Production, reproduction, and some adaptation characteristics of Romanov sheep raised under humid temperate climate.

This study aimed to determine the fertility and growth traits, viability, and body measurements of the Romanov sheep under breeder conditions in the humid region of Turkey. The animal material of the research consisted of sheep imported from Ukraine in 2019. In the study, there are two farms with 31 and 44 ewes in the first year and three farms with 45, 34, and 32 ewes in the second year. The reproductive performances of 186 sheep and lambs in three different farms were examined, and nine rams, one ram per 20 sheep, were used for mating. Two-year (2020 and 2021) data on the reproductive performance of pure Romanov ewes, survivability in ewes and lambs, and development characteristics in lambs were used in the present study. The conceived rate (88.17%), fecundity at birth (1.42) and at weaning (1.29), litter size at birth (1.76) and weaning (1.56), single (50.98%), twin (41.83%), and triplet birth rate (6.54%), and abortion rate (6.71%) were determined for 2 years average. Birth and weaning weights of lambs were affected by sex and birth type (p < 0.01). The Romanov sheep and their lambs did not satisfy the breeder regarding reproductive performance and lamb development.

Examining performance, milk, and meat in ruminants fed with macroalgae and microalgae: A meta-analysis perspective.

This meta-analysis consolidates various related studies to identify patterns in the impact of feeding algae on performance aspects, including milk fat, milk protein, and carcass yield in several ruminant species, such as cattle, sheep, and goats. The data were collected from 67 articles that examined factors such as the type of algae (macro- and microalgae), algal species, and animal breed. Barki sheep, Moghani sheep, and Zaraibi goats demonstrated an increased average daily gain (P < 0.05) when fed with both macro- and microalgae. Conversely, sheep such as Canadian Arcott and Ile-de-France showed adverse effects on the feed conversion ratio (FCR) (P < 0.05). Elevated FCR values were observed across castrated and young animals (P < 0.05). Algae extract notably increased the hot carcass weight (P < 0.001), particularly among Moghani sheep (P < 0.001). Raw algae significantly reduced the milk fat content (P < 0.001), particularly in cattle and sheep (P < 0.001). A decrease in milk fat was particularly noticeable in lactating females of Assaf sheep, Damascus goats, and Holstein cows (P < 0.001). Overall, algae inclusion tended to decrease the milk protein content (P < 0.05), leading to reduced milk production (P < 0.001) with cumulative algae feeding in Assaf sheep. However, conjugated linoleic acid (CLA; C18:2 c9,t11-CLA and C18:2 c12,t10-CLA) and docosahexaenoic acid (DHA; C22:6n-3) mostly increased in meat and milk from Holstein cow, Assaf sheep, Dorset sheep, and Ile-de-France sheep (P < 0.01). This meta-analysis highlights the necessity for additional research aimed at optimizing the sustainable use of algae in feed for ruminants, despite the demonstrated improvements in performance and the levels of CLA and DHA found in meat and milk.

Comparative assessment of growth curves in Brazilian white Morada Nova hair sheep breed.

The Morada Nova sheep breed is essential for the economy of the semi-arid region of Northeast Brazil, standing out for its adaptability, resistance to parasites and reproductive ability. However, the white variant is endangered, highlighting the importance of studies on its productivity to support conservation efforts. This study focuses on the growth curve of the Morada Nova sheep breed, using nonlinear models and analyzing flock profiles. Total of 764 observations of 165 animals from four farms in Ceará and Rio Grande do Norte, Brazil, were analyzed. Canonical discriminant analysis (CDA) was used for the exploratory analysis and four nonlinear models were used to study the growth curve. Weight from birth to 270 days of age, absolute growth rate (AGR), and the impact of sex on growth curves were assessed. Sex and farm are significant discriminating variables (P < 0.05) for the studied effects (weight and age). Weight was the primary phenotypic biomarker that discriminated between the two indicators, while age was a discriminating indicator only for the core effect. The Gompertz model was the most efficient, presenting the lowest residuals and greatest convergence. The study reveals new information about the growth of Morada Nova sheep, the white variety, including weight differences between the sexes at all analyzed ages and an inflection point before 90 days of age. These discoveries contribute to the understanding of the breed's growth and help in the formulation of conservation strategies.

Divergent planes of nutrition in mature rams influences body composition, hormone and metabolite concentrations, and offspring birth measurements, but not semen characteristics or offspring growth.

Objectives of this experiment were to characterize the effects of ram plane of nutrition on body composition, concentrations of hormones and metabolites, sperm characteristics, and offspring outcomes. Mature Rambouillet rams (n = 24, BW = 82.9 ±â€…2.63 kg) were individually housed and randomly assigned to either a positive (POS; n = 8), maintenance (MAINT; n = 8), or negative (NEG; n = 8) plane of nutrition for an 84-day feeding period. Rams were fed a common diet, with daily feed allocations adjusted weekly based on body weight (BW) to achieve the targeted weight gain or loss (approximately 12% of initial BW). On 0, 28, 56, and 84-d, body condition score (BCS) and scrotal circumference (SC) were recorded, and blood and semen were collected. Following the feeding period, rams were placed in pens with 10 ewes each for a 28-d breeding period. Ewes were managed similarly throughout gestation and body weight and measurements were recorded at birth and weaning. Data were analyzed as repeated measures in time where appropriate with the mixed procedure of SAS, and individual ram was the experimental unit for all analysis. Ram BW was influenced by a treatment × day interaction (P < 0.001), with POS (0.12 ±â€…0.01 kg) having greater daily weight change than MAINT (0.1 ±â€…0.01 kg), which was greater than NEG (-0.12 ±â€…0.01 kg). Ram BCS and SC were influenced by treatment × day interactions (P ≤ 0.01), being similar on day 0 but POS being greater than NEG by day 56. Concentrations of triiodothyronine (T3) and T3:T4 ratio exhibited treatment × day interactions (P ≤ 0.02), as POS had greater values than NEG by day 84 (P ≤ 0.02). Concentration of insulin-like growth factor-1 was greater in POS than MAINT and NEG (P ≤ 0.02), and non-esterified fatty acids and thyroxine (T4) were influenced by a day effect (P ≤ 0.01), but testosterone was unaffected (P ≥ 0.09). Minimal differences in semen volume, sperm concentration, motility, or morphology were observed among treatments (P ≥ 0.31). A similar proportion of ewes bred by rams in the respective treatments lambed and weaned lambs (P ≥ 0.54). Birth weight, chest circumference, and shoulder-hip length were greater (P ≤ 0.05) in NEG lambs compared with POS and MAINT; however, no differences were detected in weaning weight and weaning body measurements (P ≥ 0.40). Findings suggest paternal nutrition during the period of sperm development may influence offspring outcomes, potentially as a result of in-utero programming of paternal origin.

This study was conducted to evaluate whether ram nutrition during the spermatogenesis impacts their body composition, concentrations of circulating hormones and metabolites, semen characteristics, fertility, and subsequent offspring growth and development. Rams were managed on treatments to gain, lose, or maintain body weight over an 84-day period. The changes in ram body weight that were imposed by our treatments resulted in changes in body condition score, scrotal circumference, and concentrations of several metabolic hormones, including thyroid hormones and insulin-like growth factor-1. However, no differences in sperm concentration or motility were observed. After the 84-d feeding period, rams were placed with ewes for a 28-d breeding period and ewes were monitored throughout gestation, lambing, and until weaning of the resulting lambs. Although no differences in ewe pregnancy rates were observed after the breeding period, lamb birth weight and body measurements were greater in rams that lost weight during spermatogenesis. Thereafter, body weight and growth performance of offspring were similar among sire treatments, but continued evaluation of offspring throughout the postnatal period is necessary. These findings indicate that paternal nutrition during spermatogenesis can impact offspring outcomes, potentially through epigenetic alterations to the sperm and subsequent in-utero programming of paternal origin.

Estimating body composition using CT scans of cross-bred lambs fed at 2 feeding levels and 2 stages of maturity to inform predictive growth models.

Livestock producers would benefit from more precise predictions of the growth response from nutrients consumed. Previously published models are often limited by the realities of data collection and are unable to account for alterations to body composition, due in part to the response of visceral organs to an alternate diet. The computerized tomography (CT) scanning of lambs enables the analysis of changes in body composition of individual animals over time, potentially supporting better model development and testing. The aim of this experiment was to develop a repeatable method for the analysis of live lamb body composition using CT scans. A secondary aim was to compare the data collected from CT scanning during a feeding trial to 2 predictive lamb growth models. Cross-bred lambs were fed 2 feeding levels at 2 stages of maturity, with CT scans at the beginning and end of each 8-wk feeding period. The CT scan-derived values for body composition taken at the beginning of feeding periods were used as inputs for 2 existing lamb growth models. Predictions of body composition were compared with CT scan-derived values at the end of feeding periods. The CT scan analysis method used a proportion of images from each lamb to reduce manual image editing. The method was developed by comparing the estimated mass and volume of empty body components using all available CT scans to estimated values using a reduced number of scans from 12 lambs. The CT scan-derived lean tissue mass aligned with model predictions at the end of each feeding period, however, CT scan-derived fat mass was greater than predictions by both models especially for the high feeding level at the later stage of maturity. These results highlight that the analysis of body composition using CT scans requires further validation, particularly for the viscera, and that models likely require refinement to better predict the efficiency of energy utilization by different tissues. The use of live animal CT scans can provide more accurate predictions of the growth of saleable products than measuring liveweight alone and will enable ruminant growth models to better adapt to different genetics and changing diets than comparative slaughter. To replicate the current data using comparative slaughter would require 4 times the animals, as individual lambs were CT scanned 4 times in this study, demonstrating the potential value of CT scanning in live animal research.

Predictive growth models are unable to properly account for the effects of changes to body composition on the energetic efficiency of lamb growth and improving these models has been limited by the realities of data collection. By tracking changes in individual animal body composition, it is likely that better predictions of the effects of genetics, nutrition, and management on lamb growth can be made. The computerized tomography (CT) scanning of lambs enables the analysis of changes in body composition over time, potentially supporting better model development and testing. A repeatable method for analyzing lamb CT scans was developed and results were compared with 2 existing lamb growth models. Lean tissue mass derived from CT scans aligned with model predictions but fat mass estimated using CT scans was greater than model predictions, particularly for lambs fed at later stages of maturity. Further verification is needed by combining CT scanning and comparative slaughter, especially with respect to the weight of internal organs and the stomach and intestinal contents to better inform predictive growth models.

The comparisons of non-linear models to describe the growth performance of Lori-Bakhtiari sheep.

BACKGROUND: The study of growth traits is of interest to many animal scientists, regardless of specialization, due to the economic importance of growth rate, mature weight and other related traits. OBJECTIVE: This study aimed to compare six non-linear models for describing the growth of Lori-Bakhtiari sheep. METHODS: In order to collect weight data, 85 lambs (41 males and 44 females) were reared from birth to 140 days of age, and their growth patterns were recorded by measuring their body weight at 10-day intervals. Various mathematical functions, including the negative exponential, Brody, Gompertz, Logistic, Morgan-Mercer-Flodin (MMF) and Weibull, were used to model the relationship between body weight records and age. RESULTS: The results showed that the MMF and Gompertz models provided the best fit to the body weight data, whereas the negative exponential model exhibited the worst fit. In all models, the asymptotic weight of male lambs was higher than females. The research also revealed differences in growth patterns between male and female lambs. Overall, females had a lower absolute growth rate than males, but they reached their peak growth at an earlier period, and their growth rate declined faster. CONCLUSIONS: The differences in growth patterns between males and females indicate the importance of analysing male and female data separately when describing growth. As a result, Gompertz model can be recommended to Lori-Bakhtiari female and male lamb breeders to determine more accurate growth traits. In addition, it should be considered that feeding male and female lambs separately according to absolute growth rate values may increase growth performance.

Study on the expression patterns of inner root sheath-specific genes in Tan sheep hair follicle during different developmental stages.

By analyzing the expression patterns of inner root sheath (IRS) specific genes during different developmental stages of hair follicle (HF) in Tan sheep embryos and at birth, this study aims to reveal the influence of the IRS on crimped wool. Skin tissues from the scapular region of male Tan sheep were collected at 85 days (E85) and 120 days (E120) of fetal development, and at 0 days (D0), 35 days (D35), and 60 days (D60) after birth, with four samples at each stage. Real-time quantitative polymerase chain reaction (RT-qPCR) was employed to determine the relative expression levels of IRS type I keratin genes (KRT25, KRT26, KRT27, KRT28), type II keratin genes (KRT71, KRT72, KRT73, KRT74), and the trichohyalin gene (TCHH) in the skin of Tan sheep at different stages. Results showed that the expression levels of all IRS-specific genes peaked at D0, with the expression of all genes significantly higher than at E85 (P < 0.01), except for KRT73 and TCHH. The expression levels of KRT25, KRT26, and KRT72 were also significantly higher than at E120 (P < 0.01). Furthermore, the expression levels of KRT27, KRT28, KRT71, and KRT74 were significantly higher than both at E120 and D35 (P < 0.01). The expression levels of other genes at different stages showed no significant difference (P > 0.05). Conclusion: The IRS-specific genes exhibit the highest expression levels in Tan sheep at the neonatal stage. The expression levels of KRT71, KRT72, and TCHH, which are consistent with the pattern of wool crimp, may influence the morphology of the IRS and thereby affect the crimp of Tan sheep wool.

Enhancing lamb growth and meat quality: analysis of kazakh fat-tailed and crossbred in central Kazakhstan's sharply continental climate.

The article presents the results of scientific research on the production of lamb in the conditions of the Akmola region. The experiment was conducted on purebred Kazakh short-tailed rough-haired and cross-bred sheep obtained from industrial crossing of Kazakh short-tailed rough-haired queens with sheep- producers of the hampshire breed. Further, the article presents the results of feeding and fattening, as well as the morphological composition of the carcass of sheep of the Kazakh coarse-haired sheep breed of different ages. The object of the study for feeding and fattening were three groups of experimental sheep of the above-mentioned breed, where compound feed was included in the diet of the I experimental group in the form of top dressing, in the II experimental group, grain waste was also used for top dressing, and the control group was kept in the feed without top dressing. Based on the study of the feeding of experimental sheep, it was found that the absolute increase during the feeding period in experimental sheep who received fertilization in the form of compound feed is higher than in their peers, respectively, by 0.2 and 1.49 kg. In terms of morphological and varietal composition, in particular, the number of cuts of grade 1, there was also an advantage of experimental sheep that received fertilization in the form of compound feed compared to their peers, respectively, by 2.3-8.3%. In general, the results of a study on the growth, development and slaughter qualities of experimental sheep, i.e. purebred Kazakh short-tailed rough-haired and crossbred, obtained from crossing with sheep producers of the precocious breed "hampshire" showed that from the moment of birth to 2 and 4 months. For example, crossbred sheep were slightly superior to purebred peers in terms of the studied indicators. In particular, the results of feeding sheep of the Kazakh coarse-haired broad-tailed breed from 4 to 6 months, depending on the top dressing.

Genetic Variations of MSTN and Callipyge in Tibetan Sheep: Implications for Early Growth Traits.

Tibetan sheep are vital to the ecosystem and livelihood of the Tibetan Plateau; however, traditional breeding methods limit their production and growth. Modern molecular breeding techniques are required to improve these traits. This study identified a single nucleotide polymorphism (SNP) in myostatin (MSTN) and Callipyge in Tibetan sheep. The findings indicated notable associations between MSTN genotypes and growth traits including birth weight (BW), body length (BL), chest width (ChW), and chest circumference (ChC), as well as a particularly strong association with cannon circumference (CaC) at 2 months of age. Conversely, Callipyge polymorphisms did not have a significant impact on Tibetan sheep. Moreover, the analyses revealed a significant association between sex and BW or hip width (HW) at 2 months of age and ChW, ChC, and CaC at 4 months of age. Furthermore, the study's results suggested that the genotype of MSTN as a GA was associated with a notable sex effect on BW, while the genotype of Callipyge (CC) showed a significant impact of sex on CaC at 2 months of age. These results indicated that the SNP of MSTN could potentially serve as a molecular marker for early growth traits in Tibetan sheep.

Effect of quantitative feed restriction and sex class on sheep skin quality.

The aim was to evaluate the quality of the sheep skin of different sex classes submitted to different levels of feed restriction. Sheep without defined racial pattern of different sex classes (15 non-castrated males, 15 castrated males and 15 females), with initial body weight of 18.1 ± 0.4 kg and mean age of 90 days were distributed in a factorial 3 × 3, with three sex classes and 3 levels of feed restriction (ad libitum intake and restricted intake at 70 and 80%), with 5 repetitions. After slaughter, the skins were collected for physical-mechanical tests. The effect of the sex classes x levels of dietary restriction interaction was observed for transverse thickness and longitudinal rupture elongation (p < 0.05). Animals fed ad libitum had greater longitudinal transverse thickness (p < 0.05). Animals fed ad libitum and 70% feed restriction showed greater transverse elongation at break (p < 0.05). As for the difference between sex classes in the transverse thickness variable for tearing strength, the interaction sex classes x levels of feed restriction for transverse thickness, longitudinal thickness, transverse tearing strength and longitudinal tearing strength occurred (p < 0.05). Feed restriction reduces the physical quality of the skin of sheep of different sex classes, and the use of castrated male sheep in positive energy balance is recommended to obtain leather with greater thickness, longitudinal rupture elongation and transverse tear strength.

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

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

Feeding dams during gestation affects the development of the offspring for their entire life. The objective of the current experiment was to evaluate the changes of the transcriptome in the hypothalamus of the offspring lambs born from dams supplemented with (i) a control diet (without lipids or methionine supplementation), (ii) an omega-3 fatty acid supplementation, or (iii) a methionine supplementation. The supplementation took place in the last third of gestation and the hypothalamus of male and female offspring was collected after being on a fattening diet for 54 d. Hypothalamus samples were used to extract RNA and analyzed using RNA sequencing. There was an interaction due to sex and methionine supplementation. The pathways that were modified were chromatin structure, developmental processes, and organ morphology. The modification observed on these pathways could explain the sex by treatment interaction differences previously observed in growth. There were few sex by omega-3 fatty acid interactions on the hypothalamus transcriptome. Therefore, the sexual dimorphism observed by methionine supplementation may be regulated by the hypothalamus.

Ovine KRT81 Variants and Their Influence on Selected Wool Traits of Commercial Value.

Keratins are the main structural protein components of wool fibres, and variation in them and their genes (KRTs) is thought to influence wool structure and characteristics. The PCR-single strand conformation polymorphism technique has been used previously to investigate genetic variation in selected coding and intron regions of the type II sheep keratin gene KRT81, but no variation was identified. In this study, we used the same technique to explore the 5' untranslated region of KRT81 and detected three sequence variants (A, B and C) that contain four single nucleotide polymorphisms. Among the 389 Merino × Southdown cross sheep investigated, variant B was linked to a reduction in clean fleece weight, while C was associated with an increase in both greasy fleece weight and clean fleece weight. No discernible effects on staple length or mean-fibre-diameter-related traits were observed. These findings suggest that variation in ovine KRT81 might influence wool growth by changing the density of wool follicles in the skin, the density of individual fibres, or the area of the skin producing fibre, as opposed to changing the rate of extrusion of fibres or their diameter.

Biochar effect on sheep feed intake, growth rate and ruminant in vitro and in vivo methane production.

Biochar, which is the product of biomass pyrolysis, has been suggested as a feed supplement to improve performance in livestock systems and reduce greenhouse gas emissions. The aim of the current study was to investigate in vitro and in vivo potential of biochar to favourably modify rumen fermentation (e.g., an increase in total Short Chained Fatty Acid (SCFA) concentration and a change in SCFA profile), reduce methane emission and increase sheep growth performance. Four concentrates were produced with biochar inclusion of 0, 10, 23 and 46 g/kg DM. The experimental diets for the in vitro experiments consisted of straw and concentrate in a 60:40 ratio and included measurements of total gas and methane (CH4) production, pH, ammonia nitrogen, SCFA, and microbial assays (total bacteria and methanogenic archaea). Two in vivo experiments were performed where the animals received ad libitum forage with 0.4 kg concentrate daily. Experiment 1 investigated the daily DM intake of sheep while experiment 2 investigated daily growth rate and CH4 emission of lambs. The inclusion of biochar had no impact on in vitro total gas production (ml/200 mg DM substrate) (P = 0.81) and CH4 production (ml/200 mg DM substrate) (P = 0.93). In vitro total SCFA concentration increased (P < 0.05) while acetate to propionate ratio (A:P) tended to decrease (P = 0.05) with both doses of biochar. Total bacteria decreased with the highest biochar inclusion in vitro (P < 0.05). Sheep's DM intake (kg/d) increased when low and medium levels but not when a higher level of biochar was added to the diet (P < 0.001). The inclusion of biochar did not significantly impact the lamb's daily growth rate (g/d) (P = 0.61) or enteric CH4 emissions (g/kg DM) (P = 0.43). We conclude that biochar supplementation had no favourable impacts on in vitro and in vivo CH4 production or on lamb's growth rate. Further research with well-characterised biochar is needed to gain a better understanding of the potential of biochar as a feed additive for ruminant livestock.

Weighted gene co-expression network analysis reveals genes related to growth performance in Hu sheep.

Hu sheep are a unique breed in our country with great reproductive potential, the extent of whose breeding has been steadily rising in recent years. The study subjects in this experiment were 8-month-old Hu sheep (n = 112). First of all, the growth performance, slaughter performance and meat quality of their eye muscle quality were assessed, meanwhile their live weight, carcass weight, body length, body height, chest circumference, chest depth and tube circumference were respectively 33.81 ± 5.47 kg, 17.43 ± 3.21 kg, 60.36 ± 4.41 cm, 63.25 ± 3.88 cm, 72.03 ± 5.02 cm, 30.70 ± 2.32 cm and 7.36 ± 0.56 cm, with a significant difference between rams and ewes (P < 0.01). Following that, transcriptome sequencing was done, and candidate genes related to growth performance were identified using the weighted co-expression network analysis (WGCNA) approach, which was used to identified 15 modules, with the turquoise and blue modules having the strongest association with growth and slaughter performance, respectively. We discovered hub genes such as ARHGAP31, EPS8, AKT3, EPN1, PACS2, KIF1C, C12H1orf115, FSTL1, PTGFRN and IFIH1 in the gene modules connected with growth and slaughter performance. Our research identifies the hub genes associated with the growth and slaughter performance of Hu sheep, which play an important role in their muscle growth, organ and cartilage development, blood vessel development and energy metabolic pathways. Our findings might lead to the development of potentially-useful biomarkers for the selection of growth and slaughterer performance-related attributes of sheep and other livestock.

Transcriptome analysis revealed differences in gene expression in sheep muscle tissue at different developmental stages.

BACKGROUND: The analysis of differentially expressed genes in muscle tissues of sheep at different ages is helpful to analyze the gene expression trends during muscle development. In this study, the longissimus dorsi muscle of pure breeding Hu sheep (H), Suffolk sheep and Hu sheep hybrid F1 generation (SH) and East Friesian and Hu sheep hybrid sheep (EHH) three strains of sheep born 2 days (B2) and 8 months (M8) was used as the research object, and transcriptome sequencing technology was used to identify the differentially expressed genes of sheep longissimus dorsi muscle in these two stages. Subsequently, GO and KEGG enrichment analysis were performed on the differential genes. Nine differentially expressed genes were randomly selected and their expression levels were verified by qRT-PCR. RESULTS: The results showed that 842, 1301 and 1137 differentially expressed genes were identified in H group, SH group and EHH group, respectively. Among them, 191 differential genes were enriched in these three strains, including pre-folding protein subunit 6 (PFDN6), DnaJ heat shock protein family member A4 (DNAJA4), myosin heavy chain 8 (MYH8) and so on. GO and KEGG enrichment analysis was performed on 191 differentially expressed genes shared by the three strains to determine common biological pathways. The results showed that the differentially expressed genes were significantly enriched in ribosomes, unfolded protein binding, FoxO signaling pathway, glycolysis / glycogen generation and glutathione signaling pathway that regulate muscle protein synthesis and energy metabolism. The results of qRT-PCR were consistent with transcriptome sequencing, which proved that the sequencing results were reliable. CONCLUSIONS: Overall, this study revealed the important genes and signaling pathways related to sheep skeletal muscle development, and the result laid a foundation for further understanding the mechanism of sheep skeletal muscle development.

Estimation of the genetic parameters of sheep growth traits based on machine vision acquisition.

In the realm of animal phenotyping, manual measurements are frequently utilised. While machine-generated data show potential for enhancing high-throughput breeding, additional research and validation are imperative before incorporating them into genetic evaluation processes. This research presents a method for managing meat sheep and collecting data, utilising the Sheep Data Recorder system for data input and the Sheep Body Size Collector system for image capture. The study aimed to investigate the genetic parameter changes of growth traits in Ujumqin sheep by comparing machine-generated measurements with manual measurements. The dataset consisted of 552 data points from the offspring of 75 breeding rams and 399 breeding ewes. Six distinct random regression models were assessed to pinpoint the most suitable model for estimating genetic parameters linked to growth traits. These models were distinguished based on the inclusion or exclusion of maternal genetic effects, maternal permanent environmental effects, and covariance between maternal and direct genetic effects. Fixed factors such as individual age, individual sex, and ewe age were taken into account in the analysis. The genetic parameters for the yearling growth traits of Ujumqin sheep were calculated using ASReml software. The Akaike information criterion, the Bayesian information criterion, and fivefold cross-validation were employed to identify the optimal model. Research findings indicate that the most accurate models for manually measured data revealed heritability estimates of 0.12 ± 0.15 for BW, 0.05 ± 0.07 for body slanting length, 0.03 ± 0.07 for withers height, 0.15 ± 0.12 for hip height, 0.11 ± 0.11 for chest depth, 0.13 ± 0.13 for shoulder width, and 0.53 ± 0.15 for chest circumference. The optimal models for machine-predicted data showed heritability estimates of 0.1 ± 0.09 for body slanting length, 0.14 ± 0.12 for withers height, 0.55 ± 0.15 for hip height, 0.34 ± 0.15 for chest depth, 0.26 ± 0.15 for shoulder width, and 0.47 ± 0.16 for chest circumference. In manually measured data, genetic correlations ranged from 0.35 to 0.99, while phenotypic correlations ranged from 0.07 to 0.90. In machine data, genetic correlations ranged from -0.05 to 0.99, while phenotypic correlations ranged from 0.03 to 0.84. The results suggest that machine-based estimations may lead to an overestimation of heritability, but this discrepancy does not impact the selection of breeding models.

Ensiled diet improved the growth performance of Tibetan sheep by regulating the rumen microbial community and rumen epithelial morphology.

The aim of this study was to investigate the effects of ensiled agricultural byproducts from Qinghai-Tibet plateau on growth performance, rumen microbiota, ruminal epithelium morphology, and nutrient transport-related gene expression in Tibetan sheep. Fourteen male Tibetan sheep were randomly assigned to one of two diets: an untreated diet (without silage inoculum, CON, n = 7) or an ensiled diet (with silage inoculum, ESD, n = 7). The total experimental period lasted for 84 d, including early 14 d as adaption period and remaining 70 d for data collection. The ESD increased average daily gain (P = 0.046), dry matter intake (P < 0.001), ammonia nitrogen (P = 0.045), microbial crude protein (P = 0.034), and total volatile fatty acids concentration (P < 0.001), and decreased ruminal pH value (P = 0.014). The proportion of propionate (P = 0.006) and the copy numbers of bacteria (P = 0.01) and protozoa (P = 0.002) were higher, while the proportion of acetate (P = 0.028) was lower in the sheep fed ESD compared to CON. Pyrosequencing of the 16S ribosomal RNA gene revealed that ESD increased the relative abundance of Firmicutes, Ruminococcus, Lachnospiraceae_AC2044_group, Lachnospiraceae_XPB1014_group, and Christensenellaceae_R-7_group in the rumen (P < 0.05), while decreased the relative abundance of Bacteroidota, Prevotellaceae_UCG-003, and Veillonellaceae_UCG-001 (P < 0.05). Analyses with PICRUSt2 and STAMP indicated that the propionate metabolism pathway was enriched in the sheep fed ESD (P = 0.026). The ESD increased the rumen papillae height (P = 0.012), density (P = 0.036), and surface area (P = 0.001), and improved the thickness of the total epithelia (P = 0.018), stratum corneum (P = 0.040), stratum granulosum (P = 0.042), and stratum spinosum and basale (P = 0.004). The relative mRNA expression of cyclin-dependent Kinase 2, CyclinA2, CyclinD2, zonula occludens-1, Occludin, monocarboxylate transporter isoform 1 (MCT1), MCT4, sodium/potassium pump, and sodium/hydrogen antiporter 3 were higher in the rumen epithelial of sheep fed ESD than CON (P < 0.05). Conversely, the relative mRNA expressions of Caspase 3 and B-cell lymphoma-2 were lower in the sheep fed ESD than CON (P < 0.05). In conclusion, compared with an untreated diet, feeding an ensiled diet altered the rumen microbial community, enhanced nutrient transport through rumen epithelium, and improved the growth performance of Tibetan sheep.

Tibetan sheep on the Qinghai-Tibet Plateau experience significant nutrient stress while a substantial amount of agricultural byproducts in the region go discarded and wasted. In this study, agricultural byproducts were ensiled and fed to the Tibetan sheep to investigate their effects on growth performance, rumen microorganisms, and nutrient transport through rumen epithelial tissues. Fourteen male Tibetan sheep were randomly assigned to one of two diets: untreated diet (without silage inoculum, CON, n = 7) or ensiled diet (with silage inoculum, ESD, n = 7). After 70 d of feeding, the ESD-fed sheep had a higher body weight than CON. The ensiled diet changed the rumen microbial community and increased the relative abundance of cellulolytic bacteria in the rumen. In addition, the ensiled diet also promoted the development of rumen epithelia and improved the relative expression of gene related to nutrient transport. Overall, the ensiled diet optimized the use of agricultural byproducts and significantly contributed to the production of Tibetan sheep.

Methane output across life stages in sheep, how it differs from lambs to adult ewes using portable accumulation chambers.

Methane (CH4) produced from enteric fermentation is a potent greenhouse gas produced by ruminant animals. Multiple measurements are required across life stages to develop an understanding of how CH4 output changes throughout the animal's lifetime. The objectives of the current study were to estimate CH4 output across life stages in sheep and to investigate the relationship between CH4 output and dry matter (DM) intake (DMI). Data were generated on a total of 266 female Suffolk and Texel animals. Methane and carbon dioxide (CO2) output, estimated using portable accumulation chambers, and DMI, estimated using the n-alkane technique outdoors and using individual penning indoors, were quantified across the animal's life stage; as lambs (<12 mo), nulliparous hoggets (12 to 24 mo) and ewes (primiparous or greater; > 24 mo). Ewes were further classified as pregnant, lactating, and dry (non-pregnant and non-lactating). Multiple measurements were taken within and across the life stages of the same animals. A linear mixed model was used to determine if CH4 and CO2 output differed across life stages and using a separate linear mixed model the factors associated with CH4 output within each life stage were also investigated. Methane, CO2 output, and DMI differed by life stage (P < 0.05), with lactating ewes producing the greatest amount of CH4 (25.99 g CH4/d) and CO2 (1711.6 g CO2/d), while also having the highest DMI (2.18 kg DM/d). Methane output differed by live-weight of the animals across all life stages (P < 0.001). As ewe body condition score increased CH4 output declined (P < 0.05). Correlations between CH4 output measured across life stages ranged from 0.26 (SE 0.08; lambs and lactating ewes) to 0.59 (SE 0.06; hoggets and pregnant ewes), while correlations between CO2 output measured across life stages ranged from 0.12 (SE 0.06; lambs and hoggets) to 0.65 (SE 0.06; hoggets and lactating ewes). DMI was moderately correlated with CH4 (0.44; SE 0.04) and CO2 output (0.59; SE 0.03). Results from this study provide estimates of CH4 output across life stages in a pasture-based sheep production system and offer valuable information for the national inventory and the marginal abatement cost curve on the optimum time to target mitigation strategies.

Obtaining accurate estimates of methane (CH4) output across life stages is important to assess how CH4 output changes throughout the production cycle in pasture-based sheep production systems. This study investigated the factors associated with CH4 output at each life stage (lambs, hoggets, pregnant, lactating, and dry ewes), the relationship between CH4 output measured across life stages and the relationship between CH4 output and dry matter intake (DMI) in an Irish lowland sheep production system. Methane and carbon dioxide (CO2) output and DMI were measured on 266 purebred Suffolk and Texel females across their lifetime. Lactating ewes produced the highest CH4 and CO2 output, along with having the highest DMI. Across all life stages, CH4 output increased with increasing live weight while CH4 output decreased as body condition score increased. Weak to moderate relationships were found between CH4 output measured across life stages, with the strength of the relationship decreasing as the time between life stages increased. A positive relationship was found between DMI and CH4 output. Results from this study lead to the development of a profile of CH4 output across the production cycle of a pasture-based sheep system.

Whole-Genome Resequencing Revealed Selective Signatures for Growth Traits in Hu and Gangba Sheep.

A genomic study was conducted to uncover the selection signatures in sheep that show extremely significant differences in growth traits under the same breed, age in months, nutrition level, and management practices. Hu sheep from Gansu Province and Gangba sheep from the Tibet Autonomous Region in China were selected. We collected whole-genome data from 40 sheep individuals (24 Hu sheep and 16 Gangba sheep), through whole-genome sequencing. Selection signals were analyzed using parameters such as FST, π ratio, and Tajima's D. We have identified several candidate genes that have undergone strong selection, particularly those associated with growth traits. Specifically, five growth-related genes were identified in both the Hu sheep group (HDAC1, MYH7B, LCK, ACVR1, GNAI2) and the Gangba sheep group (RBBP8, ACSL3, FBXW11, PLAT, CRB1). Additionally, in a genomic region strongly selected in both the Hu and Gangba sheep groups (Chr 22: 51,425,001-51,500,000), the growth-associated gene CYP2E1 was identified, further highlighting the genetic factors influencing growth characteristics in these breeds. This study analyzes the genetic basis for significant differences in sheep phenotypes, identifies candidate genes related to sheep growth traits, lays the foundation for molecular genetic breeding in sheep, and accelerates the genetic improvement in livestock.

Supplementation of Acacia dealbata versus Acacia mearnsii leaf-meal has potential to maintain growth performance of lambs grazing low-quality communal rangelands in South Africa.

Supplementing livestock grazing communal rangelands with leaf-meals from Acacia trees, which are currently considered as problematic invasive alien plants globally, may be a sustainable way of exploiting their desirable nutritional and anthelmintic properties. The current study evaluated worm burdens and growth performance of lambs grazing low-quality communal rangelands supplemented with leaf-meals prepared from the invasive alien plant species; Acacia mearnsii or A. dealbata. Forty, three-month-old ewe lambs weighing an average of 18.9 ± 0.60 kg were randomly allocated to four supplementary diets: (1) rangeland hay only (control), (2) commercial protein supplement plus rangeland hay, (3) A. mearnsii leaf-meal plus rangeland hay and (4) A. dealbata leaf-meal plus rangeland hay. All the supplementary diets were formulated to meet the lambs' minimum maintenance requirements for protein. All the lambs were grazed on communal rangelands daily from 0800 to 1400 after which they were penned to allow them access to their respective supplementary diets until 08:00 the following morning. The respective supplementary diets were offered at the rate of 400 g ewe- 1 day- 1 for 60 days. Lambs fed the commercial protein supplement had the highest dry matter intake followed by those fed the Acacia leaf-meals and the control diet, respectively (P ≤ 0.05). Relative to the other supplementary diets, lambs fed the commercial protein supplement and A. dealbata leaf-meal had higher (P ≤ 0.05) final body weight and average daily gains. Dietary supplementation did not affect lamb faecal worm egg counts over the study period (P > 0.05). There was no association between supplementary diets and lamb FAMACHA© scores (P > 0.05). It was concluded that supplementation of Acacia dealbata versus Acacia mearnsii has the potential to emulate commercial protein in maintaining growth performance of lambs grazing communal rangelands in the dry season.