荷斯坦牛关键奶流速指标筛选及影响因素分析

Selection and Influencing Factors Analysis of Key Milking Flow Rate Indicators of Holstein Cattle

【目的】本研究旨在探究挤奶流速指标的群体表型变化规律、指标间相关性及主要影响因素,筛选荷斯坦牛关键奶流速指标。【方法】本研究收集了北京地区某规模化牧场2162头泌乳牛1181628条奶流速数据,包含班次奶量及11项奶流速指标(平均流速、挤奶时长、高峰流速、慢速出奶时间占比、脱杯流速、0―15 s流速、15―30 s流速、30―60 s流速、60―120 s流速、前2 min产量和前2 min产量占比),并对班次奶量与上述奶流速指标进行了正态性检验、回归分析、相关性分析,以及影响因素分析。【结果】班次奶量与11项奶流速指标均呈正态分布;其中0―15 s流速、15―30 s流速、30―60 s流速、60―120 s流速、前2 min产量、高峰流速、平均流速和挤奶时长与班次奶量呈正向回归关系,且在各因素水平下变化规律一致;各指标间均存在显著的相关关系(P<0.05),相关系数在—0.80~0.95之间;相关性分析结果表明,平均流速和前2 min产量可作为关键奶流速指标,随着班次奶量的增加均呈现逐渐增加的规律,且在不同年份、季节、胎次、泌乳阶段和挤奶班次均差异显著(P<0.05)。【结论】平均流速和前2 min产量可作为奶流速指标考核的关键指标,但在实际生产管理中,需根据牛群结构和环境变化来设定指标的参考值。随着精细化管理,对于平均流速和前2 min产量可以逐步设定更高参考阈值来获取更高的产奶量,进而增加经济效益。

【Objective】This study was aimed to investigate the variation of phenotype for milking flow rate traits and the correlation among the traits to identify the key indicator of milking flow rate.【Method】A total of 2162 cows with 1181628 records of milking flow rate including milk yield per milking(MMY)and 11 milking flow rate indicators:Average flow rate(AFR),milking duration(MD),peak flow rate(PFR),proportion of low flow rate(PLFR),take off flow rate(TOFR),flow during the first 0-15 s(F0-15),flow during the first 15-30 s(F15-30),flow during the first 30-60 s(F30-60),flow during the first 60-120 s(F60-120),yield during the first 2 min(Y2M),and proportion of yield during the first 2 min(PY2M)were adopted.And the normality test,regression analysis,correlation analysis and influencing factors analysis were carried out between MMY and milking flow rate indicators.【Result】MMY and 11 milking flow rate indicators were all normal distribution.Among them,F0-15,F15-30,F30-60,F60-120,Y2M,PFR,AFR,and MD had positive regression relationship with MMY,and the variation pattern is consistent at the level of each factor.The correlation between these traits were significant with a coefficient from-0.80 to 0.95.The correlation analysis results indicated that AFR and Y2M could be used as key indicators of milk flow rate,showing a gradual increase trend with the increase of milk MMY.There were significant differences in different years,seasons,parities,lactation stages,and milking shifts(P<0.05).【Conclusion】AFR and Y2M could be used as key indicators for evaluating milk flow rate indicators,but in actual production management,reference values for indicators need to be set based on changes in herd structure and environment.With refined management,higher reference thresholds could be gradually set for AFR and Y2M to achieve higher milk yield,thereby increasing economic benefits.