荷斯坦牛关键奶流速指标筛选及影响因素分析OACSTPCD

[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 2 162 cows with 1 181 628 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.