中国农业科学 ›› 2022, Vol. 55 ›› Issue (2): 403-414.doi: 10.3864/j.issn.0578-1752.2022.02.014

• 畜牧·兽医·资源昆虫 • 上一篇    下一篇

荷斯坦牛泌乳早期体细胞数对生产性能的影响及遗传参数估计

竹磊1,2(),张海亮1,陈少侃1,3,安涛1,2,罗汉鹏1,刘林4,黄锡霞2,王雅春1()   

  1. 1中国农业大学动物科技学院,北京 100193
    2新疆农业大学动物科学学院,乌鲁木齐 830052
    3北京首农畜牧发展有限公司,北京100029
    4北京奶牛中心,北京 100085
  • 收稿日期:2020-12-01 接受日期:2021-07-11 出版日期:2022-01-16 发布日期:2022-01-26
  • 通讯作者: 王雅春
  • 作者简介:竹磊,E-mail: 936510062@qq.com
  • 基金资助:
    现代农业(奶牛)产业技术体系建设专项资金(CARS-36);农业品种改良提升专项(2130135);长江学者和创新团队发展计划(IRT_15R62)

Impacts of Somatic Cell Count in Early Lactation on Production Performance over the Whole Lactation and Its Genetic Parameters in Holsteins Cattle

ZHU Lei1,2(),ZHANG HaiLiang1,CHEN ShaoKan1,3,AN Tao1,2,LUO HanPeng1,LIU Lin4,HUANG XiXia2,WANG YaChun1()   

  1. 1China Agricultural University College of Animal Science and Technology, Beijing 100193
    2Xinjiang Agricultural University College of Animal Science, Urumqi 830052
    3Beijing Sunlon Livestock Development Co., Ltd, Beijing 100029
    4Beijing Dairy Center, Beijing 100085
  • Received:2020-12-01 Accepted:2021-07-11 Online:2022-01-16 Published:2022-01-26
  • Contact: YaChun WANG

摘要:

【目的】探究荷斯坦牛泌乳早期(6—35 d)体细胞数(SCCel)的群体特征及其与不同泌乳阶段体细胞数(SCC)及产奶量(MY)之间的关系,并对荷斯坦牛泌乳早期体细胞评分(SCSel)进行遗传参数估计,以期为我国荷斯坦牛乳房炎抗性选育提供新的思路。【方法】收集了141个牧场2008—2018年182 378头牛的2 783 046条生产性能测定记录。质控后,共得到150 864头牛的1 869 976条测定日记录。将有表型的母牛至少向上追溯三代(父母、祖父母、外祖父母),通过追溯,获得用于遗传分析的系谱文件,共包含6 451头公牛和103 452头母牛。利用SAS软件的GLM过程分析了牧场测定规模、测定季节、测定年份、泌乳天数、胎次等因素对SCSel的影响;利用SAS软件的REG过程分别分析了SCSel与不同泌乳阶段的SCS和日产奶量之间的回归关系;基于DMU软件,使用单性状重复力动物模型、单性状动物模型和双性状动物模型分别估计了SCSel的遗传参数。【结果】荷斯坦牛产后前2周SCCel变化幅度较大,荷斯坦牛SCCel随着泌乳天数的增加呈逐渐下降的趋势;牧场规模、测定季节、胎次和泌乳天数均对SCSel有显著影响(P<0.05),泌乳早期年均测定规模1 000头以上牧场的奶牛SCSel显著(P<0.05)低于年均测定规模1 000头以下的牧场。SCSel随胎次的增加呈先下降后上升的趋势,奶牛在夏季SCSel最高,在冬季最低。SCSel与泌乳期各测定日SCS之间均存在极显著的回归关系(P<0.01),回归系数范围为0.06 —0.19;SCSel与泌乳期各测定日产奶量之间均存在极显著的回归关系(P<0.01),回归系数范围为-0.46 — -0.16,泌乳早期SCSel对泌乳期乳房健康状况及生产性能均有影响。荷斯坦牛1胎、2胎、3胎及各胎次SCSel的遗传力分别为0.05 ± 0.005、0.07 ± 0.01、0.04 ± 0.01和0.03 ± 0.01,SCSel为低遗传力性状;不同胎次的SCSel性状之间存在中高遗传相关,遗传相关估计范围为0.54—0.87。【结论】荷斯坦牛泌乳早期(6 —35 d)SCC受胎次、季节等影响,泌乳早期SCC具有不同于泌乳期测定日SCC的群体特征;泌乳早期SCC处于较高水平会影响荷斯坦牛在随后整个泌乳期内的健康状态和生产性能。本研究为牧场在母牛产后利用SCCel进行差异化管理提供了理论依据,为探究荷斯坦牛在泌乳早期体细胞数差异的遗传机制奠定了基础,通过开发泌乳早期SCS新性状有助于完善我国荷斯坦牛乳房炎抗性选育。

关键词: 荷斯坦牛, 泌乳早期, 体细胞数, 产奶量, 遗传参数

Abstract:

【Objective】 The objective of this study was to explore the relationship between somatic cell count in early lactation (6-35 d) (SCCel) and test-day somatic cell count (SCC), test-day milk yield in different lactation stages, and to estimate genetic parameters of SCSel in Holstein, so as to provide a new idea for the breeding of Holstein mastitis resistance. 【Method】Dairy herd improvement (DHI) records for 182 378 Holstein cows were collected from 141 dairy farms from 2008 to 2018. After quality control, a total of 1 869 976 date records were obtained for 150 864 cattle. The pedigree information of three generations were collected (father, mother, grandfather and grandmother from both father side and mother side) to form the pedigree file, comprising a total of 6 451 bulls and 103 452 cows. The GLM process of SAS software analyzed the factors affecting SCSel, such as measurement scale of pasture, measurement season, measurement year, number of lactation days and fetal secondary, etc, and the relationships between SCSel and test-day SCS and test-day milk yield in different lactation stages by REG procedure using SAS software. The genetic parameters for SCSel traits were estimated by single trait repetition model, single trait and two traits animal model using DMU software, and including heritability and genetic correlation. 【Result】The results showed that the SCC of Holstein changed significantly at 2 weeks postpartum. SCCel of Holstein showed a trend of gradual decline with the increase of lactation days. The farm scale, parity, test season and days in milk had significant impacts on SCCel (P<0.05), and the SCSel of cows with an average annual measurement size of more than 1 000 cows in early lactation was significant lower than the average annual measured size of less than 1 000 (P<0.05). SCSel was firstly decreased and then increased with the increase of parity. The SCSel was the highest in summer and the lowest in winter. There were highly significant regression relationships between SCSel and the test-day SCS in different lactation stages (P<0.01), with regression coefficients ranging from 0.06 to 0.19. There was a highly significant regression relationships between SCSel and the test-day milk yield in different lactation stages (P<0.01), and the regression coefficient ranged from -0.46 to -0.16, and early lactation SCSel could affect breast health and performance during lactation. The heritability of SCSel in 1st, 2nd, 3rd parity and over all parity was 0.05 ± 0.005, 0.07 ± 0.01, 0.04 ± 0.01, and 0.03 ± 0.01, respectively. There were moderate to high genetic correlations among SCSel traits under different parity in Holstein, ranging from 0.54 to 0.87. 【Conclusion】The SCC of Holstein cows in early lactation (6-35 days) was affected by the number of conception and season, and the SCC of early lactation had the population characteristics different from those of the SCC of the measurement date of lactation. A high level of SCCel would have impact on the health and production performance over the whole lactation in Holstein cow. This study provided a theoretical basis for differentiated management by SCCel in postpartum cow pasture, laid a foundation for exploring the genetic mechanism of somatic cell number difference in early lactation of Holstein, and the development of new SCS traits in early lactation was helpful to improve mastitis resistance selection of Holstein in China.

Key words: Holstein, early lactation, somatic cell count, milk production, genetic parameter