呼和浩特近郊奶牛乳样体细胞分与乳成分相关性分析

本试验旨在研究呼和浩特近郊两个奶牛场荷斯坦奶牛体细胞数(somatic cell count,SCC)变化规律及体细胞分(somatic cell score,SCS)与乳成分的相关性。试验按常规方法采集奶样,并借助Bentley FTS/FCM 400 Combi奶牛生产性能测定仪测定奶样,然后对所得数据用SPSS 17.0软件进行统计分析。结果显示,奶牛各胎次中SCC在第1胎时最低(P<0.01),在第7胎时最高(P<0.01);随着泌乳天数的增加奶样SCC亦明显增加;奶样SCC<100×10³/mL到SCC>1000×10³/mL的过度中,奶牛日产奶量和奶样乳糖含量明显降低(P<0.01),分别降低了6.07 kg(22.97%)和0.40%(8.06%),而奶样乳脂率和乳蛋白率显著升高(P<0.01),分别增加了0.32%(8.31%)和0.26%(8.05%)。秋、冬季奶样乳脂率要明显高于春、夏季奶样乳脂率(P<0.01),秋季奶样乳蛋白率最高,春季奶样乳蛋白率最低;春季奶样乳糖含量最高,秋、冬季奶样乳糖含量相对较低;冬季奶样SCC最高,而秋季奶样SCC则最低。SCS与日产奶量(-0.172)和乳糖含量(-0.283)之间存在极显著负相关(P<0.01),SCS与乳脂率(0.034)和乳蛋白率(0.111)之间存在极显著正相关(P<0.01)。因此,随着胎次增高,SCC有逐渐升高趋势;随着SCC的升高,日产奶量和乳糖含量有降低趋势,而乳脂率和乳蛋白率有升高趋势;季节对乳成分和SCC均有不同程度的影响;SCC对奶牛日产奶量、乳脂率、乳蛋白率、乳糖含量均有明显影响。

Correlation Analysis of Somatic Cell Score and Milk Composition of Dairy Cows in Near Hohhot

Measuring and analyzing the somatic cell count(SCC) and milk composition of Holstein cows from two farms in Hohhot suburb, to study the variation of SCC in milk and the correlations between somatic cell score(SCS) and milk composition of Holstein cows. Collecting the milk sample with standard methods, and measuring the milk sample with Bentley FTS/FCM 400 Combi, and then analyzing the data statistically. The results showed that SCC was lowest in 1st parity(P<0.01) and highest in 7th parity(P<0.01); SCC in the early stage of lactation was lower than middle and late stages of lactation(P<0.05); while SCC from lower 100×10³/mL to higher 1000×10³/mL, the milk yield and the content of lactose were statistically significant(P<0.01) decreased about 6.07 kg(22.97%) and 0.40%(8.06%), the content of fat and the content of protein  wre statistically significant(P<0.01) increased about 0.32%(8.31%) and 0.26%(8.05%). The content of fat in autumn and winter were statistically significant(P<0.01) higher than the content of fat in spring and summer, the content of protein was the highest in autumn and the lowest in spring(P<0.01), the content of lactose was the highest in spring(P<0.01) and lower in autumn and winter. SCC was the highest in winter and the lowest in autumn(P<0.01), the whole year average showed statistically significant(P<0.01) positive correlation between SCS and fat content(0.034) and protein content(0.111), and statistically significant(P<0.01) negative correlation between SCS and daily milk yield(-0.172) and lactose content(-0.283). Therefore, SCC tended to increase with advancing parity, the daily milk yield and lactose content tended to decrease with advancing SCC, the fat content tended to increase with advancing SCC, the milk composition and SCC were affected by the seasons differently, SCC significantly affected daily milk yield and the contents of milk fat, protein and lactose.