In this study, whole-genome resequencing was performed on the cold-tolerant variety ND-6 and the cold-sensitive variety ‘Sorbonne’. After evaluation, the Lilium davidii var. unicolor reference genome was selected to analyze SSR distribution characteristics. Whole-genome InDel identification and comparative analysis were conducted for the two varieties, yielding 34,812,909 and 24,497,857 InDels, respectively. Short InDels were predominant, with deletions slightly outnumbering insertions, mostly located in intergenic regions. Twenty pairs of SSR primers were screened and synthesized. Among them, 10 pairs amplified clearly, with a polymorphism rate of 82.6%, effectively distinguishing the two cultivars examined in this study. This study provides systematic data and a reliable marker resource for the analysis of lily genomic variation, laying a foundation for the identification of cold-tolerant germplasm; validation across additional cultivars and individuals will be required to extend their utility to broader germplasm.

The confirmatory factor analysis technique was used to quantify a latent variable for test-day lactation performance (TDLP) in the first parity of Chinese Holstein dairy cows by applying five measurable traits, including test-day milk yield (TDMY), test-day milk fat percentage (TDFP), test-day milk protein percentage (TDPP), test-day somatic cell score (TDSCS) and test-day milk urea nitrogen (TDMUN). The standardised factor loadings of TDMY, TDFP, TDPP, TDSCS, and TDMUN for describing TDLP were 0.46, -0.52, -0.70, -0.14 and -0.19, respectively. Genetic analysis was conducted using a multivariate repeatability model within a Bayesian framework. The posterior means for the heritability and repeatability estimates of TDLP were 0.26 ± 0.02 and 0.34 ± 0.02, respectively. In general, posterior means for heritability and repeatability estimates of the measurable traits were low to medium. The heritability estimates ranged from 0.05 for TDSCS to 0.28 for TDPP, and repeatability estimates ranged from 0.15 for TDMUN to 0.38 for TDMY. The latent variable of TDLP exhibited positive genetic (0.62) and phenotypic (0.40) correlations with TDMY, whereas its genetic and phenotypic correlations with other measurable traits were negative, ranging from -0.96 (TDLP-TDPP) to -0.11 (TDLP-TDSCS). The corresponding phenotypic correlations ranged from -0.85 (TDLP-TDPP) to -0.07 (TDLP-TDSCS). It may be concluded that breeding for higher TDLP might increase TDMY but could reduce milk composition traits. In general, the negative genetic and phenotypic correlations suggest a trade-off between milk quantity (yield) and quality (composition).

Meat quality and carcass traits are the most economically important traits affecting the value and the quality characteristics of the animal at slaughter. In this study, we analyzed the genomes of 295 domestic cattle from 20 global breeds using next-generation sequencing to identify signatures of positive selection associated with meat production and quality traits. The results of population genetic analysis revealed genetic differentiation among worldwide cattle groups. We observed clustering of samples in agreement with their geographic origins and production characteristics. We further observed noticeable genetic variety between cattle groups from different geographical regions. Generally, the lowest genetic diversity was determined for commercial cattle breeds, while the highest genetic diversity was found in African local cattle breeds. Our search for putative selective genomic regions in beef cattle populations revealed several candidate genes such as BMP2, EGR1, MAGEL2, U6, TMEM201, ELK3 and 5S_rRNA that were previously explored to be associated with carcass traits and meat quality in beef cattle. The enriched pathways and candidate genes discovered in this study could supply a basis for future improvement through the use of whole-genome technologies and selective breeding.

Bovine colostrum is rich in many immune components. Milk exosomes are secreted by mammary epithelial cells and contain proteins, nucleic acids, microRNAs (miRNAs) and other bioactive substances related to immune response and growth. MiRNAs are short non-coding RNAs (ncRNA)with various biological functions through translational inhibition or mRNA destabilisation. Mature miRNAs are involved in various regulatory pathways, including development, viral defense, cell proliferation and apoptosis, and fat metabolism. MiRNA sequencing of bovine colostrum and milk exosomes was performed, and the miRNA and mRNA data were jointly analyzed. The results suggest that bta-miR-19b, bta-miR-186 and bta-miR-151-5p may be key miRNAs associated with the immune function of bovine colostrum exosomes. Target gene prediction revealed that miRNAs are involved in multiple signalling pathways through target genes such as IL1R1, BOLA-DOA, MAP3K1, MAPK8, RELA and TNF. Our results indicate that specific miRNAs and their target genes likely contribute to immune regulation, yet the exact molecular mechanisms governing these interactions remain to be fully elucidated.

Renowned for its invaluable undercoat, the cashmere goat is well known. The growth of cashmere fibre initiates when the relatively inactive telogen stage transitions to the anagen stage, which involves active proliferation. However, the molecular mechanisms responsible for this process are still unclear. Here, SWATH mass spectrometry (MS), a comparative proteomic analysis, was conducted to examine the proteomic alterations in Inner Mongolia cashmere goat skin samples at two different developmental stages (anagen and telogen). In total, 2414 proteins were detected, with 631 proteins showing differential regulation (503 upregulated proteins and 128 downregulated proteins). Bioinformatic analysis revealed that these proteins, which are differentially regulated, play crucial roles in the pathways associated with metabolism and fatty acids according to the GO and KEGG analyses. Furthermore, interactome analysis revealed that differentially regulated keratins have a crucial impact. The localization of KRT25, KRT71, and KRT82 using immunohistochemistry revealed that these proteins were expressed in the secondary hair follicles of cashmere goat skin. The keratin family plays an irreplaceable and important role in the process of hair follicle growth.

Crossbreeding is a cornerstone of modern livestock improvement, combining desirable traits to enhance productivity and environmental resilience. This study conducts the first comprehensive genomic analysis of Red Angus × Chinese Red Steppe (RACS) crossbred cattle, evaluating their genetic architecture, diversity, and selection signatures relative to founder breeds (Red Angus and Chinese Red Steppe) and global populations. A total of 119 cattle, comprising 104 RACS crossbreds and 15 Chinese Red Steppes cattle, were genotyped using the GGP Bovine 100k SNP array. Additionally, the public available genotypic data generated using the BovineSNP50 chip from 550 animals across eight beef breeds (Angus, Hereford, Limousin, Charolais, Mongolian, Shorthorn, Red Angus, and Simmental) and one dairy breed (Holstein) were incorporated into the analysis. We aimed to (1) define the population structure of RACS cattle, (2) quantify their genomic diversity and inbreeding levels, and (3) pinpoint regions under selection linked to adaptive and economic traits. We employed runs of homozygosity (ROH) and population differentiation (Fst) analyses to detect selection signals. The results revealed that the crossbred (RACS), Angus, and Red Angus breeds exhibited similar clustering patterns in principal component analysis (PCA), but the crossbred population showed the highest nucleotide diversity and lowest inbreeding coefficients compared to other breeds. Notably, candidate regions associated with immune response, cold adaptation, and carcass traits were identified within the RACS population. These findings enhance our understanding of the genetic makeup of crossbred beef cattle and highlight their potential for genetic improvement, informing future selection and breeding strategies aimed at optimizing beef production in challenging environments.

The current study investigated the application of structural equation models for genetic analysis of lifetime reproductive traits and latent variable modelling in the Murciano-Granadina goat breed. In the current investigation, data collected between 2016 and 2023 in a private dairy farm of the Murciano-Granadina goat breed in Ghale-Ganj city, located in the southern area of Kerman Iranian province were used. The investigated lifetime reproductive traits included overall litter size at birth (OLSB), overall litter size at weaning (OLSW), overall litter weight at birth (OLWB), and overall litter weight at weaning (OLWW). Four multivariate animal models, including standard (SMM), Inductive Causation algorithm-based structural equation (ICM), ICM with biological modification (ICM-BM), and fully recursive (FRM) models were fitted on the data and compared in terms of predictive ability measures including mean squared prediction error (MSE) and Pearson's correlation coefficient between the observed and predicted values (r(y, y ̂ )) of records. ICM-BM performed better than other models in terms of the lowest MSE and the highest r(y, y ̂ ). Under ICM-BM, heritability estimates were low values of 0.08, 0.08, 0.11, and 0.10 for OLSB, OLSW, OLWB, and OLWW, respectively. Genetic correlations among lifetime reproductive traits were positive and varied from 0.72 (OLSB-OLWW) to 0.95 (OLSB-OLWB). The confirmatory factor analysis technique was used to construct a latent variable named reproductive performance (RP) from the investigated lifetime reproductive traits. The posterior mean for heritability of RP was estimated at 0.06. The genetic correlations between RP and the investigated lifetime reproductive traits were high and positive, ranging from 0.92 (RP-OLSB) to 0.99 (RP-OLSW). The corresponding phenotypic correlations were also high and positive, ranging from 0.81 (RP-OLWB) to 0.95 (RP-OLSW). Considering causal structure among the traits detected via ICM-BM had more advantages for genetic evaluation of the lifetime reproductive traits in the Murciano-Granadina goat compared with SMM. The low heritability estimates implied that the studied lifetime reproductive traits and RP were mainly controlled by non-additive genetic and environmental effects which limits the efficiency of direct genetic selection for improving these traits. Furthermore, positive genetic and phenotypic correlations favoured using RP latent variable for breeding purposes.

Consumer perception of beef is heavily influenced by overall meat quality, a critical factor in the cattle industry. Genomics has the potential to improve important beef quality traits and identify genetic markers and causal variants associated with these traits through genomic selection (GS) and genome-wide association studies (GWAS) approaches. Transcriptomics, proteomics, and metabolomics provide insights into underlying genetic mechanisms by identifying differentially expressed genes, proteins, and metabolic pathways linked to quality traits, complementing GWAS data. Leveraging these functional genomics techniques can optimize beef cattle breeding for enhanced quality traits to meet high-quality beef demand. This paper provides a comprehensive overview of the current state of applications of omics technologies in uncovering functional variants underlying beef quality complexities. By highlighting the latest findings from GWAS, GS, transcriptomics, proteomics, and metabolomics studies, this work seeks to serve as a valuable resource for fostering a deeper understanding of the complex relationships between genetics, gene expression, protein dynamics, and metabolic pathways in shaping beef quality.

Abstract Background Understanding the evolutionary forces related to climate changes that have been shaped genetic variation within species has long been a fundamental pursuit in biology. In this study, we generated whole-genome sequence (WGS) data from 65 cross-bred and 45 Mongolian cattle. Together with 62 whole-genome sequences from world-wide cattle populations, we estimated the genetic diversity and population genetic structure of cattle populations. In addition, we performed comparative population genomics analyses to explore the genetic basis underlying variation in the adaptation to cold climate and immune response in cross-bred cattle located in the cold region of China. To elucidate genomic signatures that underlie adaptation to cold climate, we performed three statistical measurements, fixation index (FST), log2 nucleotide diversity (θπ ratio) and cross population composite likelihood ratio (XP-CLR), and further investigated the results to identify genomic regions under selection for cold adaptation and immune response-related traits. Results By generating WGS data, we investigated the population genetic structure and phylogenetic relationship of studied cattle populations. The results revealed clustering of cattle groups in agreement with their geographic distribution. We detected noticeable genetic diversity between indigenous cattle ecotypes and commercial populations. Analysis of population structure demonstrated evidence of shared genetic ancestry between studied cross-bred population and both Red-Angus and Mongolian breeds. Among all studied cattle populations, the highest and lowest levels of linkage disequilibrium (LD) per Kb were detected in Holstein and Rashoki populations (ranged from ~ 0.54 to 0.73, respectively). Our search for potential genomic regions under selection in cross-bred cattle revealed several candidate genes related with immune response and cold shock protein on multiple chromosomes. We identified some adaptive introgression genes with greater than expected contributions from Mongolian ancestry into Molgolian x Red Angus composites such as TRPM8, NMUR1, PRKAA2, SMTNL2 and OXR1 that are involved in energy metabolism and metabolic homeostasis. In addition, we detected some candidate genes probably associated with immune response-related traits. Conclusion The study identified candidate genes involved in responses to cold adaptation and immune response in cross-bred cattle, including new genes or gene pathways putatively involved in these adaptations. The identification of these genes may clarify the molecular basis underlying adaptation to extreme environmental climate and as such they might be used in cattle breeding programs to select more efficient breeds for cold climate regions.

The aim of this experiment was to investigate the effects of subacute rumen acidosis（SARA） on the mRNA relative expression levels and protein relative expression levels of volatile fatty acid（VFA） absorption and metabolism related genes in ruminal epithelium of dairy goats. Twelve lactating Saanen dairy goats with similar body weight [（62.13±4.76） kg] were installed permanent rumen fistulas and randomly divided into two groups with 6 goats per group. Goats in the control group were fed a basal diet, and dietary non-fibrous carbohydrate/neutral detergent fiber（NFC/NDF） was 1.15; the others in SARA group was fed experimental diets to establish SARA model, and dietary NFC/NDF were 1.15, 1.49, 2.12 and 2.66, respectively. The trial period was 60 days. At the end of the experiment, dairy goats were slaughtered and collected the rumen epithelial tissues from ventral sac. The mRNA relative expression levels and protein relative expression levels of VFA absorption and metabolism related genes in ruminal epithelium were detected by real-time PCR（RT-PCR） and Western blotting methods. The correlation between rumen fermentation parameters, VFA absorption rate of ruminal epithelium and mRNA relative expression levels of VFA absorption and metabolism related genes was analyzed. The results showed as follows: 1) compared with the control group, the mRNA relative expression levels of Na + /H + exchanger 1（NHE1）, acyl-CoA short chain synthetase 2（ACSS2）, 3-hydroxy-3-methylglutaryl-CoA synthetase 1（HMGCS1）, 3-hydroxy-3-methylglutaryl-CoA synthetase 2（HMGCS2） and 3-hydroxy-3-methylglutaryl-CoA reductase（HMGCR） in ruminal epithelium of SARA group were significantly up-regulated（P＜0.01）, and the mRNA relative expression levels of Na + /H + exchanger 3（NHE3）, monocarboxylate transporter 1（MCT1） and down-regulated adenoma carrier（DRA） were significantly up-regulated（P＜0.05）. 2) Compared with the control group, the relative protein expression levels of NHE1, NHE3, Na + /H + exchanger 4（NHE4）, monocarboxylate transporter 2（MCT2）, anion exchanger 2（AE2）, Na + /K + -ATPase, ACSS2, acyl-CoA short-chain synthase 3（ACSS3）, 3-hydroxy-3-methylglutaryl-CoA lyase（HMGCL） and acetyl-CoA acetyltransferase 1（ACAT1） in ruminal epithelium of SARA group were significantly up-regulated（P＜0.05）. In conclusion, SARA can increase the mRNA relative expression levels of NHE1, NHE3, MCT1, DRA, ACSS2, HMGCS1, HMGCS2 and HMGCR in ruminal epithelium and the protein relative expression levels of NHE1, NHE3, NHE4, MCT2, AE2, Na + /K + -ATPase, ACSS2, ACSS3, HMGCL and ACAT1, there by accelerate the absorption and metabolism of VFA in ruminal epithelium and relieve the damage to the body of SARA.[Chinese Journal of Animal Nutrition, 2023, 35（5）:3290-3302]

【Objective】 This experiment was conducted to study the effects of dietary β-carotene supplementation on lactation performance, blood routine indexes and serum biochemical and immune indexes of dairy cows during the lactating peak period.【Method】 Twenty healthy Chinese Holstein dairy cows during the dry period with an average body weight of（550.00±32.71） kg and parities of 2-3 were randomly divided into 4 groups with 5 cows in each group.The cows in control group were fed a basal diet, the cows in experimental groups were fed the basal diet supplemented with 600,1 200 and 1 800 mg/d β-carotene, respectively.The experiment lasted for 150 days from 60 days before calving to 90 days after calving.During the experiment, the milk yield and milk composition of dairy cows were measured.Blood was collected from the tail vein to determine the blood routine indexes, and isolated serum was used to determine the indexes of biochemistry and immune at the end of the experiment.【Result】 Compared with the control group, dietary β-carotene supplementation had no significant effect on milk yield, milk fat rate, milk protein rate and lactose rate of dairy cows（P＞0.05）.600,1 200 mg/d β-carotene supplementation significantly reduced somatic cells number of dairy cows（P＜0.05）.Dietary β-carotene supplementation had no significant effect on blood white blood cell count（WBC）,red blood cell count（RBC）,platelet count（PLT）,hemoglobin（HGB） and hematocrit（HCT）（P＞0.05）.1 200 and 1 800 mg/d β-carotene supplementation significantly increased serum triglyceride（TG） content（P＜0.05）,600,1 200 mg/d β-carotene supplementation significantly increased serum high density lipoprotein（HDL） content（P＜0.05）.600 and 1 800 mg/d β-carotene supplementation significantly reduced the serum CD4 + content of dairy cows（P＜0.05）,1 200 mg/d β-carotene supplementation significantly decreased the contents of serum CD8 + ,tumor necrosis factor-α（TNF-α）,interleukin-1 β（IL-1β）,interleukin-2（IL-2） and interferon-γ（IFN-γ） contents, and significantly increased CD4 + /CD8 + ratio in serum of dairy cows（P＜0.05）.【Conclusion】 In conclusion, appropriate of β-carotene in diet could reduce somatic cell count in milk and inflammatory cytokines, and enhance cellular immune function of dairy cows during the lactating peak period, and 1 200 mg/d was the appropriate supplemental level.

本试验旨在研究复合微生态制剂对断奶前犊牛生长性能、腹泻率及血清生化、抗氧化和免疫指标的影响,以期为复合微生态制剂在犊牛生产中的应用提供科学依据.选取体重[(42.67±1.07)kg]相近、健康状况良好的1日龄新生荷斯坦犊牛30头,随机分为3组,每组10头牛.各组均饲喂牛奶和开食料,在对照组(C组)的基础上,犊泄克组(B组)2～11日龄在牛奶中添加10 g/(d·头)犊泄克;犊泄克+犊益康组(BP组)在犊牛摄入初乳后立刻灌服30 mL/头犊益康,2～11日龄在牛奶中添加10 g/(d·头)犊泄克.试验期60 d.结果表明:1)与C组相比,BP组的1～30日龄、1～60日龄平均日增重显著提高(P＜0.05).B组和BP组的腹泻率降低,腹泻持续时间缩短.2)与C组相比,BP组的30日龄血清甘油三酯(TG)含量显著降低(P＜0.05),60日龄血清尿素氮(UN)、肿瘤坏死因子-α(TNF-α)含量显著降低(P＜0.05),30日龄和60日龄血清总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性和免疫球蛋白A(IgA)含量显著提高(P＜0.05),30日龄血清免疫球蛋白G(IgG)、白细胞介素-4(IL-4)含量显著提高(P＜0.05).综上可知,添加复合微生态制剂可提高断奶前犊牛平均日增重,降低腹泻率,增强机体抗氧化能力和免疫功能.

Context Fat colour is one of the most important economic traits in the marketing of beef. There are many factors that affect fat colour, such as breed, age, diet and gender. Fat colour is observed in different ranges of colours, including white, yellow and brown. The main issue with improving fat colour is that consumer preferences of fat colour vary across the globe. Therefore, investigating the metabolic mechanisms of fat colour may provide new biomarkers for phenotyping, so as to develop effective selection strategies to achieve the locally desired fat colour. Aims This study aimed to perform a comparative metabolic analysis between white and yellow fat from crossbred cattle so as to identify potential biomarkers for the selection of fat colour and to better understand the metabolism of white and yellow fat depots. Methods Carcass samples of subcutaneous fat were collected from crossbred cattle (Simmental × Mongolian cattle) and scored for fat colour. Liquid chromatography–mass spectrophotometry analysis of extracted metabolites from the subcutaneous fat of six animals with white fat and six animals with yellow fat was performed. Key results The comparison between metabolites of white and yellow fat colour samples indicated that there were five categories of 235 significant metabolites, which included hydrocarbons, lipids and lipid-like molecules, organic acids and their derivatives, organic oxygen compounds and organoheterocyclic compounds. The principal-component analysis illustrated that yellow and white fat samples can be classified in groups; however, the metabolites of white fat samples showed greater variation than those in the yellow fat. In the white fat, there were 163 metabolites that had a higher relative abundance than in yellow fat and 72 that had a lower relative abundance than in yellow fat. 3-Hydroxyoctanoic acid, anethofuran, 9,10-DiHODE, furanoeremophilane, pregeijerene, N-glycolylneuraminic acid, and glycocholic acid were identified as the metabolites that differed the most in abundance between the white and yellow fat samples. Conclusions This study has provided insights into the metabolic differences between white and yellow fat depots and identified key metabolites associated with beef fat colour. Implications This study has provided potential biomarkers that may be useful for selection of beef fat colour in live animals.

为全面分析近 30 年(1995-2021 年)国内外肉牛肠道菌群功能基因相关研究的发展现状、研究热点和前沿动态,本研究以Web of Science、中国知网为来源数据库,检索肉牛肠道菌群功能基因的相关文献信息为研究对象;应用CiteSpace(6.0.R1)分别对文献年度发文量、国家、作者、机构、关键词进行共现分析、聚类分析、突显分析以及可视化呈现.结果显示:共发表英文文献 170 篇,中文文献 45 篇.近 30 年国内外肉牛肠道菌群功能基因相关研究领域论文数量整体呈上升趋势,且自 2011 年以来迅速增长;欧美学者逐步建立了理论框架、模型方法,奠定了该领域的研究基础,其中美国占主导地位,Guan Leluo、Auffret M D和Bryan A White等关键作者具有突出贡献.我国起步较晚但发展迅速,发文被引量居第 2,中国农业科学院等机构研究水平世界领先,毛胜勇、蒋林树、王加启和杨舒黎等研究团队代表了我国该领域研究的先进水平.近 30 年,该领域研究热点从 1995 年关注抗菌肽,到 2005 年首次关注 16S rRNA多样性和宏基因组;随着二代测序技术的成熟,自 2015 年以后 16S rRNA和宏基因组研究再度火热,以宏基因组、宏转录组等多组学对瘤胃微生物分解纤维素以及生成甲烷的功能基因研究成为目前的研究热点.此外,肠道微生物功能基因在肉牛营养代谢、饲料开发、免疫调控以及肉牛品种选育中的作用机制及应用是未来该领域的研究方向.

In the present study, we generated complete genome sequence data from 45 Mongolian cattle.Together with published sequence data from worldwide cattle populations, we explored the genetic diversity and population structure of worldwide cattle breeds.Our findings revealed clustering of cattle populations into three major groups, including commercial (Red-Angus, Hereford, Holstein and Jersey), Chinese (Mongolian and Tibetan) and other native cattle (including African cattle and Rashoki breed from Iran) breeds.The results from admixture analysis revealed evidence of shared genetic ancestry between different cattle populations.Furthermore, our findings showed a markedly higher level of linkage disequilibrium (LD) across all genomic distances in commercial breeds (specially Holstein cattle) compare to other native cattle groups.Our results provide valuable insights into the architecture of Mongolian Indigenous cattle breeds and their genomic relationship with other cattle populations.Pomelo.

本试验旨在研究苜蓿和小麦秸秆不同组合效应对呼伦贝尔断奶羔羊生长性能、血清生化指标、肝脏糖、脂代谢相关基因表达、瘤胃黏膜形态的影响.选择体重相近、体况良好的3月龄左右断奶羔羊72只,随机分为3组,每组3个重复,每个重复8只,分别为小麦秸秆组(WS组)、50％小麦秸秆+50％苜蓿干草组(AHWS组)、苜蓿干草组(AH组),饲粮精粗比为7:3,试验期为90 d.试验结束后随机挑选7只进行屠宰并采集相关组织进行后续测定.结果显示:1)在饲粮精粗比7:3条件下,AHWS组的平均日增重高于WS组(P＞0.05)和AH组(P＜0.05),料重比AH组显著高于WS组和AHWS组(P＜0.05),AHWS组与WS组间无显著差异(P＞0.05).2)血清中总蛋白(TP)、白蛋白(ALB)、尿素氮(UN)、葡萄糖(GLU)、总胆固醇(CHOL)、低密度脂蛋白(LDL)、高密度脂蛋白(HDL)含量及谷丙转氨酶(ALT)、谷草转氨酶(AST)、碱性磷酸酶(ALP)、乳酸脱氢酶(LDH)、淀粉酶(AMS)活性3组间均差异不显著(P＞0.05),WS组血清甘油三酯(TG)含量显著高于AH组(P＜0.05),与AHWS组差异不显著(P＞0.05).3)肝脏糖代谢中葡萄糖-6-磷酸酶(G6PC)、丙酮酸羧化酶(PC)、磷酸烯醇式丙酮酸羧激酶1(PCK1)基因相对表达量各组间差异不显著(P＞0.05),脂肪代谢中脂肪醛脱氢酶(ALDH3A2)基因相对表达量各组间差异不显著(P＞0.05),AH组脂肪酸合成酶(FASN)基因相对表达量显著高于WS组和AHWS组(P＜0.05).4)苜蓿和小麦秸秆比例为1∶1组合时,可以显著提高羔羊瘤胃乳头长度(P＜0.05).综上所述,本试验条件下用50％小麦秸秆与50％苜蓿干草组合可提高呼伦贝尔断奶羔羊生长性能,促进肝脏糖、脂代谢和瘤胃乳头的发育,改善动物的生产效益.

[目的]研究复合乳酸菌制剂对犊牛生长、肠道菌群、抗氧化及免疫性能的影响.[方法]选取体重相近的30日龄健康荷斯坦犊牛20头,随机分为对照组和试验组,每组10头.对照组与试验组饲喂相同的基础日粮,试验组饮水中添加复合乳酸菌制剂(饮水与复合乳酸菌制剂调配比例为50:1),对照组不添加,试验期为90 d.计算2组犊牛试验期间平均日增重、腹泻率;分别于试验1、30、60、90 d测定粪便中细菌总数以及乳酸菌和大肠杆菌数量,并测定血液生化、抗氧化与免疫指标.[结果]试验组犊牛的平均日增重与对照组相比无显著(P>0.05)差异,腹泻率低于对照组.试验组犊牛粪样中的乳酸菌数量达到1.41×107 CFU/g,显著(P<0.05)高于对照组,而大肠杆菌数量显著(P<0.05)低于对照组.在试验30、90 d时,试验组犊牛血清中的葡萄糖(GLU)含量显著(P<0.05)高于对照组;在试验60、90 d时,试验组犊牛血清中的总蛋白(TP)含量显著(P<0.05)低于对照组.2组犊牛的抗氧化指标均无显著(P>0.05)差异.在试验90 d时,试验组犊牛的血清IgG、IgA含量高于对照组.[结论]饮水中添加复合乳酸菌制剂可以改善荷斯坦犊牛肠道菌群结构并降低腹泻率.

鄂尔多斯市鄂托克旗2020年出台了《鄂托克旗优质肉牛产业高质量发展方案(2020—2022年)》旨在加速发展当地肉牛养殖业.随着进一步优化畜牧结构及乡村振兴战略的实施,发展优质肉牛产业迫在眉睫,秉承助力鄂托克旗优质肉牛产业发展及发挥内蒙古农牧业科技支持力量,对鄂托克旗肉牛产业现状进行全面调研,旨在发现问题、解决问题,为当地肉牛养殖户及产业从业者提供帮助的同时可以为当地政府及政策制定者提供参考.

[目的]研究不同部位西门塔尔牛肉原料肉的理化品质,评价烤制加工后的食用品质和感官品质.[方法]选取体重为550 kg左右的西门塔尔肉牛10头,屠宰分割后取不同部位牛肉(里脊、外脊、前腿、后腿、眼肉、米龙).4℃排酸72 h后,采用常规方法测定不同部位牛肉的蛋白质含量、脂肪含量、水分含量、pH值以及色泽指标,并对大理石花纹等级进行评分;220℃烤制10 min后,对不同部位牛肉进行剪切力和加工损失率测定,并对感官品质指标进行评价.[结果]不同部位牛肉的脂肪含量、大理石花纹评分、L*值、a*值、剪切力、色泽评分、嫩度评分、多汁性评分、香气评分和总体可接受性评分差异显著(P<0.05或P<0.01),不同部位牛肉中的蛋白质含量、水分含量、pH值、b*值、加工损失率、滋味评分差异不显著(P>0.05).眼肉中脂肪含量最高(P<0.01),前腿、后腿脂肪含量相同,均为最低(P<0.01);眼肉、外脊的大理石花纹评分显著(P<0.01)高于其他部位;眼肉、外脊的L*值显著(P<0.05)高于其他部位,里脊、后腿的L*值显著(P<0.05)低于其他部位;外脊和眼肉的a*值显著(P<0.01)低于其他部位;眼肉、外脊的剪切力显著(P<0.01)低于其他部位;眼肉的总体可接受性评分显著(P<0.05)高于其他部位,前腿、后腿和米龙的总体可接受性评分相同,均为最低(P<0.05).[结论]外脊、眼肉的肌内脂肪含量高于其他部位,烤制后产品的嫩度、滋味及总体可接受性较好.眼肉和外脊是西门塔尔牛肉中最适宜加工烤制产品的部位.

最近几年,牛肉的价格在国内外的市场上持续上升,在中国牛肉市场缺口也在不断地增大.脂肪颜色是影响牛肉价格和品质的重要因素之一,其着色原因主要是体内类胡萝卜素在脂肪组织中的沉积所致,引起该种现象有非遗传和遗传因素.对牛肉脂肪颜色的遗传及非遗传机理进行了论述.首先收集了国内外因为牛肉脂肪着色对其价格和评级的影响方面的资料,分析了肉牛黄色脂肪的形成原因,讨论了影响脂肪颜色的遗传因素和非遗传因素,然后对机体内β-胡萝卜素的代谢和调控β-胡萝卜素代谢的2个基因——BCO2和BCMO1做了简单的介绍,最后,对脂肪研究的现状做了总结,希望能够对牛肉脂肪颜色方面的研究提供参考.