南方集约化饲养条件下荷斯坦奶牛乳脂率和乳蛋白率变化规律的初步研究

Study on the Variability of Fat Percentage, Milk Protein Percentage of Holstein under Immense Feeding System in Southern Area of China

乳脂率和乳蛋白率是决定牛奶品质的重要成分,受许多因素的影响。试验旨在研究南方高度集约化饲养条件下自然月份、产犊季节、泌乳期和胎次对乳中乳脂率和乳蛋白率的影响。采样测定478头南方荷斯坦奶牛一个自然年度(2007年4—2008年3月)的主要乳成分和体细胞数(SCC),采用最小二乘法,分析自然月份、产犊季节、泌乳期和胎次对乳脂率和乳蛋白率的影响。结果表明:自然月份、泌乳期和胎次对乳脂率的影响极显著(P<0.01),产犊季节对乳脂率的影响显著(P<0.05);自然月份、产犊季节、泌乳期和胎次对乳蛋白率的影响极显著(P<0.01);乳脂率与体细胞数呈极显著负相关(P<0.01),而乳蛋白率与体细胞数呈极显著正相关(P<0.01);乳脂率和乳蛋白率与日产奶量呈极显著负相关(P<0.01)。结果提示在实际生产中,可以通过对影响乳成分因素的调控提高牛奶质量。

Milk fat percentage and milk protein percentage are two important components for the quality of milk,which were affected by many factors. This research aimed to study the impact of nature month, calving season, milking month and parity on milk fat percentage and milk protein percentage under the immense feeding system in southern area of China. The main components of milk and SCC recording 478 Chinese Holstein from April 2007 to March 2008 from a southern farm, were analysed by least mean square method to determine the effects of month, calving season, milking month and parity on milk fat percentage and milk protein percentage. The results showed that nature month, milking month and parity had significant effects on milk fat percentage（P〈0.01）, calving season had effect on milk fat percentage （P〈0.05）; nature month, calving season, milking month and parity had significant effects on milk protein percentage（P〈0.01）. The milk SCC showed significant negative correlation with milk fat percentage and positive correlation with milk protein percentage （P〈0.01）; and milk yield showed significant negative correlation with milk fat percentage and protein percentage. It suggests that, in production practice, we could control and regulate the effects of these factors to improve milk quality.