CAJ | 학술논문

奶牛的产奶量、乳脂率和乳蛋白率是衡量其泌乳性能的主要指标，也是规模化奶牛场获取高效益的关键。乳蛋白率是决定牛奶品质的重要指标，受许多因素的影响。本研究通过调查大庆肇源某奶牛场2010年-2013年奶牛个体4864条DHI数据，利用最小二乘法估计了奶牛群体平均乳蛋白率及其个体分布，分析了个体和环境因素对乳蛋白率的影响。结果表明，牛群的平均乳蛋白率为3.27±0.48%，72.4%的奶牛个体乳蛋白率高于2.95%，自然月份、季节、泌乳阶段和胎次对乳蛋白率影响显著（P＜0.05）。乳蛋白率与体细胞评分呈正相关（r=0.196），与日产奶量呈负相关（r=-0.647）。
내우적산내량、유지솔화유단백솔시형량기비유성능적주요지표，야시규모화내우장획취고효익적관건。유단백솔시결정우내품질적중요지표，수허다인소적영향。본연구통과조사대경조원모내우장2010년-2013년내우개체4864조DHI수거，이용최소이승법고계료내우군체평균유단백솔급기개체분포，분석료개체화배경인소대유단백솔적영향。결과표명，우군적평균유단백솔위3.27±0.48%，72.4%적내우개체유단백솔고우2.95%，자연월빈、계절、비유계단화태차대유단백솔영향현저（P＜0.05）。유단백솔여체세포평분정정상관（r=0.196），여일산내량정부상관（r=-0.647）。
The milk yield, milk fat percentage and milk protein percentage are the main indicators to evaluate milk performance of cows and they are the key effect factors to the economic beneifts of large-scale dairy farms. Being an important component of affecting the milk quality, milk protein percentage is inlfuenced by multiple factors. In our study, we analyzed the effects of the individual and the environmental factors on the milk protein percentage using the least square method by investigating 4864 DHI data of cows of Zhaoyuan dairy farm in Daqing from 2010 to 2013. The results indicated that the milk protein percentage for the dairy herd was 3.27±0.48%,and 72.4% individual cows milk protein percentage were higher than 2.95%.The natural months, calving season, lactation and parity could signiifcantly inlfuence milk protein percentage (P<0.05). It was positively correlated with somatic cell score (SCS) (r=0.196), but was inversely related to daily milk yield (r=-0.647). Our results may provide the scientiifc basis for the feeding and management of dairy farm and the monitoring of milk quality.