中国荷斯坦牛泌乳早期乳常规成分及乳蛋白组分变化规律的研究

对扬州大学实验农牧场7头中国荷斯坦牛泌乳早期乳常规营养成分、酸度及乳蛋白组分的相对含量进行研究。结果表明，产犊后1h的乳脂率、乳蛋白含量、总固形物含量、滴定酸度、密度最高，而pH值最低，随后乳脂率、乳蛋白率、总固形物含量、滴定酸度密度急剧下降，到60h时接近常乳水平，而pH值逐渐上升，到第7d时接近常乳水平。产犊后1h初乳中免疫球蛋白的相对含量最高，为20．6％，到第5d时接近常乳水平。研究表明，产犊后3d内所产的乳最具有开发价值。

Change of the milk components and milk protein components at first lactating period for Chinese Holstein

The milk components, acidity and relative percentage of milk protein components at first lactating period were studied for 7 Chinese Holstein in Experimental Farm of Yangzhou University, the results shows that: the fat percentage , milk protein percentage, total solid percentage, dropping acidity and density were highest after 1 hour of calving, the pH is lowest. Afterwards, the fat percentage , milk protein percentage, total solid percentage, dropping acidity and density decreased promptly and reached the levels of common milk after 60 hours of calving. The pH increased step by step and reached the level of common milk after 7 days of calving. The IgG was highest after 1 hour of calving and reached the level of common milk after 5 days of calving. The colostrums within 3 days has most potential developing volume.