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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. 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]

Regular monitoring of body condition score (BCS) changes during lactation is a crucial management tool in dairy cattle; however, the current BCS measurements are often discontinuous and unevenly spaced in time. The aim of this study was to investigate the ability of random regression test‐day models (RR‐TDM) to predict BCS for the entire lactation in dairy cows even if the actual scoring is limited to one BCS record. The data consisted of test‐day records of milk yield (MY), fat percentage (FP), protein percentage (PP) and BCS (based on a 9‐point scale with unit increments; 1–9) collected from 2014 to 2022 in 128 herds in the Walloon Region of Belgium. In total, 20,698 test‐day records on 2166 first‐parity Holstein cows (2–12 with an average of 9.42 test‐day records per cow) were available for MY, FP and PP; and 7985 records on the same animals (2–12 with an average of 3.68 records per cow) were available for BCS. To estimate the solutions, only one randomly selected BCS record per animal along with all her MY, FP and PP records were used, which were then used to predict BCS data (calibration set). The remaining BCS (1–11 with an average 2.86 BCS records per animal) were used to evaluate the goodness of the predictions (validation set). Multiple‐trait RR‐TDM was used to estimate (co)variance components through the average information restricted maximum likelihood (AI‐REML) algorithm. Predicted BCS were grouped into nine classes as the original observed BCS used for comparison. Pearson correlation between the predicted and observed BCS, prediction error (PE), absolute prediction error (APE) and root mean squared prediction error (RMSE) were calculated. Mean (standard deviation; SD) BCS was 4.97 (1.01), 4.95 (1.07) and 4.98 (1.00) BCS units in the full, calibration and validation datasets, respectively. Pearson correlation between the observed and predicted BCS was 0.71, mean (SD) PE was 0.04 (0.52) BCS units, mean (SD) APE was 0.48 (0.53) BCS units and RMSE was 0.72 BCS units. These findings demonstrate the ability of RR‐TDM to predict BCS for the entire lactation using a single BCS record along with available test‐day records of milk yield and composition in Holstein dairy cows. [ABSTRACT FROM AUTHOR]

The knowledge and modeling of lactation curves make it possible to identify factors that help explain environmental and genetic variations that allow the implementation of a selection program. This work aimed to evaluate different models for milk production, fat, and protein curves in Holstein cattle in Mexico and some factors that affect them. The information used was from 125,982 lactations belonging to 68,804 animals born from 2000 to 2020. The effect of calving number, season of the year, and herd was evaluated. R's Lactcurves package was employed to fit the 38 models included in the package, of which the best four (Wood, Wilmink, Ali & Schaeffer, and modified Pollot) were chosen and then used to model the individual curves through a nonlinear regression model. The parameters calculated for each model were statistically different among the number of lactations (P<0.05), as well as the number of calving, calving season, and herd (P<0.01). The modeled curves have similar shapes to those reported in other studies, except those obtained for protein in the third and fourth or more calvings with the modified Pollot model. The equation proposed by Wilmink was the one that presented the best fit for the study population according to the different evaluation criteria. Using the model that best suits the data will give a closer predictions to reality, and it can be applied to different areas, such as genetic improvement. [ABSTRACT FROM AUTHOR]

This study's objective was to compare two options of pasture supplementation: corn silage (CS) alone or corn silage mixed with protein concentrate. The experiment was conducted with 18 lactating Holstein cows in mid‐lactation in a crossover design that included three treatments and three data collection periods. All cows had access to pasture for 17 h/day with an average herbage allowance of 16 kg dry matter (DM)/cow/day and were offered in‐barn corn silage, corn silage mixed with protein concentrate, or no supplementation. Cows were equipped with pH sensors residing in the reticulum and, during the 7‐day data collection periods, with a jaw movement recorder. Nonsupplemented cows produced 21.3 kg energy‐corrected milk (ECM) and ate 13.3 kg DM herbage at pasture. Cows supplemented with corn silage and corn silage plus protein produced 2.5 and 4.5 kg/day more ECM, respectively, consumed 3.4 and 3.3 kg/day more DM in total, respectively, ate for a shorter period of time, and ruminated longer than their nonsupplemented peers. Supplemented cows were almost able to cover their energy requirements and mobilised less body mass in contrast to the nonsupplemented cows. Cows offered corn silage plus protein showed increased ECM production, increased milk urea content and lower nitrogen use efficiency (NUE) compared to cows supplemented with corn silage only. Nonsupplemented dairy cows had the highest milk urea content and performed worst in terms of NUE. The best feed conversion efficiency resulted from the nonsupplemented dairy cows and those supplemented with corn silage plus protein. In nonsupplemented cows, the high feed conversion efficiency seemed to be due to the increased mobilisation of body mass. As a result of the starch‐rich supplementations, the ruminal acetic:propionic acid ratio became smaller, and the proportions of n‐butyric acid increased. The mean reticular pH values did not substantially vary across the three feeding treatments. For the choice of a supplementation option, herbage allowance and cost of supplement will have to be considered, but aspects of feed–food competition as well as animal welfare should not be ignored. [ABSTRACT FROM AUTHOR]

Simple Summary: Xinjiang Brown cattle are a unique and widely distributed breed of dual-purpose cattle in Xinjiang, the People's Republic of China. It is known that this cattle breed has different milk production performance compared to Holstein cattle. However, the microbiota differences between Xinjiang Brown and Holstein cattle are not well known. Therefore, this study aimed to compare the bacterial community composition of the rumen and feces of these two cattle breeds under the same dietary and management conditions using 16s rRNA sequencing. This study identified microbiota with different relative abundance between these two cattle breeds and their biological functions might be related to milk synthesis. Our study increases the understanding of the differences in bacterial microbiota between Xinjiang Brown and Holstein cattle. Xinjiang Brown cattle are a unique and widely distributed breed of dual-purpose cattle in the Xinjiang area of China, whose milk production performance differs from Holstein cattle. It has been known that variations in bacterial species of the gastrointestinal tract influence milk protein, fat, and lactose synthesis. However, the microbiota differences between Xinjiang Brown and Holstein cattle are less known. This study aims to compare the bacterial community composition of the rumen and feces of these two cattle breeds under the same dietary and management conditions. The 16s rRNA sequencing data and milk production of 18 Xinjiang Brown cows and 20 Holstein cows on the same farm were obtained for analysis. The results confirmed differences in milk production between Xinjiang Brown and Holstein cattle. Microbiota with different relative abundance between these two cattle breeds were identified, and their biological functions might be related to milk synthesis. This study increases the understanding of the differences in microbiota between Xinjiang Brown and Holstein cattle and might provide helpful information for microbiota composition optimization of these dairy cattle. [ABSTRACT FROM AUTHOR]

Genetic research for the assessment of mastitis and milk production traits simultaneously has a long history. The main issue that arises in this context is the known existence of a positive correlation between the risk of mastitis and lactation performance due to selection. The transcriptome‐wide association study (TWAS) approach endeavors to combine the expression quantitative trait loci and genome‐wide association study summary statistics to decode complex traits or diseases. Accordingly, we used the farmgtex project results as a complete bovine database for mastitis and milk production. The results of colocalization and TWAS approaches were used for the detection of functional associated candidate genes with milk production and mastitis traits on multiple tissue‐based transcriptome records. Also, we used the david database for gene ontology to identify significant terms and associated genes. For the identification of interaction networks, the genemania and string databases were used. Also, the available z‐scores in TWAS results were used for the calculation of the correlation between tissues. Therefore, the present results confirm that LYNX1, DGAT1, C14H8orf33, and LY6E were identified as significant genes associated with milk production in eight, six, five, and five tissues, respectively. Also, FBXL6 was detected as a significant gene associated with mastitis trait. CLN3 and ZNF34 genes emerged via both the colocalization and TWAS approaches as significant genes for milk production trait. It is expected that TWAS and colocalization can improve our perception of the potential health status control mechanism in high‐yielding dairy cows. [ABSTRACT FROM AUTHOR]

A genome-wide association study (GWAS) of fat percentage (FPC) using 1,231,898 first lactation cows and 75,198 SNPs confirmed a previous result that a Chr14 region about 9.38 Mb in size (0.14–9.52 Mb) had significant inter-chromosome additive × additive (A×A) effects with all chromosomes and revealed many new such effects. This study divides this 9.38 Mb region into two sub-regions, Chr14a at 0.14–0.88 Mb (0.74 Mb in size) with 78% and Chr14b at 2.21–9.52 Mb (7.31 Mb in size) with 22% of the 2761 significant A×A effects. These two sub-regions were separated by a 1.3 Mb gap at 0.9–2.2 Mb without significant inter-chromosome A×A effects. The PPP1R16A-FOXH1-CYHR1-TONSL (PFCT) region of Chr14a (29 Kb in size) with four SNPs had the largest number of inter-chromosome A×A effects (1141 pairs) with all chromosomes, including the most significant inter-chromosome A×A effects. The SLC4A4-GC-NPFFR2 (SGN) region of Chr06, known to have highly significant additive effects for some production, fertility and health traits, specifically interacted with the PFCT region and a Chr14a region with CPSF1, ADCK5, SLC52A2, DGAT1, SMPD5 and PARP10 (CASDSP) known to have highly significant additive effects for milk production traits. The most significant effects were between an SNP in SGN and four SNPs in PFCT. The CASDSP region mostly interacted with the SGN region. In the Chr14b region, the 2.28–2.42 Mb region (138.46 Kb in size) lacking coding genes had the largest cluster of A×A effects, interacting with seventeen chromosomes. The results from this study provide high-confidence evidence towards the understanding of the genetic mechanism of FPC in Holstein cows. [ABSTRACT FROM AUTHOR]

Milk production traits as the most important economic traits of dairy cows, they directly reflect the benefits of breeding and the economic benefits of pasture. In this study, A disintegrin and metalloproteinase‐12 (ADAM12), Parkinson's disease gene 2 (PRKN) and dipeptidyl peptidase‐like protein subtype 6 (DPP6) polymorphism in 384 Chinese Holstein cows were detected by time‐of‐flight mass spectrometry and through statistical analysis using software such as Popgene 32, SAS 9.4 and Origin 2022, the relationship between single nucleotide polymorphisms (SNPs) of three genes with four milk production traits such as daily milk yield (DMY), milk fat percentage (MFP), milk protein percentage (MPP) and somatic cell score (SCS) was verified at molecular level. The results showed that four polymorphic loci (116,467,133, 116,604,487, 116,618,268 and 116,835,111) of DPP6 gene, two polymorphic loci (97,665,052 and 97,159,837) of PRKN gene and two polymorphic loci (45,542,714 and 45,553,888) of ADAM12 gene were detected. PRKN‐97665052, DPP6‐116467133, ADAM12‐45553888, DPP6‐116604487 and DPP6‐116835111 were all in Hardy–Weinberg equilibrium state (p >.05). ADAM12‐45542714, PRKN‐97159837 and PRKN‐97665052 were moderately polymorphic (0.25 ≤ PIC <0.50) in Holstein. It is evident that the selection potential and genetic variation of these five loci are relatively large, and the genetic richness is relatively high. The correlation analysis of different genotypes between these eight loci and milk production traits of Holstein showed that ADAM12‐45542714 and DPP6‐116835111 (p <.01) had an extremely significant effects on the DMY of Chinese Holstein in Ningxia, while PRKN‐97665052 had an extremely significant effect on MFP (p <.01). The effect of PRKN‐97665052 and DPP6‐116467133 on MPP of Holstein were extremely significant (p <.01). DPP6‐116618268 had an extremely significant effect on the SCS of Holstein in Ningxia (p <.01), and AA genotype individuals showed a higher SCS than GG genotype individuals; the other two loci (ADAM12‐45553888 and DPP6‐116604487) had no significant effects on milk production traits of Holstein (p >.05). In addition, through the joint analysis of DPP6, PRKN and ADAM12 gene loci, it was found that the interaction effect between the three gene loci could significantly affect the DMY, SCS (p <.01) and MPP (p <.05). In conclusion, several different loci of DPP6, PRKN and ADAM12 genes can affect the milk production traits of Holstein to different degrees. PRKN, DPP6 and ADAM12 genes can be used as potential candidate genes for milk production traits of Holstein for marker‐assisted selection, providing theoretical basis for breeding of Holstein. [ABSTRACT FROM AUTHOR]

The aim of this paper is to investigate whether characteristics of the first lactation (FL) curve of Iranian Holstein cows are associated with survival. Cows with least 10 test-days of milk production in their FL were used. The persistency of lactation (PL) and survival were estimated using a random regression model by restricted maximum likelihood with the ECHIDDNA software. We also used the Wood model to parameterize each individual lactation curve and then analyzed various curve characteristics using an animal model. The predicted breeding value (EBV) of the characteristics of the lactation curve of the cows from day 40 to 305 was predicted. The EBV of the production range (PR) and the slope of line in increasing phase (m40,Peak) of production curve of sires with higher survival EBV were lower than other sires (P < 0.05). The estimates of PL were independent of survival estimate. Therefore, the PR from 40th day after calving can be considered as a definition of PL because the lower the PR, the flatter is the milk production curve. Genetic evaluation of young bulls for survival needs the data of death or culling of their daughters. Therefore, the bulls can genetically be evaluated for survival according to the PL and m40,Peak of FL information of their daughters. [ABSTRACT FROM AUTHOR]

This study investigated the age at first calving in Holstein heifers and its impact on various production parameters. A sample of 737 Holstein heifers born between 2015 and 2018 and finishing their first lactations between 2018 and 2020 was included. Cluster analysis revealed three groups based on age at first calving: high precocity, medium precocity and low precocity. Medium-precocity group exhibited the highest 305-day milk yield and peak milk production. Additionally, the same group demonstrated superior mean production per lactation, 305-day milk protein content, and 305-day milk yield. The lowest somatic cell count was found in the low-precocity group. In conclusion, medium-precocity cows showed better results such as higher 305-day milk yield and peak milk production. [ABSTRACT FROM AUTHOR]

The purpose of the current study was to investigate the effect of gestation length (GL) on productive performance, and the incidence of calving and reproductive diseases in Holstein dairy cows. In total, 3800 Holstein singleton cows (2000 heifers and 1800 cows) from two commercial dairy farms were used. The average gestation length for 3800 cows was 276 ± 6 d. Cows with GL shorter or longer than 3 SD from the mean were removed and considered outliers. This process led to the elimination of 20 cows from the 3800 cows enrolled in the study. Therefore, 3780 cows (1994 heifers and 1786 cows) remained for data analysis, with a range of GL between 258 and 294 d. The mean of GL for the remaining 3780 cows in the study was 276 ± 5 d, which were classified as short (SGL; more than 1SD less than the population mean, mean = 267, range 258–270 d), average (AGL; population mean ± 1SD, mean = 276, range 271–281 d), and long (LGL; more than 1SD greater than the population mean, mean = 284, range 282–294 d) gestation length. In primiparous cows, the incidence of stillbirth, retained placenta, metritis, and clinical endometritis were higher in the SGL cows than in the AGL cows, but the incidence of dystocia was similar across groups. In multiparous cows, the incidence of dystocia, retained placenta, and metritis were higher in the SGL cows than in the AGL cows, and the incidence of stillbirth was higher in the SGL and LGL cows than in the AGL cows. In primiparous cows, milk yield was not different across groups. However, in multiparous cows, the SGL cows had lower milk yield than the AGL cows. In primiparous cows, the SGL cows had lower colostrum production than the AGL cows, but in multiparous cows, there was no difference in colostrum production across groups. In general, cows with either short or long gestation length had impaired health and production, but this impact was more pronounced in cows with short gestation length. • The primiparous cows with short gestation length had higher incidence of stillbirth, retained placenta, metritis, and endometritis. • The multiparous cows with short gestation length had higher incidence of dystocia, retained placenta and metritis. • The incidence of stillbirth was higher in short and long gestation length cows than average gestation length cows. • The multiparous cows with short gestation length had lower milk yield than cows with average gestation length. • The primiparous cows with short gestation length had lower colostrum than cows with average gestation length. [ABSTRACT FROM AUTHOR]

The research proposed to evaluate the influence of the seminal material on milk production. Also was studied seminal material from different countries in order to determinate if the origin influence as well, genotype - environment correlation. The study was carried out on Holstein cows from Romania and data provided by Holstein Ro association. For sires values were consulted international website, recognized worldwide, like dairybulls.com, where the data are published by CDCB (Council on Dairy Cattle Breeding) or INTERBULL. The cows that took part at the research were all at their first lactation, from farms located throughout Romania. After establishing the groups of contemporaries, the real production achieved on standard lactation was compared with the surplus amount of milk due to the sire's values, in order to see if the expected result was achieved. For avoiding error conclusions were compared cows from the same farm, same sire, in that working hypothesis the feeding influence is removed. [ABSTRACT FROM AUTHOR]

In the present socio-economic context and environmental sustainability trend it is a high accent on milk production related with increased milk yield per cow. This study aims to explore the influence of milking technology for Holstein dairy cows on "milk" productivity and quality, at the farm level. Over three consecutive years, the dynamics of milk quantity and its quality parameters (% fat, % protein, somatic cells count, % dry matter) were followed. The values of these parameters changed as a result of the increase of milkings frequency per day, from two in the first year of study, to three milkings per day in the following years. The results were statistically analyzed, from the point of view of significance, using the Fisher and Student tests. The comparative analysis of the 3 years of production shows that milk production had a positive evolution, both in terms of quantity and quality. [ABSTRACT FROM AUTHOR]

Simple Summary: Animal breeding is one of the most profitable human activities. The ultimate goal is to join genetically high performance and good health. In the last decades, the study of genetic control of important traits on the molecular level has been launched. In the study of milk performance, major genes, namely those for milk proteins, are the focus of much research. Here, we studied the polymorphisms of CSN1S1 and LALBA genes and their associations with milk performance and quality. Also, other non-genetic effects were evaluated. The polymorphisms influenced milk, fat, and protein yield percentages in the second lactation but their effects in the first lactation were not significant. The technological properties of milk were not influenced. The effect of the farm was significant in most cases. Breed influenced milk performance but did not influence technological properties. Changes in lactose content reflect the health of the udder. We evaluated the influence of CSN1S1 and LALBA polymorphisms on cow's milk yield and quality. The analysis was done on Czech Simmental and Holstein cows. Non-genetic factors were included as well. CSN1S1 did not influence the milk performance in the first lactation. In the second lactation, cows with the BB genotype had significantly higher milk, protein, and fat yields than BC. The differences between LALBA genotypes were non-significant in the first lactation, while in the second lactation, the fat percentage was significantly higher in BB than in AB. The farm significantly influenced milk, protein, and fat yields in both the first and second lactations and fat percentage in the first lactation. The effect of CSN1S1 and LALBA genotypes on the milk technological quality was non-significant. Breed did not influence any of the evaluated technological traits and SCS. The ethanol test was not influenced by farm, season, lactation phase, protein percentage, breed, or non-fat solids percentage. Farm, season, and protein percentage significantly influenced milk fermentation ability, renneting, and SCS. The lactose content is a good indicator of udder health. [ABSTRACT FROM AUTHOR]

This study aimed to find the parsimonious random regression model (RRM) to evaluate the genetic potential for milk yield (MY), fat content (FC), and protein content (PC) in Tunisian Holstein cows. For this purpose, 551,139; 331,654; and 302,396 test day records for MY, FC, and PC were analysed using various RRMs with different Legendre polynomials (LP) orders on additive genetic (AG) and permanent environmental (PE) effects, and different types of residual variances (RV). The statistical analysis was performed in a Bayesian framework with Gibbs sampling, and the model performances were assessed, mainly, on the predictive ability criteria. The study found that the optimal model for evaluating these traits was an RRM with a third LP order and nine classes of heterogeneous RV. In addition, the study found that heritability estimates for MY, FC, and PC ranged from 0.11 to 0.22, 0.11 to 0.17, and 0.12 to 0.18, respectively, indicating that genetic improvement should be accompanied by improvements in the production environment. The study also suggested that new selection rules could be used to modify lactation curves by exploiting the canonical transformation of the random coefficient covariance (RC) matrix or by using the combination of slopes of individual lactation curves and expected daily breeding values. [ABSTRACT FROM AUTHOR]

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Simple Summary: The effect of increasing metabolizable protein supply (85%, 100%, and 115% of requirement) on milk production, energy and nitrogen (N) utilization, and enteric methane (CH4) emissions of Ayrshire and Holstein cows was investigated in this study. Although Ayrshire cows consumed less dry matter and produced less milk than Holstein cows, feed efficiency (kg energy-corrected milk/kg of dry matter intake), CH4 emission intensity (g/kg milk), and urinary N excretion (g/100 g N intake) did not differ between the two breeds. Energy-corrected milk increased and N use efficiency (g N milk/100 g N intake) decreased with increasing metabolizable protein supply, whereas CH4 emissions were unaffected by metabolizable protein supply. In North America, the nutrient requirements of dairy cattle are predicted using the Cornell Net Carbohydrate and Protein System (CNCPS) or the National Research Council (NRC). As Holstein is the most predominant dairy cattle breed, these models were developed based on the phenotypic, physiological, and genetic characteristics of this breed. However, these models may not be appropriate to predict the nutrient requirements of other breeds, such as Ayrshire, that are phenotypically and genetically different from Holstein. The objective of this study was to evaluate the effects of increasing the metabolizable protein (MP) supply using CNCPS on milk performance, ruminal fermentation, apparent total-tract digestibility, energy and N utilization, and enteric methane production in Ayrshire vs. Holstein lactating dairy cows. Eighteen (nine Ayrshire; nine Holstein) lactating cows were used in a replicated 3 × 3 Latin square design (35-d periods) and fed diets formulated to meet 85%, 100%, or 115% of MP daily requirement. Except for milk production, no breed × MP supply interaction was observed for the response variables. Dry matter intake (DMI) and the yields of energy-corrected milk (ECM), fat, and protein were less (p < 0.01) in Ayrshire vs. Holstein cows. However, feed efficiency and N use efficiency for milk production did not differ between the two breeds, averaging 1.75 kg ECM/kg DMI and 33.7 g milk N/100 g N intake, respectively. Methane yield and intensity and urinary N also did not differ between the two breeds, averaging 18.8 g CH4 /kg DMI, 10.8 g CH4 /kg ECM, and 27.6 g N/100 g N intake, respectively. Yields of ECM and milk protein increased (p ≤ 0.01) with increasing MP supply from 85% to 100% but no or small increases occurred when MP supply increased from 100 to 115%. Feed efficiency increased linearly with an increasing MP supply. Nitrogen use efficiency (g N milk/100g N intake) decreased linearly (by up to 5.4 percentage units, (p < 0.01) whereas urinary N excretion (g/d or g/100 g N intake) increased linearly (p < 0.01) with an increasing MP supply. Methane yield and emission intensity were not affected by MP supply. This study shows that feed efficiency, N use efficiency, CH4 (yield and intensity), and urinary N losses did not differ between Ayrshire and Holstein cows. Energy-corrected milk yield and feed efficiency increased, but N use efficiency decreased and urinary N losses increased with increasing dietary MP supply regardless of breed. Ayrshire and Holstein breeds responded similarly to increasing MP levels in the diet. [ABSTRACT FROM AUTHOR]

Simple Summary: Quantitative characteristics of animals such as traits of productivity, reproduction, physical development, longevity, etc. are influenced by many genes, of which each individual gene has a small effect on the overall expression. There are small differences between these genes, and the number of gene combinations in the group is large, which affects the continuous variability of quantitative traits. These traits are also significantly influenced by non-genetic factors that modify their final expression. The evaluation of genetic parameters (heritability and genetic correlations) of quantitative traits is of crucial interest for breeders, and therefore, these parameters are the main imperative in selection. The genetic progress of quantitative traits is achieved by increasing the accuracy of the assessment of genetic variance and selection accuracy, which depends, among other things, on the estimated genetic correlations between the selected traits. The goal of this research was to evaluate genetic variances and covariances of milk yield, longevity, and type traits of the Holstein breed in Serbia in order to assess their role in practical breeding as well as the importance of genetic parameters in setting and revising already existing breeding goals and selection programs. In this study, the authors focused on the evaluation of the genetic parameters of longevity, milk yield traits, and type traits in dairy cattle populations in the Republic of Serbia. The total dataset used consisted of production records and pedigree data for 32,512 Holstein cows that calved from 1981 to 2015. The animal model was applied to determine the variance and covariance components and genetic parameters of the analyzed traits by applying the restricted maximum likelihood (REML) approach and using the programs VCE6 and PEST. The heritability of longevity traits was estimated using the Survival Kit V6.0 software package. Variance and covariance were estimated for five production traits: milk yield (MY), fat yield (FY), protein yield (PY), milk fat content (MC), and protein content (PC), and three longevity traits: length of productive life (LPL), lifetime milk yield (LMY), and the number of lactations achieved (NL) as well as for 18 standard type traits. Heritabilities for the milk, fat, and protein yield traits were 0.20 (MY), 0.15 (FY), and 0.19 (PY), respectively. The estimated coefficients of heritability for the longevity traits were higher when using the Weibull proportional hazards model compared to the traditional linear methods and ranged from 0.08 for NL to 0.10 for LPL. Heritability values for the type traits varied from a low of 0.10 (RLSsv—rear legs set–side view) to medium values of 0.32 (ST-stature). Genetic correlations were found between MY and the following longevity traits: LPL, LMY, and NL with values of −0.18, −0.11, and −0.09, respectively. Genetic correlations were found between MY and a number of linear type traits and varied from 0.02 (between MY and RUH-rear udder height) to 0.28 (between MY and FUA-fore udder attachment). Genetic correlations between the 18 investigated type traits ranged from −0.33 between TL (top line) and RTP (rear teats position) to 0.71 between AN (angularity) and RUH (rear udder height). Genetic correlations between most linear type traits and longevity traits (LPL, LMY, and NL) were generally negative and very low. The highest positive genetic correlation was found between UD and LPL (rxy = 0.38). [ABSTRACT FROM AUTHOR]

The udder of first-born Holstein (n = 86) and Ukrainian Black-and-White dairy (UBWD) breed (n = 112) in the Burynske herd of Sumy region of the Ukraine was evaluated. The following morphological udder traits were measured, cm: girth, length, width, depth of the front part, and distance from bottom to floor, front quarter length, conditional volume, length, diameter and shape of teats, distance between teats. Heritability coefficients of udder measurements cows of Holstein (h² = 0.125-0.488) and UBWD (h² = 0.113-0.464) breed testified that most udder traits are controlled by heredity. Correlation between udder measurements and milk yield for 305 lactation days cows of both breeds was -0.054... 0.568 in Holstein and -0.075... 0.493 in UBWD breed. A negative relationship was found between distance from udder bottom to floor and milk yield, -0.295 and -0.258, respectively. Heritability level and correlations of measurements with milk yield will allow obtaining genetic progress of udder improvement because of indirect selection. [ABSTRACT FROM AUTHOR]

The aim of the present study was to assess the effect of serum calcium (Ca) status in the early postpartum period on the quantity and quality of colostrum, milk production, and the health of Holstein dams and their calves. One hundred multiparous Holstein cows were enrolled in this study. To determine serum Ca status, blood samples were taken at 1 and 4 days in milk (DIM). Cows were categorized into 1 of 4 groups based on their serum Ca concentrations: normocalcemic (CON; Ca >1.87 at 1 DIM and >2.10 mmol/L at 4 DIM, n = 36), transient SCH (TSCH; Ca ≤1.87 at 1 DIM and >2.10 mmol/L at 4 DIM, n = 14), persistent SCH (PSCH; Ca ≤1.87 at 1 DIM and ≤2.10 mmol/L at 4 DIM, n = 15), or delayed SCH (DSCH; Ca >1.87 at 1 DIM and ≤2.10 mmol/L at 4 DIM, n = 35). The ROC curve was utilized to determine the optimal cut-off value for serum total Ca, maximizing both sensitivity and specificity in predicting metritis. Metabolic disorders such as dystocia, retained placenta, and culling within 60 DIM were not affected by serum Ca status in the early postpartum period (P > 0.10). However, the incidences of metritis and endometritis were different based on the serum Ca status of the cows. The PSCH cows had a higher incidence of metritis than the CON cows (P = 0.05). Also, the DSCH cows tended to have an increased risk of metritis than the CON cows (P = 0.09). However, metritis incidence in the TSCH and CON cows was similar (P = 0.83). Cows with PSCH (P = 0.07) and DSCH (P = 0.10) tended to be at a higher risk for endometritis than the CON cows. But, the incidence of endometritis in the TSCH and CON cows was not different (P = 0.50). The TSCH cows had higher milk yield than the PSCH and DSCH cows (P = 0.05). However, milk yield was not different between the TSCH and CON cows and the PSCH and DSCH and CON cows. The serum Ca status of cows had no effect on colostrum volume and its quality, age and weight of weaning, and average daily gain of calves (P > 0.10). The proportion of calves experiencing failure of passive transfer (FPT) was greater in the PSCH group than in the CON group (P = 0.03). Also, the FPT tended to be higher in the DSCH calves compared to the CON calves (P = 0.10). However, the FPT in the TSCH and CON calves was not different (P = 0.83). The incidence of diarrhea tended to be higher in the PSCH and DSCH calves compared to the CON calves (P = 0.10). However, diarrhea incidence between the TSCH and CON calves was similar (P = 0.97). Overall, the findings of this study suggest that cows with TSCH showed better adaptation to lactation, experienced a lower occurrence of diseases and produced higher milk compared to PSCH and DSCH cows. Furthermore, despite the similar quantity and quality of colostrum across all groups, the PSCH and DSCH groups displayed a greater proportion of calves experiencing FPT and diarrhea in comparison to the TSCH group. • Cows with transient hypocalcemia (TSCH) produced more milk than persistent (PSCH) and delayed (DSCH) SCH cows. • Compared to normocalcemic cows (CON), cows with PSCH or DSCH were at higher risk for uterine diseases. • Serum Ca status after calving of cows had no effect on colostrum volume and its quality. • Diarrhea incidence was higher in the calves born from the PSCH or DSCH cows than calves born from the TSCH and CON cows. • The proportion of failure passive transfer was higher in the PSCH or DSCH calves than the TSCH and CON calves. [ABSTRACT FROM AUTHOR]

Background: No studies have been conducted evaluating sugarcane silage associated with both Lactobacillus plantarum and Pediococcus pentosaceus for lactating dairy cows. Objective: To evaluate diets containing different roughages with and without microbial inoculants on intake, digestibility and milk yield of medium-producing cows. Methods: A total of 15 Holstein cows distributed into a randomized block design were used. Dietary treatments were: 1) a corn silage-based diet (CS), 2) a fresh sugarcane-based diet (SC), 3) a sugarcane silage ensiled without inoculant (SS), 4) sugarcane silage ensiled with Lactobacillus buchneri (SSLB), and 5) sugarcane silage ensiled with Lactobacillus plantarum and Pediococcus pentosaceus (SSLP). Results: Digestible organic matter intake (DOMI) was lower (p

Ketosis is a major metabolic disorder that can lead to huge economic losses in postpartum dairy cows by influencing milk production and reproduction performance. Therefore, it is very important to understand the characteristics and significance of plasma GH levels and dynamic changes in postpartum dairy cows for finding pathogenesis of subclinical ketosis (SK). The present study aimed to determine the role of growth hormone (GH) from the onset of SK to the fifth week postpartum and to explain the variations in GH, and metabolic markers namely, β-hydroxybutyric acid (BHBA), non-esterified fatty acid (NEFA) and glucose (GLU) at early and later SK stages in postpartum Holstein cows. A 5-wk test and an intraday 12-h test were conducted in postpartum Holstein cows. Both tests were carried out every three hours from 10:00–22:00 for 7–14 days postpartum (12-h test: n = 16) to determine plasma concentrations of GH, BHBA, NEFA and GLU. The 5-wk test results showed that GH, BHBA and NEFA concentrations were significantly higher in the SK group during the five-weeks postpartum (p < 0.01); GLU concentration was significantly lower in the SK group (p < 0.01). Intraday 12-h test results revealed that the feeding time affected the plasma concentrations of GH, BHBA, NEFA and GLU. After 1-h of feeding time, GH concentrations decreased, while BHBA, NEFA and GLU concentrations increased. After 4-h of feeding time GH, BHBA and NEFA had the highest plasma concentrations, and GLU the lowest. In both experiments, GH was positively correlated with BHBA, NEFA, and negatively correlated with GLU. It can be suggested that GH has a potential role in development and aetiology of subclinical ketosis. [ABSTRACT FROM AUTHOR]

We fit the Wood's lactation model to an extensive database of test-day milk production records of US Holstein cows to obtain lactation-specific parameter estimates and investigated the effects of temporal, spatial, and management factors on lactation curve parameters and 305-d milk yield. Our approach included 2 steps as follows: (1) individual animal-parity parameter estimation with nonlinear least-squares optimization of the Wood's lactation curve parameters, and (2) mixed-effects model analysis of 8,595,413 sets of parameter estimates from individual lactation curves. Further, we conducted an analysis that included all parities and a separate analysis for first lactation heifers. Results showed that parity had the most significant effect on the scale (parameter a), the rate of decay (parameter c), and the 305-d milk yield. The month of calving had the largest effect on the rate of increase (parameter b) for models fit with data from all lactations. The calving month had the most significant effect on all lactation curve parameters for first lactation models. However, age at first calving, year, and milking frequency accounted for a higher proportion of the variance than month for first lactation 305-d milk yield. All parameter estimates and 305-d milk yield increased as parity increased; parameter a and 305-d milk yield rose, and parameters b and c decreased as year and milking frequency increased. Calving month estimates parameters a , b , c , and 305-d milk yield were the lowest values for September, May, June, and July, respectively. The results also indicated the random effects of herd and cow improved model fit. Lactation curve parameter estimates from the mixed-model analysis of individual lactation curve fits describe well US Holstein lactation curves according to temporal, spatial, and management factors. [ABSTRACT FROM AUTHOR]

Dairy cattle must allocate energy to milk production and reproduction. Therefore, understanding the environmental factors that affect conception rates in nulliparous and primiparous cows is helpful in appropriate feeding management strategies before and after calving. Accordingly, the aim of this study was to investigate the influence of environmental factors before and after the first calving on the conception rate, representing the starting point of milk production. The records of the first artificial insemination (AI) from Holstein nulliparous cows (n = 533,672) and primiparous cows (n = 516,710) in Hokkaido, Japan, were analyzed using separate multivariable logistic regression models. The mean conception rates for nulliparous and primiparous cows from 2012 to 2018 were 55.2 and 39.2%, respectively. In both nulliparous and primiparous cows, the conception rate of crossbreeding using Japanese Black (JB) semen was significantly higher than that for purebred Holstein breeding. The conception rate using sexed semen decreased in the warmer months only in nulliparous cows. Moreover, we grouped primiparous cows according to milk yield during peak lactation (PY; < 25, 25–30, 30–35, ≥35 kg) and the interval from calving to first insemination (CFI; < 60, 60–79, 80–99, ≥100 d), and evaluated their combined effect on the conception rate. Both PY and CFI strongly affected the conception rate in primiparous cows, which decreased with an increase in PY, even for the group with CFI ≥100 d; however, the conception rate increased for a CFI ≥60 d regardless of PY. Taken together, this study demonstrates the long-term effect of PY and an independent effect of CFI on the conception rate of cows. These results provide guidance for management to execute appropriate AI implementation strategies before and after lactation. [ABSTRACT FROM AUTHOR]

Our study, which investigates the factors affecting milk yield at metabolic and oxidative stress levels in Holstein breed cows raised in Aksaray Region, is the first at the regional level. It was aimed to perform biochemical and antioxidant screenings according to milk yield levels in healthy Holstein cows raised in the province, and thus, together with the determination of general metabolic parameters, the differences in total antioxidant and total oxidant levels according to milk yield were investigated. Glucose, total protein, albumin, globulin, total cholesterol, triglyceride, and calcium were analysed from blood samples taken from Holstein cows that have been determined to be healthy, in milk yield age in a province’ s enterprises were analysed by using commercial test kits in a semi-analyser device. Total antioxidant and total oxidant levels were analysed spectrophotometrically with commercial kits. Statistical analysis was made with Basic Statistics Xs Display Descriptive Statistics in Minitab 16 ready-made package program. Biochemical parameters studied in sera obtained from 5 different groups from the lowest to the highest were found to be statistically significant with a positive correlation. Total oxidant level, total antioxidant level and oxidative stress indices, in which the general oxidant status was screened, were found to be correlated with milk yield in proportion to the intense metabolic and physiological status of the animals and were found to be significant. With this study, the data obtained by eliminating a deficiency in this field both contribute to the literature knowledge in the scientific area and provide useful knowledge in the field.

Context: The economic efficiency of a dairy system is associated with the animal's productive and reproductive abilities. Therefore, selection criteria should include milk production and quality traits as well as traits related to health and fertility. Since such phenotypes can present non-normal distributions, the use of threshold models is appropriate to study the genetic variation of such traits. Aim: To estimate variance components for dairy production and functional traits in a Brazilian Holstein cattle population using linear and threshold models under a Bayesian approach. Methods: Data comprised 64 657 test-day records for milk yield (MY, kg/day), casein percentage (CP, % of milk) and subclinical mastitis incidence (SCM), along with 4460 records for sexual precocity (PREC) from 5439 cows. Both SCM and PREC were defined as binary traits. Genetic analyses were based on linear (for MY and CP) and threshold (for SCM and PREC) models using Bayesian estimation. Non-informative and informative priors were considered for variance components, and these models were compared using the deviance information criterion (DIC) and the absolute difference between DIC (Δ). Key results: Posterior means of heritability for MY, CP, SCM and PREC were 0.14, 0.39, 0.13 and 0.38 (based on non-informative priors) and 0.13, 0.27, 0.13 and 0.44 (considering informative priors), respectively. The model based on non-informative priors was better (lower DIC) for CP, whereas for PREC, the best model used informative priors. No differences between priors (Δ < 5) were observed for MY and SCM. Conclusions: Threshold models were adequate for the analysis of non-normally distributed traits. The use of informative priors can be beneficial if specification is based on results from similar databases and models. Due to their high genetic variation, CP and PREC can be considered as selection criteria in animal breeding programs. In turn, accurate genetic evaluation for MY and SCM will depend on the pedigree and the information from genetically correlated traits. Implications: Our study contributes to the understanding of the variation under important dairy production traits in a tropical Holstein population and provides information on the use of Bayesian threshold models as an appropriate method for the evaluation of non-normally distributed phenotypes. Threshold models were used to genetically evaluate sexual precocity (PREC) and subclinical mastitis incidence (SCM), while linear models were used to analyse milk yield (MY) and casein percentage. Both models allowed the precise estimation of the high genetic influence on PREC and CP (high heritability) and the important environmental contribution on SCM and MY (low heritability and high permanent environmental variance). These differences in heritability estimates imply that different genetic selection strategies should be considered for each trait. [ABSTRACT FROM AUTHOR]

Context: There is a large gap between developed and developing countries in the field of genetic evaluation of livestock animals. Introduction of genomic evaluation procedures and methods could contribute to reducing this gap. Aims: The goal of this study was to select a reference cow population for the Holstein breed in Tunisia. Specific objectives were to update adjustments for non-genetic factors affecting milk yield, estimate genetic parameters for milk yield, and predict cow breeding values. Methods: A BLUP animal model was used for 11 175 lactations recorded between 2012 and 2017 from 6251 dairy cattle raised in 33 Holstein dairy herds from three types of herds or production sectors. A pedigree file of 16 211 males and females was included in the genetic evaluation. Multiplicative adjustment factors were computed for age and month of calving, using adjusted 305 days in milk. Key results: Month of calving, age at calving and farm ownership were significant sources of variation for milk yield. Cows calving in autumn and early winter (September–January) yielded more milk than those calving in spring (February–May) by 430 kg, and summer (June–August) by 455 kg. Holstein cows in Tunisia reached their maximum milk yield during the fourth lactation. Average adjusted milk yield for days in milk, month and age of calving was 6621 ± 2883 kg. Heritability estimates of adjusted milk yield were 0.14 ± 0.02 for all seven lactations and 0.16 ± 0.03 for the three first lactations. Phenotypic correlations among lactations were all positive, ranging from 0.25 to 0.43. On the basis of two main traditional designs (extreme yield and top accuracy), 1000 cows were selected to form the Tunisian female reference population. Conclusion: The first step of genomic evaluation has been realised by forming a reference population from cows selected for adjusted milk yield production, based on their predicted breeding values and accuracies, using a BLUP animal model. Implication: In the absence of progeny testing and sufficient proven sires, a cow reference population could represent the alternative for implementing genomic selection in developing countries. A reference population of Holstein cows was selected for milk yield production, by using lactation records from Tunisian dairy herds and BLUP modelling. Following the steps described in this study, researchers in developing countries will be able to identify a reference population toward genomic evaluation even without a progeny testing scheme. [ABSTRACT FROM AUTHOR]

The study was conducted on 41-second lactation Holstein cows of German origin. The shelter type is a semi-open field type and the research period is 12 months. The activities in the first 100 days of lactation per day were 451.4 ± 133.5, and in the second 100 days, it was determined at 420.78 ± 118.0. The activities are divided into 3 parts within 24 hours (at night, during the day between two milkings, and in the evening). While there was no statistical difference between days 100 and 200 of lactation, the lowest activity was recorded at night and the highest activity during the day. Mean daily milk yield was 28.28 ± 3.86 kg for the first 100 days and 25.15 ± 3.61 kg for the following 100 days, and the difference was found to be significant (P<0.001). In order to investigate the influence of the daily activity numbers taken into account as factors on the milking parameters, 4 groups were formed for the 100th and 200th days. Accordingly, the effect of activity on milk conductivity, milking duration, and milk yield could not be determined in the first 100 days; its effect on milk flow rate proved significant (P<0.05). No effect of activity on milking parameters was observed in 200 days of lactation. It is assumed that the inclusion of the housing type, lactation number, and lactation period as well as the seasonal effect in activity studies in cows will contribute positively to animal welfare in herd management. [ABSTRACT FROM AUTHOR]

This study was planned to investigate the effect of zearalenone (ZEA), deoxynivalenol (DON) and Fumonisin B1 (FB1) on blood metabolites, milk yield, estrous activity, pregnancy rate and uterine health in 486 heads of Holstein dairy cows. For this purpose, the data collected from the animals were divided into the four periods as follows: feeding with non-contaminated diet for 30 days (pre-contamination period), contaminated diet for 60 days (contamination period), contaminated diet supplemented with mycotoxin adsorbent for 30 days (adsorbent period) and the diet after removing the contaminated feedstuffs for 30 days (non-contamination period). Each feedstuff was analysed in contamination period and at the beginning of the non-contamination period to determine the presence or absence of ZEA, DON and FB1 in the diet. The blood metabolic profile was assessed in 21 animals in 1-10 days in milk, selected through cluster random sampling method while milk yield, estrous activity, pregnancy rate and prevalence of metritis/endometritis were compared among all four periods. The milk yield (P≤0.001) and milk fat (P≤0.05) in the contaminated period were low as compared to other periods. The concentrations of beta-hydroxybutyric acid (p≤0.001), non-esterified fatty acids (P≤0.05), gamma-glutamyl transferase (P≤0.05), and blood urea nitrogen (P≤0.001) parameters were significantly higher, while the glucose (P≤0.001) and triglycerides (P≤0.05) were lower in the contamination period, as compared to adsorbent and non-contamination periods. The pregnancy rate through artificial insemination decreased significantly during the contamination period (P≤0.05) as compared to pre-contamination period. The overall pregnancy rate in the pre-contamination period was also significantly decreased as compared to the adsorbent and non-contamination periods (P≤0.001). The percentage of type III anestrus were significantly lower during the non-contamination period (P≤0.05). The percentages of cows with metritis during the non-contamination period was significantly lower (p≤0.05) as compared to the contamination period. It was concluded that the routine feed analysis was necessary to determine the presence of ZEA, DON and FB1. Moreover, mycotoxin binder supplementation and/or removing contaminated feedstuffs from the diet under mycotoxicosis conditions may prevent the severe negative energy balance and improve the milk yield and fertility parameters. [ABSTRACT FROM AUTHOR]

Аssessment studies of sires by indicators of lifelong performance of their daughters were performed in the herd of the raising Ukrainian Red-and-White dairy breed of the Mayak agricultural company, Zolotonosha district, Cherkasy region in Ukraine. The significant influence of bull-breeders on the lifespan, rates of productive use and lifelong performance of offspring, which was determined by personal inheritance of breeders, has been established. Changeability of daughters’ lifespan of estimated breeders differed over a wide range – 3.005-3.462 days, terms of productive use – 2.188-2.626 days, and number of used lactations from 2.5 to 5.6. By the best rates of lifelong dairy productivity was differed the progeny of breeders with higher lifespan and productive use. The highest yield for one day of life and productive use was obtained by offspring of sires, which had higher rates of milk production during the first lactation and shorter longevity. The level of relationship between the yields for 305 days and lifespan indicators of sire's offspring differed by significant variability from moderate negative with longevity (r=-0.244) to positive with productive use (r=0.259). Obtained correlations between milk yield value for the first lactation and lifelong productivity of the offspring of evaluated breeders by the degree (r=0.055–0.659) and reliability (P<0.05– 0.001) were characterized by positive and reliable values. This was certifying the possibility of milk yield during the first lactation to be a predictor of cows’ lifelong production. The high productivity of daughters of the estimated breeders during the first lactation did not provide a similar growth in their economic use, but will guarantee lifelong milk productivity. The offspring of sires of domestic selection were not inferior by the productive longevity indicators to the offspring of purebred Holstein breeders. [ABSTRACT FROM AUTHOR]

The aim of the study was to analyse beta-hydroxybutyric acid concentration in the blood (BBAC) and milk (MBAC) at postpartum week 2 (PPW2) and week 4 (PPW4) in Holstein (n=216, 8 farms), Montbeliard (n=23), Simmental (n=38) and Holstein/Montbeliard Crossbreed (n=23, BBAC only). Furthermore, the prevalence of subclinical ketosis (SCK) and its association with postpartum health disorders (PPHD), body condition score (BCS) and average daily milk yield in 90 days in milk (90DIM) were evaluated in Holstein. Holstein-Crossbreed and Montbeliard had significantly lower postpartum BBAC than others. Primiparous Montbeliard and Holstein had significantly higher MBAC at PPW2 than PPW4. Cows having BCS2 and 4 at calving had higher MBAC at PPW2 and 4 that was associated significantly with metritis and multiple diseases. Holstein with BCS4 at calving had higher BBAC at PPW2 and 4. SCK prevalence in the blood (BBAC≥1.2 mmol/L, BSCK) and milk (MBAC=100 µmol/L, MSCK1), (MBAC≥200 µmol/L, MSCK2) and (MBAC≥100 µmol/L, MSCK1/2) was 8.3, 11.8, 5.8 and 17.3% at PPW2 and 4.7, 4.9, 6.9 and 11.9% at PPW4 in Holstein respectively. Holstein with SCK was more likely to develop PPHD in 90DIM. MSCK1 and MSCK1/2 did not associate milk production loss in Holstein. Holstein with BSCK and MSCK2 at PPW2 had a 6.7 kg loss of average daily milk yield in 90DIM. Culling rate was 3.7% in Holstein and MSCK2 positive Holstein at PPW2 was significantly more likely to be culled (25%, Odds:11.2, P<0.05) in 90DIM. In conclusion, cows having BCS2 and 4 at calving had higher MBAC and BBAC at PPW2 and 4. Holstein-Crossbreed and Montbeliard had much lower postpartum BBAC than Holstein and Simmental. BSCK and MSCK2 caused signifi cantly risk factor for PPHD, culling rate and milk production in Holstein. [ABSTRACT FROM AUTHOR]

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Background: Variables associated with body tissue mobilization place dairy cows at greater risk of reproductive failure. Objective: To investigate the association between blood metabolites and body condition score (BCS) at the beginning of lactation and the reproductive efficiency and milk yield of Holstein cows in a hot environment. Methods: In total, 165 Holstein cows were selected for the study from which blood samples were taken to determine the concentration of various blood metabolites and their association with the reproductive efficiency and milk yield. Results: Cows with serum β-hydroxybutyrate (BHBA) ≤0.8 mmol/L one week postpartum were 3.3 times more likely to become pregnant at first service, and 2.2 times more likely to become pregnant before 80 d postpartum than cows with higher serum BHBA levels. The odds (OR 2.7; 95% CI 1.3–5.4; p15 mg/dL, creatinine 0.40 units of BCS loss during the first 30 d postpartum were critical threshold that predicted the likelihood of 305-d milk yield higher than 10,500 kg. Conclusions: Serum BHBA and creatinine one wk after calving as well as BCS 30 and 60 d post-calving provided reasonably accurate cut-off screening values to discriminate cows with better reproductive performance and higher 305-d milk yield.

Objective: This study was conducted to obtain an objective index that can be quantified and used for establishing an animal welfare certification standard in Korea. For this purpose rumen pH, ruminating time, milk yield, milk quality, and blood components of cows reared in farms feeding high forage level (90%) and farms feeding low forage level (40%) were compared. Methods: Data on rumen pH, rumination time, milk yield, milk fat ratio, milk protein ratio, and blood metabolism were collected from 12 heads from a welfare farm (forage rate 88.5%) and 13 heads from a conventional farm (forage rate 34.5%) for three days in October 2019. Results: The rumination time was longer in cattle on the welfare farm than on the conventional farm (p<0.01), but ruminal pH fluctuation was greater in the cattle on conventional farm than the welfare farm (p<0.01). Conventional farms with a high ratio of concentrated feed were higher in average daily milk yield than welfare farms, but milk fat and milk production efficiency (milk fat and milk protein corrected milk/total digestible nutrients) was higher in cattle on welfare farms. Blood test results showed a normal range for both farm types, but concentrations of total cholesterol and non-esterified fatty acid were significantly higher in cows from conventional farms with a high milk yield (p<0.01). Conclusion: The results of this study confirmed that cows on the animal welfare farm with a high percentage of grass feed had higher milk production efficiency with healthier rumen pH and blood metabolism parameters compared to those on the conventional farm. [ABSTRACT FROM AUTHOR]

The aim of this study is to estimate lactation milk yield of Holstein cattle using first calving age, lactation period, and service period with (ANFIS) adaptive neuro-fuzzy inference system. The input variables for the system in the study were first calving age, lactation period, and service period. The output variable from the system was lactation milk yield. Predicted values obtained from the ANFIS were compared with the observed values. Twenty-seven rule functions are used to obtain the best model and 1000 epochs are used to estimate the accuracy of the training and testing error. The relations between the output and input variables are shown with 3D graphics. R2, RMSE, and MAPE evaluation criteria were used to check the accuracy of the system's estimations. As a result, ANFIS estimates of lactation milk yield were quite close to the observed values and a positive correlation (r: 0.848) was found between them. The results showed that ANFIS can be successfully applied to estimate the lactation milk yield. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effects of κ-casein, β-lactoglobulin, prolactin, and DGAT1 (diacylglycerol acyltransferase1) gene polymorphisms on milk yields in Holstein cows raised in Antalya province, Turkey. A total of 517 cows were genotyped by the PCR-RFLP method to detect κ-casein/HinfI, β-lactoglobulin/HaeIII, prolactin/RsaI, and DGAT1/Cfr1 polymorphisms. In the study, two types of alleles were identified as A and B for κ-casein, β-lactoglobulin, and prolactin loci, while K and A alleles were detected for DGAT1 locus. The frequencies of A and B allele were calculated as 0.8279 and 0.1721 for κ-casein, 0.4662 and 0.5338 for β-lactoglobulin, 0.8762 and 0.1238 for prolactin, respectively. The frequencies of the K and A allele were 0.6441 and 0.3559 for DGAT1. The studied population was found to be in Hardy-Weinberg equilibrium for all of the loci. Association analysis revealed a significant effect of prolactin-RsaI polymorphism on milk yield (p < 0.05) in which animals with the B allele showed superior value than the A allele. On the other hand, no statistically significant relation effects of κ-casein-HinfI, β-lactoglobulin-HaeIII, and DGAT1-CfrI polymorphisms on milk yield were observed (p > 0.05). It would be beneficial to increase the number of studies that determine the variation of existing genes and investigate the effects of these polymorphisms on milk yield characteristics in Holstein cattle. Thus, obtained results can be used as a selection criterion in marker-assisted selection programs. [ABSTRACT FROM AUTHOR]

Only a few, principal, weather stations in Japanese prefectures have the daily humidity records required to calculate the temperature–humidity index (THI) as a dairy cow heat-stress indicator. We compared three heat-stress indices: (1) THI calculated from daily average temperature and daily relative humidity at a principal weather station (PTHI); (2) daily average temperature at each herd’s closest local weather station (TEMP); and (3) THI calculated from daily average temperature at each herd’s closest local weather station and daily relative humidity at the principal weather station (HTHI). We used daily records from 532 provincial weather stations and test-day records of milk production from Days 6 to 305 post-first-calving in Holsteins to compare the indices as indicators of heat-stress effects on milk yield and somatic cell score (SCS). The models used the BLUPF90 package to analyze the effects of herd– year, calving age, days in milk, and PTHI, TEMP, or HTHI. We estimated each model’s mean square error (MSE) and compared suitabilities among indices for each trait. TEMP heat-stress thresholds were 〜18°C (milk yield) and 15–20°C (SCS). The MSE of the HTHI model was the smallest, but no significant differences were found among the indices for milk yield. [ABSTRACT FROM AUTHOR]

Background: No studies have been conducted evaluating sugarcane silage associated with both Lactobacillus plantarum and Pediococcus pentosaceus for lactating dairy cows. Objective: To evaluate diets containing different roughages with and without microbial inoculants on intake, digestibility and milk yield of medium-producing cows. Methods: A total of 15 Holstein cows distributed into a randomized block design were used. Dietary treatments were: 1) a corn silage-based diet (CS), 2) a fresh sugarcane-based diet (SC), 3) a sugarcane silage ensiled without inoculant (SS), 4) sugarcane silage ensiled with Lactobacillus buchneri (SSLB), and 5) sugarcane silage ensiled with Lactobacillus plantarum and Pediococcus pentosaceus (SSLP). Results: Digestible organic matter intake (DOMI) was lower (p<0.05) in cows fed SSLB (9.77 kg day-1) when compared with cows fed CS (13.29 kg day-1) and SSLP (12.42 kg day-1). Ensiling of sugarcane increased intake of neutral detergent fiber (NDF) compared to SC (mean of 6.00 kg day-1 versus 4.97 kg day-1; p<0.05). Dry matter digestibility was greater (p<0.05) in CS (77.80%) compared with diets based on sugarcane silage, whereas NDF digestibility was lower for treatments with sugarcane (p<0.05). Milk yield was similar among CS (27.99 kg), SC (25.59 kg), and silages with additives (25.47 and 27.07 for SSLB and SSLP, respectively). Cows fed CS produced more fat-corrected milk (25.89 kg) than those fed sugarcane-based diets (p<0.05). Conclusions: Fresh sugarcane or sugarcane silage with additives can be used as a roughage source for dairy cows producing up to 23.43 kg d-1 fat-corrected milk, considering the total diet is properly balanced. [ABSTRACT FROM AUTHOR]

The present research proposed to present the dynamics of urea in Holstein cows milk (as ml/dl), in order to evidence and optimize the main factors affecting this parameter. Large amount of data, including Holstein farms along the whole country was included in the study. Statistical results proved that the feeding level of protein is a main factor influencing milk urea content. Protein intake is highly related to milk market price, therefore large differences in milk urea were revealed between hot and cold season (from 40 mg/dl in the hot season to 18 mg/dl in the cold season). Relation between milk urea level, reproduction indices and the productive life was also studied. The most affected indicator by urea excess was the calving - interval (39 mg/dl - CI of 435 days). As a result, we recommend an interval between 22 - 32 mg/dl, in order to optimize milk yield and quality, as well as the reproductive parameters and longevity. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the relationships between body weight (BW) and milk yield, and post-partum BW and their changes during parity and stage of lactation in Holstein cows. This study was conducted on a private dairy cattle farm in Kastamonu province in the Mid-Black Sea Region of Turkey. The study material included 2133 records from 273 Holstein cows calved between 2016 and 2017 years. Parity (from 1 to 5) and stage of lactations (from 1 to 10) were used to be environmental factors affecting traits. The effect of parity and stage of lactation on BW and milk yield were significant (P<0.05). BW and milk yield increased with advancing lactation until the fourth parity, then declined in the fifth parity. The lowest BW was observed in the first two months of lactation, and it increased linearly with following lactation periods. Milk yield was low in the first month of lactation and then decreased linearly until the end of lactation. Correlations between BW and milk yield were all positive and ranged from 0.201 to 0.588. BW changes in early to mid-lactation were phenotypically correlated with milk yield. Finally, based on the findings in present study, it is suggested that monitoring BW change in early and mid-lactation can be used as a management tool to improve the milk yield in dairy herds. [ABSTRACT FROM AUTHOR]

There are studies investigating the relationship between bGH gene AluI polymorphism and milk yield in bovine breeds. In the presented study, the relationship between different genotypes and lactation milk yields was determined by analyzing bGH-AluI genotype and allele frequencies in Holstein breed by meta-analysis method. The study material consisted of studies investigating bGH-AluI polymorphisms that are effective on milk yield in Holstein breed. According to the determined criteria, allele and genotype frequencies of 4583 samples in 20 studies selected from 35 studies and milk yields of 932 samples in 6 studies in which milk yields were calculated according to genotypes were included in the meta analysis. In the study, meta analyzes LL, LV and VV genotypes and L and V alleles and lactation milk yields were performed for bGH gene. The study samples were proved to be unbiased with the Begg and Mazumdar Rank Correlations test and funnel plot. As a result of the study, high heterogeneity was determined between the investigated studies concerning all genotypes (LL, LV and VV) and allele frequencies (L and V), thus random effect model was used. Meta analyzes were done with Comprehensive Meta-Analysis Software (CMA). According to the random effect model, pooled ratios in LL, LV and VV genotypes are 0.710, 0.260 and 0.030; pooled ratios for L and V allele frequencies were calculated as 0.818 and 0.182 and were found statistically significant (P

Background: Somatic cell score is an important parameter to predict milk quality and health of cows. However, in countries like Brazil, this trait is still not selected on a large scale, and no genetic parameters are reported in the literature. Objective: To estimate the variance components and genetic parameters for somatic cell score, milk yield, fat yield, protein yield, fat percentage, and protein percentage in Holstein cows. Methods: Records from 56,718 animals were used to estimate variance components, heritability, and genetic correlations using a multi-trait animal model by the REML method. Results: The heritability estimates were 0.19 for somatic cell score, 0.22 for milk yield, 0.26 for fat yield, 0.18 for protein yield, 0.61 for fat percentage, and 0.65 for protein percentage. The estimates of genetic correlations among analyzed traits ranged from -0.50 to 0.82. Conclusion: The low heritability observed for somatic cell score indicates that selection for this trait should result in benefits related to animal health and milk quality, but only in the long term. The low correlation between productive traits and somatic cell score indicates that inclusion of somatic cell score in animal breeding programs does not interfere negatively with the genetic selection for milk yield or solids.

Background: Variables associated with body tissue mobilization place dairy cows at greater risk of reproductive failure. Objective: To investigate the association between blood metabolites and body condition score (BCS) at the beginning of lactation and the reproductive efficiency and milk yield of Holstein cows in a hot environment. Methods: In total, 165 Holstein cows were selected for the study from which blood samples were taken to determine the concentration of various blood metabolites and their association with the reproductive efficiency and milk yield. Results: Cows with serum β-hydroxybutyrate (BHBA) ≤0.8 mmol/L one week postpartum were 3.3 times more likely to become pregnant at first service, and 2.2 times more likely to become pregnant before 80 d postpartum than cows with higher serum BHBA levels. The odds (OR 2.7; 95% CI 1.3–5.4; p<0.01) of a cow getting pregnant at first service were higher in cows with serum creatinine levels higher than 2.0 mg/dL one week postpartum than cows with lower blood levels of this metabolite. The BCS at 30 and 60 d postpartum that predicted pregnancy at first service and pregnancy to all services was 3.0. Blood urea nitrogen >15 mg/dL, creatinine <1.8 mg/dL, total protein ≤5.0 mg/dL one week postpartum, and >0.40 units of BCS loss during the first 30 d postpartum were critical threshold that predicted the likelihood of 305-d milk yield higher than 10,500 kg. Conclusions: Serum BHBA and creatinine one wk after calving as well as BCS 30 and 60 d post-calving provided reasonably accurate cut-off screening values to discriminate cows with better reproductive performance and higher 305-d milk yield. [ABSTRACT FROM AUTHOR]

The aim of this study is to compare the pregnancy rates by applying embryo transfer to the cows which are not pregnant and should be removed from herd as repeat breeder. In this study, 87 randomly selected Holstein cows utilized. The repeat breeder cows (n=45) were selected from at least one giving birth, having regular sexual cycle, missing clinical worsening into genital organ and not displaying an abnormal discharge. On the other hand, it was selected from nonpregnant cows which inseminated artificially at least 3 times or more. Besides, cows that used as the control group (n=42) were selected from the cows without any artificial insemination postnatally. The PGF2α application was performed to all recipient cows which are considered to benefit from as a recipient in control and testing groups just 24 days before the flushing day. After this application, the cows showing estrous symptoms were recorded and determined as candidate recipients. The pregnancy rates were 35.6% and 50% for testing and control groups, respectively and the difference between the groups was significant (P<0,05). As a result, even this difference between the groups it has been concluded that embryo transfer can be used to conceive especially for high-yielding cows as a treatment method for repeat breeder cows. Thereby, embryo transfer from the cows with high superior characteristics to the high milk yielding cows which have infertility problems can economically be beneficial by utilizing the high milk yield in the later lactation without any replacement cost. [ABSTRACT FROM AUTHOR]

Brachyspina syndrome (BS) is a rare monogenic autosomal recessive hereditary disorder of the Holstein Fresian breed caused by a deletion of 3.3Kb in the Fanconi anemia complementation group I (FANCI) gene on BTA-21, which leads to a frame-shift and premature stop codon. Some of the consequences of BS are the reduction of the fertility rate and milk production. This study developed a simple, sensitive, rapid cost-effective assay method based on real time PCR and melting curve analysis for the detection of BS carrier animals. Sixty-eight normal homozygous and four heterozygous carrier genotypes were detected and confirmed through traditional PCR-electrophoresis analysis. We concluded that the assay we have developed proved to be a reliable, highly precise and low-cost tool, which could be used to monitor the presence of the BS mutation in uruguayan Holstein breed. [ABSTRACT FROM AUTHOR]

The study aimed to investigate the association between teat-end hyperkeratosis (THK) and somatic cell count (SCC) and to assess the effect of SCC on milk yield, fat, and protein percentages of Holstein cows. A total of 740 udder quarters of 185 Holstein cows kept in three commercial herds in Egypt were enrolled in the study from May to September 2019. Foremilk samples were collected from udder quarters for assessing milk SCC, fat, and protein percentages. On the same cows, a digital picture of each teat end orifice was taken with a digital camera. Cows' teats were assessed for THK and classified into two different groups of hyperkeratosis; mild and severe THK. SCC was converted to five classes of somatic cell score (SCS). Simple linear regression was performed to determine the loss of milk yield, fat, and protein percentages. SCC was significantly affected by THK (p<0.0001). About 57% of teats were classified as mild THK and 43% as severe THK. The teats with severe THK recorded higher SCC in milk. It was observed that SCS had a significant effect on fat and protein percentages (p<0.0001). A similar trend was shown for the effect of SCS on milk yield (p<0.05), where the highest values of milk traits were obtained for the lowest SCS. The loss of milk was 220 g/day. Also, fat and protein percentages decreased by 0.11% and 0.08%, respectively, for each unit increase in SCS, from zero to four. In conclusion, severe THK can lead to high SCC, which negatively affects milk traits. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the Somatic Cell Count of raw milk which obtained from Holstein-Frisian dairy cow milk and determine the effects of season and lactation number on the composition and quality of raw milk. Milk samples were collected monthly during one year from 30 Holstein-Frisian dairy cow. The fresh milk samples were collected in 250 ml flasks and delivered to laboratory at a temperature of 4 °C cold chain and analyzed. The fat, protein, lactose, dry matter rate and Somatic Cell Count of raw milk samples were automatically performed with Bentley Merkim Nexgen Series Model 1 device. While no significant differences were found in % fat, % protein, % dry matter and average daily milk according to lactation number (p>0.05), The differences determined in %lactose and SCC (p<0.01) were significant. The highest SCC content of raw milk was observed in the 4th lactation (928.30±117.93) and lowest in 1st lactation (356.47±50.55). According to the seasons the SCC observed from highest to lowest were in winter 1003.88±83.53, in spring 877.63±97.43, in autumn 575.81±63.97 and in summer 212.36±17.94. Negative correlation coefficients observed between SCC and daily milk yield of all lactations, however the correlation coefficient in first lactation was not significant different from 0. The study indicated, that were negative relationships between SCC and daily milk yield, except in first lactation and summer. It has been observed that all groups of SCC are above the threshold value specified in the Turkish Food Codex Raw Milk notification, except 1st lactation and the summer. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effects of 3-way rotational crossbreeding scheme of Holstein (HO) cows with Montbéliarde (MO), Viking Red (VR) and HO sires on body and milk quality traits. Cows were purebred HO; F1: (MO × HO; VR × HO); F2: [MO × (VR × HO); VR × (MO × HO)]; F3: {HO × [MO × (VR × HO)]}; HO × [VR x (MO × HO)]}. Data were collected on 745 cows kept in a commercial farm located in Northern Italy. Milk data were acquired from official milk recording and body condition score (BCS) and conformation traits were measured once by trained evaluator. Data were analyzed using a linear model including fixed effects of parity, DIM class and breed combinations. Average body traits: height at withers (HW), body length (BL) and heart girth (HG) of cows were 139,162 and 207 cm respectively. Crossbred cows had shorter HW, BL and HG than pure HO but greater BCS. Milk yield averaged 31.5 kg/d, with fat and protein content close to 3.8 and 3.75%, respectively. Purebred HO produced greater volume of milk than crossbreds but milk from HO had lower protein content. Different combinations of crossbred cows showed similar performance in terms of milk yield traits, but evidenced different body size. The trial is currently in progress to increase cow sample size and widen the number of herds involved.