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Plants are integral components of pig and poultry feed, and aside from their raw nutritive value, some phytochemicals contain bioactive compounds. The aim of the present paper is to review recent advances in the use of some phytochemicals in pig and poultry feed, focusing on the examples of isoquinoline alkaloids, polyphenol rich sugarcane extracts and superoxide dismutase-rich melon pulp extracts. As gut health is critical for efficient production, the review will focus on recent results modulating oxidative stress within the gastrointestinal tract and the potential mechanisms of action.

The difference in microbiota was examined for breeders with different egg-laying rates, and the impact of dietary Enterococcus faecium (EF) was also determined in the present study. A total of 256 Arbor Acres broiler breeders (48-wk-old) were used in a 2 × 2 factorial design, which encompassed 2 egg-laying rate levels [average (average egg laying: AP, 80.45 ± 0.91%) and low (lower egg laying: LP, 70.61 ± 1.16%)] and 2 different dietary groups [control (no additive), 6 × 108 cfu/kg EF]. The results showed that the AP breeders presented a lower egg weight, feed conversion ratio, abdominal fat rate, and serum leptin level (P(laying) ≤ 0.05) as well as a higher egg-laying rate (P(laying)

This study was conducted to determine the effects of supplemental dietary benzoic acid on production performance, egg quality, intestinal morphology, and intestinal microbiota of laying hens. A total of seven hundred twenty 45-wk-old Lohman pink-shell laying hens were randomly allocated to 3 dietary treatments: control (CON), diet supplemented with 1,000 mg/kg benzoic acid (BA1), and 2,000 mg/kg benzoic acid (BA2). Each treatment included 10 replicates of 24 hens; laying hens were monitored for 16 wk. Overall, the results indicate that benzoic acid supplementation had no effect on laying rate, feed intake, feed conversion ratio, and breaking rate; however, a decrease in egg weight (P

This research reflection examines the physiological links between redox balance, skeletal health and gastrointestinal functionality in dairy cows. With the increase in demand of animal products caused by the growth in human population, the dairy industry needs to develop and implement innovative strategies which are profitable, sustainable and cow friendly. Redox balance, skeletal heath and gastrointestinal functionality are three key physiological systems that are often seen as independent entities. In this research reflection we intend to stress that the antioxidant system, bone health and the microbiome are intimately intertwined. Antioxidants are crucial for the maintenance of redox homeostasis and optimal immune function. Optimal gastrointestinal functionality is important to maintain animal performance, health and welfare. In particular, the intestinal microbiome is increasingly seen as a driver of health and disease. Vitamin D metabolism is pivotal not only for optimal skeletal health, but in light of all the extra-skeletal effect of vitamin D, it is the foundation for optimal productive life. It makes sense to ask the question ‘how are redox balance and the microbiome involved in the modulation of bone health and immune function?’ In other words, are bugs and bones connected in dairy cows! The existing data available in the literature suggests that this might be the case. The characterization of the interactions between redox balance, skeletal health and the microbiome, will allow the development of a multisystem biological approach to refine nutritional interventions to improve dairy cattle health, welfare and productive longevity.

The in vitro antimicrobial activity of sophorolipids (SLs) against Eimeria maxima and Clostridium perfringens, and the in vivo effects of SLs on growth performance and gut health in necrotic enteritis (NE)-afflicted broiler chickens were studied. To test the direct killing effects of SLs on enteric pathogens, 2.5 × 105 freshly prepared sporozoites of each Eimeria acervulina, E. maxima, and E. tenella were placed in each well of a 96-well plate, and the vegetative stage of Clostridium perfringens was prepared at 1 × 109 cfu/well. Four different SLs (C18:1 lactonic diacetyled SL [SL1], C18:1 deacetyled SL [SL2], C18:1 monoacetyled SL [SL3], and C18:1 diacetyled SL [SL4]), and 2 anticoccidial chemical controls, decoquinate and monensin, were evaluated at 3 dose levels (125 µg/mL, 250 µg/mL, and 500 µg/mL). Samples were incubated at 41°C for 3 h, and microbial survival ratios were measured by using a cell counter to quantify the number of live microbes stained by fluorescent dye. A total of 336 (0-day-old) male commercial broiler chickens were used to assess the effects of SLs in vivo. Chickens were randomly allocated to 6 treatment groups (7 chickens per cage, 8 cages per treatment) as follows: a control group which received a basal diet (CON), a negative control group (NC) which received a basal diet and NE challenge, and 4 SL treatment groups with NE (NC+SL1, NC+SL2, NC+SL3, and NC+SL4). The inclusion rates of SLs in each group were 200 mg/kg of feed. NE-induced chickens were orally infected with E. maxima (10,000 oocysts/chicken) on d 14, followed by C. perfringens (1 × 109 cfu/chicken) on d 19. Disease parameters measured included gut lesion scores, intestinal cytokine production, and level of tight junction protein expression. Data were analyzed using a Mixed Model (PROC MIXED) in SAS. In vitro (Experiment 1), all SLs dose-dependently decreased (P < 0.001) the viability of the three species of Eimeria sporozoites and C. perfringens. In vivo (Experiment 2), dietary SLs increased (P < 0.001) body weight and average daily gain of broiler chickens infected with NE. Dietary SL1 and SL4s increased (P < 0.05) feed conversion ratio compared to NC. Furthermore, SL1 and SL4 decreased (P < 0.05) gut lesion scores in combination with increased expression of IL1β, IL8, TNFSF15, and IL10 genes (P < 0.05) in NE-afflicted chickens. Overall, dietary SLs promoted growth performance, intestinal immune responses, and intestinal barrier integrity of NE-afflicted, young broiler chickens.

This study was conducted to determine the effects of 25-hydroxycholecalciferol (25-OH-D3) on performance, egg quality, tibia quality, and serum hormones concentration in laying hens reared under high stocking density. A total of 800 45-week-old Lohmann laying hens were randomly allotted into a 2 × 2 factorial design with 2 levels of dietary 25-OH-D3 levels (0 and 69 μg/kg) and 2 rates of stocking densities [506 (low density) and 338 (high density) cm2/hen]. Laying hens were monitored for 16 wk. High stocking density decreased laying rate, egg weight, and feed intake compared with low stocking density (P < 0.01) during 1 to 8 wk and 1 to 16 wk. Overall, high stocking density increased eggshell lightness value and decreased shell redness and yellowness value, strength, thickness, and relative weight compared with low stocking density (P < 0.05). Dietary supplementation with 25-OH-D3 reduced the value of the eggshell lightness and increased its yellowness and eggshells weight (P ≤ 0.05). The increase in eggshell thickness was more pronounced when 25-OH-D3 was supplemented to layers under high stocking density (interaction, P < 0.05). Layers under high stocking density had lower ash content and calcium content in the tibia than layers under low stocking density (P = 0.04); dietary 25-OH-D3 increased tibia strength compared with no addition (P = 0.05). Layers under high stocking density had higher serum concentrations of 25-OH-D3, corticosterone (CORT), lipopolysaccharide (LPS), and osteocalcin (OC; P < 0.05), lower content of parathyroid hormone (PTH) compared with layers under low stocking density (P < 0.01). Dietary 25-OH-D3 increased serum concentration of 25-OH-D3, carbonic anhydrase (CA), and calcitonin (CT) (P < 0.01) and reduced corticosterone, lipopolysaccharide and osteocalcin concentration (P ≤ 0.05). The increase effect in PTH was more pronounced when 25-OH-D3 was supplemented to layers under high stocking density (interaction, P = 0.05). Overall, the results gathered in this study indicate that high stocking density result in reducing production performance, shell color and quality, and tibia health, whereas dietary 25-OH-D3 was able to maintain tibia health and to mitigate the negative impact of high stocking density on productive performance.

Objectives were to determine the effects of feeding supplemental 25-hydroxyvitamin D3 [25(OH)D3] on concentrations of vitamin D metabolites and minerals in serum, mammary immune status, and responses to intramammary bacterial infection in dairy cows. Sixty multiparous, pregnant lactating Holstein cows with somatic cell count

This study was conducted to determine the impact of different feed additives on reproductive performance, egg quality, intestinal morphology, and blood metabolic profile of broiler breeder with different egg-laying rate. A total of 512 AA broiler breeders (48 wk old) were used in a 2 × 4 factorial design which encompassed 2 egg-laying rate levels [average (AR) and low (LR)] and 4 different dietary groups [control (no additive), 6 × 108 CFU/kg Enterococcus faecium (EF), 200 mg/kg apple pectic oligosaccharide (APO), and 1,000 mg/kg tributyrin (TRI)]. As expected, the LR breeders presented higher egg weight, eggshell thickness (P < 0.05), and feed conversion ratio as well as lower egg-laying and qualified egg rate than the AR breeders (P < 0.01). Dietary supplementation with the 3 additives improved egg weight (P ≤ 0.01). Dietary APO addition improved albumen height and Haugh units (P < 0.05) in both AR and LR breeders. Compared with APO and TRI, dietary EF addition increased eggshell thickness (P ≤ 0.01). An effect of the egg-laying rate and dietary additives on eggshell thickness (P < 0.01) was noted, with the addition of EF enhancing the eggshell thickness, which is more pronounced in the AR group. The duodenum of AR breeders presented a lower crypt depth and a higher villus/crypt ratio (P < 0.05); moreover, an effect of the laying rate and dietary additives on crypt depth was noted (P < 0.05), with the addition of APO to the diet resulting in a lower crypt depth. Compared with the APO and TRI, dietary EF addition increased follicle-stimulating hormone (FSH) level in serum (P < 0.05). Overall, the results gathered in this study indicate that LR breeders have lower production performance, eggshell thickness and decreased gastrointestinal tract functionality in compared with the AR breeders. Dietary supplementation with APO might improve albumen quality and decrease duodenal morphology, while EF improved eggshell quality and FSH secretion, and the improvement was more pronounced in the breeders with an average egg-laying rate.

Two experiments were conducted to evaluate the effects of dietary sophorolipids (SLs) supplementation as antibiotic alternatives on growth performance and gut health of chickens infected with Eimeria maxima. In experiment 1, 336 (zero-day-old) male broilers were used. The chickens were weighed and randomly allocated to the following 6 treatments groups with 7 chickens/cage and 8 cages/treatment: control group that received a basal diet (NC), positive control group that received a basal diet and was challenged with E. maxima (PC), PC+C18:1 lactonic diacetyled SL (SL1), PC+C18:1 deacetyled SL (SL2), PC+C18:1 monoacetyled SL (SL3), and PC+C18:1 diacetyled SL (SL4). Each SL (200 mg/kg feed) was added to the corresponding treatment group. In experiment 2, 588 (zero-day-old) male broilers were used. The chickens were randomly allocated to the following experimental groups with 10 or 11 chickens/cage and 8 cages/treatment: NC, PC, PC+ monensin at 90 mg/kg feed (MO), PC+SL1 at 200 mg/kg feed (SL1 200), PC+SL1 at 500 mg/kg feed (SL1 500), PC+SL4 at 200 mg/kg feed (SL4 200), and PC+SL4 at 500 mg/kg of feed (SL4 500). The chickens and feed were weighed at 0, 7, 14, 20, and 22 d to determine growth performance. In both experiments, all chickens except the NC group were orally infected with E. maxima (10,000 oocysts/chicken) at d 14. One chicken per cage was euthanized at d 20 to sample jejunal tissue to measure lesion scores, cytokines, and tight junction (TJ) proteins. Excreta samples were collected daily between d 20 and 22 to measure oocyst numbers. Data were analyzed using Mixed Model (PROC MIXED) in SAS. In experiment 1, SLs did not affect the growth of broiler chickens, but SL4 decreased (P0.05) the lesion score and oocyst number compared to PC chickens. In terms of cytokines and TJ protein gene expression, SLs increased (P0.05) IL-1β, IL-6, IL-17F, IL-4, IL-13, occludin, and ZO1 levels compared to PC chickens. In experiment 2, monensin increased (P0.05) body weight, and decreased (P0.05) the lesion score and oocyst number compared to the PC group. SL4 500 increased (P0.05) average daily gain and feed conversion ratio but decreased (P0.05) lesion score and fecal oocyst number. SL4 decreased (P0.05) IL-6, IL-17F, TNFSF-15, IL-2, and IL-10 levels but increased (P0.05) occludin and ZO-1 levels. Overall, dietary SL supplementation, especially SL4, improved growth and gastrointestinal functionality of young broiler chickens, demonstrating significant potential as an antibiotic alternative.

Several nutritional studies have been performed to improve piglet health and resilience to infectious diseases during the lactation and post-weaning periods, and to identify alternatives to the use of antibiotics and antimicrobials as growth promoters. In the last decades, pharmacological levels of zinc oxide (ZnO) and copper have frequently been used as nutritional strategies to prevent post-weaning diarrhoea because of their antimicrobial activity. However, the use of ZnO was recently banned by the EU from 2022 because of the risk of promoting Anti-Microbial Resistance (AMR). Beyond their role as essential micronutrients, vitamins share several remarkable activities (antimicrobial, immunological and antioxidative) often referred to amongst many of the non-antibiotic feed additives commonly proposed and used for pigs. However, very little research and scientific emphasis are devoted to vitamin nutrition and its role in the gut function and health of livestock. This review discusses how fat-soluble (A, D, E and K) and water-soluble (B-group and C) vitamins may influence gastrointestinal (GI) functionality in general and with specific importance on the challenges associated with the early life of pig gut health and disease prevention. On the basis of the literature review it is suggested that future research and development of alternative strategies to antibiotics and medicinal ZnO should pay attention to the role of vitamins for GI functionality and health of pigs.

It has been demonstrated that tea polyphenol (TP) epigallocatechin-3-gallate (EGCG) can confer protection against vanadium (V) toxicity in laying hens; however, our understanding of the molecular mechanisms beyond this effect are still limited. In this study, 360 hens were randomly assigned to the 3 groups to study whether the potential mechanism P38MAPK-Nrf2/HO-1 signaling pathway is involved in the protective effect of EGCG on eggshell pigmentation in vanadium challenged laying hens. Treatments included a control group, a 10 mg/kg V (V10), and a V10 plus 130 mg/kg of EGCG group (V10+EGCG130). Both eggshell color and protoporphyrin IX were decreased in the V10 group compared with the control diet, while EGCG130 treatment partially improved shell color and protoporphyrin IX (P < 0.05). The V10 exposure induced higher cell apoptosis rate and oxidative stress in birds as evidenced by the histological apoptosis status, decreased uterine glutathione-S transferase (GST) and high abundance of malondialdehyde (MDA) compared with the control group, whereas EGCG130 markedly alleviated oxidative stress via reducing MDA generation (P < 0.05). Dietary vanadium reduced ferrochelatase, NF-E2-related factor 2 (Nrf2), and heme oxygenase (HO-1) mRNA expression, while EGCG up-regulated Nrf2 and HO-1 expression (P < 0.05). Protein levels of Nrf2, HO-1 and phospho-p38 (P-P38) MAPK were reduced in V10 group, while dietary supplementation with 130 mg/kg EGCG markedly increased Nrf2, HO-1 and P-P38 MAPK protein levels in the uterus compared with the V10 group (P < 0.01). In conclusion, EGCG improved eggshell color and antioxidant system in V10-challenged hens, which seems to be associated with P38MAPK-Nrf2/HO-1 signaling pathway.

Bone-derived hormones play an important role in metabolism. This study examined the hypothesis that interactions between bone and energy metabolism, particularly those involving osteocalcin, are present in dairy cattle and have feedback mechanisms over time. Associations between metabolites in blood were examined in 32 Holstein cows blocked by parity and milk yield and randomly allocated to diets containing either 0.27 mg/kg dry matter (DM) calcidiol or cholecalciferol for an anticipated intake of 3 mg/d (120,000 IU/d) at 11 kg of DM, and positive (+130 mEq/kg DM) or negative (-130 mEq/kg DM) dietary cation-anion difference (DCAD) from 252 d of gestation to calving. Blood was sampled every 3 d, from 9 d prepartum to 30 d postpartum, and plasma concentrations of vitamin D3, 25-hydroxyvitamin D3, adiponectin, C-telopeptide of type 1 collagen (CTX1), glucose, insulin-like growth factor 1 (IGF1), insulin, undercarboxylated osteocalcin (uOC), and carboxylated osteocalcin (cOC) were determined. Feeding calcidiol compared with cholecalciferol increased plasma concentrations of 25-hydroxyvitamin D3 pre- (264.2 ± 8.0 vs. 61.3 ± 8.0 ng/mL) and postpartum (170.8 ± 6.2 vs. 51.3 ± 6.2 ng/mL) but decreased concentrations of vitamin D3 pre- (1.2 ± 0.6 vs. 14.5 ± 0.6 ng/mL) and postpartum (1.9 ± 0.4 vs. 3.2 ± 0.6 ng/mL). Prepartum, cows fed the negative DCAD diet had reduced concentrations of vitamin D3 and glucose compared with cows fed a positive DCAD. The combination of negative DCAD and cholecalciferol reduced IGF1 concentrations prepartum. The DCAD treatment had no effect on postpartum concentrations of metabolites. Nulliparous cows had increased concentrations of OC, CTX1, IGF1, glucose, and insulin compared with parous cows. Time series analysis identified associations between metabolites on the same day and over 3-d lags up to ±9 d that suggest feedback between 25-hydroxyvitamin D3 and vitamin D3 in the negative lags, indicating that 25-hydroxyvitamin D3 may exert feedback on vitamin D3 but not vice versa. We found evidence of a feedback mechanism between vitamin D3 and IGF1, with positive effect size (ES) on the same day and 3 d later, and negative ES 9 d later, that was more evident in cholecalciferol-fed cows. This suggests an important role of IGF1 in integrating bone metabolism with energy and protein metabolic pathways. Evidence of feedback was found between uOC and particularly cOC with IGF1, with positive ES on the same day but negative ES 6 d before and 6 d after. An association between uOC or cOC and IGF1 has not been previously identified in cattle and suggests that both uOC and cOC may have marked biological activity. Associations between OC and insulin identified in mice were not observed herein, although associations between OC and glucose were similar to those between IGF1 and glucose, supporting associations between glucose, OC, and IGF1. We provide further statistical evidence of crosstalk between vitamin D compounds, bone hormones, and energy metabolism in cattle. In particular, associations between uOC or cOC and IGF1 may provide links between prepartum diets and observations of prolonged increases in milk production and allow better control of peripartum metabolism.

This research paper addresses the hypothesis that dietary pioglitazone (PGT), as synthetic and specific ligand for PPAR-γ or walnut meal (WM) as a natural ligand for PPAR-γ, affect plasma metabolites and reduce the oxidative status in high body condition score (BCS) dairy cows (≥4 BCS). Total of 36 multiparous Holstein cows were randomly assigned to one of the dietary treatments: 1- Control (basal diet; CTR), 2- Walnut meal (9·45% walnut meal of DMI; WM), and 3- Pioglitazone (6 mg/kg BW; PGT). The experimental diets were fed from parturition time to 21 d postpartum. Results showed that the PGT supplementation increased dry matter intake (DMI) (22·95 kg/d) compared to the CTR (21·45 kg/d) and WM (21·78 kg/d) groups. Results showed that milk yield and milk composition were not affected by the experimental diets. Body condition score losses tended to be higher in the CTR group compared to the PGT and WM cows. The PGT group had higher plasma insulin compared to the CTR group (11·84 vs. 10·68 mIU/l), and WM cows had intermediate plasma insulin. The PGT cows had lower plasma non esterified fatty acid (NEFA) and tended to have lower β-hydroxy butyric acid (BHBA) than the CTR group. Feeding pioglitazone decreased plasma malondialdehyde (MDA) and increased plasma total antioxidant capacity (TAC) and superoxide dismutase (SOD) compared to the CTR and WM groups. It was concluded that dietary pioglitazone had positive effects on DMI, BCS change, blood metabolites and oxidative status in fresh dairy cows with high pre-calving BCS. The anti-oxidant effects of walnut meal were not supported by the present data.

Objective Heat stress (HS) triggers oxidative stress and respiratory alkalosis in pigs. The objective of this experiment was to study whether a short-term supranutritional amount of dietary vitamin E (VE) can mitigate oxidative stress and respiratory alkalosis in heat-stressed pigs. Methods A total of 24 pigs were given either a control diet (17 IU/kg VE) or a high VE (200 IU/kg VE; HiVE) diet for 14 d, then exposed to thermoneutral (TN; 20°C, 45% humidity) or HS (35°C, 35% to 45% humidity, 8 h daily) conditions for 7 d. Respiration rate and rectal temperature were measured three times daily during the thermal exposure. Blood gas variables and oxidative stress markers were studied in blood samples collected on d 7. Results Although HiVE diet did not affect the elevated rectal temperature or respiration rate observed during HS, it alleviated (all p

Effective functionality of the gastrointestinal tract (GIT) and its health, are important factors in determining animal performance. Several, complex mechanisms are involved in the regulation of GIT functionality and health, therefore it is crucial to deepen our knowledge of these interactions so that strategies for the modulation of GIT functionality and health, in context of improved animal performance, can be developed. The concept of “gut health” has started to attract significant interest within the animal science community, however a clear definition of gastrointestinal health and functionality and how it can be measured is lacking. Therefore, this review will present a new definition of gastrointestinal functionality and will address how optimal gastrointestinal functionality can promote animal performances and welfare. The key components of gastrointestinal functionality reviewed in this article are: diet, effective structure and function of the gastrointestinal barrier, host interaction with the gastrointestinal microbiota, effective digestion and absorption of feed and effective immune status. While the relationships between these areas is extremely complex, a multidisciplinary approach is needed to develop nutritional strategies that would allow farm animals to become more resilient to the environmental and physiological challenges that they will have to endure during their productive career. As the demand of animal products from the rapidly growing world human population is ever-growing, the aim of this review is to present animal and veterinary scientists and nutritionists, a new definition of gastrointestinal functionality that can be used to establish a multidisciplinary approach to increase animal health, welfare and performance.

The aim of study was to determine the effect of pre-calving body condition score (BCS) and previous milk yield on BCS change, blood metabolites, oxidative stress and milk production in Holstein cows. At 3 wk before expected calving, 100 multiparous cows were grouped according to their BCS and then classified based the previous 305 milk yield. The four experimental groups (25 cows each) were medium BCS and moderate milk yield (MM), medium BCS and high milk yield (MH), high BCS and moderate milk yield (HM), and high BCS and high milk yield (HH). The cows’ BCS was recorded at −21, 0, 21, 50 and 80 d related to parturition time. Daily milk production of cows was recorded after parturition. Blood samples were taken at d −21, −7, +1, +7 and +21 postpartum. The HH cows had lower (p

Simple Summary 3-Nitrooxypropanol is an effective methane-mitigating feed additive. However, a decrease in feed intake is frequently observed in beef cattle fed a diet supplemented with 3-nitrooxypropanol. Thus, a study was conducted to determine the short-term preference of beef cattle offered diets supplemented with 3-nitrooxypropanol. When given a choice, the cattle initially showed less preference for a diet supplemented with 3-nitrooxypropanol, suggesting potential changes in organoleptic properties of the diet. However, the animals acclimatized to the supplemented diet rapidly such that there was no preference between a diet with and without 3-nitrooxypropanol within a week. Therefore, the change in the organoleptic properties of a diet supplemented with 3-nitrooxypropanol does not appear to be the main reason for reduced feed intake of beef cattle. Abstract Two experiments were conducted to examine eating preference of beef cattle for diets with or without the investigative enteric methane inhibitor 3-nitrooxypropanol (3-NOP). Nine beef steers were housed in individual stalls, each equipped with two feed bunks. The first experiment (Exp. 1) was conducted with a high forage diet and each animal received a diet without 3-NOP (CON) in one bunk and a diet with 3-NOP (dNOP) in the other bunk. The second study (Exp. 2) was conducted with the same animals about 6 months after Exp. 1 where a high grain diet without (CON) or with 3-NOP (dNOP) was offered. In Exp. 1, animals initially preferred CON compared with dNOP. Feed consumption from 0 to 3, 3 to 6, and 6 to 12 h after feeding was lower for dNOP compared with CON. However, dry matter intake (DMI) and feed consumption of dNOP gradually increased during Exp. 1 such that there was no preference between CON and dNOP on day 7. In Exp. 2, there was no preference for or against dNOP. Average DMI was greater for dNOP vs. CON, but interactions between diet and day for DMI and feed consumption rates indicated that daily preference between CON and dNOP was variable. In conclusion, beef steers initially detected a difference between CON and dNOP and selected in favor of CON rather than dNOP when they had not previously been exposed to 3-NOP. However, the animals rapidly acclimatized to a diet with 3-NOP (Exp. 1) and showed no eating preference between CON and dNOP within 7 days. This lack of preference was maintained throughout Exp. 2 when the same animals were fed a high grain diet.

Improving insulin sensitivity may reduce impacts of heat stress (HS) in pigs by facilitating heat dissipation. Chromium (Cr) has been reported to improve insulin sensitivity in pigs. Therefore, the aim of this experiment was to investigate whether Cr supplementation can mitigate HS in growing pigs. Thirty-six gilts were randomly assigned to 2 diets containing 0 (control) or 400 ppb Cr. After 14 d the supplemented pigs were allocated to either 8 d thermoneutral (20°C constant; TN) or cyclic HS (35°C, 0900 h to 1700 h) conditions and continued their respective diet (n = 9 per group). Growth performance was recorded during the 14-d supplementation period. The physiological responses to HS were monitored by measuring respiration rate, rectal temperature, blood gas chemistry, and feed intake during thermal exposure. Kinetics of plasma glucose, insulin and NEFA were studied by intravenous glucose tolerance test (IVGTT) on d 8 of thermal treatment. Results showed Cr alleviated the HS-increased rectal temperature (P < 0.05) and respiration rate (P < 0.01) at 1300 h and 1600 h during thermal exposure. However, Cr did not mitigate the reduction in average daily feed intake which was reduced by 35% during HS or the HS-induced respiratory alkalosis. Chromium tended to increase average daily gain (0.86 vs. 0.95 kg, P = 0.070) during the 14-d supplementation under TN conditions before thermal exposure, which might be associated with the potential of Cr in improving overall insulin sensitivity, as evidenced by a reduced insulin resistance index calculated by Homeostatic Model Assessment (HOMA-IR; 0.65 vs. 0.51, P = 0.013) and a tendency of reduced fasting plasma insulin concentration (1.97 vs. 1.67 μU/mL, P = 0.094). Heat stress decreased the acute insulin releasing rate (P = 0.012) and consequently slowed glucose clearance rate (P = 0.035) during IVGTT. Besides, HS enlarged the values of area under the curve of NEFA during IVGTT (P < 0.01), indicating a reduced lipid mobilization. In conclusion, HS reduced insulin response to IVGTT. Chromium supplementation exhibited a potential in improving insulin sensitivity and mitigating HS symptoms in growing pigs.

The present study was conducted to elucidate the role of dietary vitamin E (Vit E) and selenium (Se) on the oxidative status of lambs exposed to short term hot conditions during finishing. Forty-eight lambs (crossbred; 42 ± 2 kg body weight, 7 mo age) were allocated to one of three groups (16 per group) and fed 3 different doses of Vit E and Se. A standard finisher pellet ration (17% CP and 12.57 MJ ME/kg DM) was used as the basis of treatment diets. The doses of Vit E and Se for control (CON), moderate (MOD), and supranutritional (SUP) diets were 28, 130, 228 mg/kg DM as α- tocopherol acetate and 0.16, 0.66, 1.16 mg Se as SelPlex™ kg/DM, respectively. After 4 weeks feeding in individual pens, including 1 week of adaptation, lambs were moved to metabolism cages for 1 week and allocated to one of 2 heat regimes (8 per feeding group): thermoneutral (TN) (18–21 °C and 40–50% relative humidity) or heat stress (HS) (28–40 °C and 30–40% relative humidity) conditions. Dietary Vit E and Se supplementation increased average daily feed intake ( P = 0.009) and average daily gain ( P = 0.057) linearly (CON to SUP) during the 3 week finisher period before thermal treatments were applied. During thermal treatment, HS elevated ( P P = 0.05) and RT ( P = 0.08) in lambs fed SUP levels of Vit E and Se. The concentration of plasma reactive oxygen metabolites (ROM) increased ( P P

The objective of the study was to determine whether feeding a diet supplemented with 3-nitrooxypropanol (3-NOP) affects feeding behavior altering intake and rumen fermentation. Two experiments were conducted with 9 rumen-cannulated beef steers in a replicated 3 × 3 Latin square design where animals received a high-forage or high-grain diet. Treatments were 1) a basal diet (CON), the CON diet supplemented with 3-NOP (dNOP; 100 mg/kg in dietary DM or 1 g/d), or the CON diet with 3-NOP (1 g/d) infused into the rumen (infNOP). Each experimental period consisted of 14-d diet adaptation and 7-d sample collection. A 7-d washout period was provided between experiment periods. All data were analyzed as a Latin square design using Mixed Procedure of SAS. In Exp. 1 (high-forage diet), methane yield (measured by the Greenfeed system) was lowered by 18% (18.6 vs. 22.7 g/kg DMI; P < 0.01) by dNOP compared with CON. Rumen fermentation was altered similarly by both NOP treatments compared with CON where dNOP and infNOP increased (P < 0.01) rumen pH at 3 h and decreased (P < 0.01) proportion of acetate in total VFA. However, DMI, feed consumption rate (0 to 3, 3 to 6, 6 to 12, and 12 to 24 h after feeding), particle size distribution of orts, and feeding behavior (videotaped for individual animals over 48 h) were not affected by dNOP and infNOP compared with CON. In Exp. 2 (high-grain diet), methane production was not affected by dNOP or infNOP compared with CON. Dry matter intake, feed consumption rate, particle size distribution of orts, and feeding behavior were not altered by dNOP and infNOP compared with CON. However, both dNOP and infNOP affected rumen fermentation where total VFA decreased (P = 0.04) and acetate proportion in total VFA tended to decrease (P = 0.07) compared with CON. In conclusion, dietary supplementation of 3-NOP did not affect feeding behavior of beef steers fed a high-forage or high-grain diet. However, rumen fermentation was similarly changed when 3-NOP was provided in the diet or directly infused in the rumen. Thus, observed changes in rumen fermentation with 3-NOP were not due to changes in feeding behavior indicating no effects on the organoleptic property of the diets. In addition, according to small or no changes in DMI in both experiments and relatively small changes in rumen fermentation in Exp. 2, a greater dosage level of 3-NOP than 100 mg/kg (dietary DM) may need further examination of its effects on feeding behavior of beef cattle.

The relationships among nucleotide sequence polymorphisms in the genes for leptin (LEP) and leptin receptor (LEPR) and circulating concentrations of leptin and variables related to energy turnover were investigated in a Awassi-Merino crossbred sheep population. Blood sampled at several times during gestation and lactation was used for the assay of circulating leptin and for DNA extraction. Parts of the ovine LEP and LEPR genes were sequenced and, of a total of seven polymorphisms identified, two for each gene were used for genotyping. Feed intake and body weight were recorded for 199 ewes (age 2.9–9.4 years) daily and milk yield and composition were measured. The data were used for association studies between single nucleotide polymorphisms (SNPs), circulating leptin concentration and production traits. Both polymorphisms identified in the ovine LEP gene were associated with circulating leptin concentration (P

Abundant evidence from the medical, veterinary, and animal science literature demonstrates that there is substantial room for improvement of the clarity, completeness, and accuracy of reporting of intervention studies. More rigorous reporting guidelines are needed to improve the quality of data available for use in comparisons of outcomes (or meta-analyses) of multiple studies. Because of the diversity of factors that affect reproduction and the complexity of interactions between these, a systematic approach is required to design, conduct, and analyze basic and applied studies of dairy cattle reproduction. Greater consistency, clarity, completeness, and correctness of design and reporting will improve the value of each report and allow for greater depth of evaluation in meta-analyses. Each of these benefits will improve understanding and application of current knowledge and better identify questions that require additional modeling or primary research. The proposed guidelines and checklist will aid in the design, conduct, analysis, and reporting of intervention studies. We propose an adaptation of the REFLECT (Reporting Guidelines for Randomized Controlled Trials for Livestock and Food Safety) statement to provide guidelines and a checklist specific to reporting intervention studies in dairy cattle reproduction. Furthermore, we provide recommendations that will assist investigators to produce studies with greater internal and external validity that can more often be included in systematic reviews and global meta-analyses. Such studies will also assist the development of models to describe the physiology of reproduction.

This study was carried out to investigate the effects of Yerba Mate (YM) supplementation on nutrients' degradation, in vitro dry matter disappearance, gas production and rumen ammonia concentration. Three rumen-fistulated Holstein Friesian cows were used for the in situ incubations and provided rumen liquor for in vitro incubations. The inclusion of YM in a control diet (pasture+pellets) affected some in sacco degradation parameters. YM supplementation decreased the effective degradability and degradation rate of pasture crude protein (CP), and it seems to slow down the degradation of pasture neutral detergent fiber. A significant increase of degradation of pasture acid detergent fiber (ADF) was detected after YM inclusion in the control diet. YM supplementation reduced in vitro gas production of pasture and ammonia concentration of pellets. The addition of YM in ruminant diet could decrease ammonia production and increase protein availability for productive purposes. The moderate presence of tannins in YM could have affected the degradation kinetics of pasture CP and ADF and the ammonia production of pellets.

Evidence is increasing of positive effects of feeding fats during transition on fertility and the adaptation to lactation. This study used meta-analytic methods to explore the effects of including fats in the transition diet on the risk of pregnancy to service (proportion pregnant) and calving to pregnancy interval. Meta-analysis was used to integrate smaller studies and increase the statistical power over that of any single study and explore new hypotheses. We explored the effect of fats and diet composition on fertility using meta-regression methods. Relatively few highly controlled studies are available providing detailed descriptions of the diets used that examined interactions between fat nutrition and reproductive outcomes. Only 17 studies containing 26 comparisons were suitable for inclusion in statistical evaluations. Reproductive variables evaluated were risk of pregnancy (proportion pregnant), primarily to first service, and calving to pregnancy interval. Production variables examined were milk yield, milk composition, and body weight. The sources of heterogeneity in these studies were also explored. A 27% overall increase in pregnancy to service was observed (relative risk=1.27; 95% confidence interval Knapp Hartung 1.09 to 1.45), and results were relatively consistent (I2=19.9%). A strong indication of a reduction in calving to pregnancy interval was also identified, which was consistent across studies (I2=0.0%), supporting a conclusion that, overall, the inclusion of fats does improve fertility. Further exploration of the factors contributing to proportion pregnant using bivariate meta-regression identified variables that reflected changes in diet composition or animal response resulting from inclusion of the fat interventions in the experimental diets fed. Increased fermentable neutral detergent fiber and soluble fiber intakes increased the proportion pregnant, whereas increased milk yield of the treatment group decreased this measure. Unexpectedly, the estimated energy costs of urea production also had a positive association with proportion pregnant. The limited number of suitable studies for the analysis highlights the need for more work to improve understanding of the critical nutritional factors affecting fertility. These factors include specific fatty acids in dietary interventions that contribute to increasing fertility of cows in dairy production systems.

The objective of this study was to determine the efficacy of supranutritional dietary selenium and vitamin E (Vit E) to ameliorate the effect of heat stress (HS) on oxidative status and acid-base balance in sheep. Thirty-two Merino × Poll Dorset ewes were acclimated to indoor individual pen feeding of a pelleted control diet (0.24 g Se and 10 IU of Vit E/kg DM) for 1 wk. Sheep were then moved to metabolism cages in climatic chambers and randomly allocated to a 2 × 2 × 2 factorial design with the respective factors being dietary Se (0.24 and 1.20 mg/kg DM as Sel-Plex; Alltech, Australia), Vit E (10 and 100 IU/kg DM), and temperature for 2 wk. After 1 wk of acclimation in metabolic cages, 1 climatic chamber continued on thermoneutral (TN) conditions (18°C to 21°C and 40% to 50% relative humidity [RH]), and the other one was set to HS conditions (28°C to 40°C and 30% to 40% RH) for 1 wk. The sheep were then returned to individual pens and fed the control diet for 1 wk before being returned to the same diet as in the first period but a reversed thermal treatment for a further 2 wk. Physiological parameters were recorded 3 times daily, and blood samples were collected on d 1 and 7 of thermal treatment. Average respiration rate and rectal temperature of sheep were increased (P < 0.001) during HS; however, combined supranutritional supplementation of Se and Vit E reversed the effects of HS. Sheep given the high Se and high Vit E diet had a lower respiration rate (191 vs. 232 breaths/min; P = 0.012) and rectal temperature (40.33°C vs. 40.58°C; P = 0.039) under peak HS (1700 h) compared with those fed the low Se and low Vit E diet. Plasma reactive oxygen metabolites concentrations were reduced (P = 0.048) by 20%, whereas biological antioxidant potential was increased (P = 0.17) by 10% in sheep fed the high Se and high Vit E diet compared with those fed the low Se and low Vit E diet. Blood pH was elevated (P = 0.007) and bicarbonate was reduced (P = 0.049) under HS, and again, these effects were ameliorated by the high Se and high Vit E diet. Both white blood cell glutathione peroxidase gene expression and red blood cell lysate glutathione peroxidase activity were increased in sheep fed the high Se and high Vit E diet. These data suggest that supranutritional dietary Se or Vit E can reduce some of the negative effects of HS. However, the synergism between the 2 antioxidants improves their potential to ameliorate the impacts of HS in sheep.

This study was conducted to test the hypothesis that the specificity of infrared thermography (IRT) in detecting cows about to ovulate could be improved using different body parts that are less likely to be contaminated by fecal matter. In addition, the combined activity and rumination data captured by accelerometers were evaluated to provide a more accurate indication of ovulation than the activity and rumination data alone. Thermal images of 30 cows were captured for different body areas (eye, ear, muzzle, and vulva) twice daily after AM and PM milking sessions during the entire experimental period. Milk progesterone data and insemination records were used to determine the date of ovulation. Cows were fitted with SCR heat and rumination long-distance tags (SCR HR LD) for 1 month. Activity- and rumination-based estrus alerts were initially identified using default threshold values set by the manufacturer; however, a range of thresholds was also created and tested for both activity and rumination to determine the potential for higher levels of accuracy of ovulation detection. Visual assessment of mounting indicators resulted in 75% sensitivity (Se), 100% specificity (Sp), and 100% positive predictive value (PPV). Overall, IRT showed poor performance for detecting cows about to ovulate. Vulval temperature resulted in the greatest (80%) Sp but the poorest (21%) Se compared with the IRT temperatures of other body areas. The SCR HR LD tags default threshold value resulted in 78% Se, 57% Sp, and 70% PPV. Lowering the activity threshold from the default value improved the sensitivity but created a large number of false positives, which resulted in a decrease in specificity. Lowering the activity threshold to 20 resulted in a detection performance of 80% Se, 94% Sp, and 67% PPV, whereas the rumination levels achieved 35% Se, 69% Sp, and 14% PPV. The area under the curve for the activity level, rumination level, and the combined measures of activity and rumination levels were 0.82, 0.54, and 0.75, respectively. Alerts generated by SCR HR LD tags based on a lower activity threshold level had high sensitivity and may be able to detect a high proportion of cows in ovulatory periods in pasture-based system; however, the specificities and positive predictive value were lower than the visual assessment of mounting indicators.

This meta-analysis of 39 experiments containing 118 treatments explored the effects of diet interventions in early lactation on the proportion of dairy cows pregnant to artificial insemination (AI; pregnancy to AI) and on calving to pregnancy interval. It also identified factors that may explain variation in these responses. The objectives were to identify effects of diet on reproduction, rather than differences between specific dietary interventions. The examination of calving to pregnancy interval used the more traditional method of analyzing differences between a treatment and the reference treatment used for comparison within a given experiment. The systematic review identified fewer experiments (n = 39) than had been expected. Four different multivariable models including the random effect of experiment were used to examine the effects of CPM-Dairy (version 3.08) estimated diet and production variables on proportion pregnant to AI. These models examined (1) output of products, (2) balance or duodenal availability of nutrients, (3) intake of nutrients, or (4) percentage of nutrients in the diet. The multivariable models identified positive associations between estimated increased fatty acid intake [incidence rate ratio (IRR) = 1.0003 ± 0.0001g/d; ±standard error], starch intake (IRR = 1.061 ± 0.029 kg/d), metabolizable energy balance (IRR = 1.004 ± 0.002 MJ/d), and duodenal C14:0 (IRR = 1.008 ± 0.004 g/d) availability with the proportion of cows pregnant to AI, whereas rapidly fermentable sugar intake (IRR = 0.813 ± 0.054 kg/d), percentage of sugar in the diet (IRR = 0.960 ± 0.015%), and milk protein yield (IRR 0.922 ± 0.022 g/100 g per day) were associated with a reduced proportion of cows pregnant to AI. There was no multivariable model developed to assess variables associated with calving to pregnancy interval but, univariably, increased metabolizable energy balance was associated with a shorter calving to pregnancy interval whereas increased milk production was associated with longer time to pregnancy. Increased intake of some AA, particularly threonine and lysine, were associated with a longer calving to pregnancy interval. It is clear nutritional management around calving can influence reproductive success. The importance of dietary fats and increased energy and protein balances in early lactation for improved fertility outcomes is supported and suggests that starch and sugars may have different effects on the proportion of cows that are pregnant to AI. This work also highlighted a need for further focused field studies exploring the roles of specific fatty acids, AA, phosphorus, and carbohydrates on reproduction.

Pregnant Holstein cows, 28 nulliparous and 51 parous, were blocked by parity and milk yield and randomly allocated to receive diets that differed in dietary cation-anion difference (DCAD), +130 or −130 mEq/kg, and supplemented with either calcidiol or cholecalciferol at 3 mg/11 kg of dry matter from 255 d of gestation until parturition. Blood was sampled thrice weekly prepartum, and on d 0, 1, 2, 3, 6, 9, 12, 15, 18, 21, 24, 27, and 30 postpartum to evaluate effects of the diets on vitamin D, mineral and bone metabolism, and acid-base status. Blood pH and concentrations of minerals, vitamin D metabolites, and bone-related hormones were determined, as were mineral concentrations and losses in urine and colostrum. Supplementing with calcidiol increased plasma concentrations of 25-hydroxyvitamin D 3 , 3-epi 25-hydroxyvitamin D 3 , 25-hydroxyvitamin D 2 , 1,25-dihydroxyvitamin D 3 , and 24,25-dihydroxyvitamin D 3 compared with supplementing with cholecalciferol. Cows fed the diet with negative DCAD had lesser concentrations of vitamin D metabolites before and after calving than cows fed the diet with positive DCAD, except for 25-hydroxyvitamin D 2 . Feeding the diet with negative DCAD induced a compensated metabolic acidosis that attenuated the decline in blood ionized Ca (iCa) and serum total Ca (tCa) around calving, particularly in parous cows, whereas cows fed the diet with positive DCAD and supplemented with calcidiol had the greatest 1,25-dihydroxyvitamin D 3 concentrations and the lowest iCa and tCa concentrations on d 1 and 2 postpartum. The acidogenic diet or calcidiol markedly increased urinary losses of tCa and tMg, and feeding calcidiol tended to increase colostrum yield and increased losses of tCa and tMg in colostrum. Cows fed the diet with negative DCAD had increased concentrations of serotonin and C-terminal telopeptide of type 1 collagen prepartum compared with cows fed the diet with positive DCAD. Concentrations of undercarboxylated and carboxylated osteocalcin and those of adiponectin did not differ with treatment. These results provide evidence that dietary manipulations can induce metabolic adaptations that improve mineral homeostasis with the onset of lactation that might explain some of the improvements observed in health and production when cows are fed diets with negative DCAD or supplemented with calcidiol.

The balance between oxidants and antioxidants may be impaired in neonatal calves but only limited information is available on physiological changes in oxidative biomarkers in healthy calves. The aim of this study was to measure biomarkers of oxidative stress (OS) in calves from birth to weaning. Eighteen, healthy, female Holstein-Friesian calves were used in the study. Blood and exhaled breath condensate (EBC) samples were taken on the day of birth (Week 0) and then at Weeks 6, 12 and 18. Reactive oxygen metabolites (ROMs) and biological antioxidant potential (BAP) were determined on fresh blood and the degree of OS was expressed as an oxidative stress index (OSI), where OSI = ROMs/BAP × 100. Plasma concentrations of antioxidant barrier (OXY), thiol antioxidant barrier (SH), advanced oxidation protein products (AOPP), albumin, and non-esterified fatty acids (NEFA) were also measured, as was hydrogen peroxide (H2O2) concentration in EBC. Plasma concentrations of ROMs were relatively stable during the trial; AOPP concentration progressively decreased reaching its lowest values on Week 18. Albumin, SH and OXY concentrations progressively increased from birth to weaning. Concentrations of NEFA in plasma and H2O2 in EBC were relatively stable but peaked in Week 18. The results indicate that antioxidative defence not only increases with time in the plasma of new-born calves but also that it is related to protein oxidation processes. Furthermore, the data support the use EBC H2O2 as a novel biomarker to assess respiratory OS in calves.

The present study was undertaken to investigate the impact of heat (thermal) stress and dietary antioxidant supplementation on the oxidative and physiological status of sheep. Twenty-four Merino × Poll Dorset crossbred ewes were housed in 1 of 2 climatic chambers (thermoneutral or heat stress) and offered either a control (10 IU vitamin E/kg DM and 0.24 mg Se/kg DM) or high antioxidant (100 IU vitamin E/kg DM and 1.20 mg Se/kg DM) diet. The sheep were exposed to 2 thermal (temperature) treatments (thermoneutral [TN]: 18-21°C and 26-30% relative humidity; and heat stress [HS]: 28-40°C and 40-50% relative humidity) for 2 wk in a single reversal design. After 1 wk of dietary treatment, animals in 1 chamber were subjected to HS for 1 wk, with the temperature being increased to 40°C between 0900 and 1700 h and then maintained at 28°C overnight. Those sheep in the TN group were maintained at 18 to 21°C. Physiological parameters were recorded 4 times a day (0900, 1300, 1700, and 2100 h) and blood samples were collected on d 1 and 7 of heat treatment. Plasma samples and red blood cell lysates were assayed for oxidative stress biomarkers. The thermal treatments were then reversed and the above measures repeated. All measured physiological parameters were elevated (P < 0.001) by thermal treatment. Respiration rate was lower during HS in sheep supplemented with antioxidants as indicated by a diet × temperature × time interaction (P = 0.010). There was 13% decline (P = 0.014) in feed intake of the unsupplemented animals during HS whereas the same was maintained in sheep supplemented with high doses of antioxidants. Plasma reactive oxygen metabolites concentrations were reduced (114 vs. 85 units/dL; P < 0.005) while biological antioxidant potential tended to be increased (3,688 vs. 3,985 μmol/L; P = 0.070) in heat stressed sheep supplemented with antioxidants. The oxidative stress index was 30% lower (P < 0.001) in supplemented sheep (2.16 ± 0.06 arbitrary units) during HS than in unsupplemented sheep (3.12 ± 0.08 arbitrary units). Plasma advanced oxidation protein products tended (P = 0.070) to decrease in antioxidant supplemented heat stressed sheep as compared to their unsupplemented counterparts. It was concluded that heat stress negatively affects the oxidative status of sheep along with the physiological responses and some of these affects can be ameliorated through dietary antioxidants supplementation at supranutritional concentrations.

We evaluated the effect of feed additives on the risk of ruminal acidosis in Holstein heifers (n = 40) fed starch and fructose in a challenge study. Heifers were randomly allocated to feed additive groups (n = 8 heifers/group): (1) control (no additives); (2) virginiamycin (VM); (3) monensin + tylosin (MT); (4) monensin + live yeast (MLY); and (5) sodium bicarbonate + magnesium oxide (BUF). Heifers were fed 2.5% of body weight (BW) dry matter intake (DMI) per day of a total mixed ration (62:38 forage:concentrate) and feed additives for a 20-d adaptation period. Fructose (0.1% of BW/d) was included for the last 10d of the adaptation period. On d 21, heifers were fed to target a DMI of 1.0% of BW of wheat, fructose at 0.2% of BW, and their feed additives. Rumen fluid samples obtained by stomach tube and blood samples were collected weekly as well as during a 3.6-h period on challenge day (d 21). Virginiamycin and BUF groups maintained a consistently high DMI across the 20-d adaptation period. The MLY heifers had low DMI of the challenge ration. Average daily gain and feed conversion ratio were not affected by feed additives. All rumen and plasma measures changed weekly over adaptation and over the challenge sampling period with the exception of rumen total lactate and histamine concentrations, plasma oxidative stress index, and ceruloplasmin. Substantial within- and between-group variation was observed in rumen and plasma profiles at challenge sampling. No significant group changes were observed in rumen total volatile fatty acids, propionate, acetate-to-propionate ratio, isobutyrate, caproate, isovalerate, total lactate, d- and l-lactate, and pH measures on challenge day. Acetate concentration was increased in the BUF and control groups on challenge day. Butyrate concentration was lower in the MLY and MT groups compared with other groups at challenge. Valerate concentrations were lowest in the control, VM, and BUF groups and lactate concentrations were numerically lower in the MLY, VM, and BUF groups. Total lactate concentrations were >10mM for each group throughout the challenge. Ammonia concentrations were lower in the MLY and MT groups. Histamine concentrations were decreased in MLY and increased in the VM and BUF groups. Plasma oxidative stress measures were not influenced by feed additives weekly or on challenge day, except for an increase in biological antioxidant potential in the control, VM, and MT groups on challenge day. Despite the large within-animal variation, all feed additives modified rumen function and may influence the risk of acidosis by different mechanisms; however, none stabilized the rumen in all heifers.

Ruminal endotoxin and plasma oxidative stress biomarker concentrations were studied in dairy heifers challenged with grain, fructose, and histidine in a partial factorial study. Holstein-Friesian heifers [n=30; average body weight (BW) of 359.3±47.3 kg] were randomly allocated to 5 treatment groups: (1) control (no grain); (2) grain [crushed triticale at 1.2% of BW dry matter intake (DMI)]; (3) grain (0.8% of BW DMI) + fructose (0.4% of BW DMI); (4) grain (1.2% of BW DMI) + histidine (6g/head); and (5) grain (0.8% of BW DMI) + fructose (0.4% of BW DMI) + histidine (6 g/head). Rumen samples were collected by stomach tube 5, 65, 115, 165, and 215 min after diet consumption and blood samples at 5 and 215 min after consumption. Rumen fluid was analyzed for endotoxin concentrations. Plasma was analyzed for concentrations of the following oxidative stress biomarkers: reactive oxygen metabolites (dROM), biological antioxidant potential (BAP), advanced oxidation protein products, and ceruloplasmin, and activity of glutathione peroxidase. Dietary treatment had no effect on concentrations of endotoxin or oxidative stress biomarkers. We observed no interactions of treatment by time. Ruminal concentrations of endotoxin decreased during the sampling period from 1.12×10(5) ± 0.06 to 0.92×10(5) endotoxin units/mL ± 0.05 (5 and 215 min after diet consumption, respectively). Concentrations of dROM and the oxidative stress index (dROM/BAP × 100) increased over the sampling period, from 108.7 to 123.5 Carratelli units (Carr U), and from 4.1 to 4.8, respectively. Ceruloplasmin concentrations markedly declined 5 min after the consumption of diets, from 190 to 90 mg/L over the 215-min sampling period. Overall, a single feeding challenge for dairy cattle with grain, fructose, and histidine, and combinations thereof, may not be sufficient to induce marked changes in endotoxin or oxidative stress biomarker concentrations.

Summary Heat stress (HS) disrupts redox balance and insulin-related metabolism. Supplementation with supranutritional amounts of selenium (Se) may enhance glutathione peroxidase (GPX) activity and reduce oxidative stress, but may trigger insulin resistance. Therefore, the aim of this experiment was to investigate the effects of a short-term high Se supplementation on physiology, oxidative stress and insulin-related metabolism in heat-stressed pigs. Twenty-four gilts were fed either a control (0.20 ppm Se) or a high Se (1.0 ppm Se yeast, HiSe) diet for 2 weeks. Pigs were then housed in thermoneutral (20°C) or HS (35°C) conditions for 8 days. Blood samples were collected to study blood Se and oxidative stress markers. An oral glucose tolerance test (OGTT) was conducted on day 8 of thermal exposure. The HS conditions increased rectal temperature and respiration rate (both p

Yerba Mate ( Ilex paraguarensis ), a plant known for its high antioxidant content, was fed to 20 of 40 lambs for 8 weeks. Lambs were randomly divided into two groups: one group ( n = 20) was fed the control diet and one group ( n = 20) was fed the control diet with 2.5% Yerba Mate. Lambs were group housed by treatment and fed ad libitum through automatic feeders that recorded individual food intake. Lambs received the dietary treatments for a total of 8 weeks and were monitored for live weight (LW), average daily growth rate (ADG), food conversion rate (FCR) and feed intake. Blood samples (8 mL) were taken from all lambs, on weeks 0, 2, 4, 6, and 8 and plasma analysed for total antioxidant capacity (TAC), advanced oxidation protein products (AOPP), non-esterified fatty acids (NEFA), triglycerides and cholesterol. Wool growth and cell-mediated immune status (PHA) were also measured. Overall, Yerba Mate (YM) lambs ate more (mean ± sem; 989 ± 68 g/d; P P P 2 and 0.07 ± 0.005 g/cm 2 , respectively). There was a significant effect of the interaction diet × sampling time on plasma AOPP concentrations ( P P

The effects of grain, fructose, and histidine on ruminal pH and fermentation products were studied in dairy cattle during an induced subacute acidosis protocol. Thirty Holstein heifers were randomly allocated to 5 treatment groups: (1) control (no grain); (2) grain [fed at a crushed triticale dry matter intake (DMI) of 1.2% of body weight (BW)]; (3) grain (0.8% of BW DMI)+fructose (0.4% of BW DMI); (4) grain (1.2% of BW DMI)+histidine (6 g/head); and (5) grain (0.8% of BW DMI)+fructose (0.4% of BW DMI)+histidine (6 g/head) in a partial factorial arrangement. Heifers were fed 1 kg of grain daily with ad libitum access to ryegrass silage and alfalfa hay for 10 d. Feed was withheld for 14 h before challenge day, on which heifers were fed 200 g of alfalfa hay and then the treatment diets immediately thereafter. Rumen samples were collected 5 min after diet ingestion, 60 min later, and at 3 subsequent 50-min intervals. Grain decreased ruminal pH and increased ammonia, total volatile fatty acid (VFA), acetate, butyrate, propionate, and valerate concentrations compared with controls. The addition of grain had no effect on ruminal D- and L-lactate concentrations. Fructose markedly decreased ruminal pH and markedly increased D- and L-lactate concentrations. Fructose increased total VFA and butyrate and decreased valerate concentrations. Although histidine did not have a marked effect on ruminal fermentation, increased concentrations of histamine were observed following feeding. This study demonstrates that the substitution of some grain for fructose can lower ruminal pH and increase VFA and lactate concentrations, warranting further investigation into the role of sugars on the risk of acidosis in dairy cattle.

Studies used to evaluate effects of dietary intervention on fertility may be subject to confounding because modification of one nutritional input requires a change in at least one other input. Meta-analytical modeling allows examination of a main intervention for a series of studies, but also an examination of a series of related effects through use of meta-regression. Effects of dietary crude protein (CP) on fertility were examined using this approach. We obtained 21 studies containing 32 comparisons that had pregnancy or conception data and met the eligibility criteria for meta-analysis of randomized controlled experiments providing information on diets used. Publications that contained data on prospective, randomized controlled experiments examining effects of dietary CP, either concentrations or degradability, or effects of a specific feed ingredient intervention on fertility were identified. Details on dietary formulation and diet intake were extracted from the publications, as were measures of urea in blood or plasma. Estimated fixed and random effects relative risks showed that risk of conception was lower in cows fed higher CP or more degradable CP diets (fixed effect (Mantel–Haenszel Relative Risk) = 0.91 (95% CI 0.84–0.98); P =0.019). This effect was homogenous ( I 2 = 0) and not influenced by difference in blood urea N, duration of intervention, breed, parity, milk production or type of diet delivery. Significant associations among CP components of the diet and carbohydrate fractions supported the hypothesized potential for confounding, but only the amount of soluble CP eaten was a significant meta-regression covariate that reduced risk of conception. There was no evidence that the significant reduction in fiber or non-fiber carbohydrate (NFC) fractions of the diets associated with increased concentration of CP, soluble CP or rumen degradable fractions or soyabean products content of the diet influenced conception rates. Results support findings of experiments showing that increased intake of soluble CP reduced conception rates, and provides strong evidence that increased concentrations of CP or increased degradability of CP, within the ranges evaluated in the studies contributing to this meta-analysis, reduce the risk of conception in lactating dairy cattle.

Yerba Mate (Ilex paraguariensis), a tea known for its high antioxidant content, was supplemented to 30 of 60 ewes for 13 wks to assess its effect on their productive performance. A 2.5% inclusion rate of Yerba Mate (YM) in a pelleted concentrate diet decreased feed intake and live weight (LW) during the first few weeks post partum (p

The study of vitamin D in cattle has often focussed on its role in calcium and mineral metabolism. However, there is evidence of a wider role for vitamin D in bone and energy metabolism. Two studies were conducted to explore relationships between calcidiol supplementation, blood minerals and metabolites in mid-lactation dairy cows. In Experiment 1, a dose-response study was conducted in which 25 mid-lactation cows were fed one of five supplementary calcidiol doses (0, 0.5, 1, 2 or 4 mg calcidiol/day) for 30 days, with blood samples taken every 10 days. Increasing calcidiol dose increased plasma calcidiol (P = 0.001), 24,25-(OH)2-D3 (P = 0.001) and serum phosphate (P = 0.003) in a curvilinear manner, increased and then decreased plasma 25-OH-D2 (P = 0.004) and linearly increased 3-epi 25-OH-D3 (P = 0.001) and milk calcidiol concentrations (P = 0.001). Calcidiol supplementation did not affect milk yield or composition, bodyweight or condition score. In Experiment 2, relationships between blood calcidiol and mineral and metabolite concentrations over time were explored using time-series analysis. Ten mid-lactation cows were fed either 0 or 0.5 mg calcidiol/day for 27 days, with blood samples taken every 3 days. Feeding calcidiol increased plasma calcidiol (P = 0.001), 24,25-OH-D3 (P = 0.038), and insulin (P = 0.046), but decreased 25-OH-D2 (P = 0.008) concentrations. Positive associations were identified between blood calcidiol and concentrations of other metabolites, including cholecalciferol, calcium, osteocalcin, glucose, insulin, non-esterified fatty acids, β-hydroxybutyrate, cholesterol, magnesium, phosphorus and total protein at varying lags (±0, 3 or 6 days), while negative relationships were identified between calcidiol and 24,25-(OH)2-D3, and phosphorus 3 days later. Importantly, strong positive associations between calcidiol and indicators of energy metabolism were identified. Overall, these experiments provide support for a positive effect of calcidiol treatment on dairy cow metabolism.

The aim of the present work was to monitor the effect of a high versus a low diet on the metabolic and hormonal profiles of dairy goats and the progeny. Starting from the last month of pregnancy, 14 goats were randomly allocated to two groups: Low Diet (LD) and High Diet (HD) that received a diet that covered 80% and 140% of their energy requirements, respectively. Blood samples were taken from all goats, at −4, −3, −2, −1, 0 (partum), +1, +2, +3, +4, and +5 weeks from delivery. Blood samples were collected from goat kids on the day of birth prior to colostrum feeding (week 0) and then at 1, 2, 3, 4 and 5 weeks of age. Blood samples were assayed for their content of: urea, triglycerides, cholesterol, total protein, albumin, calcium and inorganic phosphorus, globulin, non-esterified fatty acids (NEFA), beta-hydroxy butyric acid (BHBA), insulin, free triiodothyronine (fT3), free thyroxine (fT4), leptin and prolactin (PRL). Kids’ live weights (LW) and growth rate were not affected by maternal nutrition. Milk yield was significantly (P < 0.05) higher in the HD goats. A significant (P < 0.001) effect of time was noted on plasma glucose, total protein, albumin, globulin and phosphorus concentrations. Concentration of plasma NEFA, BHBA, triglycerides and calcium were significantly (P < 0.01, P < 0.05, P < 0.001 and P < 0.05, respectively) higher in the LD goats than those in HD goats. Plasma insulin and PRL levels were higher in the HD goats than those in LD goats (P < 0.05 and P < 0.01, respectively). Plasma leptin level were lower on the day of partum (P < 0.05). Plasma glucose and insulin concentrations were higher in the HD kids than those in LD kids (P < 0.01) while plasma NEFA and triglycerides concentrations were higher (P < 0.05) in the LD kids than in the HD kids. Plasma leptin concentrations increased (P < 0.001) soon after kids began suckling but its values were not influenced by the dietary treatments. The thyroid hormones increased over time and their values were significantly higher in HD kids than those in LD kids at week 5. Our results showed that perinatal nutrition affects goats’ and kids’ metabolic and hormonal profiles; however this did not have an effect on foetal and kids’ growth. Nutrient restriction during pregnancy shifted nutrient partitioning towards the uterus to sustain foetal growth. This homeorhetic adaptation was continued during early lactation; however, it was not sufficient to sustain milk production.

Multiparous Holstein cows (n=82) of either high or low genetic merit (GM) (for milk fat + protein yield) were allocated to 1 of 2 diets in a 2×2 factorial design. Diets differed in the ratio of rumen-undegradable protein (RUP) to rumen-degradable protein (37% RUP vs. 15% RUP) and were fed from 21 d precalving to 150 days in milk. This study evaluated the effects of these diets and GM on concentrations of milk casein (CN) variants and aimed to identify precalving and early lactation variables that predict milk CN and protein yield and composition and fertility of dairy cows. It explored the hypothesis that low milk protein content is associated with lower fertility and extended this hypothesis to also evaluate the association of CN contents with fertility. Yields (kg/d) for CN variants were 0.49 and 0.45 of α-CN, 0.38 and 0.34 of β-CN, 0.07 and 0.06 for κ-CN, and 0.10 and 0.09 of γ-CN for high- and low-RUP diets, respectively. Increased RUP increased milk, CN, and milk protein yields. Increased GM increased milk protein and γ-CN yields and tended to increase milk CN yield. The effects of indicator variables on CN variant yields and concentrations were largely consistent, with higher body weight and α-amino nitrogen resulting in higher yields, but lower concentrations. An increase in cholesterol was associated with decreased CN variant concentrations, and disease lowered CN variant yield. A diet high in RUP increased proportion of first services that resulted in pregnancy from 41 to 58%. Increased precalving metabolizable protein (MP) balance decreased the proportion of first services that resulted in pregnancy when evaluated in a model containing CN percentage, milk protein yield, diet, and GM. This finding suggests that the positive effects of increasing dietary RUP on fertility may be curvilinear because cows with a very positive MP balance before calving were less fertile than those with a lower, but positive, MP balance. Prepartum MP balance was important to production and reproductive outcomes, but surprisingly, metabolizable energy balance was not. The hazard of pregnancy in the first 150 d of lactation was 28% lower in cows producing milk with the lowest quartile of protein percentage compared with cows with milk in the upper 3 quartiles. Milk CN percentage was positively associated with improved pregnancy at first service. This study demonstrates the importance of protein metabolism to reproductive performance of the dairy cow.

The aim of this study was to evaluate the effects of the hot season and nutrition on the oxidative status and metabolic profile of lactating goats during mid lactation. Twenty-four Red Syrian goats were allocated into three groups that were offered the following diets: natural pasture (P), pasture+500 g/h per day of concentrate (PC) and hay plus 500 g/h per day of concentrate (HC). Blood samples were taken in spring (85±7 days in milk (DIM)) and summer (120±7 DIM) and assayed for reactive oxygen metabolites (ROMs), α-tocopherol, glucose, triglycerides, cholesterol, non-esterified fatty acids, total protein, albumin and globulin concentrations and glutathione peroxidase (GHS-Px) and superoxide dismutase (SOD) activities. Milk yield and milk composition were also measured. SOD, GSH-Px and ROMs levels increased during summer when temperature humidity index values were high. The increase in ROMs in the PC and HC groups could be ascribed to the improved nutritional regime and to their higher production level. The markers of the oxidative status and of the metabolic profile measured in this study indicate that goats may have experienced moderate oxidative stress. It seems that, seasonal rather than nutritional factors have a more pronounced effect on oxidative status markers. Concentrate supplementation sustained milk yield and may represent a useful means to extend the lactation period in dairy goats during late spring and summer.

In mature Merino rams, nutrition is one of the external cues that most strongly affects the reproductive centres of the preoptic-hypothalamic continuum. The signalling pathways that link dietary status and the activity of the neurones that produce gonadotrophin-releasing hormone signals are thought to be partly hormonal in nature to reflect the amount of body reserves. Among the hormones thought to be involved are insulin and leptin. This study tested whether recombinant bovine leptin infused (0.4 microg/h) into the third cerebral ventricle would stimulate pulsatile luteinizing hormone (LH) secretion in mature Merino rams when their energy status was low or decreasing, during both chronic (fasting) and acute reductions of energy balance. Leptin may interact with other hormones that depend on energy availability, so we also monitored changes in circulating concentrations of insulin, thyroid hormones, growth hormone, prolactin and adrenocorticotrophin. Overall, our data do not support this hypothesis. The dietary regimes induced clear responses in the metabolic profiles of the animals but there was no clear effect of central leptin administration on LH pulse frequency. The relationships between the hormonal systems measured in the present study add weight to the contention that leptin plays only a permissive role in the nutritional control of the reproductive axis and that other hormonal signals (particularly insulin) or pathways are acting in concert with leptin to stimulate the reproductive axis.

This study reports preliminary data on the use of digital infrared thermography (IRT) and biomarkers of oxidative stress (OS) to diagnose foot lesions in sheep. Interdigital space skin temperatures were obtained from crossbred rams with healthy (n = 9) and with foot lesions (n = 6) with a FLIR T620 series infrared camera. Interdigital space lesions were scored using a five point scoring system (0–4). Blood was sampled from all rams and plasma was analysed for reactive oxygen metabolites (ROMs), biological antioxidant potential (BAP), and advanced oxidation protein products (AOPP). The degree of OS was estimated by the ratio of ROMs/BAP (U Carr/μmol/L) multiplied by 100 to give an OS index (OSI). Footrot scores were used to stratify the rams in two groups: healthy group (HG; n = 9) or foot lesion (FL; n = 6), if the lesions were recorded as absent or present, respectively. Differences in OS biomarkers and IRT temperatures between the two groups were analysed by a linear mixed model. A significant (P

The aim of this study was to investigate the influence of lactation on cashmere production. Two groups of cashmere bearing goats, aged between 2 and 3 years, were used in this study. The control group included 12 non-lactating, non-pregnant subjects. The experimental group was made up of 12 goats that had given birth to twins or triplets and that had begun lactating in the second half of May. Lactation therefore had begun approximately 45 days prior to the beginning of the emergence of fibre on the body surface. Live weight was not affected by the physiological state under consideration. The decrease observed in January is too remote to have been an effect of lactation. One likely explanation is that after shearing the animals were obliged to use their body reserves for thermoregulation. Prolactin concentration was higher at the beginning of the study in both groups and it was not influenced by lactation. Albeit with a varied intensity, secondary follicles were found to be active during the entire trial period but activ- ity never reached 100% in either group. Lactation significantly suppressed the percentage of secondary follicle activity and this was more evident from June to September. Fibre length and diameter did not differ between the two groups, so lactation did not affect fibre dimensions. The period of growth was shorter in lactating goats (184 vs 226 d). This did not make a difference in fibre length in so much as the lactating goats manifested a higher daily aver- age growth rate (0.27 ± 0.03 vs 0.20 ± 0.03 mm/d; P lesser than 0.05) which compensated for the shorter period of growth. Lactation caused a decrease in productivity of an insignificant nature, therefore we hold that the negative effect of lactation on cashmere production does not depend upon the physiological status as such but, most probably, upon the level of productivity and the degree to which the lactation and fibre growth cycles overlap.

This study was conducted to evaluate changes in milk profiles of oxidative stress (OS) biomarkers in dairy cows with ovulatory and an-ovulatory oestrous cycles. Thirty healthy, cycling Holstein cows averaging 60±17 days in milk, and producing 33±6kg of milk per day (the week before commencing the study) were enrolled in this study. Composite milk samples were collected thrice weekly and assayed for the following OS biomarkers: lipoperoxides (LPO), biological advanced potential, superoxide dismutase (SOD), advanced oxidation protein products (AOPP), ceruloplasmin, glutathione (GSH), β-carotene and glutathione peroxidase (GSH-Px). Milk samples were also tested for fat and protein composition and the fat:protein ratio (FPR) was categorized as low (≤1.31), medium (1.32-1.56) and high (>1.57) to evaluate their main effect and the interaction effect of FPR and the week of study on OS using linear mixed models with cow identification being a random factor. Cows with ovulatory oestrous cycles (n=20) presented significantly greater SOD levels than cows that did not ovulate ((n=10; P

Late-lactation Holstein cows (n = 144) that were offered 15 kg dry matter (DM)/cow per day of perennial ryegrass to graze were randomized into 24 groups of 6. Each group contained a fistulated cow and groups were allocated to 1 of 3 feeding strategies: (1) control (10 groups): cows were fed crushed wheat grain twice daily in the milking parlor and ryegrass silage at pasture; (2) partial mixed ration (PMR; 10 groups): PMR that was isoenergetic to the control diet and fed twice daily on a feed pad; (3) PMR+canola (4 groups): a proportion of wheat in the PMR was replaced with canola meal to produce more estimated metabolizable protein than other groups. Supplements were fed to the control and PMR cows at 8, 10, 12, 14, or 16 kg of DM/d, and to the PMR+canola cows at 14 or 16 kg of DM/d. The PMR-fed cows had a lower incidence of ruminal acidosis compared with controls, and ruminal acidosis increased linearly and quadratically with supplement fed. Yield of milk fat was highest in the PMR+canola cows fed 14 or 16 kg of total supplement DM/d, followed by the PMR-fed cows, and was lowest in controls fed at these amounts; a similar trend was observed for milk fat percentage. Milk protein yield was higher in the PMR+canola cows fed 14 or 16 kg of total supplement DM/d. Milk yield and milk protein percentage were not affected by feeding strategy. Milk, energy-corrected milk, and milk protein yields increased linearly with supplement fed, whereas milk fat percentage decreased. Ruminal butyrate and d-lactate concentrations, acetateto-propionate ratio, (acetate + butyrate)/propionate, and pH increased in PMR-fed cows compared with controls for all supplement amounts, whereas propionate and valerate concentrations decreased. Ruminal acetate, butyrate, and ammonia concentrations, acetate-topropionate ratio, (acetate + butyrate)/propionate, and pH linearly decreased with amounts of supplement fed. Ruminal propionate concentration linearly increased and valerate concentration linearly and quadratically increased with supplement feeding amount. The Bacteroidetes and Firmicutes were the dominant bacterial phyla identified. The Prevotellaceae, Ruminococcaceae, and Lachnospiraceae were the dominant bacterial families, regardless of feeding group, and were influenced by feeding strategy, supplement feeding amount, or both. The Veillonellaceae family decreased in relative abundance in PMR-fed cows compared with controls, and the Streptococcaeae and Lactobacillaceae families were present in only minor relative abundances, regardless of feeding group. Despite large among- and withingroup variation in bacterial community composition, distinct bacterial communities occurred among feeding strategies, supplement amounts, and sample times and were associated with ruminal fermentation measures. Control cows fed 16 kg of DM of total supplement per day had the most distinct ruminal bacterial community composition. Bacterial community composition was most significantly associated with supplement feeding amount and ammonia, butyrate, valerate, and propionate concentrations. Feeding supplements in a PMR reduced the incidence of ruminal acidosis and altered ruminal bacterial communities, regardless of supplement feeding amount, but did not result in increased milk measures compared with isoenergetic control diets component-fed to late-lactation cows.

Ruminal bacterial community composition (BCC) and its associations with ruminal fermentation measures were studied in dairy heifers challenged with combinations of grain, fructose, and histidine in a partial factorial study. Holstein-Friesian heifers (n=30) were randomly allocated to 5 triticale grain-based treatment groups: (1) control (no grain), (2) grain [fed at a dry matter intake (DMI) of 1.2% of body weight (BW)], (3) grain (0.8% of BW DMI) + fructose (0.4% of BW DMI), (4) grain (1.2% of BW DMI) + histidine (6g/head), and (5) grain (0.8% of BW DMI) + fructose (0.4% of BW DMI) + histidine (6g/head). Ruminal fluid was collected using a stomach tube 5, 115, and 215min after consumption of the rations and bacterial 16S ribosomal DNA sequence data was analyzed to characterize bacteria. Large variation among heifers and distinct BCC were evident in a between-group constrained principal components analysis. Bacterial composition in the fructose-fed heifers was positively related to total lactate and butyrate concentrations. Bacterial composition was positively associated with ruminal ammonia, valerate, and histamine concentrations in the grain-fed heifers. The predominant phyla were the Firmicutes (57.6% of total recovered sequences), Bacteroidetes (32.0%), and candidate phylum TM7 (4.0%). Prevotella was the dominant genus. In general, grain or histidine or their interactions with time had minimal effects on the relative abundance of bacterial phyla and families. Fructose increased and decreased the relative abundance of the Firmicutes and Proteobacteria phyla over time, respectively, and decreased the abundance of the Prevotellaceae family over time. The relative abundance of the Streptococcaceae and Veillonellaceae families was increased in the fructose-fed heifers and these heifers over time. A total of 31 operational taxonomic units differed among treatment groups in the 3.6h sampling period, Streptococcus bovis was observed in fructose fed animals. The TM7 candidate phylum had an increased abundance of sequence reads by over 2.5 fold due to the introduction of histidine into the diet. Rapid changes in BCC can occur in a short period after a single substrate challenge and the nature of these changes may influence ruminal acidosis risk and differ from those in cattle exposed to substrate challenges over a longer time period.

This study was designed to evaluate the plasma profiles of oxidative stress biomarkers, progesterone and ovarian follicle diameter in ovulatory versus an-ovulatory cows. Twenty cows were synchronised using controlled internal drug release (CIDR) and prostaglandinF2α (PGF2α) protocol. Plasma samples were analysed for progesterone (P4), oxidative stress (OS) biomarkers; reactive oxygen metabolites (ROMs), biological antioxidant potential (BAP), oxidative stress index (OSI = ROMs/BAP × 100), advanced oxidation protein products, ceruloplasmin and glutathione (GSH). Plasma P4 concentration was greater in ovulated cows 24 hours (h) after PGF2α treatment but lower 48 h after PGF2α treatment compared with that of an-ovulated cows at those sampling sessions (P < 0.05). Ovulated cows were diagnosed with greater ovarian follicle diameter compared with that of their herd mates not diagnosed for ovulation. Significant interaction of time of PGF2α treatment and ovulation status (ovulatory versus an-ovulatory) with the plasma concentrations of OSI, BAP and GSH were observed. Ovulated cows had significantly lower BAP compared with that of an-ovulated cows (P < 0.05) 9 h, 48 h, 60 h and 128 h after PGF2α treatment. Plasma concentrations of GSH were lower (P < 0.05) in ovulated cows than that of an-ovulated cows 60 h and 96 h after PGF2α treatment. However, OSI was greater (P < 0.05) in ovulated cows than that of an-ovulated cows 9 h, 48 h, 60 h and 128 h after PGF2α treatment. Significant associations were observed between OS status and sampling time. Oxidative stress status may have important physiological role in facilitating the ovulation process in oestrus synchronised dairy cows.

The development and application of an algorithm to assess the ability of an infrared thermography (IRT) device to predict cows in estrus and about to ovulate was investigated. Twenty cows were synchronized using a controlled internal drug release and PGF2α. Vulval and muzzle temperatures were measured every 12 hours from controlled internal drug release insertion to 32 hours after PGF2α treatment and then every 4 hours until ovulation occurred or until 128 hours after PGF2α treatment (whichever occurred first). Thermal images obtained with a FLIR T620 series infrared camera were analyzed using ThermaCAM Researcher Professional 2.9 software. Cows were also monitored for behavioral signs of estrus and color changes of an Estrotect applied to the tail head of each cow 36 hours after PGF2α treatment. Algorithms were developed by adjusting body surface temperature of individual animals for ambient temperature and humidity during each observation period, and were expressed as a deviation from the baseline temperature. Of the 20 cows enrolled in this study, 12 (60%) ovulated. An IRT estrus alert was defined using different thresholds (D = 1 °C, 1.25 °C, and 1.5 °C). Sensitivity and specificity to predict estrus depended upon the chosen threshold level. At a threshold D = 1 °C, the highest sensitivity (92%; n = 11) and the lowest specificity (29%) and positive predictive value (64%) were observed. Conversely, D = 1.5 °C resulted in sensitivity of 75%, specificity of 57%, and positive predictive value of 69%. The mean ± standard deviation intervals between onset and the end of IRT estrus alert to ovulation were 30.7 ± 8.2 and 13.3 ± 7.7 hours, respectively. Ovulation occurred 24 to 47 hours after the onset of the IRT estrus alert for eight out of the 11 ovulated cows (73%). Although the sensitivity of the IRT alert was greater than visual observation (67%) and Estrotect activation (67%), the specificity and positive predictive value were lower than these two aids (i.e., the IRT overpredicted the incidence of ovulation). Results presented indicate that IRT shows some potential as an estrus detection aid; however, further studies investigating the potential to improve the specificity and capturing data throughout entire 21-day reproductive cycles would be worthwhile.

The objective of this study was to investigate the effect of ruminal mechanical stimulating brushes (RMS brush) on rumen fermentation and plasma oxidative stress and subsequent milk production in early lactation dairy cattle in the Australian spring and summer. Two hundred pasture-fed Holstein, Jersey, and Holstein × Jersey multiparous cows were enrolled into Control (no treatment; n = 103) or RMS brush (n = 97) groups in a randomised controlled trial at 26 ± 15 days before calving. The RMS brush group had three brushes/cow administered orally. Each RMS brush consisted of synthetic polymer bristles held in place with a metal component and was enclosed in a paper capsule that dissolved after insertion. Milk yield (MY), bodyweight, and weather data were recorded daily for the first 30 weeks of lactation. Stomach tube rumen fluid samples and plasma were collected monthly for the first 3 months of lactation from a minimum subset of 14 cows from each group. A total of 182 cows calved successfully and 34 cows were removed during the first 30 weeks of lactation. There was no difference in survival between the groups (hazard ratio = 0.952, confidence interval = 0.481–1.88). Rumen, plasma oxidative stress, and milk production measures were not affected by group or the interaction between group and time, with the exception of a mean increase of 304 µM of biological antioxidant potential in the RMS brush cows. The mean temperature humidity index for the first 30 weeks of lactation was