Estradiol administration in Holstein heifer calves differentially affects the fatty acid composition of subcutaneous adipose and the mammary fat pad tissues.

This research communication reports the relative abundance of fatty acids in mammary fat pad (MFP) and subcutaneous adipose (SCA) tissues for Holstein heifer calves receiving 0, 3, or 12 daily injections of estradiol immediately prior to tissue collection. The objective of this study was to determine if the MFP and SCA fatty acid profiles were affected by estradiol administration and if such a response differs between adipose tissue depots. Twelve Holstein heifer calves were reared on a common diet and administered 12 daily injections prior to euthanasia. Injections were either daily injections of corn oil (n = 4; CON), 9 injections of corn oil followed by 3 injections of estradiol (n = 4; SHORT), or 12 injections of estradiol (n = 4; LONG). Fatty acids were extracted from collected MFP and SCA tissues samples and analyzed using gas chromatography. The MFP tissues contained a greater abundance of saturated fatty acids than SCA tissues which complemented a reduced abundance of mono-unsaturated fatty acids in the MFP than SCA. Extended duration of estradiol administration increased the abundance of total omega 3 fatty acids in both MFP and SCA tissues. There was a treatment by tissue interaction for several of the C18:1 and C18:2 isomers indicating that estradiol's effects on fatty acid uptake and metabolism are tissue specific. Additionally, C18 uptake and metabolisms may have important roles in mammary growth and development. Together, these results indicate that the MFP responds differently to estradiol administration than SCA tissues and that these alterations are associated with different degrees of induced mammary growth via estradiol.

Ghrelin antagonist D-Lys3-GHRP-6 counteract ghrelin effects in bovine cumulus-oocytes complexes matured in vitro.

Ghrelin is a gut hormone related to energy balance and reproductive functions. The aim of this study was to evaluate the effect of ghrelin antagonist D-Lys3-GHRP-6 (GA) as a potential agent that prevents ghrelin effects during bovine oocyte maturation on progesterone production, cumulus cell (CC) viability, CC DNA damage and embryo development and hatching rates. Ghrelin's potential to induce oxidative stress in cumulus-oocyte complexes (COC) was also evaluated. COCs were cultured for 24 hr in medium without supplementation (C) or supplemented with 60 pM ghrelin (Ghrelin60), Ghrelin60 + 20 pM GA (GA20), Ghrelin60 + 60 pM GA (GA60) or Ghrelin60 + 100 pM GA (GA100) for experiment I. For experiment II, C and Ghrelin60 treatments were used. Differences between C and Ghrelin60 and the linear or quadratic association between GAs on Ghrelin60 were evaluated. Results demonstrated that Ghrelin60 increased progesterone concentration, reduced CC viability, induced CC DNA damage and decreased blastocyst and hatching rate compared with C (p < .05). GA20, GA60 and GA100 had a linear effect on CC genetic damage index (p ≤ .05) and a quadratic effect on CC viability (p < .01). GA20 counteracted the low hatching rate produced by Ghrelin60. However, GAs did not counteract progesterone concentration and blastocyst rate (p ≥ .21). GRH60 did not differ from C in the oxidative status (p ≥ .19). Our study highlights that GA could prevent the negative effects of ghrelin during bovine IVM.

Effect of feeding a palmitic acid-enriched supplement on production responses and nitrogen metabolism of mid-lactating Holstein and Jersey cows.

This study evaluated the effect of feeding a palmitic acid-enriched supplement on production responses and nitrogen metabolism of mid-lactating Holstein and Jersey cows. Eighty mid-lactating dairy cows, 40 Holstein and 40 Jersey, were used in a randomized complete block design with a split-plot arrangement; the main plot was breed and the subplot was fatty acid treatment. Cows within each breed were assigned to 1 of 2 treatments: (1) control diet with no fat supplement or (2) control diet plus a palmitic acid-enriched supplement dosed at 1.5% of diet dry matter (PA treatment). The treatment period was 6 wk with the final 3 wk used for data and sample collection. There were no treatment × breed interactions for the variables analyzed. Compared with control, PA treatment increased milk fat yield (1.36 vs. 1.26 kg/d) and tended to increase 3.5% fat-corrected milk (35.6 vs. 34.0 kg/d) and energy-corrected milk (35.7 vs. 34.1 kg/d). There was no effect of PA treatment on dry matter intake, milk yield, milk protein yield, milk lactose yield, body condition score, body weight (BW) change, nitrogen intake, and variables related to nitrogen metabolism and excretion. Compared with Holstein cows, Jersey cows had greater dry matter intake as a percent of BW (4.90 vs. 3.37% of BW) and lower milk production (29.6 vs. 32.7 kg/d) and milk lactose yield (1.58 vs. 1.42 kg/d), but tended to have greater milk fat yield (1.36 vs. 1.26 kg/d). There was a breed effect on BW change; Holstein cows gained 0.385 kg/d during the experiment, and Jersey cows gained 0.145 kg/d. Jersey cows had lower nitrogen intake (636 vs. 694 g/d), blood urea nitrogen (12.6 vs. 13.8 mg/dL), urine total nitrogen (125 vs. 145 g/d), and urine total nitrogen as a percent of nitrogen intake (19.5 vs. 21.1%). Overall, feeding a palmitic acid-enriched supplement increased milk fat yield as well as dry matter and fiber digestibility in both Holstein and Jersey cows. The PA treatment did not have any major effects on nitrogen metabolism in both Holstein and Jersey cows. In addition, our results indicated that Jersey cows had lower urinary nitrogen excretion (g/d) than Holstein cows.

Physical response of dogs supplemented with fish oil during a treadmill training programme.

The rise in popularity of dog sports competitions has led to the evaluation of improvements in dog physical performance. The potential benefit of dietary supplementation with fish oil (FO) on the physical performance of human beings and horses has been reported. However, such effect has not been studied in dogs. We therefore evaluated the effect of FO dietary supplementation on heart rate (HR), rectal temperature (RT) and thigh circumference (TC) in dogs during aerobic treadmill training, and further determined HR response and blood lactate (BL) concentration during an incremental exercise test. Using a cross-over design, eight male dogs were randomly assigned to two groups and received a standard balanced commercial diet (control, CG, n = 7) and the same diet supplemented with 54 mg FO/kg metabolic weight per day (FOG, n = 8). All dogs had 30-min treadmill sessions at 8 km/hr and 7.5% slope twice a week for 12 weeks. Assessment of HR and RT was performed before and immediately after each session; HR was also assessed 5 min after the end of each session. Thigh circumference was evaluated before each session. All dogs performed an incremental exercise test on the treadmill at 0, 6 and 12 weeks to evaluate HR response and BL concentration. Data were analysed using the mixed procedure (SAS 9.4). In FOG, pre-HR (-4.9%) and post-HR (-2.4%) values and post-RT (-0.3%) values were lower during treadmill training, whereas TC (+2.2%) values were higher as compared with CG (p < 0.01). Through the incremental exercise test, mean HR (week 6, -5.3%; week 12, -6.0%) values in FOG were lower than in CG (p < 0.05). In conclusion, FO supplementation slightly improved the physiological response of dogs to exercise during training.

The presence of acylated ghrelin during in vitro maturation of bovine oocytes induces cumulus cell DNA damage and apoptosis, and impairs early embryo development.

The aim of this study was to investigate the effects of acylated ghrelin supplementation during in vitro maturation (IVM) of bovine oocytes. IVM medium was supplemented with 20, 40 or 60 pM acylated ghrelin concentrations. Cumulus expansion area and oocyte nuclear maturation were studied as maturation parameters. Cumulus-oocyte complexes (COC) were assessed with the comet, apoptosis and viability assays. The in vitro effects of acylated ghrelin on embryo developmental capacity and embryo quality were also evaluated. Results demonstrated that acylated ghrelin did not affect oocyte nuclear maturation and cumulus expansion area. However, it induced cumulus cell (CC) death, apoptosis and DNA damage. The damage increased as a function of the concentration employed. Additionally, the percentages of blastocyst yield, hatching and embryo quality decreased with all acylated ghrelin concentrations tested. Our study highlights the importance of acylated ghrelin in bovine reproduction, suggesting that this metabolic hormone could function as a signal that prevents the progress to reproductive processes.

Effect of peer instruction on the likelihood for choosing the correct response to a physiology question.

The aims of the present study were to measure the effects of individual answer (correct vs. incorrect), individual answer of group members (no vs. some vs. all correct), self-confidence about the responses (low vs. mid vs. high), sex (female vs. male students), and group size (2-4 students) on the odds for change and for correctness after peer instruction in a veterinary physiology course (n = 101 students). Data were assessed by multivariable logistic regression analysis. The likelihood for change after peer instruction increased when the confidence on an individual answer was low (P < 0.01), when the answer was incorrect (P < 0.01), and when group members had different responses (P < 0.01). The likelihood for correctness after peer instruction increased when the confidence in group answers was high (P < 0.01), when the individual answer was correct (P < 0.01), and when at least one of the group members had the correct response (P < 0.01). After peer discussion, more changes were from incorrect to correct responses than vice versa (72% vs. 28%, P < 0.01). Changes to correct answers occurred after discussion with peers having both the correct individual response (76% of times) and also the incorrect individual answer (24% of times). In conclusion, the benefits of peer instruction are due to students having correct answers generally prevail in discussions. Also, students who all have incorrect answers can get the correct answer through debate and discussion.

Transcriptomic analysis of sheep hypothalamus discloses regulatory genes potentially involved in sex-dependent differences in body weight of progeny born to dams supplemented with omega-3 fatty acids or methionine during late-gestation.

Fetal programming research conducted in sheep has reported sexually dimorphic responses on growth of the progeny born to in-utero methionine or omega-3 fatty acids supplementation. However, the biological mechanism behind the nutrient by sex interaction as a source of variation in offspring body weight is still unknown. A high-throughput RNA sequencing data of hypothalamus samples from 17 lambs were used in the current study to identify differentially expressed genes (DEGs) between males and females born to dams supplemented with different nutrients during late-gestation. Ewes received a basal diet without omega-3 fatty acids or methionine supplementation as the control (CONT); omega-3 fatty acids supplementation (FAS), or methionine supplementation (METS). A list of regulated genes was generated. Data was compared as CONT vs. FAS and CONT vs. METS. For CONT vs. METS, a treatment by sex interaction was found (adjusted P-value < 0.05) on 121 DEGs (112 upregulated and 9 downregulated) on female lambs born to METS compared with METS males. Importantly, with the sex interaction term, more than 100 genes were upregulated in female lamb's hypothalamuses born to METS. Gene Ontology (GO) and Ingenuity Pathway Analysis (IPA) were performed using the DEGs from female lambs. Terms under biological process (related to morphogenesis, organism, and tissue development), cellular component (related to chromatin, extracellular components), and molecular function (involved in chromatin structure and transcription and factors linked to binding DNA) were presented (adjusted P-value < 0.05) for GO. For the IPA, the top-scoring network was developmental disorder, endocrine system development and function, and organ morphology. Only a few differences were observed in the comparison between the interaction of sex and treatment for the CONT vs. FAS comparison. The markedly increased number of DEGs substantially involved in developmental and growth processes indicates the extent to which maternal methionine supplementation causes the sexually dimorphic effects observed in the offspring.

Effects of feeding α-amylase-expressed corn silage and grain on performance, enteric methane production, and carcass characteristics in beef steers.

An experiment was conducted to evaluate the effects of feeding Enogen feed corn (EFC) silage or EFC grain with different grain processing (dry-rolled corn vs. whole-shelled corn) in feedlot cattle diets. Total 68 Angus cross-bred steers were blocked by body weight and the treatments (diets) were randomly assigned to steers in each block: a basal diet with isoline corn silage and isoline dry-rolled corn grain (IIR); the basal diet with EFC silage and isoline dry-rolled corn grain (EIR); the basal diet with EFC silage and EFC dry-rolled grain (EER); and the basal diet with EFC silage and EFC whole-shelled grain (EEW). Isoline refers to the isogenic counterpart of Enogen corn silage or grain. Steers received the assigned treatment over 32 wk of the entire experiment (backgrounding and finishing) until harvested. Part of the steers (eight blocks) in each treatment were used to measure CH4 production (g/d) using the GreenFeed and CH4 production per unit of DMI. All data were analyzed using a mixed procedure of SAS in a randomized complete block design, considering diet as a fixed effect and block as a random effect. Steers fed the EIR diet increased (P = 0.03) DMI compared to IIR during the backgrounding phase. However, feeding EFC silage or grain did not affect body weight, average daily gain, and feed efficiency during backgrounding and finishing phases. Feeding EEW decreased (P ≤ 0.05) body weight, average daily gain, feed efficiency, and tended to decrease (P = 0.06) hot carcass weight compared to EER during the finishing phase. Methane production per unit of DMI decreased (P = 0.02) for steers fed EIR compared with steers fed IIR only during the backgrounding phase. Feeding EFC grain had no effect on CH4 production (g/d) in both phases. In conclusion, feeding EFC silage or grain did not improve the performance of beef steers during the backgrounding and finishing phases in the current experiment condition. Methane production per unit of DMI was reduced for steers fed EFC silage compared with isoline corn silage only during the backgrounding phase.

Effect of grain inclusion rates in diets provided to early-weaned calves and steroidal implants utilization on growth performance and carcass characteristics of beef steers.

One hundred and twenty-one Angus × SimAngus-crossbred steers (body weight (BW) = 159 ±â€…22 kg) were used to evaluate the effects of different grain inclusion (GI) rates in diets provided to early-weaned calves and steroidal implants (SI) utilization on growth performance and carcass characteristics, particularly intramuscular fat deposition, of beef steers. The experiment was conducted as a randomized complete block design with a 2 × 2 factorial arrangement of treatments, consisting of two GI rates (35% vs. 58%, dry matter (DM) basis), each one associated or not to steroidal implant utilization (no implants vs. 80 mg trenbolone acetate (TA) + 16 mg estradiol followed by 120 mg TA + 24 mg of estradiol). After being early-weaned (124 ±â€…14 d of age), steers were offered an average of 4.5 kg/d (DM basis) of a concentrate-based diet with a greater or lesser GI rate for 60 d. After being fed a concentrate-based diet with different GI rates for 60 d, steers were fed a common backgrounding diet for 56 d and subsequently fed a common high-grain diet until harvested at a constant final BW (620 kg). Steers were not implanted until the beginning of the backgrounding phase and then re-implanted when initiating the finishing phase. Data were analyzed using PROC MIXED in SAS. There were no GI × SI interactions (P ≥ 0.62) for any of the growth performance parameters throughout the experimental period. Implanted steers tended to have a greater average daily gain (P = 0.10) during the finishing phase than nonimplanted steers. For the 12th rib fat thickness and yield grade (YG), a GI × SI interaction (P = 0.03) and a tendency for a GI × SI interaction (P = 0.10) was detected, respectively. Nonimplanted steers fed diets with greater GI rates presented the greatest 12th rib fat thickness and tended to have the greatest YG among treatments. No other interactions (P ≥ 0.33) were observed for the hot carcass weight, Longissimus muscle (LM) area, quality grade, marbling score, and kidney-pelvic-heart fat content. Steers fed diets with lesser GI rates tended to have a greater LM area than steers fed diets with greater GI rates (P = 0.10). Results from this experiment indicate that varying GI rates in diets provided to early-weaned calves and subsequent implantation with steroidal hormones did not affect marbling deposition.

Effect of weaning strategy and backgrounding management on growth performance, carcass characteristics, and mRNA expression in the longissimus muscle of beef steers.

We evaluate the effect of the weaning strategy (WS; early, 130 ±â€…21 d vs. normal, 187 ±â€…20 d) and backgrounding management (BGM) on growth, carcass characteristics, and relative mRNA expression in the longissimus muscle (LM) of beef steers. One hundred and twenty Angus × SimAngus-crossbred steers (body weight (BW) = 130 ±â€…11.2 kg) were used in a randomized complete block design. Steers, blocked by age and BW, were randomly assigned to one treatment (2 × 2 factorial). Treatments consisted of early weaned (EW) or normal weaned (NW) steers subsequently backgrounded (BG) on either a forage-based (FB) or concentrates-based (CB) diet. The EW steers (d 0) were ad libitum-fed a grain-based diet for 49 d until nursing calves were NW. Steers were ad libitum-fed either a FB diet for 214 d or a CB diet for 95 d afterward. Steers were finished on a high-grain diet until harvested at an estimated constant 12th-rib fat thickness (1.5 cm). Expression of mRNA in the LM was measured over time. Data were analyzed using PROC MIXED in SAS. The EW steers were heavier (P ˂ 0.01) at the beginning of the backgrounding and finishing period. When the finishing phase began, steers FB were heavier (P ˂ 0.01) than CB steers. There was a tendency for a WS × BGM interaction (P = 0.08) for final BW, where NW-FB steers were heavier than the steers on the other three treatments, which do not differ between them. In the finishing phase, steers BG on a FB diet had greater dry matter intake and average daily gain, but lower gain-to-feed ratio (P ˂ 0.01). There was a WS × BGM interaction (P = 0.03) for days on feed (DOF) in the finishing diet, where backgrounding steers in a FB diet decreased DOF required to reach the harvesting target among EW steers, but not within NW steers. No interactions or treatment effects (P ≥ 0.17) were detected for marbling score (MS). For ZFP423, EW steers showed a greater mRNA expression on d 112 and a lower expression on d 255 than NW steers (P ˂ 0.01). In d 57, steers BG on a CB diet presented a greater delta-like homolog 1 mRNA expression than steers BG on a FB diet, whereas in d 255, this was inverted (P ˂ 0.01). For CCAAT/enhancer binding protein D (C/EBPD) mRNA expression, a tendency for a WS × BGM interaction was observed (P = 0.06), where a greater expression of C/EBPD was observed in steers BG on a FB diet among EW steers, but not within NW steers. In this study, early grain feeding followed by different BGM does not support MS improvements of beef carcasses.

The intramuscular fat depot, also called marbling, is a vital component of beef quality. This study aimed to investigate the effect of the weaning strategy (early vs. normal) and the subsequent backgrounding management on marbling deposition of beef carcasses. Early weaned calves were weaned at 130 d of age and fed a grain-based diet until nursing calves were normal weaned. Steers were subsequently fed either a forage-based diet or a concentrates-based diet until finished on a high-grain diet. Growth performance parameters and mRNA expression in the longissimus muscle were measured over time. Overall, compared to normal weaning, early weaning followed by different managements during the backgrounding did not increase the marbling score of beef steers. However, early weaned steers backgrounded on a forage-based diet required fewer days on feed in the finishing phase to reach harvesting target.

A review of the effect of nutrient and energy restriction during late gestation on beef cattle offspring growth and development.

Changes in the environment, including nutritional changes, can influence fetal and postnatal development of the offspring, which can result in differences in growth, metabolism, reproduction, and health later in life. In beef cattle research on energy and protein restriction during late gestation appears to be contradictory. Therefore, in this review, we will examine the nutrient requirements recommended for this period. We are summarizing contradictory data on effects on offspring performance with possible explanations of the reason for why the data seems contradictory. We will finish by discussing some areas that we consider important for further research to increase the knowledge on how maternal nutrition influences offspring development. In particular, suggestions are provided on the need for more accurately measuring nutrient and energy supply and use and the impact on subsequent epigenetic effects. This will improve understanding of nutritional effects during gestation on offspring performance.

The objective of this review is to summarize the current knowledge on the effect of protein and energy restriction during the last third of gestation to beef cows on growth performance of offspring, focusing principally on Bos taurus cows. We divided the review in three sections: 1) evaluating the current beef cow requirements, highlighting areas in need of a more current research, 2) demonstrating some inconsistency on growth and carcass characteristics variables due to energy and protein restriction in late gestation, and 3) offering our opinion on future research in the area.

Growth performance, carcass characteristics, and fatty acid composition of Angus- and Wagyu-sired finishing cattle fed for a similar days on feed or body weight endpoint.

This study evaluated the feedlot performance, carcass characteristics, and fatty acid (FA) composition of Wagyu-sired and Angus-sired cattle at a similar days on feed (D) or body weight (B) endpoint. Wagyu-sired steers and heifers (WA) from two different sires, selected for either growth (G) or marbling (M), were compared with Angus-sired steers (AN, n = 13) in two independent incomplete-block design experiments at a similar days on feed (DOF; WA-GD, n = 9; WA-MD, n = 12) in experiment 1 or similar final body weight (BW; WA-GB, n = 9; WA-MB, n = 13) in experiment 2. Cattle were offered a corn silage-based growing diet for 119 d before being transitioned over 3 wk to a finishing diet. Data were analyzed as a randomized incomplete block design. In experiment 1, AN and WA-GD cattle had a greater (P < 0.01) off-test BW and average daily gain (ADGP < 0.04) than WA-MD cattle and AN had a greater dry matter intake (DMI; P < 0.02) than WA-GD and WA-MD cattle. The AN and WA-GD cattle had a greater carcass weight (P < 0.02) than WA-MD cattle. Percent kidney, pelvic, and heart fat (KPH) was greatest (P < 0.01) for WA-MD cattle, followed by WA-GD cattle, and lastly AN cattle. Total lipid (P < 0.03) and polyunsaturated FA (PUFA; P < 0.01) percentage were greater for WA-MD-cattle than AN and WA-GD cattle, as they tended (P = 0.11) to have the greatest 12th rib marbling score. In experiment 2, AN-cattle needed fewer (P < 0.01) DOF and had a greater (P ≤ 0.02) ADG, DMI, and gain:feed than WA-GB- and WA-MB-cattle. The WA-MB-cattle had a greater (P < 0.01) 12th and 6th rib marbling score, USDA quality grade, and 6th rib backfat thickness than AN-cattle. Compared with AN cattle, WA-GB cattle had a greater (P ≤ 0.01) percent KPH and lesser (P ≤ 0.03) rib thickness. The WA-MB-cattle had a greater (P ≤ 0.01) concentration of total lipid and PUFA than AN- and WA-GB-cattle, and lesser saturated FA (SFA; P < 0.01) concentration than AN-cattle in the longissimus muscle (LM). The 6th rib location of the LM had a greater (P ≤ 0.01) percentage of total lipid and SFA, but less (P < 0.03) MUFA compared with the 12th rib location. In conclusion, Wagyu-sired cattle selected for marbling potential had a lesser ADG, DMI, more marbling, more PUFA, and less SFA in the LM than Angus-sired cattle regardless of slaughter endpoint. Wagyu-sired cattle selected for growth potential had a similar ADG and carcass characteristics compared with Angus-sired cattle when fed for a similar number of days on feed.

Wagyu-sired steers and heifers (WA) from two different sires, selected for either growth (G) or marbling (M), and Angus-sired steers (AN) were fed for a similar days on feed (D) or to a similar final body weight (B) in two independent experiments. In experiment 1, Angus-sired steers were compared with Wagyu-sired steers and heifers when fed for a similar number of days on feed (DOF; WA-GD and WA-MD) and in experiment 2, AN were compared with Wagyu-sired steers and heifers at a similar final body weight (BW; WA-GB and WA-MB). In experiment 1, AN and WA-GD cattle had a greater rate of gain and final BW compared with WA-MD cattle. AN cattle consumed more feed compared with Wagyu-sired cattle. WA-MD had the greatest amount of kidney fat and polyunsaturated fatty acid (FA) compared with AN and WA-GD cattle. In experiment 2, AN cattle had a greater rate of gain, feed intake, with fewer DOF compared with Wagyu-sired cattle. At a similar final BW, WA-MB cattle deposited more kidney fat, marbling at the 6th- and 12th-rib, and backfat at the 6th-rib compared with AN cattle. The FA profile of the longissimus muscle from WA-MB cattle had more polyunsaturated FA, with less saturated FA compared with AN cattle. The resulting feedlot performance and carcass characteristics vary depending on the selection of Wagyu sire for growth or marbling ability.

Effects of polyunsaturated fatty acid supplementation on plasma and follicular fluid resolvin D1 concentration and mRNA abundance in granulosa cells in ewes.

The aim of this experiment was to evaluate the effect of increasing dietary omega-3 (n-3) polyunsaturated fatty acid (PUFA) supplementation on plasma and follicular fluid resolvin D1 (RvD1) concentration and the mRNA expression of genes related to RvD1 production, inflammatory response, oxidative stress, hormone receptors and production, and free fatty acid receptors in the granulosa cells of ewes. Dorset × Hampshire ewes (n = 24) aged 2 to 4 yr and with an initial body weight (BW) of 84.08 ±â€…13.18 kg were blocked by body condition score (BCS) and BW, and randomly assigned to 12 pens. Each pen within each block was randomly assigned to one of three treatments: 1) diet without fatty acid supplementation (control), 2) diet with 0.5% n-3 PUFA supplementation (PUFA0.5), and 3) diet with 1% n-3 PUFA supplementation (PUFA1). BW, BCS, and blood samples were obtained on day 1 and every 21 d for 3 mo. Ewes were then synchronized, superstimulated, and ovariectomized. Antral follicles were aspirated to evaluate RvD1 concentration in follicular fluid, and granulosa cells were used to determine mRNA abundance. Data were analyzed as a randomized complete block design using a mixed model (MIXED or GLIMMIX with log as a link function when data presented a nonnormal distribution). A polynomial effect of treatments was used to analyze RvD1 concentration and mRNA expression when there was no interaction. In addition, the correlation between plasma and follicular fluid RvD1 concentration was evaluated. We found no differences in BW (P = 0.28) and BCS (P = 0.29) between treatments. The concentration of RvD1 in plasma and follicular fluid linearly increased (P = 0.03) and tended to increase (P = 0.06) concomitantly to increasing PUFA supplementation. Plasma and follicular fluid RvD1 concentrations were positively correlated (r = 0.61; P < 0.01). The abundance of GPX1 and GPR32 mRNA tended to increase linearly with increasing PUFA supplementation (P = 0.06). In addition, PUFA supplementation linearly decreased and tended to decrease IL-1ß and COX-2 mRNA abundance (P = 0.01 and P = 0.06, respectively). In conclusion, the correlation between plasma and follicular fluid RvD1 concentration indicates a relationship between both compartments. Also, the decrease of IL-1ß and the increase of GPX1 mRNA abundance after PUFA supplementation could have beneficial effects on follicle development.

The aim of this experiment was to evaluate the effects of increasing dietary omega-3 (n-3) polyunsaturated fatty acid (PUFA) supplementation on plasma and follicular fluid resolvin D1 (RvD1) concentration, and the mRNA expression of genes related to RvD1 synthesis, inflammatory response, oxidative stress, reproductive hormone receptors and production, and free fatty acid receptors in ewes. Twenty-four ewes aged 2 to 4 yr were assigned to 12 pens and randomly allocated to one of three treatments: 1) diet without fatty acid supplementation (control), 2) diet with 0.5% n-3 PUFA (PUFA0.5), and 3) diet with 1% n-3 PUFA (PUFA1). Body weight (BW), body condition score (BCS), and blood samples were obtained on day 1 and every 21 d for 3 mo. Ewes were then synchronized, superstimulated, and ovariectomized. Antral follicles were aspirated to evaluate follicular fluid RvD1 concentration, and granulosa cells were used to analyze mRNA concentration. We found no differences in BW and BCS between treatments. Plasma and follicular fluid RvD1 concentration increased concomitantly to increasing dietary PUFA supplementation. There was a positive correlation between plasma and follicular fluid RvD1 concentrations. Omega-3 PUFA increased the mRNA abundance of genes associated with RvD1 synthesis and oxidative damage response. In addition, PUFA supplementation linearly decreased the mRNA abundance of genes associated with inflammatory response. In conclusion, the positive correlation between plasma and follicular fluid RvD1 concentrations demonstrates a relationship between both compartments. Also, changes in gene expression after PUFA supplementation may have a beneficial effect on the follicle and, in turn, on reproduction.

Toward assessing the role of dietary fatty acids in lamb's neurological and cognitive development.

Understanding and measuring sheep cognition and behavior can provide us with measures to safeguard the welfare of these animals in production systems. Optimal neurological and cognitive development of lambs is important to equip individuals with the ability to better cope with environmental stressors. However, this development can be affected by nutrition with a special role from long-chain fatty acid supply from the dam to the fetus or in lamb's early life. Neurological development in lambs takes place primarily during the first two trimesters of gestation. Through late fetal and early postnatal life, the lamb brain has a high level of cholesterol synthesis. This rate declines rapidly at weaning and remains low throughout adulthood. The main polyunsaturated fatty acids (PUFA) in the brain are ω-6 arachidonic acid and ω-3 docosahexaenoic acid (DHA), which are elements of plasma membranes' phospholipids in neuronal cells. DHA is essential for keeping membrane integrity and is vital for normal development of the central nervous system (CNS), and its insufficiency can damage cerebral functions and the development of cognitive capacities. In sheep, there is evidence that supplying PUFA during gestation or after birth may be beneficial to lamb productive performance and expression of species-specific behaviors. The objective of this perspective is to discuss concepts of ruminant behavior and nutrition and reflect on future research directions that could help to improve our knowledge on how dietary fatty acids (FA) relate to optimal neurological and cognitive development in sheep.

Effect of supplementation with ruminal probiotics on growth performance, carcass characteristics, plasma metabolites, methane emissions, and the associated rumen microbiome changes in beef cattle.

To evaluate the effect of supplementing beef cattle with a ruminal probiotic consisting of native rumen microbes (NRM; Chordicoccus furentiruminis, Prevotella albensis, and Succinivibrio dextrinosolvens) on methane (CH4) emissions, growth performance, carcass characteristics, and plasma metabolites, Angus × SimAngus-crossbred steers (n = 32; 8 per pen) and heifers (n = 48; 12 per pen) with an initial body weight (BW) of 353 ± 64 kg were used in randomized complete block design. Cattle were blocked by sex and BW and randomly assigned to 1 of 2 treatments (2 pens per treatment). Treatments consisted of diets offered for ad libitum intake with (NRM) or without (CON) the inclusion of the ruminal probiotic. Cattle were fed a growing diet for 49 d followed by a ground corn-based diet for 124 ± 27 d until reaching the targeted final BW (635 kg for steers and 590 kg for heifers). Methane emissions were estimated using the GreenFeed system (n = 12 per treatment) prior to trial commencement (baseline; period 1), and on three (2, 3, and 4), and two (5 and 6) different sampling periods throughout the growing and finishing stage, respectively. All data were analyzed using the PROC MIXED procedure of SAS. For CH4 production (g/d), there was a tendency for an NRM supplementation × period interaction (P = 0.07) where cattle-fed diets with NRM had lower production of methane in periods 3 and 4. Including NRM in the diet decreased CH4 yield (g/kg of dry matter intake (DMI)) by 20%. For CH4 emission intensity (g/kg of average daily gain (ADG)), an interaction (P < 0.01) of NRM supplementation × period occurred. In periods 2 and 3, cattle-fed diets with NRM inclusion had lower CH4 emission intensity than CON cattle. During the 84-d period when all cattle were still on the finishing diet, feeding NRM increased (P = 0.02) ADG and tended to increase (P = 0.10) DMI. At the end of the 84-d period, cattle-fed NRM tended to be heavier (P = 0.06) than CON cattle. Cattle supplemented with NRM required less (P = 0.04) days on feed to reach the targeted final BW. No differences (P ≤ 0.11) were detected for gain-to-feed ratio and carcass characteristics. Cattle-fed NRM had greater abundance of uncultured rumen bacteria that may improve rumen digestion when fed a high grain diet and potentially promote the reduction of enteric CH4 production. Results from this study suggest that daily administration of NRM may be a strategy to mitigate methanogenesis and improve the growth performance of beef cattle.

Greenhouse gas emissions are a major concern in the beef industry. This study examined the effects of supplementation with ruminal probiotics consisting of three native ruminal microbes (NRM) for their influence on methane reduction and growth performance of beef cattle. Eighty Angus × SimAngus-crossbred cattle were grouped by sex and weight, randomly assigned to a treatment group, control or NRM supplementation, and subsequently fed commercially relevant diets for at least 134 d with or without NRM supplementation until they reached a target finishing weight. Methane emissions and growth performance metrics were recorded at regular intervals. Cattle-fed diets with NRM had a greater average daily gain during most part of the experimental period, required fewer days to reach the finishing weight, and emitted less methane than cattle in the control treatment. Supplementing NRM can be a viable method to reduce greenhouse gas emissions while improving the performance of beef cattle-fed concentrates-based diets.

Environmental stress during the last trimester of gestation in pregnant cows and its effect on offspring growth performance and response to glucose and adrenocorticotropic hormone.

Winter and spring precipitation are predicted to increase in the Midwest region of the United States, causing muddy conditions. In a previous experiment, Angus cows (8 per treatment) were paired based on initial body weight (BW) and one cow from each pair was randomly allocated to either the mud or control treatment. Though cows consumed the same amount of dry matter, cows in the mud treatment weighed 37.4 kg less than cows in the control treatment by day 269 of gestation. The objective of this experiment was to evaluate developmental programming effects of steers born to cows in the mud treatment (MUD; n = 7) or the control treatment (CON; n = 6). Steers were weighed at birth and then weekly from approximately 56 d of age until weaning and were subjected to a glucose tolerance test (GTT) and adrenocorticotropic hormone (ACTH) challenge after weaning. Steers were then placed in the feedlot for an 84-d growing phase and were weighed weekly and 12th rib back fat (BF) and ribeye area (REA) were imaged every 28 d using ultrasonography. Data were analyzed as a randomized complete block design with repeated measurements when appropriate (SAS 9.4). Although there was a 37.4 kg decrease in BW of cows by the end of gestation, there was no evidence of a pen treatment effect on calf birth weight (P = 0.60) or weaning weight (P = 0.99). Additionally, there was no evidence of a pen treatment × day effect for steer BW from birth to weaning (P = 0.67) or growing phase BW (P = 0.60). There was evidence of a treatment × day of growing phase effect (P = 0.02) for BF, such that CON steers had greater BF on day 28 of the growing phase; however, there was no evidence of a treatment × day effect for REA (P = 0.20). Furthermore, there was no evidence of a pen treatment effect for the growing phase average daily gain (P = 0.74), dry matter intake (P = 0.65), gain:feed (P = 0.48), plasma glucose concentration (P = 0.67) or plasma insulin concentration (P = 0.61) in response to the GTT, or plasma cortisol concentration in response to the ACTH challenge (P = 0.51). These results indicate that while mud increased net energy requirements for cows in the MUD treatment, there were no subsequent effects observed for steer BW, gain:feed, or response to glucose and ACTH during the growing phase.

Predictions for the Midwest U.S. indicate that both winter and spring temperatures and precipitation will increase. These climatic changes could result in muddier conditions during winter and spring in the Midwest. It has previously been demonstrated that a muddy environment increases the net energy requirements of mature cow's by approximately 3.9 Mcal/d. If cows are not provided this extra energy and are exposed to mud during late gestation, it is likely that this will cause an adverse environment for the conceptus that could result in compromised growth and metabolism later in life. This study evaluated the developmental programming effects after birth and into the growing phase with beef steers born to cows that were housed in a muddy environment during late gestation compared with steers born to cows that were housed in pens bedded with wood chips during late gestation. Based on the present results, the mature cows housed in the muddy conditions weighed approximately 37.4 kg less than cows housed in pens bedded with wood chips during late gestation, however, calf birth weight, postnatal growth, postnatal feed intake and gain:feed, and postnatal response to glucose and adrenocorticotropic hormone was not affected. This indicates that the mature cows were able to mobilize body stores and supplied the fetus with adequate nutrients during gestation without impairment of growth or postnatal response to glucose and adrenocorticotropic hormone.

Association between dietary polyunsaturated fatty acids and their concentration in blood plasma, red blood cell, and semen of dogs.

Background: In dogs, dietary omega 3 polyunsaturated fatty acids (n-3 PUFA) affect the fatty acid (FA) profile of blood plasma, erythrocyte membrane (EM), and semen, but their correlation has not yet been investigated. Aim: In this study, we evaluated the association between dietary PUFA and their profile in blood plasma, EM, and semen of dogs, with the possibility to predict the semen profile using the values of the three first. Methods: Twelve male dogs received the same standard commercial diet for 4 weeks. The FA profile was analyzed by gas chromatography in paired diet, blood (plasma and EM determinations), and semen samples. Data were analyzed with SAS Proc Corr version 9.4. Pearson´s correlation coefficient (significant if p < 0.05) was used to assess the association of dietary FA profiles with those in blood plasma, EM, and semen. Results: There was a positive correlation between dietary eicosapentaenoic acid (EPA) and blood plasma (r = 0.97), EM (r = 0.94) and semen (r = 0.92) EPA, and between dietary docosahexaenoic acid (DHA) and arachidonic acid (ARA) and semen DHA (r = 0.93) and ARA (r = 0.92), respectively. There was a negative correlation between dihomo-gamma-linolenic acid (DGLA) in the diet and EM DGLA (r = -0.94). Conclusion: The dietary EPA is correlated with blood plasma, EM, and semen EPA concentrations, and dietary DHA and ARA are associated with semen DHA and ARA concentrations in dogs. These findings suggest that dietary EPA, DHA, and ARA concentrations could be helpful to predictive markers for such concentrations in the semen of dogs.

Ewe early gestation supplementation with eicosapentaenoic and docosahexaenoic acids affects the liver, muscle, and adipose tissue fatty acid profile and liver mRNA expression in the offspring.

Our objectives were to assess the effects of eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) supplementation to pregnant ewes during the first third of gestation on their offspring's liver, adipose, and muscle tissues fatty acid (FA) profile and liver mRNA expression after a finishing period receiving diets with different FA profiles. Twenty-four post-weaning lambs, blocked by sex and body weight, were used in a 2 × 2 factorial arrangement of treatments. The first factor was dam supplementation (DS) in the first third of gestation with 1.61% of Ca salts of palm fatty acid distillate (PFAD) or Ca salts enriched with EPA-DHA. Ewes were exposed to rams with marking paint harnesses during the breeding. Ewes started DS at the day of mating, considered day 1 of conception. Twenty-eight days after mating, ultrasonography was used to confirm pregnancy, and nonpregnant ewes were removed from the groups. After weaning, the offspring lambs were supplemented (LS, second main factor) with two different FA sources (1.48% of PFAD or 1.48% of EPA-DHA) during the growing and fattening phase. Lambs were fed the LS diet for 56 d and sent to slaughter, where the liver, muscle, and adipose tissue samples were collected for FA analysis. Liver samples were collected for relative mRNA expression for genes associated with FA transport and metabolism. The data were analyzed as a mixed model in SAS (9.4). In the liver, the amount of C20:5 and C22:6 (P < 0.01) increased in lambs with LS-EPA-DHA, while some C18:1 cis FA isomers were greater in the lambs from DS-PFAD. In muscle, amounts of C22:1, C20:5, and C22:5 increased (P < 0.05) in lambs born from DS-EPA-DHA. The adipose tissue amounts of C20:5, C22:5, and C22:6 were greater (P < 0.01) in lambs from LS-EPA-DHA. Interactions (DS × LS; P < 0.05) were observed for DNMT3ß, FABP-1, FABP-5, SCD, and SREBP-1; having greater mRNA expression in liver tissue of LS-EPA-DHA, DS-PFAD and LS-PFAD, DS-EPA-DHA lambs compared with the lambs in the other two treatments. Liver ELOVL2 mRNA relative expression (P < 0.03) was greater in the offspring of DS-PFAD. Relative mRNA expression (P < 0.05) of GLUT1, IGF-1, LPL, and PPARγ increased in the liver from LS-EPA-DHA lambs. Dam supplementation during early gestation using with different FA sources changed the lipid FA profile in MT, LT, and SAT during the finishing period depending on the tissue and type of FA source administered during the growing phase.

Previous research has identified that polyunsaturated fatty acids take part in many health benefits, including fetal development during pregnancy. Also, other types of fatty acids, such as monounsaturated, have been linked to reduction of cardiovascular disease. Our study aimed to assess the effect of supplementation with different types of fatty acids, offered at 1.61% of the feed intake (as calcium salts of fatty acids), during the first 50 d of pregnancy in ewes and later continue the fatty acids supplementation during the growing phase of the offspring (at 1.48% of the feed intake). The proportions of different fatty acids were evaluated in the lambs' liver, muscle, and adipose tissue. Also, the mRNA expression of genes involved in fatty acid metabolism was analyzed in the lambs' liver. Our study demonstrated that depending on the type of fatty acids (polyunsaturated vs. monounsaturated) during early gestation, the profile of fatty acids changes in the different tissues evaluated. Also, fatty acid supplementation during early gestation modifies the expression of mRNA of genes involved in fat metabolism in the liver in the mature offspring.

Effect of age and diet on carcass and meat quality in ewes.

This study elucidated the effect of age and diet on carcass characteristics and meat quality parameters of Rambouillet ewes. Forty ewes (n = 20 yearling ewes and n = 20 cull ewes) were fed with alfalfa hay (AH) or a 100 % concentrate diet (CD). Treatments were: a) 10 cull ewes were fed only with AH, b) 10 yearling ewes were fed only with AH, c) 10 cull ewes were fed with CD, d) 10 yearling ewes were fed with CD. Productive performance, carcass and meat quality were analyzed. Animals had ten days for adaptation and 35 days were used to collect data. Dry matter intake was greater (P < 0.05) for CD. Feed conversion rates were not affected by treatments. The pH at 45 min and 24 h, carcass length, leg length, leg width, thorax width, and thorax perimeter were not affected by treatments. Hot carcass weight was heavier (P < 0.05) in cull ewes, cold carcass weight was increased (P < 0.05) with CD. Carcass yield (CY) was heavier in CD (P < 0.05). Cull ewes had greater (P < 0.05) lean CIELAB L*, a*, b*, c*, and h* values compared to yearling ewes. The color changes increased with age at five days (P < 0.05), but a decrease (P < 0.05) with diet was observed at ten days. Cathepsins B, B + L, and Lowry protein content were not affected by treatments. In conclusion, feeding cull ewes with concentrate diets may enhance body weight gain and carcass yield compared to a diet based on 100 % alfalfa hay.

Effects of maternal calcium propionate supplementation on offspring productivity and meat metabolomic profile in sheep.

This study determined the effect of dietary calcium propionate (CaPr) as a source of energy supplementation during the First Half of Gestation (FMG), the Second Half of Gestation (SMG), and during All Gestation (AG), on offspring post-weaning growth performance, meat quality, and meat metabolomic profile. Thirty-one pregnant ewes were assigned to one of four treatments: a) supplementation of 30 gd-1 of CaPr during the first half of gestation (day 1 to day 75, n = 8) (FMG); b) supplementation of 30 gd-1 of CaPr during the second half of gestation (day 76 to day 150, n = 8) (SMG); c) supplementation of 30 gd-1 of CaPr during all gestation (AG, n = 8); d) no CaPr supplementation (control; CS, n = 7). The ewes were ad libitum fed a basal diet based on oat hay and corn silage. Ewes were distributed in a completely randomized unbalanced design to four treatments. The FMG group had lower (P ≤ 0.05) birth weight and weaning weight than the CS group. However, the average daily gain was similar across all treatments. Empty body weight and FMG had lower values (P ≤ 0.05) than the other groups. Both FMG and AG had lower hot carcass weight (P ≤ 0.05) compared to CS, while CaPr treatments resulted in reduced hot carcass yield (P ≤ 0.05). Meat color and texture were similar among treatments. A principal component analysis between gestation stages showed a trend for separating CS and FMG from SMG and AG, and that was explained by 93.7% of the data variability (PC1 = 87.9% and PC2 = 5.8%). Regarding meat metabolomic profile, 23 compounds were positively correlated between all treatments. Only 2 were negatively correlated (eicosane and naphthalene 1,2,3); but tetradecanoic acid, hexadecane, undecane 5-methyl, (-)-alpha, hexadecenoic acid, octadecanoic acid, and octadecane had a highly significant correlation (P ≤ 0.05). Overall, dam supplementation with CaPr during different periods of gestation provoked changes in meat metabolites related to the biosynthesis of fatty acids in lambs without negative changes in lamb's growth performance and carcass quality.