Search Results (141)

Despite the known impacts of weaning on animal health, the underlying molecular mechanisms remain unclear, particularly how psychological and nutritional stress differentially affect gut health and immune function over time. This study hypothesized that early weaning exerts distinct short- and long-term effects on lamb stress physiology, immunity, and gut health, mediated by specific molecular pathways. Twelve pairs of full-sibling male Hu sheep lambs were assigned to control (CON) or early-weaned (EW) groups. Plasma stress/immune markers were dynamically monitored, and intestinal morphology, antioxidant capacity, apoptosis, and transcriptomic profiles were analyzed at 5 and 28 days post-weaning. Early weaning triggered transient psychological stress, elevating hypothalamic–pituitary–adrenal (HPA) axis hormones (cortisol, catecholamines) and inflammatory cytokines (TNF-α) within 1 day (p < 0.05); however, stress responses were transient and recovered by 7 days post-weaning. Sustained intestinal remodeling was observed in EW lambs, featuring reduced ileal villus height, increased crypt depth (p < 0.05), and oxidative damage (MDA levels doubled vs. CON; p < 0.01). Compensatory epithelial adaptation included increased crypt depth but paradoxically reduced villus tip apoptosis. The transcriptome analysis revealed significant changes in gene expression related to immune function, fat digestion, and metabolism. Key DEGs included APOA4, linked to lipid transport adaptation; NOS2, associated with nitric oxide-mediated immune–metabolic crosstalk; and mitochondrial gene COX1, reflecting energy metabolism dysregulation. Protein–protein interaction analysis revealed NOS2 as a hub gene interacting with IDO1 and CXCL11, connecting oxidative stress to immune cell recruitment. Early weaning exerts minimal lasting psychological stress but drives persistent gut dysfunction through transcriptome-mediated changes in metabolic and immune pathways, highlighting key genes such as APOA4, NOS2, and COX1 as potential regulators of these effects. Full article

Utilizing agro-industrial by-products to feed livestock is crucial for environmental protection and, simultaneously, lowering production and feeding costs. In light of these aims, in this study, two trials were conducted to evaluate the impact of jojoba meal (JJM) on Awassi ewes’ milk properties, nutrient intake, digestibility, and the pre-weaning growth of their nursing lambs. In the first trial, 22 Awassi ewes were divided equally between two experimental diets at random (11 ewes per diet): 0% JJM (CON) and 15% JJM (JJM15) of dietary dry matter (DM). In the second trial, 10 ewes were randomly selected (5 ewes/diet) to assess nutritional digestibility and N balance. The results of trial 1 showed that neutral detergent fiber (NDF), acid detergent fiber (ADF), and ether extract (EE) intake values were greater (p ≤ 0.02) in the JJM15 group compared to the CON group. The total gain and average daily gain (ADG) of the lambs in the JJM15 group were significantly higher compared to those of the CON group (p < 0.05). The average milk yield of nursing ewes was similar between the two dietary groups (p ˃ 0.05). The percentage and yield of solids-not-fat (SNF) in the JJM15 group were significantly higher compared to the CON group. The other milk components, including protein, lactose, fat, and total solids yields, were similar between the dietary groups (p ˃ 0.05). The milk production cost was significantly lower for the JJM15 diet than the CON diet (p = 0.004). Triglyceride levels were lower (p = 0.001) in the JJM15 diet group than in the CON diet group. In trial 2, nutrient digestibility and N balance were not affected (p ≥ 0.073) by the consumption of JJM15. In conclusion, JJM at 15% of dietary DM resulted in no negative effects on the health, performance, or milk quality of Awassi ewes. Most significantly, by lowering the cost of production, our results appear to indicate that this dietary supplement improves economic efficiency. Full article

This study evaluated the feasibility of including grape pomace in the diet of Santa Inês ewes during lactation, aiming to reduce the effects of gastrointestinal nematode (GIN) infections and improve productive performance. Grape pomace, which contains phenolic compounds and tannins, was provided as a dietary supplement, replacing 20% of the concentrate over 28 days of lactation, starting on day 7 after lambing. A total of 18 ewes were used, divided into two groups: supplemented (n = 8) and control (n = 10). The supplemented group showed significant reduction in fecal egg count on day 14 of lactation (p < 0.05) in comparison with the control group. Lambs from the supplemented group had higher weaning weights (p < 0.05). Additionally, the supplemented group showed higher values for packed cell volume and circulating eosinophils, indicating greater resilience to infections. Analysis of anti-L3 IgG against Haemonchus contortus revealed no significant differences between the groups. It is concluded that grape pomace supplementation demonstrated potential to improve hematological and productive parameters in lactating ewes, with more evident effects during early lactation. Although the results suggest a possible complementary role in controlling gastrointestinal nematodes, future studies are needed to confirm and optimize this nutritional strategy. Full article

In the Australian primary industries, beef cows are recognized as monovular while sheep are less so, and both seem likely to benefit from increased litter sizes. In both species, there have been genetic developments causing increased litter sizes, but these have only had limited commercial application. This report describes the commercial use of the FecB (Booroola) gene in prime lamb ewes to increase lambing percentage from the 111% typical of the local industry to 145% in the flock described. In cattle, the use of the USMARC Twinner selection line genetics raised calf weaning percentage from the 89% typical of the local industry to 115% in the herds described. Full article

This study aimed to assess the effect of co-supplementing rumen-protected fat and rumen-protected choline on growth performance, carcass traits, and meat quality in lambs. Using a randomized experimental design, 45 weaned female Tian×Hu crossbred lambs (3 months old; average body weight: 27.34 ± 0.57 kg, mean ± SD) were randomly allocated to one of three dietary treatment groups. The three dietary treatments were as follows: a basal diet group (CON), a group receiving 2% rumen-protected fat in place of 2% barley (RPF), and a group supplemented with 2% rumen-protected fat and 0.4% rumen-protected choline, replacing 2% barley and 0.4% corn germ in the basal diet (RPFC). Compared to the CON group, neither the RPF nor RPFC treatments resulted in significant differences in growth performance (p > 0.05). However, the RPFC group showed a 5.3% increase in dry matter intake (DMI) compared to the RPF group (p < 0.05). Compared with the CON, the RPF treatment increased 69.23% the relative abundance of C18:2n-6t (p < 0.05), but the content of C17:0, C17:1, C18:1n-9c, and iso-C18:0 in Longissimus lumborum was decreased by 16.49%, 15.78%, 6.45% and 27.78%, respectively (p < 0.05). The RPFC treatment increased the relative abundance of C16:1 in Longissimus lumborum (p < 0.05). The RPF and RPFC treatments significantly increased serum levels of high-density lipoprotein (HDL) and total cholesterol compared to the CON group (p < 0.05). The RPF treatment raised HDL by 50.00% and total cholesterol by 38.03%, while the RPFC treatment increased HDL by 39.47% and total cholesterol by 26.03%. Furthermore, compared to the RPF group, the RPFC treatment led to a 13.47% increase in the 45 min b* color value of the Longissimus lumborum (p < 0.01) and a significant 45.45% reduction in the relative abundance of C18:2n-6t fatty acid in the same muscle (p < 0.05). In summary, rumen-protected choline reduces the negative effects of rumen-protected fat on feed intake in lambs and changes fatty acid profile in meat. Full article

With economic development and improved living standards, the demand for mutton and wool continues to grow, and improving the production performance and genetic potential of sheep breeds has become the key to promoting the high-quality development of the sheep industry. Thus, this study analyzes the influencing factors of the early production traits of Yunnan semi-fine wool sheep, optimizes the genetic evaluation model, and relies on accurate genetic parameter estimation to provide a theoretical basis for formulating a scientific and efficient breeding strategy for this breed. Data were collected from the Laishishan and Xiaohai breeding farms in Qiaojia, Yunnan, covering production records of the core flock from 2018 to 2022. Using the GLM procedure in SAS 9.4 software, this study analyzed the non-genetic influences on early production traits in Yunnan semi-fine wool sheep. Concurrently, Danish Milk Unit 5 (DMU 5) software estimated the variance components across various animal models for each trait. Employing the Akaike Information Criterion (AIC) and likelihood ratio test (LRT), six models were tested, incorporating or excluding maternal inheritance and environmental impacts, to identify the optimal model for deriving the genetic parameters. The results show that the birth year, dam age, sex, flock and litter size significantly affect both the Birth Weight (BWT) and Weaning Weight (WWT) (p < 0.01). Additionally, the birth month was found to exert a significant effect on Birth Weight (BWT) (p < 0.01), the weaning month has a significant effect on the Weaning Weight (WWT) (p < 0.05). No significant effects of farm location were observed on either trait (p > 0.05). The most accurate genetic evaluation model determined the heritability of the Birth Weight (BWT) and Weaning Weight (WWT) as 0.3123 and 0.3471. From a production perspective, improving lamb birth, Weaning Weight (WWT), feed composition, and maternal nutrition during gestation is vital for breeding efficiency. This study not only identified the optimal animal models for early growth traits in Yunnan semi-fine wool sheep, offering a precise basis for estimating genetic parameters but also provides theoretical guidance for genetic selection and breed improvement in this population. Full article

Through an integrated multi-omics analysis of rumen microbial communities, muscle transcriptomes, metabolic profiles, and liver metabolic profiles, this study systematically compared high- and low-performing lambs to elucidate their divergent effects on meat quality attributes and growth development. A total of 100 male lambs with similar birth weight (3.07 ± 0.06 kg) were selected within 72 h. All test lambs were synchronized weaning at 45 days of age and uniformly fed the same diet (total mixed ration) in the same pen until 180 days of age, with ad libitum access to food and water throughout this period. Subsequently, the eight lambs with the highest (HADG) and lowest (LADG) average daily gains were slaughtered for performance evaluation and multi-omics analysis. This study found that HADG lambs increased body weight, muscle fiber diameter, eye muscle area, improved amino acid (histidine, arginine, valine, isoleucine, essential amino acid/total amino acid, and essential amino acid/nonessential amino acid), and fatty acid (linoleic acid, behenic acid, and arachidonic acid) composition enhanced rumen enzymes (pepsase, lipase, xylanase, amylase, and carboxymethyl cellulose) and promoted efficient fermentation (p < 0.05). Analysis of microbial populations indicated a notable increase in Prevotella levels within the rumen of HADG lambs. Furthermore, the rumen markers Schwartzia and Streptococcus exhibited significant correlations with differential meat quality traits. Analysis of the muscle transcriptome indicated a significant correlation between the turquoise module and host phenotypes, particularly body weight. Additionally, muscle metabolism is primarily concentrated within the black module; however, it exhibits a significant correlation with the host body phenotype in the yellow module (p < 0.05). Moreover, liver metabolites, rumen microbes, host phenotype, and muscle transcripts were significantly correlated (p < 0.05). In conclusion, the interactions among rumen microbes, muscle, and liver in lambs promote rumen fermentation, which in turn regulate muscle transcriptional activity and modify metabolic profiles in both the liver and muscle. Moreover, PCK1, SPP1, FGF7, NR4A1, DUSP5, GADD45B, etc., can be candidate genes for muscle growth and development. This finding provides a theoretical basis for further exploiting the production potential of Hu lambs. Full article

In research flocks, supplementing pregnant ewes with melatonin has been shown to be a novel approach to ameliorate parturient neurological damage and improve twin lamb survival. This study investigated the commercial applicability of melatonin supplementation for Merino flocks managed under extensive grazing conditions. Multiparous twin-bearing ewes were implanted with one melatonin implant (18 mg, Regulin^®) each on two properties in South Australia and one in Western Australia (n = 585) at a median 79 days of gestation, with control ewes not implanted (n = 586). Ewes were managed as per standard protocols for each property. Lambs and ewes were counted at tail docking and weaning, and the lambs were weighed at weaning. Lamb survival was not influenced by melatonin treatment at either tail docking (p = 0.327) or weaning (p = 0.546). Across all sites, lamb survival at weaning for control and melatonin treatments was 74.7% and 74.0%, respectively, with lamb weaning weight of 27.2 ± 0.1 kg and 26.8 ± 0.1 kg (p = 0.020). These results indicate that supplementing twin-bearing Merino ewes with melatonin during mid-gestation was not a practical strategy to increase either lamb survival or weaning weight on commercial farms. Full article

The U.S. range sheep industry uses estimated breeding values (EBVs) as part of their breeding objectives to increase post-weaning weight. The study objective was to quantify the relationship between lamb growth EBVs, feed intake, and feed efficiency. Eighty-one range ewe lambs were enrolled in the study to measure residual feed intake (RFI) over two 42-d periods at both the weaning and yearling stages. The ewe lambs’ post-weaning weight EBVs (PWWT EBVs) were linearly associated with their phenotypic traits. Preliminary genome wide associations (GWAs) were also performed with Dry Matter Intake (DMI), RFI, mid-test body size, and average daily gain (ADG) and Ovine 50K SNP genotypes. Post-weaning weight EBVs were associated with dry matter intake (DMI) (p < 0.05) but had no association with residual feed intake (RFI) (p > 0.05) in both experimental periods. However, PWWT EBV was predictive of mid-test body weight in both periods (p < 0.05). A single SNP at Oar2:68,812,505, located within DMRT2, was associated with DMI and RFI in the second experimental period (Bonferroni corrected p <0.05). While selecting for higher post-weaning weight range ewes may increase feed consumed due to a larger body size, it was not associated with feed efficiency. Full article

The early weaning of lambs frequently leads to weakened immunity, impaired intestinal function, and increased susceptibility to intestinal disease. Lactobacillus plays a role in regulating immunity, enhancing antioxidant capacity, and maintaining intestinal health. This study aims to isolate a strain of Lactobacillus with favorable probiotic properties from sheep feces and investigate its effects on the intestinal health of early-weaned lambs. In this study, the growth characteristics, acid production capacity, bacteriostatic capacity, bile salt tolerance, gastrointestinal fluid tolerance, self-coagulation capacity, and surface hydrophobicity of Lactobacillus isolated from sheep feces were analyzed for in vitro probiotic properties. Lactobacilli with strong probiotic properties were used for in vivo validation. A total of 72 Hu lambs were allocated into four groups: a ewe-reared group (ER), early-weaning group (EW), low-dose Lactobacillus group (LL), and high-dose Lactobacillus group (HL). Early weaning was performed in the EW, LL, and HL groups at the age of 28 days. Lactobacillus johnsonii M5 (L. johnsonii M5), isolated from sheep feces, exhibited strong probiotic properties in vitro. Feeding EW lambs with a low dose of L. johnsonii M5 significantly reduced their diarrhea rate (p < 0.05). Its supplementation increased the levels of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) and total antioxidant capacity (T-AOC) in serum and jejunal mucosa and decreased levels of malondialdehyde (MDA) (p < 0.05). Compared to the EW group, serum immunoglobulin G (IgG) levels were significantly increased in the LL group (p < 0.05). Compared to the EW group, feeding with L. johnsonii M5 increased the content of anti-inflammatory cytokines, while reducing the content of pro-inflammatory cytokines in serum and jejunal mucosa (p < 0.05). Feeding early-weaned lambs with L. johnsonii M5 also decreased jejunal crypt depth and increased occludin and claudin-1 in jejunal mucosa (p < 0.05). These findings indicate that feeding early-weaned lambs with L. johnsonii M5 enhances their immunity and antioxidant capacity, improving intestinal health, and mitigates diarrhea in early-weaned lambs. Full article

This study aimed to evaluate the potential benefits and feasibility of adding dried and ground grape pomace to the concentrate fed to lambs experimentally infected with Haemonchus contortus. Eighteen male Santa Inês lambs, recently weaned, were housed in individual pens and were allocated into two groups based on their body weight. The lambs in the supplemented group (n = 9) initially received a diet composed of 50% ground hay and 50% concentrate. Subsequently, these animals were gradually adapted to grape pomace until its final inclusion in the concentrate reached 20%. The lambs in the control group received a concentrate without grape pomace. Both groups of lambs were artificially infected with 4000 infective larvae of H. contortus, and 28 days later, the lambs were euthanized for quantification of the nematodes present in the abomasum. The following variables showed no statistical differences (p > 0.05) between the groups: worm burden, packed cell volume, total plasma protein, blood eosinophil count, and daily weight gain. Regarding anti-Haemonchus IgG plasma levels, there was a significant time * treatment interaction (p = 0.0099) with higher values in the supplemented group. At the two final samplings, the supplemented group showed significantly lower values of eggs per gram of feces than the control group (p < 0.05). The supplemented group showed female worms shorter and with less eggs in utero than those of the control group, with significant difference for these variables (p < 0.05). In conclusion, grape pomace can be included in the diet, as it promotes more sustainable animal production, and, additionally, it can cause a reduction in H. contortus fecundity, benefiting haemonchosis prophylaxis. Full article

In lactating ewes, energy demand increases for milk production, reserve mobilizations, and body weight maintenance. For reconversion to energy, ruminants require ruminal propionate production because it is the most predominant substrate for gluconeogenesis and one of the most relevant pathways since it allows an adequate supply of glucose. Calcium propionate supplementation is an alternative to increase glucose production by an external additive. Thus, the objective was to evaluate the effect of calcium propionate (CaPr) on milk production and milk metabolomic profile on lactating ewes. Sixteen Rambouillet (65.3 ± 6.2 kg BW; three years old) were randomly assigned one of two experimental treatments: (a) basal diet without supplementation (CP/0S) and (b) basal diet + 30 g d⁻¹ of CaPr (CP/30S). The experimental period was from parturition day until day 60 (baby lamb weaning). A completely randomized design was used and analyzed with a mixed model. Initial and final lactating weight and milk production differed statistically (p < 0.05) between treatments. CP/30S led to differential changes (p < 0.05) in the lactation curve, showing significant milk production over eight-week measurements. Lactation peak (mL), maximum production (mL), and lactational persistency (d) were superior (p < 0.05) for supplemented ewes. An 11.4% variability was shown in a principal component analysis between treatments. For CP/0S, 63 bioactive compounds were detected, and 55 for CP/30S treatment. The metabolites detected in CP/0S showed that only fatty acid biosynthesis, biosynthesis of unsaturated fatty acids, and fatty acid elongation pathways were affected (p < 0.05) in milk. However, for CP/30S, metabolic pathways related (p < 0.05) were fatty acid biosynthesis, biosynthesis of unsaturated fatty acids, fatty acid elongation, phenylalanine metabolism, and steroid metabolism in milk samples. Calcium propionate supplementation increases milk performance and lactation persistency-induced changes in specific metabolic milk production pathways. Full article

As global demand for sheep products increases, improving reproductive efficiency and lamb growth performance has become a priority for sheep farmers. Artificial insemination (AI) offers several advantages over natural mating, including improved genetic selection and disease control. This study contributes to understanding the impact of different mating methods and semen preservation techniques on reproductive performance and growth traits in Palestinian Assaf sheep under local breeding conditions. The research included 123 adult Assaf ewes from two farms, which were hormonally synchronized and divided into three groups for different reproductive biotechnologies. Group 1 (G1) comprised 50 ewes inseminated with frozen semen straws, while Group 2 (G2) had 37 ewes inseminated with fresh semen from genetically superior rams. Both G1 and G2 used 0.5 mL straws containing 250 million sperm, with insemination occurring 48 h post sponge removal and eCG hormone injection. Group 3 (G3) consisted of 36 ewes that underwent natural mating at a ratio of 1 ram to 6 ewes. The study revealed that insemination methods significantly affected fertility rates (45.4, 61.1, and 71.9% for G1, G2, and G3, respectively; p < 0.05). Artificial insemination notably enhanced lamb performance indicators (p < 0.05), although it did not significantly influence prolific lambing (p > 0.05). Prolific lambing significantly impacted birth weight, weaning weight, and average daily gain at 60 days across all groups (p < 0.05), but not the average daily gain or final weight at 180 days (p > 0.05). The management system significantly affected birth and weaning weights at 60 days (p < 0.05), but not the final weight at 180 days or prolific lambing (p > 0.05). Lamb sex significantly influenced average daily gains at 60 and 180 days, as well as final weight at 180 days (p < 0.05). The findings suggest that, while artificial insemination with semen from elite rams may reduce fertility rates, it significantly improves lamb performance rates. In conclusion, our study demonstrates that, while natural mating offers higher fertility rates, AI with fresh semen can be a valuable tool for improving lamb growth performance in Palestinian Assaf sheep. These findings provide valuable insights for sheep farmers in the region to optimize reproductive strategies and enhance lamb production Full article

Background: Lamb health is crucial for producers; however, the percentage of lambs that die before weaning is still 15–20%. One factor that can contribute to lamb deaths is congenital diseases. A novel semi-lethal disease has been identified in newborn Polypay lambs and termed dozer lamb syndrome. This study aims to determine if there is a genetic predisposition to dozer lamb syndrome. These lambs are weak and unable to lift their heads, suckle, and swallow, resulting in nasal reflux. Methods: Genetic analyses, including a genome-wide association, runs of homozygosity, and fine mapping to determine haploblock within regions of interest, were utilized in determining genetic predispositions to dozer lamb syndrome. Results: The genome-wide association study identified a region of chromosome 15 with three significant SNPs (p-values of 6.81 × 10⁻⁶, 5.71 × 10⁻⁶, and 8.52 × 10⁻⁶). Genetic analysis identified a run of homozygosity on the same region of chromosome 15 with an odds ratio of 236.7. Fine mapping of this region identified three haploblocks associated with the dozer lamb syndrome (p-value = 2.41 × 10⁻⁵). Conclusions: The most significant and promising gene in this region is CELF1, which is known to play an important role in muscle development. Abnormal CELF1 abundance and cellular location are reported to result in abnormal muscle development. Identification of genetic aberrations associated with dozer lamb syndrome provides a tool for decreasing or eliminating the genotype and, thus, the associated phenotype(s) from Polypay sheep. Full article

Butyrate supplementation has gained considerable attention for its potential benefits in livestock, particularly concerning intestinal health and growth performance. This review synthesizes recent research on the diverse roles of butyrate, across various livestock species. As a short-chain fatty acid, butyrate is known for enhancing intestinal development, improving immune function, and modulating microbial diversity. Studies indicate that butyrate supports gut barrier integrity, reduces inflammation, and optimizes feed efficiency, especially during the critical weaning and post-weaning periods in calves, piglets, and lambs. Supplementation with butyrate in livestock has been shown to increase average daily gain (ADG), improve gut microbiota balance, promote growth, enhance gut health, boost antioxidant capacity, and reduce diarrhea. Additionally, butyrate plays a role in the epigenetic regulation of gene expression through histone acetylation, influencing tissue development and immune modulation. Its anti-inflammatory and antioxidant effects have been demonstrated across various species, positioning butyrate as a potential therapeutic agent in animal nutrition. This review suggests that optimizing butyrate supplementation strategies to meet the specific needs of each species may yield additional benefits, establishing butyrate as an important dietary additive for enhancing growth performance and health in livestock. Full article