Goat production contributes significantly to food security, nutrition and rural livelihoods, particularly in tropical and developing regions where goats are valued for their adaptability and efficient utilization of low-quality feed resources. However, traditional breeding systems are often limited by low productivity, poor genetic potential, nutritional deficiencies, disease challenges, and inadequate access to improved breeding technologies. Modern breeding approaches offer opportunities to overcome these constraints and improve production efficiency. This review examines recent advances in goat breeding and management, focusing on genetic improvement, reproductive technologies, nutritional strategies, and health management practices that support sustainable production. Key technologies discussed include selective breeding, genomic selection, artificial insemination, embryo transfer, cryopreservation, and gene-editing approaches. It also highlights the roles of precision feeding, nutrigenomics, probiotics, vaccination programs, and biosecurity measures in enhancing growth performance, reproduction efficiency, disease resistance, and product quality. Furthermore, the socioeconomic contributions of goat production to rural development, household income, and climate resilience are considered. Current evidence indicates that integrating improved genetics with effective nutrition and health management can substantially enhance goat productivity while promoting sustainability. However, the adoption of advanced technologies remains constrained in many smallholder production systems by limited infrastructure, technical capacity, and financial resources. Therefore, practical interventions such as strategic feeding, disease control, farmer training, and gradual implementation of reproductive technologies represent realistic pathways for improving production. Overall, modern goat breeding practices provide important opportunities to meet the increasing demand for goat products while supporting sustainable and resilient livestock systems.

Benzalkonium chlorides (BACs), a class of quaternary ammonium compounds (QACs) widely used as disinfectants and preservatives, have increasingly replaced triclosan and triclocarban in personal care products following their global restriction. However, the potential reproductive toxicity of BACs remains largely unexplored. Notably, we investigated the effects of BACs exposure on porcine oocyte maturation and fertilization competence, as well as the underlying mitochondrial mechanisms. COCs were cultured under in vitro maturation (IVM) conditions for 44 h with 0.2-50.0 μg/mL BACs. BACs exposure markedly inhibited cumulus expansion, reduced first polar body extrusion, and impaired fertilization and early embryonic development in a dose-dependent manner. Cytological analysis revealed disrupted spindle assembly, decreased microtubule stability, and disorganized F-actin structures. BACs also caused abnormal cortical granule distribution, diminished Ovastacin expression, and reduced sperm-binding capacity. Mechanistically, BACs induced mitochondrial depolarization, reduced mitochondrial abundance, elevated mitochondrial ROS, and disrupted Ca²⁺ homeostasis, leading to oxidative stress, DNA damage, apoptosis, and autophagy-lysosomal imbalance. Further, BACs exposure suppressed the mitochondrial SIRT3-SOD2 antioxidant axis, while pharmacological activation of SIRT3 by UBCS039 or ROS scavenging with Mito-TEMPO partially rescued mitochondrial dysfunction and oocyte maturation defects. Collectively, these findings demonstrate that BACs exposure compromises oocyte quality and developmental competence via mitochondrial oxidative stress and SIRT3-SOD2 axis inhibition, providing new insights into the reproductive risks associated with emerging disinfectant contaminants.

Non-coding regulatory variation drives complex traits, domestication, and evolutionary adaptation, yet the sheep genome lacks high-resolution functional annotation. Here we present SheepEpimap, a multi-tissue regulatory atlas harmonizing 516 CUT&Tag histone modifications, ATAC-seq, and RNA-seq datasets across 43 adult tissues in sheep. We annotated 2.93 million cis-regulatory elements, yielding 557,441 enhancer-gene pairs and 145,407 variants with allele-specific effects. By training a sequence-to-function deep-learning model, we decoded the base-pair syntax of chromatin accessibility, annotated transcription factor motif instances genome-wide, and constructed 12,210 tissue-specific gene regulatory networks (GRNs). Integrating this resource with multi-tissue expression quantitative trait loci, selection sweeps, and genome-wide association studies prioritized non-coding variants driving domestication and complex traits. Finally, cross-species analysis revealed that sequence-conserved, tissue-matched enhancers were significantly enriched in the heritability of complex traits and diseases in humans. In summary, SheepEpimap (https://genome.ucsc.edu/s/mengzhu/SheepEpimap) provides an open-access foundational ecosystem for sheep functional genomics, precision breeding, and comparative biology.

Off-site fattening of Tibetan sheep is a key strategy to mitigate the effects of high-altitude grassland degradation and winter forage scarcity, promoting sustainable development in plateau animal husbandry. However, transport stress (TS) presents a significant challenge to realizing its benefits. The mechanism by which TS affects the health of Tibetan sheep by regulating rumen microbial and serum metabolite rhythmic changes remains unclear. This study selected six healthy male Tibetan sheep, aged seven months and of comparable body weight, for the transport experiment. Blood and rumen fluid samples were collected at four-hour intervals during 24-hour periods pre-transport (CON) and post-transport (TS) for serum indicators, serum metabolome, and rumen microbiome analyses. The results showed that TS significantly increased serum concentrations of cortisol (COR), melatonin (MT), lipopolysaccharide-binding protein (LBP), serum amyloid A (SAA), and non-esterified fatty acid (NEFA), while significantly decreasing glucose (GLU), total antioxidant capacity (T-AOC), and glutathione peroxidase (GPx) (P < 0.05). Furthermore, the circadian rhythms of COR, MT, LBP, SAA, NEFA, and GPx were significantly disrupted (ADJ.P < 0.05). TS reduced the proportion of rumen microbial circadian rhythms from 3.46

1Key Laboratory of Animal Genetics and Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China 2College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China. Article Information Received 18 January 2022 Revised 05 April 2022 Accepted 23 April 2022 Available online 08 September 2023 (early access)

Phospholipase A (PLA) in goat semen aggregates with egg yolk in semen diluent, leading to sperm death. The aim of this study is to address the issue of sperm death caused by the interaction between PLA and egg yolk, and to explore the protective effect and metabolic regulation mechanism of the combination of dexamethasone (DXMS) and azithromycin (AZM) on goat sperm under low temperature conditions. At a low temperature of 4 °C, different concentrations of DXMS were added to semen diluents containing 30 μg/mL AZM to detect the quality of goat sperm. The optimal concentration of DXMS was determined to be 20 μg/mL. On the 5th day of storage, antioxidant capacity, total cholesterol (TC) levels, energy metabolism, and metabolomics analysis were performed on the sperm of the 20 μg/mL DXMS group. The results showed that there was no aggregation caused by the interaction between PLA and egg yolk in the group containing 30 μg/mL AZM at 4 °C. 20 μg/mL DXMS significantly improved sperm motility, plasma membrane integrity, acrosome integrity, glutathione peroxidase (GPX) (P < 0.05), catalase (CAT) (P < 0.01), and superoxide dismutase (SOD) activity (P < 0.01). The content of reactive oxygen species (ROS) and Fe2+ significantly decreased (P < 0.01), while the content of ATP (P < 0.01) and TC (P < 0.05) significantly increased. Through metabolomics analysis, a total of 56 differential metabolites (P < 0.05) were screened, including 5a, 6-Anhydrotetracycline, Betamethasone, and 11-Dehydrocorticosterone, mainly enriched in 8 metabolic pathways (P < 0.05), including steroid hormone biosynthesis, glycerophospholipid metabolism, and choline metabolism in cancer. Among them, 5 metabolic pathways are related to lipid metabolism. The results indicate that AZM effectively inhibits the aggregation of PLA and yolk, and the combination of AZM and DXMS enhances the preservation quality of goat sperm during low-temperature preservation by regulating lipid metabolism.

Tibetan sheep are highly adaptable to cold and hypoxic environments, allowing them to thrive on the Qinghai‒Tibet Plateau. Although many studies have investigated the mechanisms underlying their cold tolerance and hypoxia adaptation, it is still unclear how Tibetan sheep cope with the challenges of heat stress (HS) when raised in southern China. In this study, Tibetan sheep and heat-tolerant breeds (Hu sheep and Huanghuai sheep) were selected, and we conducted physiological observations, biochemical measurements, and metabolomic analysis on serum from a nonheat stress (NH) group, where the temperature-humidity index (THI) was 59.13, and a heat-stressed group (THI = 82.78). The results revealed that HS significantly increased the rectal temperature, respiratory rate, and heart rate of Tibetan sheep, and these values were significantly greater than those in the heat-tolerant breeds. Serum antioxidant indices revealed that catalase activity, total antioxidant capacity, and total superoxide dismutase activity were significantly lower in Tibetan sheep than in Hu sheep under HS. Metabolomic analysis revealed that HS reduced the levels of serum antioxidant metabolites, such as creatine, ornithine, l-arginine, and guanosine, and increased the levels of the oxidative stress marker metabolite 3-nitrotyrosine in Tibetan sheep. Additionally, the ratio of serum antioxidant metabolites to 3-nitrotyrosine in Tibetan sheep was significantly lower than that in heat-tolerant breeds, and these ratios were correlated with physiological parameters. Therefore, these results suggest that Tibetan sheep are relatively sensitive to HS.

Transport stress poses a major challenge to the livestock industry. Studies have shown that transportation stress can cause depression, elevated body temperature and dysbiosis of intestinal microbiota in meat goats, and in severe cases, even lead to death of the animals, which in turn affects the economic efficiency of the farming industry. However, the changes in blood biochemical indicators and flora of Tibetan sheep throughout the receiving period after long-distance transport remain unclear. In this study, six 7-month-old Tibetan sheep with similar body weights were selected for a 30-d transport trial, and blood and faecal samples were collected for blood biochemical indices and 16 S microbiome sequencing before transport (BT), and on day 1 (AT 1), day 16 (AT 16), and day 30 (AT 30) after the end of the transport, respectively. And a number of blood biochemical indices (creatine kinase (CK), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), aspartate aminotransferase (AST), cortisol (COR), and adrenocorticotropic hormone (ACTH)) were significantly elevated (P < 0.05). Combined analysis of physiological and biochemical indices with 16 S rDNA sequencing showed that Turicibacter, Romboutsia and Clostridium_sensu_stricto_1 were positively correlated with LDH, ALP, CK, AST, and ACTH, while Prevotellaceae_UCG_004 was negatively correlated. Furthermore, the observed recovery trends in vital signs after AT 16 suggest that Tibetan sheep may be able to adapt to the new environment within one month post-transport. The present study illustrated the effects of transport without measures on the vital signs, serum biochemical indicators and faecal microorganisms of Tibetan sheep throughout the receiving period, which is of great significance in guiding the transport of Tibetan sheep and solving the damage caused by transport stress on the economic benefits of the farming industry.

IntroductionComprehensive functional annotation of the genome is crucial for elucidating the molecular mechanisms underlying complex traits and diseases. Although functional annotation has been partially completed in sheep, a systematic annotation focused on reproductive tissues remains absent.MethodsIn this study, we integrated 60 transcriptomic and epigenomic datasets from five reproductive tissues. Using a multi-omics approach, we predicted 15 distinct chromatin states and conducted thorough functional annotation.ResultsWe established the first regulatory element atlas for sheep reproductive tissues and examined the roles of these elements in reproductive traits and disease. In total, we annotated 1,680,172 regulatory elements, including 83,980 tissue-specific strong active enhancers (EnhAs).DiscussionEnhancers were identified as critical drivers of tissue-specific functions, operating through sequence-specific transcription factor binding and direct regulation of target genes. Key transcription factors associated with reproductive function included INHBA (ovary), KITLG (oviduct), Snai2 (cervix), WNT7A (uterine horn), FOLR1 (uterine body), and SALL1 (shared uterine regions). Additionally, our findings support the potential of sheep as a promising model for investigating embryonic development and miscarriage. This work lays a theoretical foundation for future research into the molecular mechanisms of complex traits and diseases in sheep.

Reproduction traits are crucial for livestock breeding and represent key economic indicators in the domestic goat (Capra hircus) industry. The oviduct, a critical organ in female mammals, plays a pivotal role in several reproductive processes; however, its molecular mechanisms remain largely unknown. Non-coding RNA and mRNAs are essential regulatory elements in reproductive processes; yet their specific roles and regulatory networks in goat oviducts remain unclear. In this study, we conducted small RNA sequencing of the oviduct in high- and low-fecundity goats during the follicular (FH and FL groups, n = 10) and luteal (LH and LL groups, n = 10) phase, profiling 20 tissue samples. Combinatorial whole-transcriptome expression profiles were applied to the same samples to uncover the competitive endogenous RNA (ceRNA) regulation network associated with goat fecundity. RT-qPCR was employed to validate the miRNA profiling results, and ceRNA regulatory networks were analyzed through luciferase assay. Gene set enrichment analysis (GSEA) confirmed that the cytokine-cytokine receptor interaction and TGF-β signaling pathway, both related to embryonic development, were enriched in DEM target genes. Additionally, miR-328-3p, a core miRNA, targets SMAD3 and BOP1, which are involved in the negative regulation of cell growth and embryonic development. TOB1 and TOB2, targeted by miR-204-3p, regulate cell proliferation via the protein kinase C-activating G-protein coupled receptor signaling pathway. Analyses of ceRNA regulatory networks revealed that LNC_005981 − miR-328-3p − SMAD3 and circ_0021923 − miR-204-3p − DOT1L may affect goats’ reproduction, findings that were validated using luciferase assay. Analysis of whole-transcriptome profiling of goat oviducts identified several key miRNAs and ceRNAs that may regulate oocyte maturation, embryo development, and the interactions between the oviduct and gametes/early embryos, providing insights into the molecular mechanisms of reproductive regulatory networks.

Milk whey proteins are sensitive to heat processing; however, differences in the whey proteome across various species following homogenization and heat treatment remain inadequately understood. This study aimed to examine changes in the abundance of whey proteins in milk from five species after homogenization (50 degrees C, 20 MPa) and heat treatment (63 degrees C/30 min and 90 degrees C/15 min) using an LC-MS/MS approach. A total of 759 proteins were identified and quantified in raw and treated milk. Homogenization and heat treatment affected the abundance of fatty acid-binding protein 3, apolipoprotein A-I, lactoperoxidase, and lactoferrin, with speciesspecific variations depending on the heat intensity. Notably, after homogenization and 63 degrees C for 30 min treatment, lactoferrin abundance decreased in cow (6.2- and 6.4-fold) and goat (1.8- and 1.5-fold) milk whey, while no significant changes were observed in buffalo, camel, and yak milk. Additionally, the dissociation of caseins in whey fractions varied by species. In goat milk, the abundances of beta-casein, kappa-casein, alpha-S1-casein, and alpha-S2-casein increased, indicating a higher sensitivity to heat treatment, whereas in camel milk, only kappa-casein increased. These findings highlight that variation in the milk whey proteome, influenced by both species-specific differences and processing-induced changes, contribute to the optimization of dairy processing techniques, warranting further investigation.

Y-27632, as a cytoskeleton protector, is commonly used for low-temperature preservation of cells. Goat sperm are prone to damage to the cytoskeleton under low-temperature conditions, leading to a loss of sperm vitality. However, the Y-27632 small molecule has not yet been used in research on low-temperature preservation of goat semen. This study aims to address the issue of low temperature-induced loss of sperm motility in goats by using Y-27632, and explore the regulation of Y-27632 on goat sperm metabolism. At a low temperature of 4 °C, different concentrations of Y-27632 were added to the sperm diluent. The regulation of Y-27632 on the quality of low temperature-preserved goat semen was evaluated by detecting goat sperm motility, antioxidant capacity, mitochondrial activity, cholesterol levels, and metabolomics analysis. The results indicated that 20 µM Y-27632 significantly increased plasma membrane integrity (p < 0.05), and acrosome integrity (p < 0.05) and sperm motility (p < 0.05), increased levels of superoxide dismutase (SOD) and catalase (CAT) (p < 0.01), increased total antioxidant capacity (T-AOC) (p < 0.05), decreased levels of malondialdehyde (MDA) and reactive oxygen species (ROS) (p < 0.01), and significantly increased mitochondrial membrane potential (MMP). The levels of ATP, Ca2+, and TC in sperm increased (p < 0.01). Twenty metabolites with significant differences were identified, with six metabolic pathways having a significant impact, among which the D-glutamic acid and D-glutamine metabolic pathways had the most significant impact. The artificial insemination effect of goat semen treated with 20 μM Y-27632 was not significantly different from that of fresh semen. This study indicates that Y-27632 improves the quality of low-temperature preservation of sperm by protecting the sperm plasma membrane, enhancing sperm antioxidant capacity, regulating D-glutamine and D-glutamate metabolism, and promoting the application of low-temperature preservation of semen in artificial insemination technology.

Heat stress (HS) has become a common stressor, owing to the increasing frequency of extreme high-temperature weather triggered by global warming, which has seriously affected the reproductive capacity of important livestock such as sheep. However, little is known about whether HS reduces sperm motility by inducing circadian rhythm disorders in rumen microorganisms and metabolites in sheep. In this study, the year-round reproduction of two-year-old Hu rams was selected, and the samples were collected in May and July 2022 at average environmental temperatures between 18.71 °C and 33.58 °C, respectively. The experiment revealed that the mean temperature-humidity index was 86.34 in July, indicating that Hu rams suffered from HS. Our research revealed that HS significantly decreased sperm motility in Hu rams. Microbiome analysis further revealed that HS reshaped the composition and circadian rhythm of rumen microorganisms, leading to the circadian disruption of microorganisms that drive cortisol and testosterone synthesis. Serum indicators further confirmed that HS significantly increased the concentrations of cortisol during the daytime and decreased the testosterone concentration at the highest body temperature. Untargeted metabolomics analysis revealed that the circadian rhythm of rumen fluid metabolites in the HS group was enriched by the cortisol and steroid synthesis pathways. Moreover, HS downregulated metabolites, such as kaempferol and L-tryptophan in rumen fluid and seminal plasma, which are associated with promotion of spermatogenesis and sperm motility; furthermore, these metabolites were found to be strongly positively correlated with Veillonellaceae_UCG_001. Overall, this study revealed the relationship between the HS-induced circadian rhythm disruption of rumen microorganisms and metabolites and sperm motility decline. Our findings provide a new perspective for further interventions in enhancing sheep sperm motility with regard to the circadian time scale.

Allicin is a sulfur-containing compound extracted from raw garlic (Allium sativum L.). We compared the effect of allicin addition on growth performance, serum biochemical parameters, and rumen microbiota of goats compared to monensin. Twenty-four Anhui white goats were assigned randomly to one of three dietary treatments: 1) a basal diet (CON); 2) the basal diet with allicin addition at 750 mg per head per day (AC); 3) the basal diet with monensin addition at 30 mg per kg of diet (MS). Animals were fed for 8 weeks. Results showed the average daily gain, and feed efficiency was increased with allicin and monensin addition. Serum levels of IgG, total superoxide dismutase, and glutathione peroxidase were higher in the AC group than those in the CON and MS groups. The microbiota analysis revealed that monensin addition mainly affected genera related to carbohydrate and protein metabolism, and allicin mainly affected genera related to energy metabolism and intestinal health. In conclusion, allicin could improve growth performance and have advantages over monensin in improving the antioxidant capacity and immune function of goats. Allicin may be a potential alternative to monensin.

Sleep deprivation (SD) disrupts circadian rhythms; however, its effects on SD and the mechanisms involved require further investigation. Previous studies on SD were mainly conducted on rodents, such as mice, with few studies on its effects on the liver of large diurnal animals, such as sheep. In this study, we used a Tibetan sheep model for the first time to investigate the effects of SD on the liver by exposing Tibetan sheep (Ovis aries) to 7 days of SD (6 h/day) and performed transcriptome sequencing analysis on liver samples taken at 4 h intervals over 24 h. The results revealed that SD significantly altered the circadian expression of genes and their expression patterns in the liver of Tibetan sheep. Enrichment analysis of the circadian rhythm-altered genes revealed changes in the pathways related to lipid metabolism in the liver. Further evidence from serum markers and gene expression analyses using qualitative real-time polymerase chain reaction and Oil Red O and apoptosis staining indicated that SD leads to abnormal lipid metabolism in the liver, potentially causing liver damage. Therefore, our results suggest that SD disrupts the circadian rhythms of metabolism-related genes in the Tibetan sheep liver, thereby affecting metabolic homeostasis.

This study aimed to investigate the effects of different dietary concentrate-to-forage ratios on slaughter performance, meat quality, rumen fermentation, rumen microbiota and fecal microbiota in Tibetan sheep. A total of sixty male Tibetan sheep were equally allocated into three dietary groups based on concentrate-to-forage ratios, i.e., 30:70 (C30), 50:50 (C50), and 70:30 (C70). Compared with the C30 group, sheep fed the C70 diet resulted in a higher (p < 0.05) slaughter live weight (SLW), hot carcass weight (HCW), dressing percentage (DP), eye muscle area, average daily gain (ADG), and ruminal total volatile fatty acids concentration and propionate molar proportion and lower (p < 0.05) shear force and cooking loss of meat, and ruminal acetate molar proportion and acetate:propionate ratio. Sheep in the C50 group exhibited a higher (p < 0.05) SLW, HCW, ADG, and ruminal propionate molar proportion and lower (p < 0.05) shear force and cooking loss of meat, and ruminal acetate molar proportion and acetate: propionate ratio compared with the C30 group. In rumen fluid, the relative abundance of Butyrivibrio was lower (p = 0.031) in the C30 group, and that of Ruminococcus was higher (p = 0.003) in the C70 group compared with the C50 group. In feces, genus Monoglobus and UCG_002 were the most abundant in the C30 group (p < 0.05), and the relative abundance of Prevotella was significantly higher in the C70 group than in other groups (p = 0.013). Correlation analysis revealed possible links between slaughter performance and meat quality and altered microbiota composition in the rumen and feces of Tibetan sheep. Overall, feeding a C70 diet resulted in superior carcass characteristics and meat quality in Tibetan sheep, thus laying a theoretical basis for the application of short-term remote feeding during the cold season.

Ram sperm undergo a sequence of physiological and biochemical changes collectively termed as capacitation to perform oocyte fertilization. However, the protein changes induced by capacitation remain in need of further exploration. Thus, the present study investigated the comparative proteomic profiling in ram spermatozoa under non-capacitating (NC) and capacitating (CAP) conditions in vitro using a liquid chromatography-tandem mass spectrometry combined with tandem mass tag labeling strategy. As a results, 2050 proteins were identified and quantified; 348 of them were differentially abundant, with 280 of the proteins upregulated and 68 of the proteins downregulated between the CAP and NC spermatozoa, respectively. Functional enrichment analysis indicated that the differentially abundant proteins Prune Exopolyphosphatase 1, Galactose-1-Phosphate Uridylyltransferase, and ATP Citrate Lyase were strictly related to energy production and conversion, and Phosphoglycolate phosphatase, Glucosamine-6-Phosphate Deaminase 1 and 2 were related to metabolism, RNA processing, and vesicular transport pathways. Furthermore, the networks of protein-protein interaction indicated a strong interaction among these differential proteins in annotated pathways such as ubiquitin and transport metabolism. Our findings indicate that capacitation progress might be regulated through different pathways, providing insights into mechanisms involved in ram sperm capacitation and fertility.

OBJECTIVE:The purpose of this study was to explore the effect of sodium salicylate (SS) on semen preservation and metabolic regulation in goats.METHODS:Under the condition of low temperature, SS was added to goat semen diluent to detect goat sperm motility, plasma membrane, acrosome, antioxidant capacity, mitochondrial membrane potential (MMP) and metabonomics.RESULTS:The results show that at the 8th day of low-temperature storage, the sperm motility of the 20 μM SS group was 66.64%, and the integrity rates of the plasma membrane and acrosome were both above 60%, significantly higher than those of the other groups. The activities of catalase and superoxide dismutase in the sperm of the 20 μM SS group were significantly higher than those of the control group, the contents of reactive oxygen species and malondialdehyde were significantly lower than those in the control group, the MMP was significantly higher than that in the control group, and the contents of Ca2+ and total cholesterol were significantly higher than those in the control group. Through metabonomics analysis, there were significant metabolic differences between the control group and the 20 μM SS group. Twenty of the most significant metabolic markers were screened, mainly involving five metabolic pathways, of which nicotinic acid and nicotinamide metabolic pathways were the most significant.CONCLUSION:The results indicate that SS can effectively improve the low-temperature preservation quality of goat sperm.

The aim of this study was to determine whether the inclusion of 40% of common vetch (CV) hay as a feed ingredient in place of alfalfa hay (AH) would improve performance and ruminal fermentation and microbiota in fattening lambs. Twenty lambs were equally divided into two groups: control group (fed 40% AH with 20% rice straw) and CV group (fed 40% CV hay with 20% rice straw). Concerning hay quality, CV hay had greater in vitro digestibility of dry matter and neutral detergent fiber (p < 0.05) than AH. Lambs fed the CV diet had a higher average daily gain (ADG) and efficiency of feed and economy than lambs fed the control group. The NH3-N content and estimated methane produced per unit of ADG of the CV diet group were significantly lower (p < 0.05) than control group. Multiple differential microbial genera were identified, with Prevotella being the most dominant genus and a tendency towards higher (p = 0.095) in lambs offered CV diet. The higher Ruminococcus abundance (p < 0.05) was found in animals of the CV group compared to the control group. In summary, CV can be incorporated into lamb diets as a low-cost forage alternative to AH to improve feed efficiency and animal performance and to reduce methane produced per unit of ADG.

Growth rate, carcass attributes, and meat quality traits of small ruminants (i.e., sheep and goats) depend on various factors, among which the feeding system is one of the most important factors. However, how feeding systems affect these parameters differ between sheep and goats. Therefore, this review aimed to evaluate the differences in how different feeding systems affect the growth performance, carcass characteristics, and meat quality of sheep and goats. It also explored the effects of a new finishing strategy-time-limited grazing with supplements on these traits. Compared with stalled feeding, finishing lambs/kids on pasture-only feed reduced the average daily gain (ADG) and carcass yield, while supplemented-grazing lambs/kids had near-equivalent or higher ADG and carcass attributes. Pasture-grazing increased the meat flavor intensity and healthy fatty acid content (HFAC) of lamb/kid meat. Supplemental grazing lambs had comparable or superior meat sensory attributes and increased meat protein and HFAC compared to stall-fed ones. In contrast, supplemental grazing only improved the meat color of kids but had little effect on other meat qualities. Moreover, time-limited grazing with supplemental concentrates increased the carcass yield and meat quality in lamb meat. Overall, the effects of different feeding systems on growth performance and carcass traits were comparable between sheep and goats but differed in terms of the meat quality.