西南地区一直以来是我国肉牛产业的重要主成部分,在良好的政策和较高的经济效益刺激下肉牛产业发展迅速,但是由于受气候、地型等影响,西南地区肉牛产业还相对落后.本文以西南丘陵山区(四川省、重庆市)肉牛产业发展现状为背景,分析了近年来西南丘陵山区肉牛产业发展现状、生产水平以及面临转型升级所出现的问题,结合作者调研情况,对西南丘陵山区肉牛发展提出了对策和建议,旨在为新形势下西南丘陵山区肉牛产业健康可持续发展提供参考.

[Objective] To analyze the correlation between body weight and body size index of Kongshan cattle, clarify the direct and indirect effects of body size on body weight, and establish regression equation. [Method] The body weight and body size indexes of 77 5-6-year-old empty pregnant cows of Kongshan cattle were collected under the condition of stall-feeding, and SPSS 19.0 software for correlation, path and stepwise regression analysis, and establish the optimal linear regression equation. [Result] The results showed that the body weight of Kongshan cattle was positively correlated with chest circumference, bun height, body oblique length, cross height, tube circumference, waist angle width and rump length（P ＜ 0.01）; the direct effect of chest circumference on body weight was the largest（coefficient 0.857）; the optimal regression equation was Y =-772.054 + 4.481 × X 3 +2.965 × X 1 （R~2 = 0.779, P ＜ 0.01）. The equation was statistically significant after test. [Conclusion] The formula can be used to estimate the weight of empty pregnant cows of 5-6-year-old Kongshan cattle under stall-feeding conditions. The breeding of Kongshan cattle should not only pay attention to the selection of weight, but also strengthen the selection of chest circumference, body oblique length, tube circumference and waist angle width.

为探究肉牛胚胎移植技术在旺苍县的应用前景,本试验组建了 83头西杂母牛开展同期发情,对筛选的34头受体母牛进行西门塔尔牛冷冻胚胎移植.结果得出:旺苍县西杂母牛的同期发情率为75.90％,胚胎移植妊娠率为38.24％;体况评分在6～6.5分时妊娠率最高(为42.86％),具有1.5 cm及以上黄体的受体母牛,其妊娠率也较高(为50.00％).综上,肉牛胚胎移植技术适宜在旺苍县推广应用.

为明确蜀宣花牛无角新类群胴体不同部位肌内脂肪酸组分和结构情况,选择10头体重为324.79 kg±43.51 kg的7～8月龄健康无角公犊牛作为试验动物开展育肥试验,试验期300 d,屠宰后45 min内采集里脊、外脊、眼肉、上脑、辣椒条、米龙、大黄瓜条、小黄瓜条、臀肉、牛霖、胸肉、腹肉和腱子肉共13个部位的组织样本,通过索氏抽提、GC-MS测定不同部位肌内脂肪含量及其脂肪酸组成.结果表明,蜀宣花无角牛不同部位肌内脂肪酸主要为C16:0、C16:0和C18:1,C18:3 N6、C20:3 N3和C15:1的含量极少;外脊、眼肉和上脑的MUFA/SFA、UFA/SFA和C18:1/C16:0较高,分别在0.49～0.53、0.69～0.70、0.80～0.90;外脊、眼肉和辣椒条的MUFA/SFA和PUFA/SFA分别在0.51～0.53和0.16～0.20.说明通过脂肪酸成分和结构的综合评价,外脊、眼肉和上脑3个肉块具有较好的口感,外脊、眼肉和辣椒条相对符合人体健康要求.

文章旨在分析蜀宣花牛体重与体尺指标的相关关系,以明确体尺对体重的直接影响和间接影响,进而为蜀宣花牛公牛的选择和育肥效果评估提供重要方法.采集舍饲条件下74头15～18月龄蜀宣花牛公牛的体重和体尺指标,运用SPSS 19.0软件进行相关性、通径以及逐步回归分析,并建立最优线性回归方程.结果表明,蜀宣花牛体重与体高、体斜长、胸围、管围、坐骨端宽、腰角宽和十字部高指标间均呈极显著正相关(P<0.01);胸围对体重的直接作用最大(系数为0.410);最优回归方程为Y(体重)=-751.782+2.075X2(体斜长)+3.225X3(胸围)+8.512X4(管围)+3.363X6(腰角宽)(R2=0.877,P<0.01),经过检验该方程具有统计学意义.说明该回归方程可用于舍饲条件下10～18月龄蜀宣花牛公牛的体重估算;对蜀宣花牛的选育在重视体重选择的同时,也要加强胸围、体斜长、管围和腰角宽的选择.

Sichuan Province spawned abundant of indigenous buffalo varieties, which probably harbor valuable gene resources beneficial to the genetic improvement of buffalo. However, limited genetic information was publicly available. To better understand their selection signatures between different populations, we performed a restriction site-associated DNA sequencing (RADseq) to explore genome-wide SNPs among two indigenous breeds of Sichuan buffaloes. As a result, a total of 2,110,077 high-quality SNPs were finally obtained. Population genetic analysis indicated a obviously genetic differentiation between two breeds. The detection of selective genes showed that 995 and 910 protein-coding genes underwent positive selection in Yibin buffalo (GYBS) and Dechang buffalo (XCS). Further functional analysis revealed distinctly discrepant selection in two breeds. Candidate genes that positively selected from Yibin buffaloes have mainly occurred in functions closely related to meat quality, complex living environment adaption capability, and disease resistance. While they were significantly enriched in cell proliferation and cell components in Dechang buffalo, indicating the selection pressure primarily derived from the requirement of organism growth and development speed during breed formation. Our dataset constitutes a promising reservoir of genome-wide SNP markers of Sichuan buffaloes and provides potentially traits selected in different local populations. Such comprehensive genetic resources offer an unprecedented opportunity for genetic association analysis of economically important traits and precision breeding programs in buffaloes.

昭觉县地处大凉山腹心地带,是全国最大的彝族聚居县.近年来,肉牛养殖业作为该县农户增收脱贫、发展农村集体经济的主要产业之一,得到了稳步发展,建成了一定数量和适度规模的肉牛养殖场,通过肉牛科学养殖助推全县脱贫摘帽,在脱贫攻坚的征程中发挥了重要作用.在乡村振兴的开局之年,为做好团队示范基地县针对性的帮扶指导,团队本年度以发放调查问卷、现场实地走访、座谈交流等形式先后6次深入昭觉县7个肉牛养殖乡镇,并联合科技下乡万里行肉牛产业技术服务团15团开展产业调研指导.累计发放不同规模的养殖场(户)及散养户调查问卷50份,基本了解到昭觉县肉牛产业的发展现状及存在的问题,现将相关情况报告如下,以期能为地方政府部门和产业发展部门、肉牛产业链经营企业等提供一些基本信息,共同助推昭觉县肉牛产业可持续发展.

This study aimed to investigate the effects of different feeding modes on the growth performance, gut microbiota, and immunity of Black Fattening Goat ( Capra hircus ). A total of 30 goats were grouped in three groups by their feeding modes (pasture grazing group, PG; barn feeding group, BF; barn feeding + probiotics, BF + P; n = 10) and the study was performed for 114 days. After a 2-week adaptation period, the first growth performance test was conducted, and the blood and fecal samplings (day 0) were collected on January 17, 2020, while the second and third test and samplings were conducted on days 53 and 100 of feeding. The species-composition of fecal microbiota was analyzed by 16S ribosomal RNA gene-sequencing using PacBio single molecule real time (SMRT) sequencing technology. Both the BF and BF + P groups had the highest ( P < 0.05) body’s weight and length, and chest circumference at days 53 and 100, especially at day 100, the body’s weight of both the BF groups were more than 18 kg. The levels of immunoglobulin A (IgA) and immunoglobulin G (IgG) were found to be significantly higher ( P < 0.05) in the PG and BF + P groups at day 100. The PG group exhibited the highest number of operational taxonomic unit (OTUs) and alpha diversity. Firmicutes, Bacteroidetes, and Verrucomicrobia were the predominant phyla in all the fecal samples. The relative abundance of Akkermansia muciniphila and Ruminococcus flavefaciens were found to be significantly higher ( P < 0.05) in PG group and BF + P group at day 100, respectively, which might partially explain the significantly higher ( P < 0.05) levels of IgA and IgG in these two groups. These findings suggested that BF supplemented with 5 g probiotics ( Saccharomyces cerevisiae and mannan oligosaccharides) per day has the potential to enhance the growth and immunity of Black Fattening Goats.

为研究发酵床养牛温室气体的排放特点,利用四因素三水平正交试验方法,检测模拟发酵床养殖肉牛过程中CO2、CH4和N2O气体的排放水平.结果表明:发酵床中CO2排放高峰期集中在发酵中期,N2O和CH4排放高峰期集中在发酵初期;影响发酵床温室气体排放总量的关键因素是微生物菌剂,其次是发酵床垫料的厚度、垫料翻抛频率和每日添粪重量.模拟发酵床养殖肉牛过程中温室气体的排放量随发酵时间的延长逐渐减少.在使用仰韶生酵剂、垫料厚度30 cm、翻抛周期15 d、牛粪日添加量3.06 kg时温室气体排放量最少.