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Rumen microbes play an important role in the growth and development of ruminants. Differences in variety will affect the rumen community structure. The three excellent sheep breeds were selected for this study (Hu sheep, Tan sheep, and Dorper sheep) have different uses and origins. The sheep were raised on the same diet to 180 d of age in a consistent environment. 16S rDNA V3 to V4 region sequencing was used to assess the rumen microbes of 180 individuals (60 per breed). There were differences in microbial diversity among different sheep breeds (P0.05). Principal coordinate analysis showed that the three varieties were separated, but also partially overlapped. Linear discriminant analysis effect size identified a total of 19 biomarkers in three breeds. Of these biomarkers, five in Hu sheep were significantly negatively correlated with average feed conversion rate (P0.05). Six biomarkers were identified in the rumen of Dorper sheep, among which Ruminococcus was significantly positively correlated with body weight at 80 d (P0.05). In Tan sheep, Rikenellaceae_RC9_gut_group was significantly positively correlated with meat fat, and significantly positively correlated with volatile fatty acids (VFAs), such as butyric acid and isobutyric acid (P0.05). The Rikenellaceae_RC9_gut_group may regulate Tan mutton fat deposition by affecting the concentration of VFAs. Functional prediction revealed enrichment differences of functional pathways among different sheep breeds were small. All were enriched in functions, such as fermentation and chemoheterotrophy. The results show that there are differences in the rumen microorganisms of the different sheep breeds, and that the microorganisms influence the host.The rumen is the most important digestive organ of ruminants, and the rumen microflora plays an important role in the process of digestion. This study compared the differences in rumen microbes of different breeds of sheep, identified key biomarkers of each breed, and analyzed their correlation with important economic traits of sheep. The results showed that the biomarkers of various breeds were significantly correlated with key traits. Therefore, we believe that there is a link between sheep rumen microbes and the differential traits of different breeds of sheep. This provides a new idea for sheep trait improvement.

Intrauterine growth restriction (IUGR) is linked to lifelong reductions in muscle mass due to intrinsic functional deficits in myoblasts, but the mechanisms underlying these deficits are not known. Our objective was to determine if the deficits were associated with changes in inflammatory and adrenergic regulation of IUGR myoblasts, as was previously observed in IUGR muscle. Primary myoblasts were isolated from IUGR fetal sheep produced by hyperthermia-induced placental insufficiency (PI-IUGR; n = 9) and their controls (n = 9) and from IUGR fetal sheep produced by maternofetal inflammation (MI-IUGR; n = 6) and their controls (n = 7). Proliferation rates were less (P0.05) for PI-IUGR myoblasts than their controls and were not affected by incubation with IL-6, TNF-α, norepinephrine, or insulin. IκB kinase inhibition reduced (P0.05) proliferation of control myoblasts modestly in basal media but substantially in TNF-α-added media and reduced (P0.05) PI-IUGR myoblast proliferation substantially in basal and TNF-α-added media. Proliferation was greater (P0.05) for MI-IUGR myoblasts than their controls and was not affected by incubation with TNF-α. Insulin increased (P0.05) proliferation in both MI-IUGR and control myoblasts. After 72-h differentiation, fewer (P0.05) PI-IUGR myoblasts were myogenin+ than controls in basal and IL-6 added media but not TNF-α-added media. Fewer (P0.05) PI-IUGR myoblasts were desmin+ than controls in basal media only. Incubation with norepinephrine did not affect myogenin+ or desmin+ percentages, but insulin increased (P0.05) both markers in control and PI-IUGR myoblasts. After 96-h differentiation, fewer (P0.05) MI-IUGR myoblasts were myogenin+ and desmin+ than controls regardless of media, although TNF-α reduced (P0.05) desmin+ myoblasts for both groups. Differentiated PI-IUGR myoblasts had greater (P0.05) TNFR1, ULK2, and TNF-α-stimulated TLR4 gene expression, and PI-IUGR semitendinosus muscle had greater (P0.05) TNFR1 and IL6 gene expression, greater (P0.05) c-Fos protein, and less (P0.05) IκBα protein. Differentiated MI-IUGR myoblasts had greater (P0.05) TNFR1 and IL6R gene expression, tended to have greater (P = 0.07) ULK2 gene expression, and had greater (P0.05) β-catenin protein and TNF-α-stimulated phosphorylation of NFκB. We conclude that these enriched components of TNF-α/TNFR1/NFκB and other inflammatory pathways in IUGR myoblasts contribute to their dysfunction and help explain impaired muscle growth in the IUGR fetus.Myoblasts are stems cells whose functional capacity can limit muscle growth. However, stressful intrauterine conditions cause these cells to be intrinsically dysfunctional. This restricts muscle growth capacity, leading to intrauterine growth restriction (IUGR) of the fetus, low birth weight, and less muscle mass after birth. Consequently, meat yield is reduced in IUGR-born food animals and glucose homeostasis is impaired in IUGR-born humans, which contributes to metabolic dysfunction. Intrinsic dysfunction of IUGR myoblasts has been previously observed, but the fetal programming changes (i.e., permanent changes in the development of cellular mechanisms that explains different functional outcomes) have not been identified. This study shows that one mechanism is the enhancement of signaling pathways for TNF-α and other inflammatory cytokines. These cytokines have roles in stress responses and regulation of muscle growth. Programmed enhancement of these pathways means that IUGR myoblasts are more responsive to even normal amounts of circulating cytokines. Unfortunately, the primary response of myoblasts to cytokines is slower differentiation (i.e., cellular transformation necessary for muscle growth). Programmed enhancement of this response directly impedes myoblast-dependent muscle growth, and the deficit is lifelong. However, identifying this mechanism is a fundamental step for developing strategies to improve muscle growth in low birth weight offspring.

ZNF280BY, a bovid-specific Y chromosome gene, was firstly found to be highly expressed in bovine testis, indicating that it may play important roles in testicular development and male fertility. In this study, we firstly cloned the full-length cDNA of ovine ZNF280BY containing 1,993 bp, and with a 1,632 bp open reading frame. ZNF280BY was predominantly expressed in the testis, and its expression level was significantly higher in large testis than in small testis in Hu sheep at 6 months of age. In addition, the expression level of ZNF280BY significantly increased during testicular development, showing the highest expression level at 12 mo of age. ZNF280BY showed copy number variation (CNV) in 723 rams from eight sheep breeds, ranging from 17 to 514 copies, with a median copy number of 188. Pearson correlation analysis showed that the CNV of ZNF280BY was negatively correlated with testis size in Hu sheep. Furthermore, its mRNA expression level in testis had no significant correlation with the CNV but was significantly correlated with testis size. This study concluded that the expression of ZNF280BY was closely related to testicular development, and the CNV of ZNF280BY could be used as an important genetic marker to evaluate the ram reproductive capacity at an early stage in Hu sheep.The zinc finger protein 280B-like, Y-linked ZNF280BY is a bovid-specific Y chromosome gene, playing important roles in testicular development and male fertility. In this study, we found that the ovine ZNF280BY was highly expressed in the testis and significantly upregulated during testicular development. The copy number of ZNF280BY was negatively correlated with testicular size in Hu sheep. Our results demonstrated that the CNV of ZNF280BY could be used as an important candidate marker for selecting elite rams at an early stage in Hu sheep.

Animal growth traits are important and complex traits that determine the productivity of animal husbandry. There are many factors that affect growth traits, among which diet digestion is the key factor. In the process of animal digestion and absorption, the role of gastrointestinal microbes is essential. In this study, we transplanted two groups of sheep intestinal microorganisms with different body weights into the intestines of mice of the same age to observe the effect of fecal bacteria transplantation on the growth characteristics of the mouse model. The results showed that receiving fecal microbiota transplantation (FMT) had an effect on the growth traits of recipient mice (P 0.05). Interestingly, only mice receiving high-weight donor microorganisms showed differences. Use 16S rDNA sequencing technology to analyze the stool microorganisms of sheep and mice. The microbial analysis of mouse feces showed that receiving FMT could improve the diversity and richness of microorganisms (P 0.05), and the microbial composition of mouse feces receiving low-weight donor microorganisms was similar to that of the control group, which was consistent with the change trend of growth traits. The feces of high-weight sheep may have higher colonization ability. The same five biomarkers were identified in the donor and recipient, all belonging to Firmicutes, and were positively correlated with the body weight of mice at each stage. These results suggest that FMT affects the growth traits of receptors by remodeling their gut microflora.The rate of development of growth traits determines the productivity of sheep. Shortening the fattening cycle of sheep can effectively improve economic efficiency. Gut microbes have important effects on host growth traits. In this study, the method of fecal microbiota transplantation (FMT) was used to transplant the intestinal microbes of sheep into the mouse model, and the changes of the growth traits and intestinal microbes of the mice were observed. The results suggest that FMT can effectively affect growth traits by altering recipient gut microbes. This provides a new idea for the regulation of sheep growth traits.

Poor maternal nutrition during gestation can result in reduced offspring muscle growth and altered muscle metabolism. We hypothesized that over- or restricted-nutrition during gestation would alter the longissimus dorsi muscle (LM) proteome of offspring. Pregnant ewes were fed 60% (restricted), 100% (control), or 140% (over) of National Research Council requirements for total digestible nutrients from day 30 of gestation until parturition. Fetal (RES, CON, OVER) LM were collected at days 90 and 135 of gestation, or from offspring within 24 h of birth. Sarcoplasmic proteins were isolated, trypsin digested, and subjected to multiplexed, label-based quantitative mass spectrometry analysis integrating tandem mass tag technology. Differential expression of proteins was identified by ANOVA followed by Tukey's HSD post hoc tests, and regularized regression via the elastic net. Significance was set at P0.05. Over-represented pathways containing differentially expressed proteins were identified by Reactome and included metabolism of proteins, immune system, cellular response to stress/external stimuli, developmental biology, and infectious disease. As a result of maternal diet, a total of 312 proteins were differentially expressed (day 90 = 89 proteins; day 135 = 115 proteins; birth = 131 proteins). Expression of eukaryotic initiation factor (EIF) 2S3, EIF3L, and EIF4G2 was lower in OVER fetuses at day 90 of gestation (P0.05). Calcineurin A and mitogen-activated protein kinase 1 were greater in RES fetuses at day 90 (P0.04). At day 135 of gestation, pyruvate kinase and lactate dehydrogenase A expression were greater in OVER fetuses than CON (P0.04). Thioredoxin expression was greater in RES fetuses relative to CON at day 135 (P = 0.05). At birth, proteins of the COP9 signalosome complex were greater in RES offspring relative to OVER (P0.05). Together, these data indicate that protein degradation and synthesis, metabolism, and oxidative stress are altered in a time and diet-specific manner, which may contribute to the phenotypic and metabolic changes observed during fetal development and postnatal growth.Poor maternal diet during gestation results in changes in body composition and metabolism in the offspring. Here, we demonstrate that over- and restricted-feeding during gestation alter global protein expression in the longissimus dorsi muscle of offspring during gestation and just after birth. These protein changes are related to protein synthesis and degradation, stress responses, metabolism, and oxidative stress. Proteins related to the initiation of protein translation were increased in offspring of over-fed dams at mid-gestation, while changes in abundance of enzymes associated with metabolism were altered in late gestation and just after birth. In offspring of restricted-fed ewes, proteins relating to cell signaling were increased at mid-gestation, while again, changes in late gestation and birth were related to metabolism, protein degradation, and stress responses. Together, these may provide a mechanism by which poor maternal diet during gestation alters the poor growth and development that occurs in these offspring.

Fecal egg count (FEC) is an indicative measurement for parasite infection in sheep. Different FEC methods may show inconsistent results. Not accounting for inconsistencies can be problematic when integrating measurements from different FEC methods for genetic evaluation. The objectives of this study were to evaluate the difference in means and variances between two fecal egg counting methods used in sheep—the Modified McMaster (LMMR) and the Triple Chamber McMaster (LTCM); to estimate variance components for the two FEC methods, treating them as two different traits; and to integrate FEC data from the two different methods and estimate genetic parameters for FEC and other gastrointestinal parasite resistance traits. Fecal samples were collected from a commercial Rideau-Arcott sheep farm in Ontario. Fecal egg counting was performed using both LMMR and the LTCM methods. Other parasite resistance trait records were collected from the same farm including eye score (FAMACHA), body condition score (BCS), and body weight (WT). The two FEC methods were highly genetically (0.94) and phenotypically (0.88) correlated. However, the mean and variance between the two FEC methods were significantly different (P < 0.0001). Therefore, re-scaling is required prior to integrating data from the different methods. For the multiple trait analysis, data from the two fecal egg counting methods were integrated (LFEC) by using records for the LMMR when available and replacing missing records with re-standardized LTCM records converted to the same mean and variance of LMMR. Heritability estimates were 0.12 ± 0.04, 0.07 ± 0.05, 0.17 ± 0.06, and 0.24 ± 0.07 for LFEC egg count, FAMACHA, BCS, and WT, respectively. The estimated genetic correlations between FEC and the other parasite resistance traits were low and not significant (P > 0.05) for FAMACHA (r = 0.24 ± 0.32) and WT (r = 0.22 ± 0.19), and essentially zero for BCS (r = −0.03 ± 0.25), suggesting little to no benefit of using such traits as indicators for LFEC.

In rodents, an acute-phase protein, α-1-acid-glycoprotein (AGP), was shown to provide a link between inflammation and suppression of feed intake by acting as a leptin receptor agonist. The objective of this study was to determine the effects of AGP on feed intake and rectal temperature in sheep. Ewes were ovariectomized, implanted with a cannula into a lateral ventricle of the brain, and kept indoors in individual pens. Feed intake and rectal temperature were determined for sheep in all experiments. In the first experiment, ewes (n = 4) received 1 of 4 treatments [0 (control), 0.012 (low), 0.06 (medium), or 0.30 (high) mg/kg BW AGP] into the lateral ventricle (ICV). All sheep received all treatments in a Latin square design balanced for carryover effects with 10 d between treatments. In the second experiment, ewes (n = 10) received 1 of 2 treatments (0 and 3 mg/kg BW of AGP) intravenously (IV) in a completely randomized design. In the third experiment, ewes (n = 19) received peripheral treatments (IV) of an antipyretic [0 (control) or 2.2 mg/kg BW flunixin meglumine (FLU)] 30 min before receiving central AGP [0 (control) or 0.3 mg/kg BW of AGP] in a completely randomized design. All data were analyzed using a mixed model analysis of variance and tested for effects of treatment, time, and the interaction of treatment and time. Cumulative 48-h feed intake after administration of treatments was also determined. In the first experiment, there was no effect of ICV treatment (P = 0.37) on feed intake rate or on cumulative feed intake (P = 0.31). There was an effect of ICV treatment (P = 0.002) on rectal temperatures, which were greater (P < 0.05) after the high dose of centrally administered AGP. In the second experiment, there was no effect of AGP administration IV on feed intake rate (P = 0.98), on cumulative feed intake (P = 0.41) or on rectal temperature (P = 0.71). In the third experiment, there was an effect of central AGP treatment (P < 0.0001) and an interaction of central AGP and time (P < 0.0001) on rectal temperature, whereas FLU had no effect (P = 0.93), demonstrating that AGP increased rectal temperatures regardless of antipyretic treatment. These results indicate that central AGP increases rectal temperature in sheep by pathways that do not involve prostaglandins. Further research is needed to determine whether AGP may be an important integrator of energy balance and inflammation.

Portable accumulation chambers (PAC) enable gaseous emissions from small ruminants to be measured over a 50 min period, to date however, the repeatability of consecutive days of measurement in the PAC has not been investigated. The objectives of this study were to investigate: 1) the repeatability of consecutive days of gaseous measurements in the PAC, 2) the number of days required to achieve precise gaseous measurements, and 3) to develop a prediction equation for gaseous emissions in sheep. A total of 48 ewe lambs (c. 10 to 11 mo of age) were randomly divided into four measurement groups each day, for 17 consecutive days. Gaseous measurements were conducted between 0800 h and 1200 h daily. Animals were removed from perennial ryegrass silage for at least 1 h before measurements in the PAC and animals were assigned randomly to each of the 12 chambers. Methane (CH4; ppm) concentration, oxygen (O2; percentage) and carbon dioxide (CO2; percentage) were measured at 3 time points (0, 25, and 50 min after entry of the first animal into the first chamber). To quantify the effect of animal and day variation on gaseous emissions, between-animal, between-day and error variances were calculated for each gaseous measurement using a linear mixed model. The number of days required to gain a certain precision (defined as the 95% confidence interval (CI) range) for each gaseous measurement was also calculated. For all 3 gases the between-day variance (39% to 40%) accounted for a larger proportion of total variance compared to between-animal variance, while the repeatability of 17 consecutive days of measurement was 0.36, 0.31 and 0.23 for CH4, CO2 and O2, respectively. Correlations between consecutive days of measurement were strong for all 3 gases; the strongest correlation between d 1 and the remaining days for CH4, CO2 and O2 was 0.71 (d 1 and d 6), 0.77 (d 1 and d 2) and 0.83 (d 1 and d 5), respectively. A high level of precision was achieved when gaseous measurements from PAC were taken over 3 consecutive days. The prediction equation over-estimated gaseous production for all 3 gases: the correlations between actual and predicted gaseous output ranged from 0.67 to 0.71, with the r 2 ranging from 0.45 to 0.71. Results from this study will aid the refinement of the protocol for the measurement of gaseous emissions in sheep using the PAC.

Physical traits that improve welfare and disease outcomes for sheep are becoming increasingly important due to both increased climate challenges and societal expectations. Such traits include tail length, the amount of skin (versus wool) on the underside of the tail, and the area of no-wool (hair) on the belly and breech areas (surrounding the anus) of the animal. An industry dataset consisting of records from individual stud breeders and industry progeny tests was available to estimate the genetic parameters associated with these traits and to investigate the potential for within-breed genetic selection. The heritability estimate for tail length was 0.68 ± 0.01 when breed was not fitted, and 0.63 ± 0.01 when breed was fitted. Similar trends were observed for breech and belly bareness which had heritability estimates around 0.50 (± 0.01). The estimates for these bareness traits are both higher than previous reports from animals of the same age. There was, however, between breed variation in the starting point for these traits, with some breeds having significantly longer tails and a wooly breech and belly, and limited variability. Overall, the results of this study show that flocks exhibiting some variation will be able to make rapid genetic progress in selecting for bareness and tail length traits, and therefore have the potential to make progress towards a sheep that is easier to look after and suffers fewer welfare insults. For those breeds that showed limited within-breed variation, outcrossing may be required to introduce genotypes that exhibit shorter tail length and bareness of belly and breech to increase the rate of genetic gain. Whatever approach is taken by the industry, these results support that genetic improvement can be used to breed “ethically improved sheep”.

To investigate single nucleotide polymorphism (SNP) loci associated with yearling wool traits of fine-wool sheep for optimizing marker-assisted selection and dissection of the genetic architecture of wool traits, we conducted a genome-wide association study (GWAS) based on the fixed and random model circulating probability unification (FarmCPU) for yearling staple length (YSL), yearling mean fiber diameter (YFD), yearling greasy fleece weight (YGFW), and yearling clean fleece rate (YCFR) by using the whole-genome re-sequenced data (totaling 577 sheep) from the following four fine-wool sheep breeds in China: Alpine Merino sheep (AMS), Chinese Merino sheep (CMS), Qinghai fine-wool sheep (QHS), and Aohan fine-wool sheep (AHS). A total of 16 SNPs were detected above the genome-wise significant threshold (P = 5.45E-09), and 79 SNPs were located above the suggestive significance threshold (P = 5.00E-07) from the GWAS results. For YFD and YGFW traits, 7 and 9 SNPs reached the genome-wise significance thresholds, whereas 10 and 12 SNPs reached the suggestive significance threshold, respectively. For YSL and YCFR traits, none of the SNPs reached the genome-wise significance thresholds, whereas 57 SNPs exceeded the suggestive significance threshold. We recorded 14 genes located at the region of ±50-kb near the genome-wise significant SNPs and 59 genes located at the region of ±50-kb near the suggestive significant SNPs. Meanwhile, we used the Average Information Restricted Maximum likelihood algorithm (AI-REML) in the “HIBLUP” package to estimate the heritability and variance components of the four desired yearling wool traits. The estimated heritability values (h2) of YSL, YFD, YGFW, and YCFR were 0.6208, 0.7460, 0.6758, and 0.5559, respectively. We noted that the genetic parameters in this study can be used for fine-wool sheep breeding. The newly detected significant SNPs and the newly identified candidate genes in this study would enhance our understanding of yearling wool formation, and significant SNPs can be applied to genome selection in fine-wool sheep breeding.

Exogenous fibrolytic enzyme (EFE) products in ruminant nutrition may be an important alternative to meet the increased demands for animal products in the future with reduced environmental impacts. This study aimed to evaluate the dose–response of EFE supplementation on the nutrient digestibility, nitrogen and energy utilization, and methane (CH4) emissions of Tan sheep grazed in summer and winter. A total of 20 Tan wether sheep with an initial body weight of 23.17 ± 0.24 kg were used in a randomized complete block design and categorized into two groups. Animals fed orally with 1 g of EFE (10,000 U/g) mixed with 30 mL of water using a drencher constituted the EFE group. For experimental accuracy, the control (CON) group was orally administered with 30 mL of normal saline daily before grazing. The following results were obtained: EFE in the diet increased dry matter intake (DMI) (P 0.05), but reduced pH (P > 0.05), compared with CON in summer and winter. EFE increased nitrogen (N) intake, digestible N, retained N, and retained N/digestible N (P

α-Lipoic acid (α-LA) was usually applied to improve the ability of removing the reactive oxygen species of host. The affection of α-LA on ruminants was mainly focused on the variation of serum antioxidant and immune indexes, but the research on tissues or organs remained limited. The aim of this study was to explore the effects of dietary supplementation with different levels of α-LA on growth performance, antioxidant status, and immune indexes of serum and tissues in sheep. One hundred Duhu F1 hybrid (Dupo♀ × Hu sheep♂) sheep aged 2 to 3 mo with similar body weight (27.49 ± 2.10 kg) were randomly allocated into five groups. Five diets supplemented with 0 (CTL), 300 (LA300), 450 (LA450), 600 (LA600), and 750 (LA750) mg/kg α-LA were fed to sheep for 60 d. The results showed that α-LA supplementation significantly increased the average daily feed intake (P < 0.05); however, no significant variation was found in the average daily gain, feed conversion rate, carcass weight, and slaughter rate among groups (P > 0.05). Compared with CTL group, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities in serum of LA600 and LA750 groups were increased (P < 0.05). At LA450–LA750 groups, SOD, CAT activities in liver and ileum tissues and GSH-Px activities in ileum tissues were increased than CTL group (P < 0.05), while malondialdehyde (MDA) contents in serum and muscle tissue were decreased than CTL group (P < 0.05). The total antioxidant capacity contents in liver, muscle, and ileum tissues of LA600 group were increased compared with CTL group (P < 0.05). Additionally, the interleukin-10 (IL-10) contents of serum in LA450–LA750 groups were increased than CTL group (P < 0.05); the contents of interleukin-1β (IL-1β) in serum, interleukin-2 (IL-2) in liver, and interleukin-6, IL-1β in muscle were decreased than CTL group (P < 0.05). The content of immunoglobulin A in serum of LA600 group, ileum, and muscle of LA750 group was increased than CTL group (P < 0.05). Based on the quadratic regression analysis of GSH-Px, MDA, IL-2, IL-10, and IL-1β, the optimal dietary α-LA levels were estimated to be 495.75, 571.43, 679.03, 749.75, and 678.25 mg/kg, respectively. This research will provide certain contribution for the effective utilization of α-LA in sheep production.

Gastrointestinal nematodes (GIN) negatively affect the performance and well-being of sheep. Due to anthelmintic resistance, GIN are difficult to control leading producers to choose breeds that can exhibit resistance to parasitism. An example is Katahdin sheep. Katahdins are raised in various climates and management systems in the United States. These environmental factors can be combined to form eco-management groupings or clusters. We hypothesized that GIN challenge varies predictably based on the characteristics of these environmental clusters. Forty Katahdin producers from across the United States were surveyed for management information, with body weights (BW), fecal egg counts (FEC), and FAMACHA scores (FAM) available from 17 of the 40 flocks. The performance data included 3,426 lambs evaluated around 90 d of age. Management and climate data were combined into clusters using multiple correspondence and principal component (PC) analysis. Performance data were aligned with their corresponding cluster. Depending on the trait, eco-management cluster, birth-rearing type, sex, and, as a covariate, dam age, were fitted as systematic effects with ANOVA. Clusters also were formed based on climate or management data alone. When compared with fitting the eco-management clusters, they defined less variation in each of the traits based on Akaike and Bayesian information criterion, and adjusted r2 values. To further examine variation defined by eco-management clusters, residuals from an ANOVA model excluding eco-management cluster were retained, and their correlation with PC loadings calculated. All PC loadings were included as potential independent variables and tested for significance using backward stepwise regression. The PC loadings with a correlation |≥0.49| explained significant variation in each trait and were included in the final models chosen; adjusted r2 values for BW, FEC, and FAM were 0.90, 0.81, and 0.97, respectively. When analyzing GIN challenge, eco-management clusters corresponding with hotter temperatures and greater rainfall, and with pasture-born lambs, suffered greater parasitism. Conversely, the eco-management clusters with lambs turned out to pasture at older ages benefited from reduced parasitism. Through the formation of eco-management clusters, an environmental variable can be defined to study interactions of genotypes to their environment, providing a potentially useful tool for identifying parasite-resistant sheep.

As one of the most obvious phenotypic traits, the coat color of sheep is an ideal model to study the genetic mechanisms underlying coat color varieties of mammals. One distinguishable coat color is the black-headed type, such as the famous black-headed Dorper sheep from Africa and Bayinbuluke sheep from Asia. In this study, we compared the genome sequences of black-headed and all-white sheep to identify causative genes for the black-headed sheep, including black-headed Dorper vs. white-headed Dorper, as well as Bayinbuluke (black-headed) vs. Small-tailed Han (all-white). The most differentiating region between black-headed sheep and all-white sheep was found to harbor a haplotype covering melanocortin receptor 1 (MC1R) gene. The share of this haplotype by the black-headed sheep from Africa and Asia suggested that the convergent change in the MC1R region is likely to determine this unique coat color. Two missense mutations (g. 14251947T > A and g. 14252090G > A) within this haplotype of MC1R gene were found. We further analyzed whole genome sequence data of 460 worldwide sheep with diverse coat colors and confirmed the association between the MC1R haplotype with pigmentation variations. Our study provides novel insights into coat color genetics in sheep and expands our knowledge of the link between MC1R gene and varying pigmentation patterns in sheep.

Animal-to-animal variation in methane (CH4) emissions determined in respiration chambers has a genetic basis, but rapid phenotyping methods that can be applied on-farm are required to enable increased genetic progress by the farming industry. Fermentation of carbohydrates in the rumen results in the formation of VFA with hydrogen (H2) as a byproduct that is used for CH4 formation. Generally, fermentation pathways leading to acetate are associated with the most H2 production, less H2 formation is associated with butyrate production, and propionate and valerate production are associated with reduced H2 production. Therefore, VFA may constitute a potential correlated proxy for CH4 emissions to enable high-throughput animal screening. The objective of the present study was to determine the genetic parameters for ruminal and plasma VFA concentrations in sheep fed alfalfa (Medicago sativa L.) pellets and their genetic (rg) and phenotypic (rp) correlations with CH4 emissions. Measurements of CH4 emissions in respiration chambers and ruminal (stomach tubing 18 h from last meal) and blood plasma (3 h post-feeding) VFA concentrations were made on 1,538 lambs from 5 birth years (2007 and 2009 to 2012) aged between 5 and 10 mo, while the animals were fed alfalfa pellets at 2.0 times maintenance requirements in 2 equal size meals (0900 and 1500 h). These measurements were repeated twice (rounds) 14 d apart. Mean (± SD) CH4 production was 24.4 ± 3.08 g/d, and the mean CH4 yield was 15.8 ± 1.51 g/kg DMI. Mean concentration of total ruminal VFA was 52.2 mM, with concentrations of acetate, propionate and butyrate of 35.97, 8.83, and 4.02 mM, respectively. Ruminal total VFA concentration had heritability (h2) and repeatability estimates (± SE) of 0.24 ± 0.05 and 0.35 ± 0.03, respectively, and similar estimates were found for acetate, propionate, and butyrate. Blood plasma concentrations of VFA had much lower estimates of h2 and repeatability than ruminal VFA. Genetic correlations with CH4 yield were greatest for total concentrations of ruminal VFA and acetate, with 0.54 ± 0.12 and 0.56 ± 0.12, respectively, which were much greater than their corresponding rp. The rp and rg of ruminal VFA proportions and blood VFAs with CH4 emissions were in general lower than for ruminal VFA concentrations. However, minor ruminal VFA proportions had also moderate rg with CH4 yield. Pre-feeding concentrations of total VFA and acetate were the strongest correlated proxies to select sheep that are genetically low CH4 emitters.

Cryopreservation of tissues from domesticated and wild relatives has been suggested to conserve genetic diversity. Ensuring that the tissues have live cells prior to preservation, especially in postmortem tissues, is an essential stem for success. How long cells live after clinical death is not precisely known in animals. The objective of this study was to evaluate the limits of cell survival in sheep skin stored at 4°C postmortem. Ear skin was procured from six random but healthy slaughtered animals and stored at 4°C in the lab. Ten explants (2–3 mm2) were cultured from each animal in DMEM media with 10% FBS, 50 units/mL of penicillin, 50 µg/mL of streptomycin, and 2.5 µg/mL of fungizone on two 60 mm dishes after 0, 10, 20, 27, 30, 35, 38, 41, 45, 50, 55, 60, 65 and 70 days of storage. Outgrowth of fibroblast-like cells around the explants was scored after 10 days of culture in a CO2 incubator. Results show outgrowth of cells up to 65 days of postmortem storage. Out of 476 explants adhered to dish surface, 374 (78.58%) exhibited outgrowth. The number of outgrowing cells decreased with increasing postmortem storage time interval. To test the differences between cell cultures obtained from postmortem fresh and stored tissues, we established secondary cultures from primary cells of 0-dpm and 65-dpm time points from selected cell lines. Both cultures exhibited similar growth morphology and growth curve, could be cryopreserved with >80% post freezing cell viability, lasted in cultures up to 35 passages, and expressed GFP gene upon transfection with a GFP gene containing plasmid vector. The karyotype analysis of 65-dpm tissue derived cells revealed a normal female karyotype without any genetic aberrations. These results suggest that normal proliferative cells can be recovered from sheep skin up to about 2 months postmortem, if kept refrigerated.

St. Croix sheep are hair sheep whose production characteristics make them suitable for low-input, sustainable production systems. They are parasite resistant and can live in a wide variety of climates. Natural immune modulators, such as garlic, can enhance animal production, health, and well-being. Garlic (Allium Sativa) is recognized as an eco-friendly alternative to antibiotics and contributes to a reduction in methane emissions. It has antibiotic, anti-helminthic and anti-inflammatory properties. The present study was carried out to determine the effect of garlic extracts on health variables and gut health indicators in St Croix sheep. Clinically, healthy adult, age-matched non-pregnant St Croix sheep (n = 12) from the NC A&T University farm were divided into treatment group (n = 6) and control group (n = 6). The treatment group was drenched with 5 mL garlic [Garlic Barrier (Glendale, CA)] concentrate diluted 1:1 with sterile distilled water (10 mL total). The control group was drenched with 10ml sterile distilled water for four weeks. The body weight, body condition, and FAMACHA scores and fecal samples were collected weekly. Fecal egg count was evaluated using the modified McMaster technique. Fecal samples were analyzed for eggs per gram using the McMaster slide. Total microbial DNA was isolated from fecal samples using Fast stool DNA Isolation kit (Qiagen, CA). DNA concentrations and purity were analyzed using a Nanodrop spectrophotometer. The relative abundance of Lactobacillus, bifidobacteria,16s RNA and Haemonchus are measured by using specific primers by running real time PCR. All variables were analyzed using the statistical analysis software package SAS version 9.4 (SAS Institute, Cary, NC). Garlic reduced fecal egg count significantly in weeks 1 (P < 0.034) and 3 (P < 0.003). There were no significant changes in fecal DNA Concentration. The relative of abundance of Lactobacillus is significantly increased whereas for Haemonchus decreased. Further studies are needed to define the pathways involved and consequences of changes in gut microbe community on immune function. These studies will aim in improved animal and human health and well-being and sustainable production.

Data from cattle and sheep studies are often utilized interchangeably to make inferences regarding ruminant nutrition and physiology, but few studies have directly compared rumen microbiological responses. The objective of this study was to evaluate species differences in ex vivo fermentation of concentrates and forages. Rumen fluid was obtained via oral intubation from Holstein steers (n = 3; age: 212 ± 8 d) and Polypay ram lambs (n = 3; age; 34 ± d) fed a 100% tall fescue (TF) hay diet ad libitum. Mixed bacterial cell suspensions in buffered media contained the following feed substrate treatments (3% wt/vol): TF hay (HY), 2:1 TF hay-to-corn (HC), 2:1 corn-to-TF hay (CH), and corn (CN). Samples were collected after 2, 4, 8, and 24 h of incubation (39°C) for analysis of pH and lactate. Data were analyzed by PROC MIXED in SAS (v. 9.4, SAS Inst. Inc., Cary, NC). The pH differed by species (P = 0.004), treatment (P = 0.005), and time (P < 0.001), with a species by treatment by time interaction (P = 0.001). The pH at 2 h was 6.61 ± 0.02 regardless of species or treatment, and pH declined by 24 h for both steer and ram rumen cell suspensions in all treatments (P < 0.001). Final pH at 24 h did not differ between species for HY (6.15 ± 0.03), but for all treatments including corn, pH was lower in steer rumen cell suspensions (HC: steer – 5.86, ram – 6.06; CH: steer – 5.59, ram – 5.98; CN: steer – 5.26, ram – 5.91 ± 0.05; P ≤ 0.004). Lactate accumulation differed by species (P = 0.038), treatment (P = 0.048), and time (P < 0.0001), with a species by treatment by time interaction (P < 0.001). Lactate at 8 h did not differ between species for HY (steer:3.06, ram: 9.22 ±.84 mmolּ L-1), but was greater in steer than in ram cell suspensions fermenting HC (steer: 12.64; ram: 6.39 ±.84 mmolּ L-1), CH (steer: 13.44; ram: 3.21 ±.84 mmolּ L-1), and CN (steer:3.63; ram:.10 ±.84 mmolּ L-1; P ≤ 0.023). By 24 h, lactate accumulation was minimal for HY, HC, and CH (≤ 1.50 mmolּ L-1) and did not differ between species (P ≥ 0.657). However, lactate at 24 h was greater in steer rumen cell suspensions fermenting CN (steer: 25.78; ram: 182 ± 1.84 mmolּ L-1; P < 0.001). These results indicate that the rumen microbial community of sheep and cattle may differ both in composition and function resulting in different capacities to utilize common dietary feed ingredients.

Rendering male lambs short-scrotum interferes with testicular development and thermoregulation, and has been proposed as a management tool to control male reproduction. This study evaluated at the effect of timing of the procedure (birth or weaning) on growth rate, testis size, libido, ejaculate characteristics and carcass traits in male landrace hair sheep lambs. April- (n = 31) and August-born (n = 23) Barbados Blackbelly (BB) and St. Croix (SC) male hair sheep lambs, balanced by breed and birth type, were rendered short-scrotum (SS) using elastrator bands at birth (B) or weaning (W), or left intact (I). Lambs were born on pasture, weaned at 9 weeks, transitioned in pens for two months post weaning, and then rotationally grazed as a single group to a target weight of 40 kg. At 6-mo of age (peri-pubertal), and again at target weight (post-pubertal), mating behavior was recorded (day) and ejaculate samples collected (day 2). Mating behavior was recorded in a0-min test with males individually exposed to estrus-induced ewes pen. An initial attempt was made to collect semen using an estrus-induced teaser ewe, and if not successful, the semen sample was collected by electro-ejaculation. At target weight lambs were harvested, scrotal content collected, and carcass characteristics (April cohort) determined. Data were analyzed in a model with sex class, breed and cohort as main effects. Pen and pasture ADG (142 and 129 g/d, respectively) and age at target weight (287 d) was not affected (P > 0.1) by SS treatment. However, April-born lambs grew 19 g/d less (P < 0.01) and reached target weight 40 d later (P < 0.001) than August-born males. As for breed, STX had greater pasture ADG (139 vs 124 g/d; P < 0.05) and reached target age 19 days earlier (P< 0.05) than BB males. Libido (number of mounts and services) was not affected by SS treatment, breed or cohort. The frequency of ejaculates containing sperm was less (P < 0.001) in SS (26 to 33%) than intact males (97%) and increased with age in SS but not I males. Sperm concentration and motile sperm in ejaculates were greater (P< 0.05) in I than SS males. Testis and epididymis were larger (P < 0.001) in I (300 and 44.3 g) than in B (134 and 20.0 g) and W (154 and 23.8 g), which were not different. Cohort and breed had no effect (P > 0.1) on mating behavior, ejaculate characteristics, and organ weights. Results suggest that SS and its timing had no effect on growth rate or on mating behavior. Though the procedure depressed the presence of sperm in the ejaculate and decreased testis weight, the suppression was not complete, and caution is warranted in utilizing the technique to facilitate co-grazing ewe lambs.

Genetic evaluation programs can provide valuable selection tools for sheep breeders. However, industry acceptance and utilization of these tools is still limited. The objective here was to evaluate the performance and value of rams enrolled in the National Sheep Improvement Program (NSIP) compared with those not enrolled during a ram test program. Rams (Katahdin = 16, Texel = 3) were delivered to the Southwest Virginia Agricultural Research and Extension Center Ram Test on May 31. Rams were dewormed and rested for two weeks. On June 21, rams were given Haemonchus contortus L3 larvae adjusted for body weight (average = 5000 L3). FAMACHA scores and fecal egg counts (FEC) were monitored every two weeks until August 30. Rams were dewormed based on FAMACHA ≥ 3. The top 50% of rams, excluding any dewormed rams, based on the sale index [Sale Index = 0.50*(0.33*average daily gain ratio + 0.67*weight per day of age ratio) + 0.50*logFEC ratio] were sold at auction as breeding stock. Rams were classified as NSIP if enrolled. Statistical analyses were performed using SAS (SAS Institute, Cary, NC). Of the19 rams on test, 52% were NSIP. Thirteen rams required deworming during the test (38% of these were NSIP rams). Average sale index of NSIP rams tended to be greater than that of non-NSIP rams (101.4 vs. 98.3, P = 0.06). Of rams with sale index ≥ 100 (top 50%), a greater percentage of these rams were NSIP vs. non-NSIP (61% vs. 39%, respectively; P < 0.05). When NSIP status was evaluated for the top 20% of rams (sale index ≥07), a greater percentage of these rams were also NSIP vs. non-NSIP (78% vs. 22%, respectively; P < 0.01). Rams (n = 57) were sold on September 23 with an average sale price of $1,482. Rams enrolled in NSIP commanded greater prices than those not enrolled ($1,659 vs. $1,222, P < 0.05). When sale price was regressed on sale index for NSIP and non-NSIP rams, R2 for NSIP rams was 0.19 compared with the R2 for non-NSIP rams of 0.76. Given the weaker relationship between price and sale index for NSIP rams, estimated breeding values (EBVs) were evaluated. NSIP rams with EBVs reported for post-weaning weight, post-weaning FEC, and Maternal Hair Index sold for greater prices than those rams missing one or all of these EBVs ($1,837 vs. $971, respectively; P < 0.05). In summary, NSIP rams had greater performance (as indicated by sale index) and value compared with non-NSIP rams. For rams enrolled in NSIP, sale index was a poor predictor of value indicating buyers may be considering other factors besides sale index, such as EBVs, when purchasing NSIP rams.

Katahdin lambs with decreased post weaning worm egg count estimated breeding values (PWEC EBV) generated greater antibody in response to vaccination and survive better to weaning. Thus, lambs with decreased PWEC values may be more disease resistant and immunocompetent. To test this hypothesis, parasite-resistant St. Croix sheep, (STC, n = 10), and parasite-susceptible Suffolk sheep (SUF, n = 10) were compared with Katahdin sheep divergent in PWEC EBV (HiKAT, n = 10; LoKAT, n = 10) and challenged with lipopolysaccharide (LPS). Sheep were intravenously administered LPS at a dose of 2.5 ug/kg; blood and body temperature data were collected hourly. Behavioral observations were recorded during sampling and videos within pens were obtained 30 min after blood collection. An increase of body temperature by 1 ºC was observed in all groups. Interestingly, STC and SUF temperature peaked at 4 hours whereas LoKAT and HiKAT both peaked at 6 hours. One metric of behavior recorded from video was Sheep Grimace Score (SGS; 1 = normal; 7 = extremely abnormal). Peak SGS in all groups was 3 hours after LPS administration. Main effects of group on SGS indicated a stepwise increase with STC having the least SGS (1.25) and SUF greatest score (2.45) and both groups of Katahdin sheep intermediate (1.65 LoKAT, 2.00 HiKAT; P < 0.001). Evaluation of “return to normal” (RTN), when SGS scores average between 0 and, revealed that STC and LoKAT RTN segregated from the other groups and this occurred at 5.1 and 6.6 hours after LPS treatment, respectively. HiKAT and SUF RTN was at 9.3 and 9.6 hours, respectively. Average SGS RTN in STC and LoKAT were significantly less than HiKAT and SUF (P < 0.01), indicating segregation in behavior. Typical behaviors associated with LPS response, such as fever and ill-behaviors, can be attributed to the rapid and systemic influx of proinflammatory cytokines like tumor necrosis factor alpha (TNFα). Analysis of circulating TNFα revealed similar segregation whereas STC and LoKAT have early TNFα peak at 4 hours and then gradually decline, HiKAT and SUF peak at 9hrs and remain elevated to2hrs. The transition period between these two disparate groups is 6 hours post LPS administration. Thus, TNFα was evaluated before (-2 to 6 hours) and post (7 to 12hours) TNFα shift. With STC sheep having greater TNFα before (45.96 pg/mL, P < 0.001) and SUF sheep having greater TNFα post (47.51 pg/mL, P < 0.001) indicating that despite similar average TNFα there exists timing differences of TNFα that correspond with SGS. These differences are mirrored in the production of TNFα in LoKAT and HiKAT sheep. Taken together these data indicate that early resolvement of TNFα cytokine production within the parasite-resistant groups (STC and LoKAT) is associated with reduced duration of sick behaviors.

This study evaluated meat quality parameters of short scrotum and castrated Barbados Blackbelly (BB; n = 16) and St. Croix (STX; n = 15) hair sheep ram lambs. Ram lambs born in April (n = 21) and December (n = 10) were rendered short scrotum (SS; n = 17) or castrated (CA; n = 14) using elastrator bands at weaning (63 days of age). Following a transition period of 2 months in a dry lot, ram lambs co-grazed with ewe lambs in a rotational pasture system and were provided soy hull at 3% BW daily. At target weights of app. 40 kg lambs were slaughtered and loin cuts from individual carcasses were collected for meat quality analysis. Data from the two lambing groups were pooled and analyzed as a completely randomized design with a 2 x 2 factorial treatment arrangement for breed (BB or STX) and sex class (SS or CA). The CIE L* (lightness), a* (redness), and b* (yellowness) values of loin cuts were not significantly influenced by breed or sex class. The longissimus muscle (LM) in loin cuts from CA lambs had a greater (P < 0.0001) fat content (3.73 vs 2.55 ± 0.155%) and tended (P = 0.06) to have a decreased moisture content (69.63 vs 70.75 ± 0.413%) than that from SS lambs. Neither breed nor sex class significantly affected the myoglobin content, percent metmyoglobin and thiobarbituric acid reactive substances (TBARS) values of LM from lamb cuts. Cuts from SS lambs had greater (P < 0.0001) shear force values (3.22 vs 2.64 ± 0.093 kg) than those from CA lambs. However, the cooking loss of loin cuts was not significantly influenced by breed or sex class. The fatty acid profiles of LM from experimental lambs were significantly influenced by breed and sex class. Compared with BB, STX had greater (P < 0.05) concentrations of myristic (C14:0;.38 vs.23%), palmitic (C16:0; 20.15 vs8.98%) and oleic (C18:1n9; 45.01 vs 42.81%), but less than (P < 0.05) concentrations of stearic (C18:0;7.29 vs9.33%) and linoleic (C18:2n6; 6.14 vs 7.47%) acids in LM. Furthermore, the LM from SS lambs had greater (P < 0.05) concentrations of C18:2n6 (8.09 vs 5.51%) and arachidonic (C20:4n6, 2.04 vs.40%), but lless than (P < 0.05) concentrations of C16:0 (19.07 vs 20.06%) and C18:1n9 (41.57 vs 46.24%) acids than that from CA lambs. Data suggest that meat quality parameters were more greatly influenced by sex class than breed when landrace hair sheep lambs were slaughtered at a target weight. Loin cuts from SS lambs were leaner, but less tender than those of CA lambs, and also differed in their fatty acid profiles. Hence meat quality will be impacted by the choice of rendering male lambs sterile.

An androgen excess ovarian micro-environment may limit follicle progression in sheep. Two populations of ewes with divergent follicular fluid androstenedione (A4) were identified in a flock in Jordan: High A4; (A4) ≥ 30 ng/mL, (N = 12) or Control A4 (Control); A4 ≤ 15 ng/mL; (N = 12). We hypothesized High A4 ewes would have increased steroidogenic enzyme mRNA abundance, inflammation, and follicular arrest. Messenger RNA abundance for steroidogenic enzymes StAR, CYP17A1, CYP11A1, and HSD3B1 were increased in theca cells while CYP17A1, CYP19A1, and HSD3B1 were increased in granulosa cells in High A4 ewes compared to Control. Gonadotropin receptor mRNA expression for LHCGR was increased in theca and FSHR in granulosa in High A4 ewes. Messenger RNA expression of FOS when reduced, increases expression of CYP17A1 which was observed in High A4 granulosa cells compared to Control. Furthermore, High A4 ewes had greater numbers of primordial follicles (P

Supplementation with omega-3 and omega-9 fatty acids (FA) during late gestation regulates offspring development; however, their effect in the first third of gestation is unknown in sheep. The objective of this experiment was to evaluate the effects of the maternal supplementation with an enriched source of monounsaturated FA (MUFA) or an enriched source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) during the first third of gestation on productive performance on ewes and offspring, and hypothalamic neuropeptides on offspring. Seventy-nine post-weaning lambs, born of sheep supplemented in the first third of gestation with 1.61% Ca salts rich with MUFA or EPA+DHA (dam supplementation, DS), were distributed in a 2×2 factorial arrangement of treatments to finishing diets containing 1.48% of Ca salts of MUFA or EPA+DHA (lamb supplementation, LS). The finishing period of the offspring lasted for 56 d. During the finishing period dry matter intake (DMI, daily) and body weight (BW) were recorded. Plasma was collected for metabolites analysis. Twenty-four lambs were slaughtered, and hypothalamus was collected for mRNA expression of hormone receptors, neuropeptides, and lipid transport genes. The data were analyzed with a mixed model in SAS (9.4) using repeated measurements, when needed. There was a DS×LS interaction for BW (P = 0.10) where LS with EPA+DHA born from DS with MUFA were heavier than the other 3 treatments. Lambs born from DS with MUFA have a greater DMI (P < 0.01) than the offspring born from DS with EPA+DHA. Lambs born from MUFA supplemented dams had a greater (P ≤ 0.05) hypothalamus mRNA expression for cocaine and amphetamine regulated transcript, growth hormone receptor, metastasis suppressor 1, leptin receptor, pro-opiomelanocortin, and Neuropeptide Y. These results indicate that growth depends not on the type of FA during the finishing phase but the interaction of different sources of FA ad different stages. Also, supplementation with FA during early pregnancy changes productive performance and neuropeptides’ mRNA expression of lambs independently of the finishing diet.

The inverses of the pedigree and genomic relationship matrices (A, G) are required for single-step GBLUP (ssGBLUP). While, inverting A is possible for millions of animals at a linear cost, inverting G has a cubic cost and feasible for at most 150,000 animals, using the current conventional algorithms. The algorithm for proven and young (APY) provides approximations of the regular ssGBLUP by splitting genotyped animals into core and noncore groups, with computational costs being cubic for core and linear for noncore animals. The data consisted of 9,406,096 animals in the pedigree, 6,243,753 weaning weight phenotypes, and 46,949 genotyped animals from 5 breeds, composites, and animals with missing breed information from New Zealand. Aiming to find a core sample for a multibreed sheep population that can provide evaluations similar to those from the regular ssGBLUP, different core types, and core sizes were studied. Core types random, composite, oldest, youngest, the most inbred animals in G (GINB), and in A (AINB) were studied in 5K, 10K, and 20K core sizes (K = 1,000). Romney core was studied in 5K and 10K, and Coopworth-Perendale core was studied in 5K. Correlation and regression coefficient (slope) between GEBV from the non-APY and the APY analyses, as indicators for consistency with non-APY and bias from non-APY, showed a large impact of APY on noncore and a small impact on nongenotyped animals. Breed-based 5K cores resulted in large bias from non-APY even for nongenotyped animals. Random and GINB at 20K core size resulted in the highest consistency with non-APY and the lowest bias from non-APY. However, GINB did not perform as well as Random at lower core sizes. The number of animals from a breed in the core sample was very important for the evaluation of that breed. We observed that cores without Texel or Highlander animals resulted in poor evaluations for those breeds. Solving the mixed model equations, within core type, the smallest core size, and within core size, Random core converged in the least number of iterations. However, APY per se did not necessarily reduce the solving time. Random cores performed the best, as they could give a good coverage on the generations and breeds, representative for the genotyped population. Core size 20K performed better than 5K and 10K, and the optimum core size was found to be 18.8K, according to the eigenvalue decomposition of G.

The study was conducted to evaluate body temperature of hair sheep ewes at various stages of the production cycle in an accelerated lambing system in the tropics. Multiparous St. Croix White (STX: n = 7) and Dorper x STX (DRPX; n = 7) ewes lambing in October and raising single lambs weaned at 120 d were used. Synchronized breeding began at 96 d postpartum. Vaginal temperature (VT) was measured at 10-min intervals for 96 h at 38 and 66 d post-partum (PP1, PP2) and at 2 days after mating (PM) using data loggers. Daily minimum, maximum and range of VT were determined for ewes within PP1, PP2 and PB. Data were analyzed using GLM procedures of SAS with breed, day and time (PP1, PP2, PM) in the model. Mean ambient temperature, temperature-humidity index and solar radiation at PP1, PP2 and PM were 24.8 °C, 25.2 °C, 23.8 °C, and 74.7, 74.9, 73.3, and 180 W/m2, 160 W/m2 and 155 W/m2, respectively. Minimum VT was lower (P < 0.002) in STX than DRPX ewes at PP1, PP2 but not PM (38.27 ± 0.04 vs 38.44 ± 0.04 °C, 38.16 ± 0.04 vs 38.33 ± 0.04 °C, 38.47 ± 0.04 vs 38.58 ± 0.04 °C, respectively). There was no difference in maximum VT between breed or time (P > 01.0). There was no breed difference (P > 0.10) in range of VT, but the range of VT was lower (P < 0.0001) at PM compared to PP1 and PP2 (1.22 ± 0.04 vs 1.77 ± 0.04 vs 1.63 ± 0.04 °C, respectively). These results show that tropically adapted STX ewes have lower body temperatures, as shown by the lower minimal VT which indicates a degree of nighttime cooling, during the postpartum period compared to DRPX ewes in a tropical environment.

Portable accumulation chambers (PAC) enable short-term spot measurements of gaseous emissions including methane (CH4), carbon dioxide (CO2), and oxygen (O2) consumption from small ruminants. To date the differences in morning and evening gaseous measurements in the PAC have not been investigated. The objectives of this study were to investigate: 1) the optimal measurement time in the PAC, 2) the appropriate method of accounting for the animal’s size when calculating the animal’s gaseous output, and 3) the intra-day variability of gaseous measurements. A total of 12 ewe lambs (c. 10 to 11 months of age) were randomly selected each day from a cohort of 48 animals over nine consecutive days. Methane emissions from the 12 lambs were measured in 12 PAC during two measurement runs daily, AM (8 to 10 h) and PM (14 to 16 h). Animals were removed from Perennial ryegrass silage for at least 1 h prior to measurements in the PAC and animals were assigned randomly to each of the 12 chambers. Methane (ppm) concentration, O2 and CO2 percentage were measured at 5 time points (T1 = 0.0 min, T2 = 12.5 min, T3 = 25.0 min, T4 = 37.5 min, and T5 = 50.0 min from entry of the first animal into the first chamber) using an Eagle 2 monitor. The correlation between time points T5-T1 (i.e., 50 min minus 0 min after entry of the animal to the chamber) and T4-T1 was 0.95, 0.92, and 0.77 for CH4, O2, and CO2, respectively (P < 0.01). The correlation between CH4 and CO2 output and O2 consumption, calculated with live-weight and with body volume was 0.99 (P < 0.001). The correlation between the PAC measurement recorded on the same animal in the AM and PM measurement runs was 0.73. Factors associated with CH4 production included: day and time of measurement, the live-weight of the animal and the hourly relative humidity. Results from this study suggest that the optimal time for measuring an animal’s gaseous output in the PAC is 50 min, that live-weight should be used in the calculation of gaseous output from an animal and that the measurement of an animal’s gaseous emissions in either the AM or PM does not impact on the ranking of animals when gaseous emissions are measured using the feeding and measurement protocol outlined in the present study.

This study aimed to determine the regulatory mechanism of bone morphogenetic protein 4 (BMP4) gene in the testes of Tibetan sheep and its role in the blood–testis barrier (BTB). First, we cloned BMP4 gene for bioinformatics analysis, and detected the mRNA and protein expression levels of BMP4 in the testes of Tibetan sheep pre-puberty (3-mo-old), during sexual maturity (1-yr-old), and in adulthood (3-yr-old) by qRT-PCR and Western blot. In addition, the subcellular localization of BMP4 was analyzed by immunohistochemical staining. Next, BMP4 overexpression and silencing vectors were constructed and transfected into primary Sertoli cells (SCs) to promote and inhibit the proliferation of BMP4, respectively. Then, CCK-8 was used to detect the proliferation effect of SCs. The expression of BMP4 and downstream genes, pathway receptors, tight junction-related proteins, and cell proliferation and apoptosis-related genes in SCs were studied using qRT-PCR and Western blot. The results revealed that the relative expression of BMP4 mRNA and protein in testicular tissues of 1Y group and 3Y group was dramatically higher than that of 3M group (P < 0.01), and BMP4 protein is mainly located in SCs and Leydig cells at different development stages. The CDS region of the Tibetan sheep BMP4 gene was 1,229 bp. CCK-8 results demonstrated that the proliferation rate of BMP4 was significantly increased in the overexpression group (pc-DNA-3.1(+)-BMP4; P < 0.05). In addition, the mRNA and protein expressions of SMAD5, BMPR1A, and BMPR1B and tight junction-related proteins Claudin11, Occludin, and ZO1 were significantly increased (P < 0.05). The mRNA expression of cell proliferation-related gene Bcl2 was significantly enhanced (P < 0.05), and the expression of GDNF was enhanced (P > 0.05). The mRNA expression of apoptosis-related genes Caspase3 and Bax decreased significantly (P < 0.05), while the mRNA expression of cell cycle-related genes CyclinA2 and CDK2 increased significantly (P < 0.05). It is worth noting that the opposite results were observed after transfection with si-BMP4. In summary, what should be clear from the results reported here is that BMP4 affects testicular development by regulating the Sertoli cells and BTB, thereby modulating the spermatogenesis of Tibetan sheep.

The efficiency of molecular breeding largely depends on inexpensive genotyping arrays. In this study, we aimed to develop an ovine high-resolution multiple-single-nucleotide polymorphism (SNP) capture array, based on genotyping by target sequencing (GBTS) system with capture-in-solution (liquid chip) technology. All the markers were from 40K captured regions, including genes located within selective sweep regions, breed-specific regions, quantitative trait loci (QTL), and the potential functional SNPs on the sheep genome. The results showed that a total of 210K high-quality SNPs were identified in the 40K regions, indicating a high average capture ratio (99.7%) for the target genomic regions. Using genotyped data (n = 317) from liquid chip technology, we further performed genome-wide association studies (GWAS) to detect the genetic loci affecting sheep hair types and teat number. A single significant association signal for hair types was identified on 6.7-7.1 Mb of chromosome 25. The IRF2BP2 gene (chr25: 7,067,974-7,071,785), which is located within this genomic region, has been previously known to be involved in hair/wool traits in sheep. The results further showed a new candidate region around 26.4 Mb of chromosome 13, between the ARHGAP21 and KIAA1217 genes, that was significantly related to teat number in sheep. The haplotype patterns of this region also showed differences in animals with 2, 3, or 4 teats. Advances in using the high-accuracy and low-cost liquid chip are expected to accelerate sheep genomic and breeding studies in the coming years.

Fatty acid (FA) composition contributes greatly to the quality and nutritional value of lamb meat. In the present study, FA was measured in longissimus thoracis (LT) muscles of 1,085 Hu sheep using gas chromatography. Comparative transcriptomic analysis was conducted in LT muscles to identify differentially expressed genes (DEGs) between six individuals with high polyunsaturated fatty acids (H-PUFA, 15.27% ± 0.42%) and six with low PUFA (L-PUFA, 5.22% ± 0.25%). Subsequently, the single nucleotide polymorphisms (SNPs) in a candidate gene PLIN2 were correlated with FA traits. The results showed a total of 29 FA compositions and 8 FA groups were identified, with the highest content of monounsaturated fatty acids (MUFA, 46.54%, mainly C18:1n9c), followed by saturated fatty acids (SFA, 44.32%, mainly C16:0), and PUFA (8.72%, mainly C18:2n6c), and significant correlations were observed among the most of FA traits. Transcriptomic analyses identified 110 upregulated and 302 downregulated DEGs between H-PUFA and L-PUFA groups. The functional enrichment analysis revealed three significant Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways and 17 gene ontology (GO) terms, in which regulation of lipolysis in adipocytes, the AMPK signaling pathway, and the PPAR signaling pathway may play important roles in FA metabolism and biosynthesis. In addition, weighted gene co-expression network analysis (WGCNA) identified 37 module genes associated with PUFA-related traits. In general, PLIN1, LIPE, FABP4, LEP, ACACA, ADIPOQ, SCD, PCK2, FASN, PLIN2, LPL, FABP3, THRSP, and ACADVL may have a great impact on PUFA metabolism and lipid deposition. Four SNPs within PLIN2 were significantly associated with FA. Of those, SNP1 (g.287 G>A) was significantly associated with C18:1n9c and MUFA, and SNP4 (g.7807 T>C) was significantly correlated with PUFA (C18:3n3). In addition, the combined genotype of SNP1 (g.287 G>A), SNP3 (g.7664 T>C), and SNP4 (g.7807 T>C) were significantly correlated with C16:1, C17:0, C18:1C6, PUFA (C18:3n3, C22:6n3), and n-6/n-3 PUFA. These results contribute to the knowledge of the biological mechanisms and genetic markers involved in the composition of FA in Hu sheep.

Previous studies have indicated the importance of Nod-like receptor pyrin containing domain 3 (NLRP3) to early immune response in St. Croix (STC) sheep. NLRP3 is important to Th2 immune response, which is the classical response to Haemonchus contortus larval antigen (HcLA). Th2 response is driven by interleukin (IL) -4 and IL-13 cytokine production and early production prevents parasite establishment and further resistance as seen in STC response to LPS, classical NLRP3 activation. Distinct differences have been seen in the structure of NLRP3 between both STC and SUF. STC upregulates inflammatory genes NLRP3, TLR4 and TLR2 in response to LPS, while SUF showed delayed responses leading to their susceptibility. The objective of this study was to investigate the role of NLRP3 in differential breed response, in the context of Hc infection. P Peripheral blood mononuclear cells (PBMC) from both SUF and STC were isolated and stimulated with HcLA antigen only, HcLA antigen in combination with pharmacological inhibitor of NLRP3 (MCC950) and complete media for 6 hours. Gene expression revealed that treatment with MCC950 upregulated TLR2 (P < 0.001), TLR4 (P < 0.001), STAT6 (P < 0.001), IL-4 and IL-10 (P < 0.001) in SUF PBMC while STC showed an increase in IL-1β (P < 0.001). This indicates that inhibition of NLRP3 improves response of SUF to Hc antigen and confirms importance of NLRP3 to immune response in STC.

This study reports genetic parameters for yearling and adult wool and growth traits, and ewe reproductive performance. Data were sourced from an Uruguayan Merino flock involved in a long-term selection program focused on reduced fiber diameter (FD), and increased clean fleece weight (CFW) and live weight (LW). Pedigree and performance data from approximately 5,700 mixed-sex yearling lambs and 2,000 mixed-age ewes born between 1999 and 2019 were analyzed. The number of records ranged from 1,267 to 5,738 for yearling traits, and from 1,931 to 7,079 for ewe productive and reproductive performance. Data on yearling and adult wool traits, LW and body condition score (BCS), yearling eye muscle area (Y_EMA), and fat thickness (Y_FAT), and several reproduction traits were analyzed. The genetic relationships between FD and reproduction traits were not different from zero. Moderate unfavorable genetic correlations were found between adult CFW and ewe lifetime reproduction traits (−0.34 ± 0.08 and −0.33 ± 0.09 for the total number of lambs weaned and total lamb LW at weaning, respectively). There were moderate to strong positive genetic correlations between yearling LW and all reproduction traits other than ewe-rearing ability (−0.08 ± 0.11) and pregnancy rate (0.18 ± 0.08). The genetic correlations between Y_EMA and reproduction traits were positive and ranged from 0.15 to 0.49. Moderate unfavorable genetic correlations were observed between yearling FD and Y_FAT and between adult FD and BCS at mating (0.31 ± 0.12 and 0.23 ± 0.07, respectively). The genetic correlations between adult fleece weight and ewe BCS at different stages of the cycle were negative, but generally not different from zero. This study shows that selection for reduced FD is unlikely to have any effect on reproduction traits. Selection for increased yearling LW and Y_EMA will improve ewe reproductive performance. On the other hand, selection for increased adult CFW will reduce ewe reproductive performance, whereas selection for reduced FD will negatively impact body fat levels. Although unfavorable genetic relationships between wool traits and both FAT and ewe reproductive performance existed, simultaneous improvements in the traits would occur using appropriately designed indexes.

Sheep reproductive performance is one of the important economic traits in sheep farming. The bone morphogenetic protein receptor 1B (BMPR1B) gene and protein may play an important role in sheep fertility. This study was to investigate the association of blood BMPR1B protein expression with reproductive performance in sheep. Mongolian sheep with single and twin births and polytocous Small Tail Han sheep were selected due to differences in birth numbers. The BMPR1B mRNA in sheep blood was measured by a reverse transcription-polymerase chain reaction as well as the BMPR1B protein was measured by enzyme-linked immunosorbent assay in blood samples of Mongolian and Small Tail Han sheep. The results demonstrated that blood BMPR1B concentration in Mongolian sheep with twin birth was higher (P < 0.05) than Small Tail Han sheep and Mongolian sheep with single birth. The protein concentration in the anestrus season was higher (P < 0.045) than those in the estrus season for both Mongolian and Small Tail Han sheep. Moreover, BMPR1B concentration in Mongolian sheep increased (P < 0.05) at the age of 6 to 12 mo and that in Small Tail Han sheep increased (P < 0.05) at the age of 3 to 6 mo. The result indicates that the increase in BMPR1B protein concentrations in the blood of Mongolian ewes and Small Tail Han ewes may be beneficial to follicular development, but too high or too low of this blood protein concentration in Mongolian and Small Tail Han sheep is not conducive to ovulation.

The objective of this study was to determine the influence of biochar obtained from exothermic production of lodgepole pine (Pinus contorta) and quaking aspen (Populus tremuloides) on sheep performance and diet digestibility and on preference for a ration enriched with this carbon-based material. Twenty-four lambs were housed in individual pens and assigned to one of three treatment groups (eight animals per group), where they received: 1) a 60:40 ration of alfalfa:barley (Control), 2) an isoenergetic and isonitrogenous ration with alfalfa, barley, and 2% biochar (BC), and 3) a simultaneous offer of the Control and BC rations (Choice). Lambs were exposed to two consecutive feeding periods (Period 1: 13 d and Period 2: 21 d), representing time intervals where the evolution of intake, animal performance, and rumen parameters were assessed; in vivo digestibility was determined during the last 5 d of the study. Ration intake did not differ among groups of lambs (P > 0.10), although during some days in Period 2, intake was greater for the BC and Choice groups than for the Control group (P < 0.05). Lambs in Choice had a lower preference for BC than for the Control ration (Period 1: P < 0.05; Period 2: P < 0.10), although they incorporated a substantial amount of BC (39 and 40%, for Periods 1 and 2, respectively) into their diets. No differences in body weight gains (ADG) or gain-to-feed ratios were found among groups of animals (P > 0.10), although dry matter digestibility and digestible dry matter intake was greater for lambs in the BC group than for lambs in Control group (P < 0.05). The ruminal concentration of the volatile acid acetate in Period 2 was greater for BC than for Choice (P < 0.05). During the same period, the concentration of valerate and ruminal pH values were greater in BC than in Control (P < 0.05). Thus, the addition of biochar to grain-based diets enhanced diet digestibility and influenced some ruminal parameters in lambs. Nevertheless, these positive effects were not reflected in significant improvements on ADG or feed conversion efficiencies. Lambs offered choices between Control and BC rations formed a diet with concentrations of biochar of ~1.2%, suggesting that these animals would tolerate such levels without reductions in ration palatability.

This study determined whether extracellular citrulline is degraded by ruminal bacteria of sheep. In the first experiment, whole rumen fluid (3 mL) from six adult Suffolk sheep was incubated at 37 °C with 5 mM l-glutamine (Gln), l-glutamate (Glu), l-arginine (Arg), or l-citrulline (Cit) for 0, 0.5, 1, and 2 h or with 0, 0.5, 2, or 5 mM Gln, Glu, Arg, or Cit for 2 h. An aliquot (50 µL) of the incubation solution was collected at the predetermined time points for amino acids (AA) analyses. Results showed extensive hydrolysis of Gln into Glu and ammonia, of Arg into l-ornithine and l-proline, but little or no degradation of extracellular Cit or Glu by ruminal microbes. In the second experiment, six adult Suffolk sheep were individually fed each of three separate supplements (8 g Gln , Cit, or urea) on three separate days along with regular feed (800 g/animal). Blood (2 mL) was sampled from the jugular vein prior to feeding (time 0) and at 0.5, 1, 2, and 4 h after consuming the supplement. Plasma was analyzed for AA, glucose, ammonia, and urea. The concentrations of Cit in the plasma of sheep consuming this AA increased (P < 0.001) by 117% at 4 h and those of Arg increased by 23% at 4 h, compared with the baseline values. Urea or Gln feeding did not affect (P > 0.05) the concentrations of Cit or Arg in plasma. These results indicate that Cit is not metabolized by ruminal microbes of sheep and is, therefore, absorbed as such by the small intestine and used for the synthesis of Arg by extrahepatic tissues.

This systematic review and meta-analysis aim to summarize the effects of maternal undernutrition or overnutrition during pregnancy on fetal weight and morphometric measurements during pregnancy, at birth, and postnatal period in sheep. After completing the search, selection, and data extraction steps, the measure of effect was generated by the individual comparison of each indicator with the average of the control and treated group (undernutrition or overnutrition) using the DerSimonian and Laird method for random effects. Subgroup analyses were also performed for lambing order, litter size, sex, as well as level, timing, and duration of the intervention. Fetal weight during the first third of pregnancy was not affected by maternal undernutrition or overnutrition. On the other hand, undernutrition in the second and last third of gestation reduces the weight of the lamb both during pregnancy, at birth, and during the postnatal period, requiring at least 120 postnatal days to achieve the same weight as its contemporaries in the control treatment. However, this reduction in weight is not accompanied by reductions in morphometric measurements, demonstrating that the animals were lighter, but of equal size. In overnutrition, there is an increase in fetal weight in the second third of gestation. However, in the last third of the gestational period, there are no differences in fetal weight for the multiparous subgroup, but it was reduced in primiparous ewes. There are no effects of overnutrition on birth weight; however, this result is highly heterogeneous. Thus, maternal nutrition of ewe during pregnancy has effects on fetal and postnatal weight, but not on size. Furthermore, the effects of undernutrition are more homogeneous while overnutrition showed heterogeneous responses.

The use of portable X-ray fluorescence (PXRF) spectrometry to detect external markers on processed or unprocessed cattle and sheep fecal specimens to estimate apparent total tract digestibility (ATTD) was evaluated. Exp. 1: ruminally cannulated Angus-crossbred steers (n = 7; BW = 520 ± 30 kg) were individually fed ad libitum for 21 d in a completely randomized design (CRD). Markers (Cr2O3 and TiO2) were placed inside the rumen twice daily (7.5 g of each marker). Fecal samples were collected twice daily from day 14 to 21. Exp. 2: crossbred wethers (n = 8; BW = 68 ± 3 kg) were individually fed ad libitum for 21 d in a CRD. During this period, 2 g of Cr2O3 and TiO2 were top-dressed onto the feed twice daily. Sheep were housed in metabolism crates for 5 d for total fecal collection. Concentration of markers was determined on diets, refusals, and fecal specimens (fresh, dry-only, and dried/ground) using atomic absorption to detect Cr and spectrophotometry for Ti. Concentration of both markers was also determined via the PXRF spectrometer. Delta between ATTD estimated by wet chemistry and PXRF was not different from zero (P ≥ 0.14) when using cattle fresh fecal specimens for both markers, whereas ATTD estimated by PXRF with dry-only and dried/ground fecal specimens were 3.6 and 1.1 percent units lower (P ≤ 0.04), respectively, than ATTD estimated by wet chemistry for Cr and Ti, respectively. Regardless of the fecal sample preparation method on cattle specimens, Ti concentration was similar (P = 0.39) among methodologies, while Cr was underestimated (P < 0.01) by 13% when PXRF was used in dry-only or dried/ground samples. The ATTD of sheep was underestimated (P < 0.01) by 2.4 percent units compared with control when Cr was measured by PXRF in dry-only samples. The Cr concentration in dry-only fecal specimens of sheep tended (P = 0.09) to be lower compared with wet chemistry analysis. Fresh and dry/ground sheep fecal samples assessed for Cr, and dry-only assessed for Ti were not (P ≥ 0.49) affected by detection method. The Cr fecal recovery tended (P = 0.10) to be the lowest for dry-only, the greatest for wet chemistry, intermediate for fresh and dry/ground sheep-fecal specimens; while not affected (P = 0.40) for Ti. The PXRF is an accurate technology to detect Cr and Ti in fresh cattle fecal samples to estimate ATTD. For fresh and dry/ground, the technology was effective for determining the concentration of Cr, or dry-only fecal specimens when detecting Ti in sheep specimens.

Gastrointestinal nematodes (GIN) pose a significant risk to the health and productivity of Rambouillet sheep, a noted wool and meat producing breed, in the United States. Capturing phenotypic measurements of Rambouillet while infected with GIN is essential for the calculation of estimated breeding values (EBV) as a selection tool to improve host resistance to GIN. Weaned (age= ~120 d.) Rambouillet lambs (n = 75) were each inoculated with 10,000 Haemonchus contortus L3 larvae and placed in a feedlot. Lambs were offspring of two representative sires, A (n = 26) and B (n = 49), with post-weaning fecal egg count EBV (PFEC) from LAMBPLAN, of -9.94 and +9.20%, respectively. Lamb fecal egg count (FEC), packed-cell volume (PCV) and body weight (BWT) measurements were captured at 7-day intervals for 6 subsequent weeks. Actual FEC were loge transformed (lnFEC) to meet normality and then backtransformed least squares means (LSM) are reported. lnFEC, PCV and BWT were analyzed using a mixed model with repeated measures including fixed effects of sex, sire and average daily gain (ADG) classification (for lnFEC and PCV), and sex and sire (for BWT). Significant differences (P = 0.0216) in average lnFEC were observed between offspring from sires A [2242 eggs per gram (epg)] and B (2914 epg). Weekly lnFEC differed (P < 0.0001) and a trend identified between sexes (females = 3414 epg vs males = 2712 epg, P = 0.0909). Interestingly, females exhibited a higher average PCV than males, (34.93% v. 31.15%, P < 0.0001), suggesting potential pathological differences by sex in response to GIN infection. Artificial GIN infections offer a more controlled test than under natural conditions and are a viable option to aid in identifying Rambouillet sheep more resistant to GIN. These results indicate EBV calculated with FEC from a natural GIN infection are predictive of the response of Rambouillet lambs to an artificial infection of H. contortus.

For the past 2 decades, the Spooner Agriculture Research Station (ARS) of the University of Wisconsin-Madison operated the only dairy sheep research flock in North America. The objectives of the present study were to 1) obtain estimates of genetic parameters for lactation and reproductive traits in dairy ewes, 2) estimate the amount of genetic change in these traits over time, and 3) quantify the level of inbreeding in this flock over the last 20 yr. Multiple-trait repeatability models (MTRM) were used to analyze ewe traits through their first 6 parities. The first MTRM jointly analyzed milk (180-d-adjusted milk yield [180d MY]), fat (180-d-adjusted fat yield [180d FY]), and protein (180-d-adjusted protein yield [180d PY]) yields adjusted to 180 d of lactation; number of lambs born per ewe lambing (NLB); and lactation average test-day somatic cell score (LSCS). A second MTRM analyzed 180d MY, NLB, LSCS, and percentage milk fat (%F) and percentage milk protein (%P). The 3 yield traits were moderately heritable (0.26 to 0.32) and strongly genetically correlated (0.91 to 0.96). Percentage milk fat and %P were highly heritable (0.53 and 0.61, respectively) and moderately genetically correlated (0.61). Milk yield adjusted to 180 d was negatively genetically correlated with %F and %P (-0.31 and -0.34, respectively). Ewe prolificacy was not significantly ( > 0.67) genetically correlated with yield traits, %P, or LSCS but lowly negatively correlated with %F (-0.26). Lactation somatic cell score was unfavorably genetically correlated with yield traits (0.28 to 0.39) but not significantly ( > 0.09) correlated with %F, %P, and NLB. Within-trait multiple-trait models through the first 4 parities revealed that 180d MY, 180d FY, 180d PY, %F, and %P were strongly genetically correlated across parity (0.67 to 1.00). However, the genetic correlations across parity for NLB and LSCS were somewhat lower (0.51 to 0.96). Regressing predicted breeding values for 180d MY, without and with the addition of breed effects, on ewe year of birth revealed a positive genetic gain of 2.30 and 6.24 kg/yr, respectively, over the past 20 yr in this flock. Inbreeding coefficients of ewes with an extended pedigree ranged from 0.0 to 0.29, with an average of 0.07. To optimize genetic gains and avoid excessive inbreeding, the development of a national genetic improvement program should be a top priority for the growing dairy sheep industry.

Energy supplementation may reduce oxidative stress by correcting a negative energy balance, but in some contexts, it has been shown to increase oxidative stress, especially at peak lactation. The current experiment examined if a pelleted energy supplement with or without the addition of Lactobacillus-fermented seaweed or seaweed plus terrestrial plants extracts affected oxidative stress of ewes from late gestation through to weaning and ewe and lamb production from lambing to weaning. Treatments were either no supplement (CON−), a pelleted supplement only (CON+, 100 g/ewe per d), CON+ with seaweed extract only (SWO, 10 mL/ewe per day), or CON+ with seaweed plus an arrangement of terrestrial plant extract (SWP, 10 mL/ewe per d). Ewes (n = 160; mean initial BW = 72.3 ± 9.5 kg [mean ± SD]) were randomized to pastures (n = 4 pastures per treatment with 10 ewes each). After lambing, ewes with twins were reallocated to pastures (n = 3 pastures per treatment with 10 ewes each) according to lambing date. At 4 wk in milk, supplementation tended to reduce total antioxidant status (TAS; P = 0.10) and increased glutathione peroxidase (GPx) activity compared with nonsupplemented ewes (P = 0.04). The addition of seaweed and terrestrial plants extracts to the concentrate, that is, SWO and SWP, increased TAS and reduced GPx activity compared with CON+ (P < 0.01). Supplementation increased milk yield at weeks 4, 6, and 8 of lactation, and protein, lactose, and total milk solids yield at peak lactation (week 4; P < 0.05). The CON− ewes had greater somatic cell count than the supplemented ewes at weeks 4, 8, and 10 of lactation (P = 0.03). Our results suggest that energy supplementation, alone, increases oxidative stress of lactating ewes, which may relate to increased oxidative phosphorylation. Most importantly, these results indicate that in situations where energy supplementation is needed to increase animal performance, negative effects of energy supplementation around peak lactation can be offset by the addition of Lactobacillus-fermented plant extracts (SWO and SWP) to improve antioxidant status.

The aim of this study was to investigate how intraduodenal infusions of fatty acids (FA) affect appetite-related gut peptides such as glucagon-like peptide-1 (GLP-1) and ghrelin in sheep. We hypothesized that these peptides can be highly reactive to unsaturated long-chain FA, because they are well known to decrease dry matter intake (DMI). Four ewes were fitted with a duodenal cannula and a jugular vein catheter for a 6-h duodenal infusion of the 9 FA (C8:0, C10:0, C12:0, C14:0, C16:0, C18:0, C18:1, C18:2, and C18:3) and water (control). The concentration of each FA was 1.6 g per metabolic body weight (BW), approximately corresponding to the amount of supplemented fat in a standard dairy cow diet. Each infusion was separated by at least 2 d. During the infusion period, blood samples were collected periodically to determine changes in plasma GLP-1, ghrelin, and metabolite concentrations. Duodenal infusions of C18:1, C18:2, and C18:3 led to higher plasma GLP-1 (P < 0.05) and lower glucose (P < 0.05) than control. Plasma ghrelin concentrations were greater in C18:1 and C18:3 infusions than control (P < 0.05). Plasma ketone bodies were higher in C8:0 and C10:0 infusions (P < 0.05), but plasma triglyceride concentrations were lower in C8:0, C10:0, C12:0, and C16:0 infusions (P < 0.05) than control. Fatty acid infusions except for C18:3 led to higher plasma NEFA concentrations than control (P < 0.05). These results confirmed that the hypophagic effect of dietary unsaturated long-chain FA is mediated by GLP-1 (an anorexigenic effect) secretion. However, we also observed higher plasma ghrelin (an orexigenic effect) partially by unsaturated long-chain FA. Thus, the gut peptide secretions when ruminant animals ingest FA supplements would complexly affect satiety and further studies are needed to determine their each impact on DMI.

Fatty acids are involved in the regulation of many physiological pathways, including those involved in gene expression and energy metabolism. Through effects on these pathways, fatty acids may have lifelong impacts on offspring development and metabolism via maternal supplementation. Therefore, our objective was to investigate the impact of supplementing a source of omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) during late gestation on productive and metabolic responses of ewes and their offspring. Eighty-four gestating ewes (28 pens) were blocked and randomly assigned to a diet with 0.39% added fat during the last 50 d of gestation (d −0). The fat sources were Ca salts of a palmitic fatty acid distillate (PFAD) or EPA + DHA. After lambing (d 1), all ewes and lambs were placed on the same pasture. The ewes were weighed and BCS was measured on d −50, −20, 30, and 60 (weaning) of the experiment. Blood samples were taken from the ewes on d −50, −20, 1 (lambing), 30, and 60. Milk yield and composition were measured at 30 d postpartum. Lambs were weighed and bled at d 1, 30, and 60, and ADG was calculated. All plasma samples were analyzed for glucose and NEFA. Ghrelin, prostaglandin E metabolites (PGEM), and the prostaglandin D2 metabolite 11β-PGF2α were measured in d −20 ewe samples. Insulin and adropin were measured in lamb samples at d 60. There was no difference on ewe BW (P = 0.48) or BCS (P = 0.55), or plasma concentrations of glucose (P = 0.57), NEFA (P = 0.44), ghrelin (P = 0.36), PGEM (P = 0.32), and 11β-PGF2α (P = 0.86) between ewes supplemented with PFAD or EPA + DHA. Neither milk yield nor its composition was different (P > 0.10) among treatments. Lambs born from ewes supplemented with PFAD or EPA + DHA did not have different BW (P = 0.22), ADG (P = 0.21) or plasma NEFA (P = 0.52), glucose (P = 0.50), insulin (P = 0.59), and adropin (P = 0.72) concentrations. These results suggest that supplementation of EPA and DHA during late gestation did not affect ewe metabolic profile or milk production. Lamb performance and metabolism through weaning were not affected by maternal supplementation with an enriched source of EPA and DHA. Fil: Coleman, D. N.. The Ohio State University, Ohio Agricultural Research and Development Center (OARDC), Department of Animal Sciences; Estados Unidos Fil: Rivera Acevedo, K. C.. University Of Puerto Rico-mayaguez; Puerto Rico Fil: Relling, Alejandro Enrique. The Ohio State University, Ohio Agricultural Research and Development Center (OARDC), Department of Animal Sciences; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; Argentina

Backfat and carcass fatness is an important quality attribute in meat animals. A substantial economic gain in the livestock industry may result from the discovery of metabolites, which can improve methods for predicting desirable livestock traits before harvest. Complex phenotypes can be identified for genetic selection or precision management using metabolic and genetic biomarkers. An analysis of ovine samples collected before harvest from wethers with different degrees of back fat was conducted using serum samples obtained from 15 sheep (5 from each back fat class), 60 d, 30 d, and just before harvest. This study quantified 55 serum metabolites that play important roles in ovine metabolism by 1H nuclear magnetic resonance (NMR) spectroscopy. An RNAseq dataset was generated from each sheep's muscle and adipose tissue at harvest. A statistical analysis of the data was performed using MetaboAnalyst Version 5.0 software in R. The results of multiple analyses showed that three metabolites, betaine, choline, and dimethylamine, are associated with sheep's fat class at a significance of (P < 0.01). Integration with gene expression datasets is still underway due to the limitations of annotating sheep genes. In addition, these metabolites are novel and have never been shown to modulate fat class in sheep. To elucidate methods of predicting which livestock produce ideal carcasses, further research is needed to investigate how betaine and choline impact fatness in sheep.

Cache Valley Fever (CVF) is a mosquito-born, viral disease endemic to North America. While generally not associated with clinical symptoms in ewes, it affects fetal development during the first trimester of pregnancy resulting in malformations and pregnancy loss. A suspected outbreak of CVF was recorded in a flock of Barbados Blackbelly and St. Croix hair sheep managed under an 8-mo, accelerated mating system with ewes bred in March, July and November. The outbreak was associated with a July breeding, in a summer with unusually high rainfall and standing water in pastures. There had been no previous occurrence of CVF or other abortion storms in the flock (20+ years). Lambing outcome associated with the suspected outbreak of CVF was compared with that of the three prior July matings (CON). Ewes (n = 32-35) were managed in a pasture-based system under rotational grazing. Ewes were mated in two single sire groups of 16 to 18 ewes to like-breed sires each breeding season. Pregnancy was determined by transrectal ultrasound at end and 21 d after the 25-day breeding season. Ewes lambed on pasture, and lambs were tagged, and birth weights recorded within 24 hours. Blood samples were collected from all ewes following the CVF lambing and submitted for CVF antibody testing. All ewes showed CVF antibody titers. Pregnancy rate for the CVF lambing was not different from CON (85.7 vs. 89.8%; P = 0.512), whereas lambing rate was less in CVF for both ewes exposed (74.3 vs. 88.8%; P = 0.039) and ewes lambing (86.7 vs. 98.9%; P = 0.004). Incidence of stillborn and neonatal death of lambs was greater in CVF than CON (37.0 vs.5.6%; P = 0.002), as was the number of malformed lambs (13.0 vs. 0%; P < 0.001). Malformed lambs were associated with breech presentations. Litter size was not different in the CVF lambing (1.77 vs 1.86; P = 0.471), but lamb birth weight tended to be less (2.80 vs. 3.04 kg; P = 0.055) while ewe postpartum weight was not different (45.3 vs. 47.0 kg; P = 0.384). The outbreak of CVF reduced the lambing rate and increased the incidence of neonatal death and malformations. The outbreak occurred during a summer with unusually high rainfall and may be associated with changing weather patterns linked to climate change. Delaying summer breeding may be considered a mitigation strategy if feasible.

Energy is a key factor regulated by the neuroendocrine system. The objective of this study was to compare growth performance, serum biochemical indices, carcass traits, meat quality, and nutrient composition of lambs fed restricted metabolizable energy (ME) intakes to mimic the seasonal changes of the natural grasslands of northwest China. Nineteen male Dorper × Small Tailed Han lambs were assigned to treatments, control (CON) fed at 1.0 MJ/W(0.75) × d(−1) throughout the 180 d study, and restricted ME (RES) fed by sequentially restricting ME every 30 d (0.56, 0.84, 1.0, 0.84, 0.56, and 0.28 MJ/W(0.75) × d(−1)). Lambs were harvested at the end of the study. Lambs fed the CON diet demonstrated higher (P < 0.05) average daily gain (ADG) compared with RES-fed lambs (158.79 and 57.01 g/d, for CON and RES, respectively), although ADG were lower in each period with the last period being a negative ADG for RES-fed lambs resulting in a loss of body weight. Both treatments demonstrated lower ADG in the last 3 study periods compared with the first 2 periods, which may be explained by cold stress ( 0.05) for cholesterol and high-density lipoprotein-cholesterol. Feeding lambs a restricted ME diet increased (P < 0.05) meat pH, while reducing the cooked meat rate compared with CON-fed lambs. Thus, the carcass yield, rib eye muscle area, and shear force were lower (P < 0.05) for RES-fed lambs compared with CON-fed lambs. The meat water concentration was higher (P < 0.05), whereas the concentrations of dry matter, crude fat, crude protein, and carbohydrate were lower (P < 0.05) for lambs fed a RES ME diet compared to CON-fed lambs. These results demonstrate that sequentially restricting ME intake, as natural grasslands might experience during seasonal forage quality and quantity changes, resulted in a reduction of body weight because lambs were mobilizing body reserves as a source of ME. The reduction in concentrations of key serum nutrients, as well as carcass traits and meat composition, demonstrate the body is responding to the meet the lambs ME requirements, which has implications for both meat quality and the animal’s physiological functions.

To examine the effects of nutrient restriction during midgestation to late gestation on maternal and fetal digestive enzyme activities, 41 singleton ewes (48.3 ± 0.6 kg of BW) were randomly assigned to dietary treatments: 100% (control; CON; n = 20) or 60% of nutrient requirements (restricted; RES; n = 21) from day 50 until day 90 (midgestation). At day 90, 14 ewes (CON, n = 7; RES, n = 7) were euthanized. The remaining ewes were subjected to treatments of nutrient restriction or remained on a control diet from day 90 until day 130 (late gestation): CON-CON (n = 6), CON-RES (n = 7), RES-CON (n = 7), and RES-RES (n = 7) and were euthanized on day 130. The fetal and maternal pancreas and small intestines were weighed, subsampled, and assayed for digestive enzyme activity. One unit (U) of enzyme activity is equal to 1 µmol of product produced per minute for amylase, glucoamylase, lactase, and trypsin and 0.5 µmol of product produced per minute for maltase and isomaltase. Nutrient restriction during midgestation and late gestation decreased (P

Poor maternal nutrition during gestation can have immediate and life-long negative effects on offspring growth and health. In livestock, this leads to reduced product quality and increased costs of production. Based on previous evidence that both restricted- and overfeeding during gestation decrease offspring muscle growth and alter metabolism postnatally, we hypothesized that poor maternal nutrition during gestation would reduce the growth and development of offspring muscle prenatally, reduce the number of myogenic progenitor cells, and result in changes in the global expression of genes involved in prenatal muscle development and function. Ewes were fed a control (100% NRC)-, restricted (60% NRC)-, or overfed (140% NRC) diet beginning on day 30 of gestation until days 45, 90, and 135 of gestation or until parturition. At each time point fetuses and offspring (referred to as CON, RES, and OVER) were euthanized and longissimus dorsi (LM), semitendinosus (STN), and triceps brachii (TB) were collected at each time point for histological and RNA-Seq analysis. In fetuses and offspring, we did not observe an effect of diet on cross-sectional area (CSA), but CSA increased over time (P < 0.05). At day 90, RES and OVER had reduced secondary:primary muscle fiber ratios in LM (P < 0.05), but not in STN and TB. However, in STN and TB percent PAX7-positive cells were decreased compared with CON (P < 0.05). Maternal diet altered LM mRNA expression of 20 genes (7 genes downregulated in OVER and 2 downregulated in RES compared with CON; 5 downregulated in OVER compared with RES; false discovery rate (FDR)-adj. P < 0.05). A diet by time interaction was not observed for any genes in the RNA-Seq analysis; however, 2,205 genes were differentially expressed over time between days 90 and 135 and birth (FDR-adj. P < 0.05). Specifically, consistent with increased protein accretion, changes in muscle function, and increased metabolic activity during myogenesis, changes in genes involved in cell cycle, metabolic processes, and protein synthesis were observed during fetal myogenesis. In conclusion, poor maternal nutrition during gestation contributes to altered offspring muscle growth during early fetal development which persists throughout the fetal stage. Based on muscle-type-specific effects of maternal diet, it is important to evaluate more than one type of muscle to fully elucidate the effects of maternal diet on offspring muscle development.

Animal robustness may be defined as a complex trait characterizing the ability of an individual to be adapted, productive and healthy under contrasted and fluctuating environmental situations. Such a trait is now considered an essential criterion in order to meet the more ambitious goals of farming sustainability. In ruminants, one of the key mechanisms via which robustness is expressed is the capacity to mobilize or restore body reserves (BR) to cope with the challenges of negative energy balances. The objectives of this work were as follows: 1) to estimate the genetic parameters related to BR dynamics in ewes over successive production cycles and 2) to investigate BR management relationships between different physiological stages. For this, historical individual BW and BCS data from 2,920 phenotyped ewes were used for genetic analysis. The changes in BW (∆BW) and BCS (∆BCS) over time were analyzed. Eight physiological stages were considered to investigate these changes over time: mating, early pregnancy, mid-pregnancy, lambing, early suckling, mid-suckling, weaning, and postweaning. The estimated heritability were low for both ∆BW (h2 = 0.13 to 0.18) and ∆BCS (h2 = 0.04 to 0.16). Moderate to high positive genetic correlations (from 0.48 to 0.91) were obtained between BR mobilization phases and between BR accretion phases. Similarly, moderate to high negative genetic correlations (from -0.36 to -0.75) were estimated between the BR mobilization and accretion periods, suggesting that mechanisms driving BR mobilization and accretion processes were genetically correlated. This is the first study in ruminants that demonstrate that the extent and temporal changes in profiles of BR mobilization and accretion are heritable and genetically linked, indicating that such traits could be considered in genetic programs aimed at improving robustness. Nevertheless, further research is needed for a more comprehensive understanding of BR dynamics, notably by including other physiological parameters (i.e., metabolites and hormones) and additional information on the productive and reproductive life of the ewe.

Lab scoured yield (LSY) is a major indicator of wool quality. LSY is used for the valuation of wool in commercial settings and can be used by growers as selection criteria for breeding stock. Current laboratory methods for LSY are costly and labor intensive. Evaluation of fleece core samples using Near-Infrared Reflectance Spectroscopy (NIR) may present an efficient, cost-effective alternative to predict LSY. Lamb and yearling fleece core samples from flocks originating from Texas were scanned on a FOSS 6500 spectrometer. Constituent data were obtained from the Bill Sims Wool and Mohair Laboratory using ASTM methodology. LSY ranged from 48–68%. Spectral data were pretreated with a 14 nm moving average and Savitsky-Golay 2nd derivative. Eight outlier spectra were removed. Samples were parsed from the center of the distribution to minimize the Dunn effect creating calibration (n = 108) and test (n = 41) sets. Calibrations were executed using a partial least squares regression on spectra from 1100 to 2492 nm. Test set calibration statistics for LSY were: r2=0.64, RMSE=3.39, and slope=0.91. Independent validation statistics for LSY using spectra for different years were: r2=0.33, RMSE=3.69, and slope=0.29. RMSE for independent validation and lab methods on side samples are similar. Between flock independent validations were less promising. Accuracy of laboratory methods for estimating yield is 2 percentage units. NIRS calibrations can be improved by developing calibration sets with a uniform distribution, which can be difficult within flocks because of the small number of fleeces in the tails of the distribution. These data demonstrate that when calibration and test sets are developed such that test samples are drawn from the calibration population, NIR is a reliable predictor of LSY. However, when test samples are drawn from populations dissimilar to the calibration set, reliability of NIR predictions are greatly reduced.

Haemonchus contortous (Hc) infections have decreased profitability of flocks worldwide through loss of production efficiency and in severe cases death. Countless research efforts have been made in order to further understand the extensive impact of this gastrointestinal nematode (GIN). Quantifying the impact feeding behavior after Hc infection may prove vital, in understanding internal effect on growing lambs. The aim of this study was to evaluate Katahdin lambs with extensive genetic evaluation for feed efficiency and behavior utilizing a Growsafe™ system. Katahdin ewes from the Virginia Tech Southwest Agriculture Research and Extension Center in Glade Springs Virginia were divergently selected based on fecal egg count (FEC) EBV and mated to rams (n = 8) of similar genotype. A subset of lambs was selected for feedlot evaluation and transported to West Virginia University. Lambs were fed a complete pellet (16% CP) ad libitum while individual intake was measured in pen-fed groups with a GrowSafe™ system. Half of the lambs from each sire FEC EBV group were infected with 5,000 Hc L3 larvae and observed for 6 weeks alongside uninfected contemporaries. Artificial Hc infection resulted in lambs becoming modestly infected with FEC peaking in week 5 at 324 eggs/g. Infection level was not significant between all 4 groups (P < 0.05). Lambs administered H.C. had observably lower feed intake 2 days after infection. Both infected groups returned to normal intake with their control groups shortly after. Feed intake dropped again at day 10 and remained low until day 16 for LoFEC sired lambs and day 20 for HiFEC sired lambs. Offspring of low FEC rams exhibited an ability to return to normal intake levels earlier than lambs with high FEC EBV sires. Further analysis is needed with greater levels of parasite infection to confirm negative FEC EBV have a shorter duration of lower feed intake.