTs, °C) at 11 areas on the external body surface of the cow (inner vulval lip, outer vulval surface, inner tail base surface, ocular area, muzzle, armpit area, paralumbar fossa area, fore udder, rear udder, forehoof and hind hoof), assessed by an Infrared Camera. Univariate linear mixed models and a 10‐fold cross‐validation approach were applied for GS. Univariate single SNP mixed linear models were applied for the GWAS. Estimated h2 (using the genotype information to build relationships among animals) were moderate (0.20–0.37) for ECMbw, mFA, mPR, mRE, BW, BCS and IRT at rear udder; low (0.08–0.19) for PS and other IRTs; and very low (≤ 0.07) for MILK, ECM and mDM. Accuracy of genomic estimated breeding values (GEBVs) was low (≤ 0.12) for MILK, ECM, mDM and IRT at hind hoof; and moderate to high (0.32–0.46) for all other traits. The most significant regions on chromosomes (BTA) associated with milk production traits were 0.47–1.18 Mb on BTA14. Moderate to high h2 and moderate accuracies of GEBVs for mFA, mPR, ECMbw, BCS, BW, PS and IRTs at rear udder and outer vulval surface suggested that GS using single test day phenotypic data could be applied for these traits. However, a greater sample size is required to decrease the bias of GEBVs by GS and increase the power of detecting significant quantitative trait loci (QTLs) by GWAS. [ABSTRACT FROM AUTHOR]

Identifying genetic regions and candidate genes that influence milk production traits is critical for understanding genetic inheritance and improving both the quality and quantity of milk in dairy cattle. Crossbred dairy cattle significantly contribute to increasing milk production and ensuring food security in the middle‐ and high‐altitude regions of Ethiopia. However, the genetic architecture underlying their milk yield and composition traits has not yet been thoroughly investigated. This study conducted a genome‐wide association study (GWAS) on 308 crossbred dairy cows from central, northeastern, and southern Ethiopia to identify genetic markers associated with key milk production traits. Using high‐density SNP chip data and the fixed and random model circulating probability unification (Farm CPU) method via the Memory‐efficient, Visualization‐enhanced, and Parallel‐accelerated R package (rMVP) (Version 1.0.7.), we analyzed traits including test‐day milk yield (TDMY), total protein (TP), casein (CN), whey (W), protein percentage (P), fat percentage (F), lactose percentage (L), total solids (TS), density (D), solids‐not‐fat (SNF), salt (S), and freezing point (FP). This study identified 16 significant SNPs associated with these traits, including rs41661899 on Chromosome 6, which was significantly associated with both TP and W, and rs42274954 on Chromosome 12, which was significantly associated with CN. Eight SNPs, such as rs43560693, rs109098713, rs111029661, rs134499665, rs133908307, rs133627532, rs42098411, and rs110066280, were found across multiple chromosomes (8, 10, 14, 15, 19, 21, 26, and 28, respectively) and were significantly associated with milk P. Additionally, SNPs rs110844447 and rs135995768 on Chromosomes 6 and 14 were significantly associated with D and FP, respectively. Three SNPs, including rs109564259, rs135552551, and rs41620904 on Chromosomes 6, 11, and 24, were significant associations with S. Candidate genes identified near and within these SNPs include TRAM1L1, DIAPH3, PEBP4, WDR89, BCAS3, RALGAPA1, HABP2, NRG3, HPSE, PCDH7, LINC02579, TRNAS‐GGA, and OR5CN1P. These findings enhance our understanding of the genetic architecture of milk‐related traits in Ethiopian dairy cattle and highlight the potential for marker‐assisted selection to improve milk production and composition in breeding programs. [ABSTRACT FROM AUTHOR]

The Regional Pastoral Livelihood Resilience Project Community-Based Breeding Programme (CBBP) was designed with the objective of increasing production and productivity of local Zebu cattle by introducing Sahiwal bulls among sedentary and agro-pastoral livestock farmers. This study mapped out actors, their roles and level of influence in the CBBP as well as the opportunities and challenges encountered during its implementation using the Process Net-Map tool. The results revealed that there were differences in number and type of influential actors between sedentary and agro-pastoral livestock farmers. The bull host and subcounty veterinary officer were the most influential actors among the sedentary livestock farmers whereas it was the herdsman, bull host, and Community Animal Health Workers (CAHWs) among the agro-pastoral farmers. The CBBP was associated with benefits such as increased market value for cattle, reduced chances for cattle rustling, increased cattle productivity in terms of milk and beef production volumes and ease of access to veterinary services. In contrast, the challenges encountered were related to both governance (limited availability of veterinarians, cattle rustling, exclusion of farmers in the planning phase of the CBBP, political interference and failure of collective action) and bull management (high costs of keeping and maintaining the bulls in terms of feeding, housing, watering and veterinary care, heavy bulls injuring or breaking the small cows, sexually transmitted reproductive diseases among others). Lastly, this paper recommends adoption of a combination of well-organized and facilitated Artificial Insemination (AI) programmes alongside the improved bull service scheme as each has capacity to address the challenges of another. [ABSTRACT FROM AUTHOR]

Level of dam milk production (DMP) and dam milk fat to protein ratio (DFPR), as an indicator of metabolic status in dairy cows, have been identified to be associated with productive and reproductive performance of the offspring. Yet whether the interaction of DMP by DFPR can be associated with performance of the offspring have not been studied to our knowledge. Therefore, the present study was conducted to investigate the association of the main and interactive effects of DMP and DFPR with offspring's birth weight, survival, milk yield and fertility. To this end, data of birth weight, culling rate, milk yield and reproductive variables of offspring born to lactating dams (n = 14,582) and data associated with DMP and DFPR during 305-day lactation were retrieved. Afterwards, offspring were classified in three categories of DMP, including DMP1 (dams with <10.00 × 103 kg of 305-day milk production), DMP2 (dams with ≥10.00 × 103 kg and <14.00 × 103 kg of 305-day milk production), DMP3 (dams with ≥14.00 × 103 kg of 305-day milk production), and three categories of DFPR, including DFPR1 (offspring born to dams with <1.00 FPR), DFPR2 (offspring born to dams with ≥1.00 and < 1.40 FPR) and DFPR3 (offspring born to dams with ≥1.40 FPR). Statistical analysis revealed no association of the interaction effect of DMP by DFPR with investigated variables in the offspring (P > 0.05). However, the main effect of DMP was positively associated with milk yield, but negatively associated with survival, age at first insemination and conception during nulliparity, and transgenerational improvement in milk yield in the offspring (P < 0.05). Moreover, the main effect of DFPR was positively associated with birth weight, survival and first service conception rate during nulliparity, but negatively associated with metabolic status and reproductive performance during primiparity in the offspring (P < 0.05). In conclusion, the present study did not find any interaction effect of DMP by DFPR on productive and reproductive variables in the offspring. This finding implicates the association of DMP with milk production in the offspring was regardless of DFPR. Moreover, this finding implies the association of DFPR with postpartum metabolic status and reproductive performance in the offspring was regardless of DMP. • The interaction effect of dam milk production (DMP) by dam fat to protein ratio (DFPR) was not associated with productive and reproductive performance of the offspring. • Although the main effect of DMP was positively associated with milk production of the offspring, it was negatively associated with transgenerational improvement in milk production. • The main effect of DFPR was associated with postpartum metabolic status and reproductive performance of the offspring. [ABSTRACT FROM AUTHOR]

Introduction: The use of dairy x dairy crossbreeding has increased in Sweden. This study aimed to compare crosses between Swedish Red (R), Holstein (H), Jersey (J), and Montbéliarde (M) to purebred R, H, and J for fertility, calving, production, and survival traits. The focus was on F1 crosses between either H or R on the one hand and J or M on the other hand, but three-breed crosses were also studied. Material and methods: There were 2,154,241 observations collected from the official cattle recording database for cows that calved between 2005 and 2020 in 7,390 herds. The dataset was separated into first and second parity and analyzed using a mixed linear model including fixed effects of breed group, herd, and year-season and a random effect of herd-year. Results and discussion: Fertility traits were improved in the F1 crosses with J or M compared with R or H (i.e., JR and MR vs. R; JH and MH vs. H), especially in the first parity. In parity 2, the difference was often not significant. Crossing R or H with Jersey gave lower calving difficulty than in the pure breeds in the first parity. However, crossing with Montbé liarde rather tended to give slightly more calving difficulties, albeit not significantly so. Generally, there was no significant change in stillbirths when crossing purebred R or H with J or M. There was a general tendency for better survival in the F1-crosses, however, only significantly so for Jersey crosses in parity 2 with respect to R or H. F1 between J and H (JH) had a higher 305-day fat yield than H, but lower milk and protein yields. MH had higher fat and protein yields than H and MR had higher 305-d milk and protein yields than R. In conclusion, crossing R or H with either Jersey or Montbeéliarde can be expected to improve fertility and probably also survival. Depending on the current situation, one could choose to improve fat yield (crossing with J) or protein yield (crossing with M), however, depending on the breed, there could be a trade-off, e.g., in milk yield. For other traits, one would not expect any deterioration. [ABSTRACT FROM AUTHOR]

Introduction: The current global concern over increasing antimicrobial resistance among animal and human pathogens has motivated efforts to reduce antimicrobial drug use in food animals and its impact on antimicrobial resistance. One such strategy is to use selective dry cow therapy (SDCT) in dairy cows, which involves treating only cows with intramammary infection (IMI) at dry-off. However, efficient methods are needed to identify cows with IMI at dry-off to implement SDCT. Automatic Milking Systems (AMS) data may help farmers identify cows with IMI when individual Somatic Cell Count (SCC) is not routinely tested. This study assessed the correlation between cow-level and quarter-level AMS parameters and IMI at dry-off. Methods & Results: A total of 733 udder quarters (comprising both Primiparous [PRIM] and Multiparous [MULT] cows) were sampled and categorized for IMI based on bacterial growth and SCC. Data were aggregated both daily and into 7-day and 15-day intervals preceding dry-off. The quarter-level prevalence of bacterial growth at dry-off was 24.28% overall. When stratified by parity, logistic regression analysis at 15 days to dry-off revealed that the average difference in mastitis detection index (MDi) in PRIM, MDi, and standard deviation milk flow rate in MULT were associated with increased odds of IMI at dry-off. Similarly, data from 7 days to dry-off revealed that average peak milk flow rate in PRIM, and MDi in MULT were associated with increased odds of IMI at dry-off. However, an increase in average milk yield was associated with decreased odds of IMI. Discussion & Conclusion: Our findings underscore the significance of MDi, milk flow rate, peak milk flow rate, and milk yield in predicting IMI at dry-off. Notably, stronger associations were observed with data collected 7 days preceding dry-off. Further research is warranted to refine and validate algorithms amalgamating these variables for precise IMI prediction in cows at dry-off. [ABSTRACT FROM AUTHOR]

ABSTRACT Recently, the potential of using chitosan (CHI) as a feed additive to enhance ruminal fermentation and improve animal performance has gained increasing attention in ruminant nutrition. This study was undertaken to investigate the effect of dietary supplementation with increasing doses of CHI on rumen fermentation attributes and microbial composition, digestibility and milk performance in Dhofari goats. Twenty‐four lactating goats (27 ± 1.8 kg of initial live body weight) were fed a control diet comprising of Rhodes grass hay plus a concentrate feed mixture. Goats were assigned to one of three experimental treatments (n = 8 per treatment) as: (1) control diet with no supplement (CTRL), (2) control diet with 0.300 g/day CHI (CHI0.3) and (3) control diet supplemented with 0.600 g/day CHI (CHI0.6) for a 45‐day experimental period. Dietary supplementation with increasing doses of CHI decreased (p < 0.05) linearly ruminal pH (p = 0.023), total short chain fatty acids concentrations (p = 0.011), acetate (p = 0.013) and butyrate (p = 0.042) proportions, acetate to propionate ratio (p < 0.001), estimated methane (CH4) production (p < 0.001), ammonia nitrogen concentrations (p = 0.003) and protozoa abundance (p = 0.003). However, the ruminal propionate proportion augmented (p = 0.002) linearly with increasing doses of CHI in the diet. Increasing doses of CHI linearly increased the abundance of the ruminal propionate‐producing bacteria, while diminished acetate and CH4‐producing bacteria (p < 0.05). Serum total protein (p = 0.037) and glucose (p = 0.042) levels linearly increased as CHI doses increased in the diet. However, serum UREA levels decreased linearly (p = 0.002) by 21% with increasing CHI amounts in the diet. The digestibility of organic matter, crude protein and neutral detergent fibre increased linearly with the increasing CHI doses (p < 0.05). Neither linear nor quadratic responses (p > 0.05) were observed in daily milk yield and feed efficiency by supplementing the diet with CHI. In conclusion, supplementing the diet with CHI at a dose of 0.600 g/day as a feed additive for dairy goats reduced estimated CH4 generation and improved fibre and protein digestion, with no influence on feed intake, milk yield or composition. [ABSTRACT FROM AUTHOR]

Improving the synchronization between the pattern of milk synthesis and nutrient availability throughout the day could enhance production efficiency. In this study, we evaluated the effects of changing feed delivery time on milk production, feeding behavior, and the daily rhythms of blood biomarkers. Eight multiparous Holstein cows housed in a tie-stall barn with controlled environmental conditions were enrolled in a crossover experimental design with three periods of 14 days and three treatments each. Cows were milked twice daily (0530 and 1730 h) and were individually fed with two equal meals of forage and eight equal meals of concentrate during the day. Forage meals were provided at 12-hour intervals either: (i) 5 h before each milking (0030 and 1230 h; BM), (ii) at the end of each milking (0530 and 1730 h;ME), (iii) or 2 h after (0730 and 1930 h; AM). Feed intake and feeding behavior were monitored, and milk production and composition were measured. Blood samples were collected every 4 days at 0700 h and, during the last day of each period, 15 times daily to determine metabolic profiles, hormones, and their daily rhythmicity by the cosinor analysis. Changing forage delivery time did not affect milk yield and dry matter intake. No difference was observed in feeding behavior when expressed relative to the first meal. There were no significant differences in milk component contents and yields. In samples collected at 0700 h, ME had reduced plasma calcium (Ca), magnesium (Mg), and potassium (K) and increased sodium (Na). AM had increased inflammation, as suggested by the greater blood globulin and ceruloplasmin. The patterns of metabolic biomarkers had limited variations when expressed relative to the first forage meal. Nevertheless, the daily rhythms of these biomarkers were remarkably different. Under our conditions, feeding forage meals to cows at different times of the day did not influence productive performance but highlighted the importance of considering the sampling time when interpreting metabolic profiles. [ABSTRACT FROM AUTHOR]

Simple Summary: Using bypass protein in ruminants' diets is crucial as it allows essential amino acids, like lysine, to escape rumen degradation and be absorbed in the intestine. This improves protein utilization and enhances growth, milk production, and overall animal health, leading to more efficient and sustainable livestock farming. This study explores the use of beeswax (BW) and carnauba wax (CW) lipid matrices to create bypass lysine (Lys) for ruminants, with tannins from Mimosa tenuiflora hay enhancing the protection of Lys. The research tested eight microencapsulated treatments with varying tannin levels (0%, 1%, 2%; 3%) using the fusion–emulsification technique. The results showed that adding tannins improved the microencapsulation yield and efficiency. Among the treatments, CWLys3% demonstrated the highest efficiency in retaining Lys and provided superior protection against rumen degradation. Our study demonstrated the efficiency of encapsulating the material (bypass protein) and making it available for the nutrition and growth of sheep. Future studies should determine what levels can be added to the diet and the consequences of using Lys bypass on the digestion and metabolism of sheep. Tannins are compounds present in forage plants that, in small quantities in the diet of ruminants, produce protein complexes that promote passage through the rumen and use in the intestine. This study tested the hypothesis that beeswax (BW) and carnauba wax (CW) lipid matrices are effective encapsulants for creating bypass lysine (Lys) for ruminants, with tannin extracted from the Mimosa tenuiflora hay source enhancing material protection. Microencapsulated systems were made using the fusion–emulsification technique with a 2:1 shell-to-core ratio and four tannin levels (0%, 1%, 2%; 3%). The following eight treatments were tested: BWLys0%, BWLys1%, BWLys2%, BWLys3%, CWLys0%, CWLys1%, CWLys2%, and CWLys3%. Tannin inclusion improved microencapsulation yield and efficiency. CWLys3% had the highest microencapsulation efficiency and retained Lys. Lysine in BW and CW matrices showed higher thermal stability than in its free form. Material retention was greater in BW than CW. Rumen pH and temperature remained unaffected, indicating that BW and CW as the shell and tannin as the adjuvant are efficient encapsulants for Lys bypass production. The formulation CWLys3% is recommended as it is more efficient in protecting the lysin amino acid from rumen degradation. [ABSTRACT FROM AUTHOR]

Simple Summary: This study reports the results of two studies aiming to determine, under commercial farm conditions, the effects of electronic sow feeders on the production and economic yields of lactating sows. The results indicate remarkable technical and economic outputs compared with traditional feeders due to the weaning of heavier piglets with a lower amount of feed per kg of weaned piglet. Adequate nutritional management in maternities is one of the most challenging aspects of swine production. This study reports the results of two studies aiming to determine, under commercial farm conditions, the effects of precision feeding (electronic sow feeders, ESFs) on the production and economic yields of lactating sows and possible nutritional and metabolic differences when compared to a control group fed with traditional feeders. The first trial showed that sows fed with ESFs weaned heavier piglets than sows fed with traditional feeders. Feed intake during the lactation period was similar in the sows of both groups; consequently, the amount of feed per kg of weaned piglet was lower in the sows fed with ESFs, which is a remarkable economic output. The second trial confirmed these findings and showed that, despite similar feed intakes, the sows fed with ESFs had lower bodyweight losses during the lactation period, but there were no major differences in milk composition or metabolic traits of sows and piglets. [ABSTRACT FROM AUTHOR]

Simple Summary: This study evaluated the effects of heat stress on the productivity of dairy cows. During the experimental period, THI values ranged from 46.9 to 81.0, with the most severe heat stress occurring in August. A decrease in productivity was observed when the THI exceeded 72. It was found that milk production took about one month to recover after the high-temperature period ended. The THI ratio, calculated based on the daily THI distribution, showed a strong negative correlation with rumen temperature (− 0.744; p < 0.001). During periods of significant productivity decreases due to high-temperature stress, rumen temperatures were higher than 39.15 °C. Based on the rumen temperature and daily THI distribution, it is suggested that these findings could serve as foundational data for developing technologies to manage high-temperature environments for dairy cows. This study was conducted to evaluate the effects of high-temperature stress on dairy cow productivity and the correlation between rumen sensors. The data were collected on the temperature, humidity, milk productivity, milk components, blood components, and rumen sensor data from 125 dairy cows during the experimental period (1 May 2020 to 30 October 2020). High-temperature stress of dairy cows was evaluated based on the temperature–humidity index (THI). The correlations between the high-temperature stress, productivity, and sensor data were analyzed using SAS and R programs. The THI ranged from 46.9 to 81.0 during the experimental period, and a significant decrease was observed in the milk production of dairy cows during August (p < 0.05). Milk production was evaluated to decrease by 1.8% because of high-temperature stress during the experimental period. There was a significantly high negative correlation between the THI ratio of day and rumen temperature (r = 0.744; p < 0.001). The other rumen sensor data did not show a significant correlation with the productivity of dairy cows. The results can be utilized as a guideline for managing temperature and humidity to maintain dairy cow productivity on farms in high-temperature stress conditions. [ABSTRACT FROM AUTHOR]

Simple Summary: In pasture-based dairy systems, supplementing the diet is crucial during periods when pasture availability is low. Field peas, which can be locally produced, offer relatively high concentrations of crude protein, along with significant energy content in the form of starch, all at a lower price. These qualities make field peas a sustainable alternative to traditional protein and energy sources such as soybean meal and corn grain. This study explored the impact of substituting traditional feeds with field peas in the concentrates of grazing dairy cows. Our findings indicate that using field peas maintains milk production and composition (protein and fat) without affecting intake or ruminal and blood parameters. This suggests that field peas are a viable alternative for feeding dairy cows, supporting consistent production under grazing conditions. This study assessed the effects of replacing soybean meal (SBM) and corn grain with field peas in the concentrate of grazing dairy cows on milk production, intake, ruminal fermentation, and blood indicators. Twelve multiparous lactating Holstein-Friesian cows were utilized in a replicated 3 × 3 Latin square design, comprising three periods and three treatments: (1) Pea-0 (Control diet): 6 kg dry matter (DM) of fresh pasture, 7.2 kg DM of grass silage, and 7 kg DM of a concentrate containing 0% pea; (2) Pea-30: Control diet with the concentrate composed of 30% pea; (3) Pea-60: Control diet with the concentrate composed of 60% pea. The effect of treatments on productive and metabolic parameters was evaluated using linear-mixed models. Pasture and total DM intake, milk production, and composition were unaffected by treatments. Despite the concentrates being isonitrogenous and isoenergetic, crude protein (CP) intake was slightly higher in Pea-30 and significantly higher in Pea-60 due to higher pasture CP content in the pasture grazed by these groups, leading to higher milk urea content, though within recommended ranges. Blood parameters showed no significant changes, except for plasma β-hydroxybutyrate, which was lowest in the Pea-60 treatment; however, all values were within ranges not indicative of subclinical ketosis. Ruminal fermentation parameters were similar across treatments. These findings support the use of field peas as a viable alternative to replace SBM and corn grain in concentrates, enabling similar milk production and composition in grazing dairy cows. [ABSTRACT FROM AUTHOR]

Simple Summary: The performance of milking machines, whether in conventional or automated systems, can be evaluated using new-generation vacuum meters (dynamic testing). Access to data from these tests on automatic milking systems (AMSs) from various manufacturers and herds enabled the design of a retrospective study aimed at describing and comparing key milk emission parameters for different AMS brands, while also identifying potential mastitis risk factors. In total, 4878 individual quarter milkings were evaluated from cows in 48 different dairy herds. The findings revealed that factors such as milk yield and brand significantly influenced the variability of milking parameters. These results suggest that the interaction between AMSs and cows, along with the related milk emission physiology, plays a crucial role, similar to conventional milking. The observed differences in main milking parameters also correspond to parameters considered to predispose cows to mastitis. The most surprising result was the high frequency of two major mastitis risk factors (bimodality and irregular vacuum fluctuations). Automatic milking systems (AMSs) are revolutionizing the dairy industry by boosting herd efficiency, primarily through an increased milk yield per cow and reduced labor costs. The performance of milking machines, whether traditional or automated, can be evaluated using advanced vacuum meters through dynamic testing. This process involves scrutinizing the system and milking routine to identify critical points, utilizing the VaDia™ logger (BioControl AS, Rakkestad, Norway). Vacuum recordings were downloaded and analyzed using the VaDia Suite™ software under the guidance of a milking specialist. Access to data from AMSs across various manufacturers and herds facilitated a retrospective study aimed at describing and comparing key milk emission parameters for different AMS brands while identifying potential mastitis risk factors. Using the proper statistical procedures of SPSS 29.1 (IBM Corp., Armonk, NY, USA), researchers analyzed data from 4878 individual quarter milkings from cows in 48 dairy herds. Results indicated a significant variability in milking parameters associated with quarter milk yield and AMS brand. Notably, despite AMSs standardizing teat preparation and stimulation, this study revealed a surprisingly high frequency of two major mastitis risk factors—bimodality and irregular vacuum fluctuations—occurring more frequently than in conventional milking systems. This study, one of the few comparing different AMS brands and their performance, highlights the crucial role of dynamic testing in evaluating AMS performance under real-world conditions. [ABSTRACT FROM AUTHOR]

Simple Summary: The goat is used as a tool of poverty reduction at the village level in developing countries. The Black Bengal is a popular goat breed in Bangladesh and the eastern part of India. They have high prolificacy and skin quality and delicious meat. A high level of kid mortality and poor growth rate represent a significant barrier to increasing the productivity of Black Bengal goats. Low birth weight and insufficient milk yield of dams are responsible for the poor growth and high mortality of these kids. It is considered that maternal nutrition during pregnancy plays an important role in the birth weight of kids and the lactation performance of dams. In the present study, the effects of three levels (18, 14, and 10 percent) of dietary crude protein (CP) during late pregnancy on the growth performance of dams and kids, birth weight of kids, and milk production of does, as well as blood parameters, survivability rate, carcass characteristics and meat composition of kids, and expression of the H-FABP gene related to muscle fat content, were investigated. The results show that maternal dietary protein during late pregnancy enhances the milk production of does and the growth and carcass characteristics of Black Bengal kids. The present study aimed to elucidate the effect of different levels of dietary protein during late pregnancy on the performance of Black Bengal does and their kids. Twelve does were divided into three groups, with four in each, and three diets, i.e., high protein (18% CP), medium protein (14% CP), and low protein (10% CP) were supplied for 50 days, commencing from 100 days post-coitum to parturition. During the first 100 days of pregnancy, uniform rations with similar ingredients were provided to fulfill the nutrient requirements depending on the live weight of does. All three diets were isocaloric (10.0 MJ/kg DM). Data were subjected to one-way ANOVA, and the significance of the difference among means was determined by Duncan's Multiple Range Test (DMRT). The main effects of diet and sex, as well as their interaction, were analyzed by two-way ANOVA by using the GLM procedure. The relative expression values of qPCR were calculated by using the 2−ΔΔCt analysis method. Live weight gain was significantly (p < 0.05) higher in high-protein-fed dams than other groups during the experimental period. The milk yield of does was significantly (p < 0.05) higher in high-protein-fed goats than in the low-protein group. The lactation length of does was significantly (p < 0.05) higher in the high- and medium-protein-fed does than in the low-protein-fed does. The duration of post-partum anestrus of does was significantly (p < 0.05) higher in the low-protein-fed dams than in the high-protein group. The birth weight of kids tended to be higher in the high-protein group but did not differ significantly among the treatment groups. In male kids, weaning weight, final weight, live weight gain, and average daily gain were significantly (p < 0.05) higher than in female kids. Weaning weight was higher (p < 0.05) in kids of the high-protein-fed does than the low-protein group. Final weight and live weight gain were significantly (p < 0.05) higher in kids of the high-protein-fed does than in the low-protein-fed group. On the other hand, average daily gain was significantly (p < 0.05) higher in kids of the high- and medium-protein-fed does than the low-protein group. The average body length and wither height of kids at the 32nd week was significantly (p < 0.05) higher in kids of high-protein-fed does than those of the low-protein-fed group. The average heart girth of kids at the 32nd week was significantly (p < 0.05) higher in kids of high-protein-fed does than the medium- and low-protein groups. The survival rate of kids was higher in the medium- and high-protein-fed does than in low-protein group. Hot carcass weight and ether extract content of meat were significantly (p < 0.05) higher in the high-protein group than in the other groups. The dressing percentage was significantly (p < 0.05) higher in the kids of high-protein-fed does than low-protein-fed goats. The expression of the H-FABP gene was significantly (p < 0.05) higher in kids of high-protein-fed does than those of the medium- and low-protein groups. In conclusion, maternal dietary protein levels positively influences the production performance of Black Bengal does and their kids. [ABSTRACT FROM AUTHOR]

Simple Summary: This study aimed to estimate the phenotypic and genetic parameters of milk production rate (MPR) traits in Holstein cattle. The MPR, a metric for evaluating a cow's milk secretion per hour, was calculated using milk yield and milking interval data from 4760 cows. This study defined four milk yield and six MPR traits, and used the MIXED procedure to assess the effects of parity, season, and lactation stage on these traits. Significant effects of these non-genetic factors were found for both milk yield and MPR traits. Heritability estimates for milk yield and MPR traits were high, ranging from 0.25 to 0.39, while the stability of MPR had low heritability (0.04 to 0.05). This study concluded that MPR is a valuable trait for dairy breeding, providing new insights for herd management and genetic selection to improve dairy cattle production performance. Milk production rate (MPR) refers to the rate of milk secretion per hour (kg/h), calculated from the harvested milk yield and milking interval, and it is considered an appropriate measure to evaluate the production potential of cows. The objective of this study was to estimate the phenotypic and genetic parameters of milk production rate traits. In this study, the milking records of 4760 Holstein cows were collected, and four milk yield traits and six milk production rate traits were defined. The MIXED procedure was used to detect the impacts of non-genetic effects on milk yield and milk production rate traits, including parity, measured season and lactation stage. Variance and covariance components for milk yield and milk production rate traits were estimated using a univariate linear repeatability model. Parity, measurement season and lactation stage had significant effects (p < 0.01) on milk yield, milk production rate and its stability. Milk yield and milk production traits had high heritability, and ranged from 0.25 to 0.39. The stability of milk production rate had low heritability (0.04~0.05). Milk production rate is beneficial for the devolving novel trait in dairy breeding and provides new insights for herd management and genetic selection of production performance of dairy cattle. [ABSTRACT FROM AUTHOR]

Milk production is an essential economic trait in cattle, and understanding the genetic regulation of this trait can enhance breeding strategies. The discoidin domain receptor 1 (DDR1) gene has been identified as a key candidate gene that influences milk production, and ETS homologous factor (EHF) is recognized as a critical transcription factor that regulates DDR1 expression. Codon usage bias, which affects gene expression and protein function, has not been fully explored in cattle. This study aims to examine the codon usage bias of DDR1 and EHF transcription factors to understand their roles in dairy production traits. Data from 24 species revealed that both DDR1 and EHF predominantly used G/C-ending codons, with the GC3 content averaging 75.49% for DDR1 and 61.72% for EHF. Synonymous codon usage analysis identified high-frequency codons for both DDR1 and EHF, with 17 codons common to both genes. Correlation analysis indicated a negative relationship between the effective number of codons and codon adaptation index for both DDR1 and EHF. Phylogenetic and clustering analyses revealed similar codon usage patterns among closely related species. These findings suggest that EHF plays a crucial role in regulating DDR1 expression, offering new insights into genetically regulating milk production in cattle. [ABSTRACT FROM AUTHOR]

Background: Although several cell culture systems have been developed to investigate the function of the mammary gland in dairy livestock, they have potential limitations, such as the loss of alveolar structure or genetic and phenotypic differences from their native counterparts. Overcoming these challenges is crucial for lactation research. Development of protocols to establish lactating organoid of livestock represents a promising goal for the future. In this study, we developed a protocol to establish a culture system for mammary organoids in dairy goats to model the mammary gland development and lactation process. Results: The organoids cultured within an extracellular matrix gel maintained a bilayer structure that closely resembled the native architecture of mammary tissue. The expansion of mammary organoids was significantly promoted by growth factors containing epidermal growth factor and fibroblast growth factor 2 whereas the proliferative index of the organoids was significantly inhibited by the treatment with WNT inhibitors. Upon stimulation with a lactogenic medium containing prolactin, the mammary organoids exhibited efficient lactation, characterized by the accumulation of lipid droplets in the lumen space. The lactation could be sustained for more than 3 weeks. Importantly, the expression patterns of genes related to fatty acid synthesis and milk proteins in lactating organoids closely mirrored those observed in mammary tissues. These observations were confirmed by data from proteomic analysis that the bulk of milk proteins was produced in the lactating organoids. Conclusion: This study is the first to establish a mammary organoid culture system modeling the mammary gland development and lactation process in ruminants. The efficient induction of lactation in ruminant mammary organoids holds promises for advancing the field of cell-based milk bio-manufacture in the food industry. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Dairy cows experiencing heat stress (HS) during the precalving portion of the transition period give birth to smaller calves and produce less milk and milk protein. Supplementation of rumen-protected methionine (RPM) has been shown to modulate protein, energy, and placenta metabolism, making it a potential candidate to ameliorate HS effects. We investigated the effects of supplementing RPM to transition cows under HS induced by electric heat blanket (EHB) on cow-calf performance. Six weeks before expected calving, 53 Holstein cows were housed in a tiestall barn and fed a control diet (CON, 2.2% Met of MP) or a CON diet supplemented with SmartamineM (MET, 2.6% Met of MP, Adisseo Inc., France). Four weeks precalving, all MET and half CON cows were fitted with an EHB. The other half of the CON cows were considered thermoneutral (TN), resulting in 3 treatments: CONTN (n = 19), CONHS (n = 17), and METHS (n = 17). Respiratory rate (RR), skin temperature (ST), and rectal temperature (RT) were measured thrice weekly and core body temperatures recorded biweekly. Postcalving BW and BCS were recorded weekly, and DMI was calculated and averaged weekly. Milk yield was recorded daily and milk components were analyzed every third DIM. Biweekly AA and weekly nonesterified fatty acids (NEFA), BHB, insulin, and glucose were measured from plasma. Calf birth weight and 24 h growth, thermoregulation, and hematology profile were measured and apparent efficiency of absorption (AEA) of immunoglobulins was calculated. Data were analyzed using the MIXED procedure of SAS with 2 preplanned orthogonal contrasts: CONTN versus the average of CONHS and METHS (C1) and CONHS versus METHS (C2). Relative to TN, EHB cows had increased RT during the postcalving weeks and increased RR and ST during the entire transition period. Body weight, BCS, DMI, and milk yield were not affected by the EHB or RPM. However, protein percentage and SNF were lower in CONHS, relative to METHS cows. At calving, METHS dams had higher glucose concentrations, relative to CONHS, and during the postcalving weeks, the EHB cows had lower NEFA concentrations than TN cows. Calf birthweight and AEA were reduced by HS, whereas RR was increased by HS. Calf withers height tended to be shorter and RT were lower in CONHS, compared with METHS heifers. Overall, RPM supplementation to transition cows reverts the negative effect of HS on blood glucose concentration at calving and milk protein percentage in the dams and increases wither height while decreasing RT in the calf. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Brown Swiss (BS) cows have greater urea concentrations in milk and blood compared with Holstein (HO) cows. We tested the hypothesis that BS and HO cows differ in kidney function and nitrogen excretion. Blood, saliva, urine, and feces were sampled in 31 multiparous BS and 46 HO cows kept under identical feeding and management conditions. Samples were collected at different lactational stages after the monthly DHIA control test-day. To test the glomerular filtration rate (GFR) and urea excretion, concentrations of creatinine and urea were measured in serum, urine, and saliva. As an additional marker to estimate GFR, we determined symmetric dimethylarginine (SDMA) in serum. Feces were analyzed for DM content and nitrogen concentration. Data on milk urea and protein concentrations and daily milk yield were obtained from the monthly DHIA test-day records. The effects of breed, time, and parity number on blood, saliva, urine, feces, and milk parameters were evaluated with the GLM procedure of SAS, with breed, time, and parity number as fixed effects. Differences between BS and HO were assessed by the Tukey-corrected t -test. Concentrations of urea, creatinine, and SDMA in serum, were greater in BS than in HO cows: 5.46 ± 0.19 versus 4.72 ± 0.13 mmol/L (urea), 105.96 ± 2.23 versus 93.07 ± 1.50 mmol/L (creatinine), and 16.78 ± 0.69 versus 13.39 ± 0.44 µg/dL (SDMA). We observed a greater urea concentration in BS cows (25.8 ± 0.7 vs. 21.8 ± 0.7 mg/dL) and protein content in milk (3.70% ± 0.08% vs. 3.45% ± 0.07%) than in HO cows. Urea and creatinine concentrations in urine and saliva did not differ between breeds. No differences between BS and HO were observed for milk yield, fecal DM, and fecal nitrogen content. Dry matter intake and BW were similar in BS and HO cows. Despite greater urea, creatinine, and SDMA concentrations in blood, as well as a higher milk urea content in BS compared with HO, respective concentrations in urine did not differ between breeds. In conclusion, our results demonstrate a lower renal GFR in BS compared with HO cows, thereby contributing to the greater plasma urea concentration in BS cows. However, estimation of nitrogen excretion via milk, urine, and feces does not entirely reflect nitrogen turnover within the animal. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. The effects of high (2.5% of DM) versus normal dietary sodium chloride (NaCl) intake on renal urea-N kinetics and urea-N metabolism were investigated in 9 rumen-cannulated and multicatheterized lactating dairy cows in a crossover design with 21-d periods. It was hypothesized that urinary urea-N excretion would be greater, and BUN concentration lower in response to greater diuresis induced by high NaCl intake. Also, urea-N transport across ruminal and portal-drained viscera (PDV) tissues was hypothesized to be affected by dietary sodium intake. A second experiment was conducted using 8 lactating cows in a crossover design with 14-d periods to test high NaCl (2.5% of DM) versus high KCl (3.2% of DM) intake on milk yield and MUN concentrations. Experiment 1 showed that despite greater diuresis, high NaCl intake had no effect on urinary urea-N excretion or BUN concentration. The high NaCl intake did not affect rumen ammonia concentrations, total rumen VFA concentrations, ruminal venous − arterial concentration differences for ammonia, or ammonia absorption indicating that high NaCl did not adversely affect ruminal fermentation and microbial protein synthesis. High NaCl intake did not affect the total amount of urea-N transport from blood to gut, but ruminal venous − arterial concentration differences for urea-N were lower with high NaCl and ruminal extraction of arterial urea-N was numerically smaller, indicating that the ruminal epithelial urea-N transport was lower with high NaCl. Energy-corrected milk yield was greater with high NaCl (3.2 ± 1.5 kg/d); however, MUN concentrations were not affected by treatment. In experiment 2, ECM was greater with NaCl (1.4 ± 0.31 kg/d) compared with KCl (30.2 and 28.8 ± 0.91 kg ECM/d, respectively). Milk urea-N concentration was lower with KCl, suggesting a urea-N lowering effect in milk not evident with high NaCl intake. In conclusion, the present data show that dietary Na intake of 12 to 13 g/kg DM was followed by greater diuresis but did not affect urea-N excretion or BUN concentration. High NaCl intake did not affect the total amount of urea-N transfer across PDV tissues. Energy-corrected milk yield was greater with high NaCl compared with both control and feeding KCl; however, with KCl, MUN decreased. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Milk production and overall dairy farm economics depend on rearing dairy heifers. This study investigated the presence of a genotype by environment interaction in Holstein (HOL), Nordic Red dairy cattle (RDC), and their F 1 crossbreeds (HOL × RDC) when provided different feed rations. The aim of our study was to assess how different energy concentrations in feed rations affect growth, BCS, feed intake, and feed efficiency in the 3 groups during the prepubertal period. The 3 breed groups were randomly allocated to receive either a standard or a low-energy feed ration. Holstein heifers exhibited reduced growth and a lower BCS when they were fed the low-energy feed ration. In contrast, the RDC heifers demonstrated similar growth rates with the different feed rations and maintained similar BCS irrespective of feed energy concentration. The HOL × RDC crossbred heifers performed as an intermediate between the HOL and RDC groups. Significant differences were observed in DMI and energy intake in the HOL and HOL × RDC groups depending on feed ration treatment. The RDC heifers had similar feed intake irrespective of treatment. There were no significant differences in the feed conversion ratio among breeds and feed treatments. These results indicate the presence of a genotype by environment interaction in prepubertal HOL and RDC heifers in response to differences in feed ration treatment. Due to the influence of prepubertal growth on future milk production, reproduction, and health status, it is important to be aware of breed-specific requirements during the prepubertal period, particularly in mixed breed and crossbred groups, to optimize growth rates and production potential. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Most trace minerals (TM) are fed above dairy cow requirements in commercial herds but their fate and effects on dairy cows have not been well documented. In this study, we evaluated the effects of feeding short-term sulfate TM above recommendations on apparent total-tract digestibility of nutrients, rumen fermentation characteristics, serum concentrations, and milk yield and composition, as well as milk, fecal, and urinary TM excretion in midlactation dairy cows. Eight multiparous Holstein cows with an average body weight (± SD) of 684 ± 29 kg at 82 ± 10 DIM in a quadruple 2 × 2 crossover design were fed a basal diet, differing in sulfate TM supplement concentrations, to provide either 0.11, 17, and 63 (control; CON) or 0.95, 114, and 123 (high trace minerals; HTM) mg of dietary Co, Mn, and Zn per kilogram of DM, respectively. Each experimental period had a 21-d adaptation to the diet, followed by a 10-d sample collection period. Feed ingredients and total feces and urine were collected during 4 consecutive d and rumen fluid was collected 0, 1, 2, 4, and 6 h relative to feeding. Milk yield was recorded daily, and milk samples were collected on 4 consecutive milkings. Ingestion of Co, Mn, and Zn was higher for the HTM group compared with the CON group by 216%, 233%, and 93%, respectively. Dry matter intake averaged 25.0 (SE = 0.6) kg/d, and apparent total-tract digestibility of major nutrients was similar between treatments. High trace minerals had no measurable effect on ruminal pH, major volatile fatty acids, and protozoa counts. Isovalerate molar proportion was 9.4% greater for the HTM group compared with the CON group. Neither milk yield (43.5 kg/d; SE = 0.8) nor milk fat and protein concentrations differed between treatments. Milk urea nitrogen concentration was significantly higher for HTM (11.7 mg/dL) compared with CON (9.7 mg/dL; SE = 0.7). Fecal excretion of Co, Mn, and Zn increased by 223%, 198%, and 75%, respectively, for the HTM group compared with the CON group. Urinary excretions of TM were marginal compared with feces, and only urinary Co and Mn were significantly higher for HTM cows than CON cows, as was similarly obtained for serum Co and Mn concentrations. Milk TM yields were not modified by treatments. In summary, short-term dietary sulfate TM supply over the recommendation did not improve cow performance but significantly increased fecal TM excretion, which could affect TM accumulation in soils where manure is applied and could potentially result in leaching into nearby watersheds. Further studies are needed to evaluate the impact of high fecal TM excretion on the environment using the One Health approach. Moreover, the effects of TM oversupply on milk production and cow health should be evaluated by long-term experiments. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Mastitis is one of the most common diseases of dairy cattle. It has a high impact on-farm economy, farmers' working time, and antimicrobial usage (AMU). Selective dry cow therapy (SDCT) is an effective means of reducing AMU without negatively affecting udder health. The objective of our study was to evaluate the impact of SDCT implementation on farmer income, working time, and AMU, using a bioeconomic model. A stochastic dairy simulation model (DairyHealthSim) based on a weekly model was used to simulate herd dynamics, reproduction, milk production, culling decisions, health outcomes, and the management of health events. A specific module was developed for the simulation of quarter-level IMI acquisition and elimination during the lactation and dry-off periods, and 25 different farm settings were defined to represent herds with various udder health situations. We then defined 20 scenarios of SDCT by combining both the use of different thresholds of SCC and milk bacteriology for treatment allocation and the use of internal teat sealant (ITS). All SDCT protocols had little effect on farmer income, and we identified some protocols with a positive farm gross margin (up to Can$15.83/dried cow; at time of writing, Can$1 = US$0.72). We also found that adding an ITS to all cows led to greater economic gain. The application of SDCT had little effect on farmers' working time, except when milk bacteriology was used for decision making. Antimicrobial treatment to all cows above 200,000 cells/mL at last control, with the use of ITS on all cows, seems a good choice in most dairy farms. These findings could be used to convince farmers to adopt this strategy at dry-off. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. The objective of this study was to evaluate the effect of energy and protein in the diet on the recovery of milk ethanol stability (MES) induced by feed restriction. Twelve Holstein and Holstein × Jersey crossbred cows with an average of 146 ± 50 DIM, 575.4 ± 70 kg of BW, and 18.93 ± 5.46 kg/d of milk yield were distributed in a 3 × 3 Latin square design with 3 treatments and 3 experimental periods. Each experimental period lasted 24 d, comprising 3 phases: a 13-d adaptation phase (100E+100P), a 4-d induction phase for milk ethanol instability (50E+50P), and a 7-d recovery phase for MES (3 treatments). The 3 treatments during the recovery phase consisted of 3 diets aiming to meet the requirements of energy and protein (100E+100P), only energy (100E+50P), or only protein (50E+100P). The diet during the adaptation and induction phases was common for all cows. The energy and protein levels to meet each cow's requirements were based on the group average. Restriction of energy and protein reduced DM, CP, and total digestive nutrient intake for cows fed 100E+50P and 50E+100P. The lowest BW was observed for cows fed 50E+100P, with no difference for BCS. During the induction phase, MES was reduced by 9 percentage units. Cows fed 100E+100P recovered MES in the first days of the recovery phase, whereas 100E+50P slightly improved MES, and 50E+100P had a constant decrease in MES. Cows fed 100E+50P and 50E+100P produced, respectively, 3.6 and 5.9 kg less milk than those fed 100E+100P. The 50E+100P treatment exhibited the highest milk fat content and SCS, along with the lowest milk lactose content. Protein content was higher in the 100E+100P treatment. Cows fed 50E+100P showed higher serum albumin levels compared with those on the 100E+100P treatment, not differing from the 100E+50P treatment. We concluded that the complete recovery of MES in cows with feed restrictions is possible only by supplying both the energy and protein requirements in the cows' diet. However, restricting energy intake poses a greater limitation on MES recovery compared with restricting protein. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. The objectives of this study were to determine the effects of 2 dietary microbial additives on productive performance and feed efficiency when supplemented to diets of Holstein cows. One hundred seventeen Holstein cows were enrolled at 61 d (31–87 d) postpartum in a randomized complete block design experiment. Cows were blocked by parity group, as nulliparous or multiparous cows and, within parity, by pretreatment ECM yield. Within block, cows were randomly assigned to one of 3 treatments administered as top-dress for 140 d. Treatments consisted of either 100 g of corn meal containing no microbial additive (CON; 15 primiparous and 25 multiparous), 100 g of corn meal containing 5 g of a mixture of Clostridium beijerinckii and Pichia kudriavzevii (G1; 4 × 107 cfu of C. beijerinckii and 1 × 109 cfu of P. kudriavzevii ; 14 primiparous and 24 multiparous), or 100 g of corn meal containing 5 g of a mixture of C. beijerinckii , P. kudriavzevii , Butyrivibrio fibrisolvens , and Ruminococcus bovis (G2; 4 × 107 cfu of C. beijerinckii, 1 × 109 cfu of P. kudriavzevii, 1 × 108 cfu of B. fibrisolvens , and 1 × 108 cfu of R. bovis ; 15 primiparous and 24 multiparous). Intake of DM, milk yield, and BW were measured daily, whereas milk composition was analyzed at each milking 2 d a week, and body condition was scored twice weekly. Milk samples were collected on d 60 and 62 in the experiment and analyzed for individual fatty acids. The data were analyzed with mixed-effects models with orthogonal contrast to determine the effect of microbial additive (MA; CON vs. 1/2 G1 + 1/2 G2) and type of microbial additive (TMA; G1 vs. G2). Results are described in sequence as CON, G1, and G2. Intake of DM (22.2 vs. 22.4 vs. 22.4 kg/d), BW (685 vs. 685 vs. 685 kg) and the daily BW change (0.40 vs. 0.39 vs. 0.39 kg/d) did not differ among treatments; however, feeding MA tended to increase BCS (3.28 vs. 3.33 vs. 3.36). Supplementing MA increased yields of milk (39.9 vs. 41.3 vs. 41.5 kg/d), ECM (37.9 vs. 39.3 vs. 39.9 kg/d), fat (1.31 vs. 1.37 vs. 1.40 kg/d), TS (4.59 vs. 4.75 vs. 4.79 kg/d), and ECM per kg of DMI (1.72 vs. 1.76 vs. 1.80 kg/kg). Furthermore, cows fed MA increased yields of preformed fatty acids in milk fat (>16C; 435 vs. 463 vs. 488 g/d), particularly UFA (367 vs. 387 vs. 410 g/d), such as linoleic (C18:2 cis -9, cis -12; 30.9 vs. 33.5 vs. 35.4 g/d) and α-linolenic acids (C18:3 cis -9, cis -12, cis -15; 2.46 vs. 2.68 vs. 2.82 g/d) on d 60 and 62 in the experiment. Collectively, supplementing G1 and G2 improved productive performance of cows with no differences between the 2 MA. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. The aim of this study was to evaluate the effects of different anti-mycotoxin feed additives on the concentration of mycotoxins in milk, urine, and blood plasma of dairy cows fed diets artificially contaminated with mycotoxins. Secondarily, performance, total-tract apparent digestibility of nutrients, and blood parameters were evaluated. Twelve multiparous cows (165 ± 45 DIM, 557 ± 49 kg BW, and 32.1 ± 4.57 kg/d milk yield at the start of the experiment) were blocked according to parity, milk yield, and DIM and used in a 4 × 4 Latin square design experiment with 21-d periods, where the last 7 d were used for sampling and data analysis. Treatments were (1) mycotoxin group (MTX), basal diet (BD) without anti-mycotoxin feed additives; (2) hydrated sodium calcium aluminosilicate (HSCA), HSCA added to the BD at 25 g/cow per day; (3) mycotoxin deactivator (MD; Mycofix Plus, dsm-firmenich) added to the BD at 15 g/cow per day (MD15); and (4) MD added to the BD at 30 g/cow per day (MD30). Cows from all treatments were challenged with a blend of mycotoxins containing 404 μg of aflatoxin B 1 , 5,025 μg of deoxynivalenol (DON), 8,046 μg of fumonisins (FUM), 195 μg of T2 toxin (T2), and 2,034 μg of zearalenone (ZEN) added daily to the BD during the last 7 d of each period. Neither performance (milk yield and composition) nor nutrient digestibility was affected by treatments. All additives reduced aflatoxin M 1 (AFM1) concentration in milk, whereas MD15 and MD30 group had lower excretion of AFM1 in milk than HSCA. Deoxynivalenol, FUM, T2, or ZEN were not detected in milk of MD15 and MD30. Concentrations in milk of DON, FUM, T2, and ZEN were similar between MTX and HSCA. Except for AFM1, none of the analyzed mycotoxins were detected in urine of MD30 group. Comparing HSCA to MD treatments, the concentration of AFM1 was greater for HSCA, whereas MD30 was more efficient at reducing AFM1 in urine than MD15. Aflatoxin M1, DON, FUM, and ZEN were not detected in the plasma of cows fed MD30, and DON was also not detected in MD15 group. Plasma concentration of FUM was lower for MD15, similar plasma FUM concentration was reported for HSCA and MTX. Plasma concentration of ZEN was lower for MD15 than MTX and HSCA. Serum concentrations of haptoglobin and hepatic enzymes were not affected by treatments. Blood concentration of sodium was lower in HSCA compared with MD15 and MD30 groups. In conclusion, the mycotoxin deactivator proved to be effective in reducing the secretion of mycotoxins in milk, urine, and blood plasma, regardless of the dosage. This reduction was achieved without adverse effects on milk production or total-tract digestibility in cows fed multi-mycotoxin-contaminated diets over a short-term period. Greater reductions in mycotoxin secretion were observed with full dose of MD. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. This study aimed to evaluate the effect of heat stress on mammary epithelial cell (MEC) losses into milk, secretory mammary tissue structure, and mammary epithelial cell activity. Sixteen multiparous Holstein cows (632 ± 12 kg BW) approximately 100 DIM housed in climate-controlled rooms were paired by BW and randomly allocated to one of 2 treatments, heat stress (HS) or pair-feeding thermoneutral (PFTN) using 2 cohorts. Each cohort was subjected to 2 periods of 4 d each. In period 1, both treatments had ad libitum access to a common TMR and were exposed to a controlled daily temperature-humidity index (THI) of 64. In period 2, HS cows were exposed to controlled cyclical heat stress (THI: 74–80), while PFTN cows remained at 64 THI and daily DMI was matched to that of the HS cows. Cows were milked twice daily, and milk yield was recorded at each milking. Individual milk samples on the last day of each period were used to quantify MEC losses by flow cytometry using butyrophilin as a cell surface marker. On the final day of period 2, individual bovine mammary tissue samples were obtained for histomorphology analysis, assessment of protein abundance, and evaluation of gene expression of targets associated with cellular capacity for milk and milk component synthesis, heat response, cellular proliferation, and autophagy. Statistical analysis was performed using the GLIMMIX procedure of SAS. Milk yield was reduced by 4.3 kg by HS (n = 7) compared with PFTN (n = 8). Independent of treatment, MEC in milk averaged 174 cells/mL (2.9% of total cells). There was no difference between HS and PFTN cows for MEC shed or concentration in milk. Alveolar area was reduced 25% by HS, and HS had 4.1 more alveoli than PFTN. The total number of nucleated MEC per area was greater in HS cows (389 ± 1.05; mean ± SE) compared with PFTN (321 ± 1.05); however, cell number per alveolus was similar between groups (25 ± 1.5 vs. 26 ± 1.4). There were no differences in relative fold expression for GLUT1 , GLUT8 , CSN2 , CSN3 , LALBA , FASN , HSPA5 , and HSPA8 in HS cows compared with PFTN cows. Immunoblotting analyses showed a decrease in abundance for phosphorylated STAT5 and S6K1, and an increase in LC3 II in HS cows compared with PFTN cows. These results suggest that even if milk yield differences and histological changes occur in the bovine mammary gland after 4 d of heat exposure, MEC loss into milk, nucleated MEC number per alveolus, and gene expression of nutrient transport, milk component synthesis, and heat-stress-related targets are unaffected. In contrast, the abundance of proteins related to protein synthesis and cell survival decreased significantly, whereas proteins associated with autophagy were upregulated in HS cows compared with PFTN cows. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. We determined the effects of increasing the dietary inclusion of whole cottonseed (WCS) on nutrient digestibility and the milk production responses of high-producing dairy cows. Twenty-four multiparous Holstein cows (mean ± SD; 52.7 ± 2.63 kg/d milk; 104 ± 23 DIM) were randomly assigned to treatment sequences in a replicated 4 × 4 Latin square design with 21-d periods. Treatments were increasing doses of WCS at 0%, 8%, 16%, and 24% DM, with WCS replacing soybean meal and hulls to maintain similar diet nutrient composition (% DM) of NDF (32%), forage NDF (21%), starch (27%), and CP (17%). Total fatty acid (FA) content of each treatment was 1.70%, 2.96%, 4.20%, and 5.40% DM, respectively. Three preplanned contrasts were used to test the linear, quadratic, and cubic effects of increasing dietary WCS. Increasing dietary WCS from 0% to 24% DM quadratically influenced the intake of DM and NDF, with the highest value being the inclusion of 8% WCS, and intakes of 16- and 18-carbon, and total FA, with maximum values obtained up to 24% WCS. Increasing dietary WCS affected digestibility of DM (cubic) and NDF (quadratic), with the lowest values being the inclusion of 8% WCS. Increasing WCS increased 16-carbon digestibility (quadratic) but decreased digestibility of 18-carbon and total FA (both quadratic), with highest and lowest values for the inclusion of 24% WCS, respectively. Increasing dietary WCS quadratically increased absorbed 16- and 18-carbon, and total FA, with maximum values obtained for 24% WCS. Increasing dietary WCS quadratically increased yields of milk, milk fat, milk protein, milk lactose, 3.5% FCM, and ECM, and linearly increased BW gain. The source of milk FA was affected by dietary WCS, with a quadratic decrease in the yield of de novo and mixed milk FA and a quadratic increase in preformed milk FA. Increasing dietary WCS linearly increased trans- 10 C18:1 milk FA content. As dietary WCS increased, plasma insulin linearly decreased, and plasma gossypol levels linearly increased. Despite the decrease in total FA digestibility, increasing dietary WCS from 0% to 24% DM increased FA absorption. Increasing the dietary inclusion of WCS up to 16% DM increased milk production responses and DM intake. Under the current dietary conditions, high-producing dairy cows benefited best from a diet containing an inclusion of 8% to 16% WCS in DM. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Animals vary in the way in which they use energy due to diet, genetics, and management. Energy consumed by the animal supports milk production, but considerable variation among animals in energy utilization is thought to exist. The study objective was to estimate the among-animal variance in energy utilization in data collected from Jersey cows using indirect calorimetry. Individual animal-period data from 15 studies (n = 560) were used. The dataset included 115 animals from 44 to 410 DIM producing 11.5 to 39.1 kg/d of milk. On average, the 63 treatments in the dataset ranged 14.8% to 19.5% CP, 21.4% to 43.0% NDF, 16.2% to 33.3% starch, and 2.21% to 6.44% crude fat. Data were analyzed with the GLIMMIX procedure of SAS (9.4) with random effects of cow, treatment nested within period, square, and experiment. The percentage of among-animal, dietary treatment, and experimental variance was calculated as the variance associated with each fraction divided by the sum of variance from animal, dietary treatment, experiment, and residual, which was considered the total variance. The percentage of among-animal variance was characterized as high or low when the value was greater than or less than the mean value of 29.2%. Among-animal variance explained approximately 29.3% to 42.5% of the total variance in DMI, gross energy (GE), digestible energy (DE), ME, and NE L in megacalories per day. When energetic components of feces, urine, heat, and lactation in megacalories per day were expressed per unit of DMI, the among-animal variance decreased by 20.4, 4.82, 9.55, and 3.80 percentage units, respectively. However, among-animal variance explained 4.80 and 5.02 percentage units more of the total variation for methane energy and tissue energy in megacalories per day when expressed per unit of DMI. Variance in energetic efficiencies of DE/GE, ME/GE, and ME/DE were explained to a lesser extent by among-animal variance (averaging 17.8 ± 1.95%). The among-animal contribution to total variance in milk energy was 28.8%. Milk energy was a large proportion of the energy efficiency calculation, which included milk energy plus corrected tissue energy over net energy intake, which likely contributed to the 22.2% of total among-animal variance in energy efficiency. Results indicate that among-animal variance explains a large proportion of the total variation in DMI. This contributes to the variance observed for energy fractions as well as energy components when expressed in megacalories per day. Variation in energetic loss associated with methane was primarily explained by differences among animals and was increased when expressed per unit of DMI, highlighting the role of inherent animal differences in these losses. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Dietary carbohydrate manipulation can be used to reduce enteric CH 4 emission, but few studies have focused on the interaction of the different types of carbohydrates that can affect feed intake and ruminal fermentation. Understanding this interaction is necessary to make the most out of CH 4 mitigation feeding strategies using different dietary carbohydrates. The aim of this study was to test the effect on enteric CH 4 emission, feed intake, and milk production response when cows were fed either grass-clover silage (GCS) or corn silage (CS) as the sole forage source (55% of dry matter, DM), in combination with either barley (BAR) or dried beet pulp (DBP) as a concentrate (21.5% of DM). A total of 24 (half first-parity and half second-parity) cows were used in a crossover design with 2 periods of 21 d each, receiving 2 of 4 diets obtained from a 2 × 2 factorial arrangement of the experimental diet. Feed intake, CH 4 emission metrics, and milk production were recorded at the end of the experimental periods. The diets had NDF concentrations between 258 and 340 g/kg of DM and starch concentrations between 340 and 7.45 g/kg of DM (CS-BAR and GCS-DBP, respectively). The effects of silage and concentrate on dry matter intake (DMI) were additive, with the highest feed intake in cows fed CS-BAR, followed by cows fed CS-DBP, GCS-BAR, and GCS-DBP (21.2, 19.9, 19.1, and 18.3 kg/d, respectively). Energy corrected milk (ECM) yield was not affected by silage source in first parity cows, but it was higher for cows fed CS than cows fed GCS in second parity. The effects of silage and concentrate on CH 4 production (g/d), yield (g/kg of DMI), and intensity (g/kg of ECM) were not additive, as cows fed GCS had similar responses regardless of the concentrate used, but cows fed CS had lower CH 4 production, yield, and intensity when fed BAR instead of DBP. The lower CH 4 production, yield, and intensity in cows fed CS-BAR compared with other diets could be partially explained by the nonlinear relationship between ruminal VFA and carbohydrates (NDF and starch) concentration reported in the literature; however, we observed a linear relationship between the acetate/propionate ratio and CH 4 yield, suggesting possible other effects. The effects of silage and concentrate on the ruminal VFA were additive in first parity cows, but not in second parity cows. The interaction between dietary carbohydrate type and parity might indicate an effect of feed intake or the energy balance of the cow. Feeding cows silage and concentrate both rich in starch can result in the lowest enteric CH 4 emission. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. The objectives of this observational cohort study were to evaluate the associations of rumination time (RT) in the last week of pregnancy with transition cow metabolism, inflammation, health, and subsequent milk production, reproduction, and culling. Pregnant nulliparous (n = 199) and parous (n = 337) cows were enrolled 21 d before expected calving. Rumination time and physical activity were monitored automatically by sensors from d −21 to 15 relative to calving. Blood samples were collected on d −14, −5, 4, 8, and 12 ± 1 relative to calving. Diagnoses of clinical health problems were performed by researchers from calving to 15 DIM. In classification 1, cows were ranked based on average daily RT in the last week of pregnancy and classified into terciles as short RT (SRT), moderate RT (MRT), or long RT (LRT) for association analyses. In classification 2, RT deviation from the parity average was used in a receiver operating characteristic curve to identify the best threshold to predict postpartum clinical disease. Cows were then classified as above the threshold (AT) or below the threshold (BT). Compared with cows with LRT, cows with SRT had greater serum concentrations of nonesterified fatty acids (0.47 vs. 0.40 ± 0.01 mmol/L), BHB (0.58 vs. 0.52 ± 0.01 mmol/L), and haptoglobin (0.22 vs. 0.18 ± 0.008 g/L) throughout the transition period, and reduced concentrations of glucose, cholesterol, albumin, and magnesium in a time-dependent manner. Parous cows with SRT had higher odds of postpartum clinical disease (adjusted odds ratio [AOR] = 3.7; 95% CI: 2.1–6.4), lower odds of pregnancy by 210 DIM (AOR = 0.34; 95% CI = 0.15–0.75), and lower milk production (46.9 vs. 48.6 ± 0.5 kg/d) than parous cows with LRT. Deviation in prepartum RT had good predictive value for clinical disease in parous cows (area under the curve = 0.65; 95% CI = 0.60–0.71) but not in nulliparous (area under the curve = 0.51; 95% CI = 0.42–0.59). Separation of parous cows according to the identified threshold (≤−53 min from the parity average) resulted in differences in serum concentrations of nonesterified fatty acids (AT = 0.31 ± 0.006, BT = 0.38 ± 0.014 mmol/L), BHB (AT = 0.49 ± 0.008, BT = 0.53 ± 0.015 mmol/L), and globulin (AT = 32.3 ± 0.3, BT = 34.8 ± 0.5 g/L) throughout the transition period, as well as in serum cholesterol, urea, magnesium, albumin, and haptoglobin in a time-dependent manner. Below threshold parous cows had higher odds of clinical disease (AOR = 3.7; 95% CI = 2.1–6.4), reduced hazard of pregnancy (adjusted hazard ratio = 0.64, 95% CI: 0.47–0.89), greater hazard of culling (adjusted hazard ratio = 2.1, 95% CI: 1.2–3.6), and lower milk production (46.3 ± 0.7 vs. 48.5 ± 0.3 kg/d). External validation using data from 153 parous cows from a different herd and the established threshold in RT deviation (≤−53 min) resulted in similar predictive value, with the odds of postpartum disease 2.4 times greater in BT than AT (37.5% vs. 20.1%). In conclusion, RT in the week preceding calving was a reasonable predictor of postpartum health and future milk production, reproduction, and culling in parous cows but not in nulliparous cows. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Missing pedigrees may produce bias in genomic evaluations. Thus, strategies to deal with this problem have been proposed as using unknown parent groups (UPG) or truncated pedigrees. The aim of this study was to investigate the impact of modeling missing pedigrees under single-step genomic best linear unbiased prediction (ssGBLUP) evaluations for productive and reproductive traits in dairy buffalo using different approaches: (1) traditional BLUP without UPG (BLUP), (2) traditional BLUP including UPG (BLUP/UPG), (3) ssGBLUP without UPG (ssGBLUP), (4) ssGBLUP including UPG in the A and A 22 matrices (ssGBLUP/A_UPG), (5) ssGBLUP including UPG in all elements of the H matrix (ssGBLUP/H_UPG), (6) BLUP with pedigree truncation for the last 3 generations (BLUP/truncated), and (7) ssGBLUP with pedigree truncation for the last 3 generations (ssGBLUP/truncated). Unknown parent groups were not used in the scenarios with truncated pedigree. A total of 3,717, 4,126, and 3,823 records of the first lactation for accumulated 305-d milk yield (MY), age at first calving (AFC), and lactation length (LL), respectively, were used. Accuracies ranged from 0.27 for LL (BLUP) to 0.46 for MY (BLUP), bias ranged from −0.62 for MY (ssGBLUP) to 0.0002 for AFC (BLUP/truncated), and dispersion ranged from 0.88 for MY (BLUP/A_UPG) to 1.13 for LL (BLUP). Genetic trend showed genetic gains for all traits across 20 years of selection, and the impact of including genomic information, UPG, or pedigree truncation under GEBV accuracies ranged among the evaluated traits. Overall, methods using UPG, truncation pedigree, and genomic information exhibited potential to improve GEBV accuracies, bias, and dispersion for all traits compared with other methods. Truncated scenarios promoted high genetic gains. In small populations with few genotyped animals, combining truncated pedigree or UPG with genomic information is a feasible approach to deal with missing pedigrees. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Our objectives were to compare the efficacy of ketoprofen or ceftiofur for treatment of metritis in dairy cows considering subsequent health, production, and reproduction. Cows from 2 commercial dairy farms in Ontario, Canada were examined with a Metricheck device 3 times per week from 2 to 14 DIM. Cows with metritis (fetid vaginal discharge; n = 193) were blocked by parity and fever (rectal temperature ≥39.5°C or <39.5°C) and within each block per farm, randomly assigned to receive 3 mg/kg BW of ketoprofen (KET) or 2.2 mg/kg of ceftiofur hydrochloride (CEF), once a day for 3 d. Day of enrollment was considered study d 0. Rectal temperature and attitude were evaluated in cows with metritis on study d 0, 3, 4, 7, 10, and 13, and vaginal discharge was evaluated on study d 4, 7, 10, and 13. Body condition was scored at enrollment and at 35 DIM, and serum concentration of haptoglobin was measured at d 0, 2, 4, and 7. Cows with rectal temperature ≥39.5°C or a depressed attitude on d 3 were classified as clinical failure and received treatment with ceftiofur for 3 d (KET), or 2 additional days (CEF), to a maximum of 5 d of treatment with ceftiofur. At 35 ± 3 DIM cows were examined for uterine involution via transrectal palpation, purulent vaginal discharge (PVD) via Metricheck, and endometritis via endometrial cytology. Time to onset of cyclicity was assessed by serum progesterone (P4) measurements at 28, 42, and 56 DIM. Contemporary cows from the same farms without metritis (NOMET; n = 1,043) were used for comparison. Data were analyzed with mixed linear or logistic regression or Cox's proportional hazard models, including herd as a random effect. The proportion of clinical resolution of metritis on d 3 (96% vs. 92%), of cows with fever (from d 3 to d 13 after enrollment) or fetid discharge (from d 4 to d 13 after enrollment), and the number of medical treatments (3.1 vs. 3.3) were not different between CEF and KET, respectively. Cows in KET received fewer antibiotic treatments than cows in CEF (0.3 vs. 3.1). Uterine involution, prevalence of PVD (50% vs. 47%) and subclinical endometritis (6.6% vs. 4.3%), and proportion of cyclic cows (82% vs. 86%) did not differ between CEF and KET. Cows in KET had greater serum haptoglobin concentration from d 2 to 7 after enrollment. The incidence of mastitis, lameness, or displaced abomasum to 60 DIM and subclinical ketosis to 21 DIM did not differ among CEF, KET, and NOMET. There were no differences in median time to first AI (CEF = 68 d, 95% CI: 65–70; KET = 69 d, 95% CI: 68–72; NOMET = 69 d, 95% CI: 68–70), median time to pregnancy (CEF = 118 d, 95% CI: 92–145; KET = 113 d, 95% CI: 90–135; NOMET = 105 d, 95% CI: 101–109), pregnancy at first AI at 33 d after insemination (CEF = 42%; KET = 41%; NOMET = 41%), pregnancy loss after first AI (CEF = 8%; KET = 11%; NOMET = 8%), hazard of pregnancy, or hazard of culling up to 300 DIM. Milk yield was not different between CEF and KET during the first 10 wk, but was lesser in KET at wk 2 and 4 and CEF at wk 2, 4, and 6 than in NOMET. In this pilot-scale study, given early detection, we did not detect differences in subsequent health, milk yield, or reproductive performance in cows with metritis initially treated for 3 d with CEF or KET. Additional, larger studies are warranted. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Supplemental dietary rumen available fats show promise as enteric methane (eCH 4) mitigators for lactating dairy cows. However, concerns include variability in eCH 4 response and possible negative effects on dairy cow performance. Successful implementation of this mitigation option requires better prediction of responses specifically to rumen available fatty acids (FA) as well as understanding the modulating effects of other dietary and animal characteristics. Using meta-analytic and meta-regression techniques, 35 published studies with diet definition were used to assess changes in eCH 4 emissions and lactation performance associated with supplemental fat, specific supplemental rumen available FA types, and other dietary characteristics. Enteric CH 4 (g/d) was reduced by 3.77% per percentage unit of supplemental rumen available ether extract (EE). Supplemental rumen available PUFA (C18:2 and C18:3) and UFA (C18:1, C18:2, C18:3) mitigated eCH 4 (g/d) emissions in dairy cows by 6.88 and 4.65% per percentage unit increase, respectively. The anti-methanogenic effects of PUFA, MUFA and MCFA increased with correspondingly greater basal dietary levels of each FA type. Higher rumen-degradable starch (RDS; >18% DM) in the basal diet promoted greater reductions in eCH 4 yield (eCH 4 /DMI, g/kg) with supplemental rumen available PUFA and UFA. Both milk fat percentage and yield (kg/d) were reduced with rumen available fat supplementation with a reduction of 7.8% and 6.0%, respectively, relative to control diets. Our results highlight the importance of determining basal levels of the rumen available FA before providing supplemental rumen available FA as an option for enteric eCH 4 mitigation. Dairy nutritionists can use estimates generated from this analysis to predict changes in eCH 4 emissions and dairy cow performance associated with dietary supplementation of rumen available EE and specific rumen available FA types for the purpose of eCH 4 mitigation. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Early lactation is a critical period for dairy cows, as energy requirements rapidly increase with the onset of lactation; however, early-lactation DMI in pasture-based systems are under measured. The objectives of this study were (1) to measure and profile total DMI (TDMI) and animal performance of dairy cows during early lactation in a pasture-based system, (2) to investigate early-lactation energy balance in pasture-based systems, and (3) to examine production efficiencies, including TDMI and milk solids production per 100 kg of BW. Eighty spring-calving dairy cows were allocated to a grazing group as they calved over a 2-yr period (2021 and 2022). Cows were offered a daily herbage allowance to achieve a postgrazing sward height of 4 cm, with silage supplementation when necessary due to inclement weather. Total DMI was measured using the n-alkane technique over a 12-wk period from February 1, 2021, to April 23, 2022. Total DMI and daily milk yield were significantly affected by parity with both variables being greatest for third-parity animals (17.7 kg of DM and 26.3 kg/cow per day, respectively), lowest for first parity (13.2 kg of DM and 19.6 kg/cow per day, respectively) and intermediate for second-parity animals (16.8 kg of DM and 24.1 kg/cow per day, respectively). Peak TDMI was reached on wk 10 for first-parity animals (14.6 kg of DM), wk 11 for second parity animals (19.3 kg of DM) and wk 12 for third-parity animals (19.9 kg of DM). Parity also had a significant effect on unité fouragère lait (UFL; feed units for milk) feed balance as first-parity animals experienced a greater degree of negative energy balance (−3.2 UFL) compared with second- and third-parity animals (−2.3 UFL). Breed and parity had an effect on production efficiencies during the first 12 wk of lactation as Jersey × Holstein Friesian cows had greater TDMI/100 kg of BW and milk solids/100 kg of BW compared with Holstein Friesian cows. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. In this study, the main objective was to assess if long luteal phases could have causes other than pregnancy loss. We enrolled Holstein dairy cows ≥50 DIM from a commercial herd in Brazil from October 2016 to August 2017. All cows received an estradiol-based synchronization protocol, and, on the day of insemination (d 0), were randomly assigned either an AI or a placebo insemination (PBO) in a 3:1 ratio. An ultrasound was used to assess the presence of a corpus luteum (CL) on d 17, 24, and 31, which, combined to the information from patches for the detection of estrus, was used to determine the length of the luteal phase following AI or PBO. Pregnancy was assessed by ultrasound on d 31 and cows that were pregnant were excluded from the analyses. The length of the estrous cycles was categorized as short (<17 d), normal (17–23 d), long (24–30 d), and very long (≥31 d). We compared the proportion of cows in each category between the AI and PBO groups using a cumulative ordinal mixed model. We define prolonged luteal phase as estrous cycles ≥24 d and tested its association with potential risk factors (parity, season, DIM, uterine size and position score, milk production, BCS, and the presence of a CL at enrollment to the synchronization protocol) using mixed logistic regression models. Results are presented as odds ratio (OR) and 95% Bayesian credible intervals (BCI). Data from 876 inseminations (AI: n = 616, PBO: n = 260) was collected. Overall, 12% of estrous cycles were short, 31% were normal, 19% were long, and 38% were very long. There was no difference in the odds of being in longer estrous cycle categories for the AI compared with the PBO group (OR = 0.92; 95% BCI = 0.76–1.10). Season and presence of a CL at enrollment were associated with prolonged luteal phase. In the AI group, there was a possible effect of early pregnancy losses on the lifespan of the CL, but not the PBO group, which led us to conclude that long and very long estrous cycles were not all caused by the embryonic loss. In fact, the high prevalence of cows with an extended CL lifespan in the present study suggests this could be an under- or miss-reported characteristic of high-producing lactating Holstein cows. This finding may have important repercussions in the understanding of the CL function physiology of lactating Holstein cows. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. The objective of this study was to evaluate the effect of selective dry cow therapy (SDCT) strategies based on 2 different algorithms in comparison with blanket dry cow therapy for measures of udder health, milk yield, and culling in herds not using internal teat sealant. Cows from 2 commercial farms in west Texas were randomized into 3 different groups: SDCT algorithm 1 (ALG1; n = 455) cows treated with an intramammary antimicrobial at dry-off if SCC >200,000 cells/mL at any Dairy Herd Improvement Association test date or if the cow had 2 or more cases of clinical mastitis (CM) during the enrollment lactation; SDCT algorithm 2 (ALG2; n = 458) cows treated with an intramammary antimicrobial at dry-off if SCC >200,000 cell/mL at last test date or any case of CM during the enrollment lactation; and control cows (CON = 447) received blanket dry cow therapy. None of the cows enrolled in the study received an internal or external teat sealant. Data related to milk and SCC linear score (LSCC) were collected monthly. Milk yield and LSCC during the first 6 mo of lactation were analyzed using repeated measures ANOVA models, while Cox proportional hazards models were fitted to culling and CM data. The farm was fitted as a random effect in all models. The percentage of cows receiving antimicrobials at dry-off was 51.3%, 24.7%, and 100% for ALG1, ALG2, and CON, respectively. Treatment did not influence the IMI dynamics during the dry period. Additionally, no statistical differences related to treatment were observed for LSCC and milk yield. The LSCC for ALG1, ALG2, and CON cows was 2.44, 2.41, and 2.26, respectively. The average milk yield for ALG1, ALG2, and CON cows was 43.2, 43.2, and 44.0 kg/d, respectively. Treatment did not affect CM incidence or culling. The cumulative incidence of CM was 19.6%, 19.4%, and 21.4% for ALG1, ALG2, and CON cows, respectively. Additionally, the cumulative risk of death or culling was 18.5%, 17.1%, and 19.5% for ALG1, ALG2, and CON cows, respectively. In conclusion, SDCT strategies led to a decrease in antimicrobial drug use at dry-off, without significantly affecting the incidence of CM, the risk of culling, LSCC, or milk yield of dairy cows. However, numerical differences in LSCC and milk yield were observed between treatment groups. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. The study investigated the effects of dietary protein level and the inclusion of hydroponic barley sprouts (HB) on lactation performance, blood biochemistry and N use efficiency in mid-lactation dairy cows. Treatments were arranged in a 2 × 2 factorial design with 2 CP levels (16.8% and 15.5% of DM), with HB (4.8% of DM, replacing 4.3% of alfalfa hay and 0.5% of distillers dried grains with solubles [DDGS]) or without HB. Forty-eight multiparous Holstein dairy cows (146 ± 15 DIM, 40 ± 5 kg/d of milk) were randomly allocated to 1 of 4 diets: high-protein diet (16.8% CP, HP), HP diet with HB (HP+HB), low-protein diet (15.5% CP, LP), or LP diet with HB (LP+HB). An interaction between CP × HB on DMI was detected, with DMI being unaffected by HB inclusion in cows fed the high-protein diets, but was lower in cows fed HB when the low-protein diet was fed. A CP × HB interaction was also observed on milk and milk protein yield, which was higher in cows fed HB with HP, but not LP. Inclusion of HB also tended to reduce milk fat content, and feeding HP resulted in a higher milk protein and MUN content, but lower milk lactose content. Feed efficiency was increased by feeding HP or HB diets, whereas N use efficiency was higher for cows fed LP or HB diets. There was an interaction on the apparent total-tract digestibility of DM and CP, which was higher when HB was fed along with HP, but reduced when fed with LP, whereas the digestibility of ADF was increased by feeding low-protein diets. In conclusion, feeding a low-protein diet had no adverse effect on cow performance, while feeding HB improved milk and milk component yield, and N efficiency when fed with a high-CP diet, but compromised cow performance with a low-CP diet. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Omitting or shortening the dry period may result in a fairly constant ration throughout the transition period of dairy cows, reducing the need for adaptation of cow metabolism and rumen function to a new lactation. The objective of this study was to determine the effect of dry period length (DP) on rumen adaptation and cow metabolic state during the transition period. Twelve pregnant, rumen-cannulated Holstein Friesian dairy cows at the end of their first lactation were assigned to 1 of 3 treatments: a conventional (60 d), short (30 d), or no dry period (0 d). At dry-off, cows received a dry-cow ration until calving. Lactating cows received a lactation ration. Cows were monitored from 8 wk before calving until 8 wk after calving for milk yield and DMI. Rumen biopsies were taken from 3 locations in the rumen at 60, 40, and 10 d before calving and 3, 7, 14, 28, and 56 d after calving to assess papillae dimensions. Blood was sampled weekly from 3 wk before until 8 wk after calving, and liver biopsies were taken at wk −2, 2, and 4 relative to calving. Prepartum, DMI, and milk yield were greater for cows with a short or no dry period, compared with cows with a conventional dry period. Postpartum, DMI was greater for cows with a short dry period compared with cows with a conventional dry period. Plasma glucose concentration was greater for cows without a dry period, compared with the other DP postpartum. Plasma concentrations of nonesterified fatty acids and BHB, and liver triglyceride content, did not differ among dry period. Rumen papillae differed in size based on biopsy location, but there was no interaction between biopsy location and the effect of DP. Rumen papillae surface area for cows managed for a 30- or 60-d dry period decreased toward calving. At 40 d prepartum, papillae surface area was greater for short and no dry period treatment compared with a conventional dry period. At 10 d prepartum, papillae surface area was greater for the no dry period treatment compared with both other treatments, and this difference was still present 3 d postpartum. Cows managed for a short dry period showed faster increase in papillae dimensions after calving compared with cows managed for a conventional dry period. From d 28 onwards, no differences in papillae surface area were observed. The faster rumen adaptation postpartum may be related to the increased DMI during the first weeks postpartum for cows managed for a short dry period. However, this did not result in improved metabolic status or milk yield. The results from the present study demonstrate that the dietary changes related to a conventional DP affected rumen papillae development, not only prepartum but also early postpartum. Further optimization of DP as well as dietary composition throughout the transition period may support cows in their adaptation to a new lactation. [ABSTRACT FROM AUTHOR]

Objective: Previous research reported that dietary addition with phytosterols improved the energy utilisation of the rumen microbiome, suggesting its potential to alleviate the negative energy balance of perinatal cows. This experiment aimed to explore the effects of feeding phytosterols on the metabolic status of perinatal cows through plasma metabolomics and faecal bacteria metabolism. Methods: Ten perinatal Holstein cows (multiparous, 2 parities) with a similar calving date were selected four weeks before calving. After 7 days for adaptation, cows were allocated to two groups (n = 5), which respectively received the basal rations supplementing commercial phytosterols at 0 and 200 mg/d during a 42-day experiment. The milk yield of each cow was recorded daily after calving. On days 1 and 42, blood and faeces samples were all collected from perinatal cows before morning feeding for analysing plasma biochemicals and metabolome, and faecal bacteria metabolism. Results: Dietary addition with phytosterols at 200 mg/d had no effects on plasma cholesterol and numerically increased milk yield by 1.82 kg/d (p>0.10) but attenuated their negative energy balance in perinatal cows as observed from the significantly decreased plasma level of β-hydroxybutyric acid (p = 0.002). Dietary addition with phytosterols significantly altered 12 and 15 metabolites (p<0.05) within the plasma and faeces of perinatal cows, respectively. Of these metabolites, 5 upregulated plasma fatty acids indicated an improved energy status (i.e., C18:1T, C14:0, C17:0, C18:0, and C16:0). Milk yield negatively correlated with plasma concentrations of ketone bodies (p = 0.035) and 5-methoxytryptamine (p = 0.039). Furthermore, dietary addition with phytosterols at 200 mg/d had no effects on fermentation characteristics and bacterial diversity of cow faeces (p>0.10) but improved potentially beneficial bacteria such as Christensenellaceae family (p<0.05) that positively correlated with feed efficiency. Conclusion: Dietary addition with phytosterols at 200 mg/d could effectively improve the energy status in perinatal cows by attenuating their negative energy balance. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate two levels of forage allowance (FA) during the prepartum period on metabolic, hormonal, productive, and reproductive variables in primiparous (P) and multiparous (M) beef cows. Six weeks before calving, 40 P and 42 M cows were assigned to two FA (native pastures) treatments until calving (day 0): High (15 kg DM/100 BW; H) and Low (5 kg DM/100 BW; L). After calving all cows were managed together. High FA cows presented greater intake than L cows, while M tended to have greater intake than P cows. Increased herbage allowance in late gestation in beef cows successfully improved forage intake and energy balance reflected in body condition score and metabolic and endocrine markers. Also, high forage allowance increased milk yield (5.4 vs 4.6 kg/d, P < 0.05) and calves daily gain rate during the first two months of age (0.88 vs 0.82 kg/d, P < 0.05) in H respect to L cows. Pregnancy rate was greater in H vs L cows (40 vs 28 %, P < 0,05). The endocrine metabolic response to higher forage allowance depended on parity, as primiparous cows showed a greater imbalance around calving. Moreover, most primiparous cows were not pregnant at the end of the breeding season, consistent with their prolonged anestrous. Multiparous cows had better productive and reproductive performance than primiparous cows, showing that growing cows have a pronounced negative energy balance reflected in most of the evaluated parameters. • Increased herbage allowance in late gestation improved forage intake, energy balance, milk yield and pregnancy rate. • The productive and reproductive response to forage allowance was lower in primiparous respect to multiparous cows. • Reproductive and productive parameters can be explained by metabolic and endocrine markers. [ABSTRACT FROM AUTHOR]

Lameness is one of the most common health issues in cattle, which is a significant cause of health disorders and economic losses in livestock. Due to the numerous and varied causes, its treatment and prevention are complex and challenging. Lameness is associated with intense pain, leading to discomfort, reduced milk yield, weight loss, and reproductive issues, which can ultimately result in chronic lameness and substantial financial losses. A number of simple, visual scoring scales have been developed for their detection and evaluation, which enable them to be detected quickly on the one hand, and appropriate interventions to be taken and their effectiveness evaluated on the other. The consistent application of these scoring systems is becoming a critical component of herd management strategies, aimed not only at reducing the prevalence of lameness but also at minimizing the associated economic impacts. This dual focus-improving animal welfare and reducing financial losses-highlights their importance in maintaining both herd health and cost-effectiveness. [ABSTRACT FROM AUTHOR]

Fat supplements are well known for their multiple beneficial effects on ruminant health, reproduction and productivity, and as a source for certain bioactive compounds in ruminant products. On the other hand, numerous phytochemicals have demonstrated the potential to improve rumen fermentation through modifying the volatile fatty acid (VFA) pattern to favour those with greater energy efficiency, boosting microbial protein synthesis, and decreasing methane emission and ruminal ammonia concentration. Savory is an aromatic plant rich in various phytochemicals (mainly carvacrol and flavonoids) that can alter ruminal metabolism of dietary fatty acids, potentially increasing the production of some bioactive compounds such as conjugated linoleic acids (CLAs). This study aimed to investigate combined effects of oil type (fish oil (FO) versus soybean oil (SO)) and the inclusion of savory (Satureja khuzistanica) plant (SP) in the diet on total tract digestibility of nutrients, rumen fermentation, milk yield and milk fatty acid profile in dairy cattle. Eight multiparous lactating Holstein cows were used in a replicated 4 × 4 Latin square design experiment with four diets and four 21-d periods. During each experimental period consisted of 14 days of adaptation and a 7-day sampling period, cows were randomly assigned to one of the four dietary treatments: the diet supplemented with 2% (DM basis) fish oil (FOD) or soybean oil (SOD), the FOD or SOD plus 370 g DM/d/head SP (FODs, SODs, respectively). The experimental diets were arranged in a 2 × 2 factorial design, with the fat sources as the first and SP as the second factor. The FO-supplemented diets had lower dry matter intake (DMI) and higher total tract digestibility than SO-supplemented diets (P < 0.05), and including SP in the diet improved total tract digestibility of dry matter (DM), organic matter (OM), ether extract (EE), and non-fibrous carbohydrates (NFC) (P < 0.05) without negatively affecting DMI. Rumen pH was lower with SO than with FO diets (P < 0.01) and increased with SP inclusion in the diet (P < 0.05). Total protozoa count and ruminal ammonia concentration decreased, and the branched-chain VFA (BCVFA) proportion increased with SP inclusion in the diet (P < 0.05). Milk production, as well as the concentration and yield of milk components (except lactose concentration) were higher with SO than with FO diets (P < 0.05), but these variables remained unaffected by SP. The milk concentrations of both non-esterified fatty acids (NEFA) and beta-hydroxybutyrate (BHB) were lower with SO compared to FO diets, and these variables were reduced by SP (P < 0.01). The proportions of both mono- and polyunsaturated FA (MUFA and PUFA, respectively) in milk were higher with FO than with SO diets (P < 0.01), and their proportions increased by SP at the expense of saturated FA (SFA) (P < 0.01). Including SP in the diet increased the proportions of all the milk n-3 FA (C18:3c, C20:5, and C22:6) by 21%, 40%, and 97%, respectively, and those of conjugated linoleic acids (C18:2 (c9,t11-CLA) and C18:2 (t10,c12-CLA)) by 23% and 62%, respectively. There was no interaction between oil type and SP for the assessed variables. Fish oil, despite reducing milk production and milk components, was more effective than soybean oil in enriching milk with healthy FA. These findings also show promise for SP as a feed additive with the potential to improve total tract digestibility, rumen fermentation and milk FA composition. [ABSTRACT FROM AUTHOR]

Background: Productive life (PL) of a cow is the time the cow remains in the milking herd from first calving to exit from the herd due to culling or death and is an important economic trait in U.S. Holstein cattle. The large samples of Holstein genomic evaluation data that have become available recently provided unprecedented statistical power to identify genetic factors affecting PL in Holstein cows using the approach of genome-wide association study (GWAS). Methods: The GWAS analysis used 1,103,641 Holstein cows with phenotypic observations on PL and genotypes of 75,282 single nucleotide polymorphism (SNP) markers. The statistical tests and estimation of SNP additive and dominance effects used the approximate generalized least squares method implemented by the EPISNPmpi computer program. Results: The GWAS detected 5390 significant additive effects of PL distributed over all 29 autosomes and the X–Y nonrecombining region of the X chromosome (Chr31). Two chromosome regions had the most significant and largest cluster of additive effects, the SLC4A4-GC-NPFFR2 (SGN) region of Chr06 with pleiotropic effects for PL, fertility, somatic cell score and milk yield; and the 32–52 Mb region of Chr10 with peak effects for PL in or near RASGRP1 with many important immunity functions. The dominance tests detected 38 significant dominance effects including 12 dominance effects with sharply negative homozygous recessive genotypes on Chr18, Chr05, Chr23 and Chr24. Conclusions: The GWAS results showed that highly significant genetic effects for PL were in chromosome regions known to have highly significant effects for fertility and health and a chromosome region with multiple genes with reproductive and immunity functions. SNPs with rare but sharply negative homozygous recessive genotypes for PL existed and should be used for eliminating heifers carrying those homozygous recessive genotypes. [ABSTRACT FROM AUTHOR]

In the realm of animal breeding for sustainability, domestic camels have traditionally been valued for their milk and meat production. However, key aspects such as zoometrics, biomechanics, and behavior have often been overlooked in terms of their genetic foundations. Recognizing this gap, the present study perfomed genome-wide association analyses to identify genetic markers associated with zoometrics-, biomechanics-, and behavior-related traits in dromedary camels (Camelus dromedarius). 16 and 108 genetic markers were significantly associated (q < 0.05) at genome and chromosome-wide levels of significance, respectively, with zoometrics- (width, length, and perimeter/girth), biomechanics- (acceleration, displacement, spatial position, and velocity), and behavior-related traits (general cognition, intelligence, and Intelligence Quotient (IQ)) in dromedaries. In most association loci, the nearest protein-coding genes are linkedto neurodevelopmental and sensory disorders. This suggests that genetic variations related to neural development and sensory perception play crucial roles in shaping a dromedary camel's physical characteristics and behavior. In summary, this research advances our understanding of the genomic basis of essential traits in dromedary camels. Identifying specific genetic markers associated with zoometrics, biomechanics, and behavior provides valuable insights into camel domestication. Moreover, the links between these traits and genes related to neurodevelopmental and sensory disorders highlight the broader implications of domestication and modern selection on the health and welfare of dromedary camels. This knowledge could guide future breeding strategies, fostering a more holistic approach to camel husbandry and ensuring the sustainability of these animals in diverse agricultural contexts. [ABSTRACT FROM AUTHOR]

Some New Zealand dairy farmers are using semen from Norwegian Red (NR) bulls to explore the performance of this breed under local grazing conditions. The objective of this study was to compare the first lactation performance of first cross NR cattle with traditional New Zealand breeds. Data were collected from six dairy farms in Southland, New Zealand, during 2022–2023 milk production seasons. Data were collected from 1178 first lactation cows including herd test of daily yields of milk, fat and protein and somatic cell counts, and persistency. Breeds included 386 NR cross (NRX), 231 Holstein Friesian (F), 84 Holstein Friesian cross (FX), 134 Holstein Friesian x Jersey (FJ) and 58 Jersey cross (JX) cows. Findings indicate F cows produced the greatest cumulative milk yield (3,744 kg), 138.6 kg more than NRX cows. There were no significant differences among the breed groups for milk yield and milk solids yield persistency and SCS (SCS = Log2 SCC). The total lactation milk yield of NRX cows was lower than that of the other breeds, excluding JX. These results pertain specifically to first lactation cows; therefore, it is necessary to undertake further analysis to evaluate the long-term productivity and longevity of NR breeds under New Zealand conditions. [ABSTRACT FROM AUTHOR]