RELATIONSHIPS BETWEEN SOMATIC-CELL COUNTS AND MILK-PRODUCTION
RELATIONSHIPS BETWEEN SOMATIC-CELL COUNTS AND MILK-PRODUCTION
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DOI：
10.3168/jds.s0022-0302(84)81510-6
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发表时间：
1984-01-01
影响因子：
3.5
通讯作者：
HEALD, CW
中科院分区：
文献类型：
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作者：
JONES, GM;PEARSON, RE;HEALD, CW
对34个奶牛群3年以上试验日产奶量与乳中体细胞计数[乳腺炎]之间的关系进行了分析。当体细胞计数转换为自然对数而不是实际对数时，这种关系的估计更为准确。在67,707次观察中，试验日产奶量随体细胞计数的增加而降低。第2次及以后泌乳产奶量随体细胞数的增加而下降，降幅大于第1次泌乳。当按奶牛产奶量（7700 kg/年、6500 ~ 7700 kg/年和< 6500 kg/年）进行分组时，平均产奶量低于7700 kg的奶牛，产奶量随体细胞数的增加呈线性下降。在产量超过7700公斤/年的高产畜群中，两个胎次组的回归均为线性、二次和三次回归。每头奶牛合成四分之一的样品并进行培养。随着体细胞数的增加，感染奶牛的比例也在增加，感染率在400倍以上。103.
The relationship between Dairy Herd Improvement progran test-day milk yield and somatic cell counts [mastitis] in milk was analyzed in 34 dairy herds over 3 yr. Estimates of this relationship were more accurate when somatic cell counts were transformed to natural logarithms rather than actual. For 67,707 observations, test-day milk yield decreased with increasing somatic cell count. The decrease of milk yield for 2nd and later lactations, as somatic cell count increased, was greater than for 1st lactations. When herds were partitioned according to herd milk production (> 7700, 6500-7700 and < 6500 kg/yr), decrease of milk yield was linear with increasing somatic cell counts for herds averaging below 7700 kg milk. Regressions were linear, quadratic and cubic for both parity groups in herds with high production, over 7700 kg/yr. Quarter samples were composited for each cow and cultured. Percentage of infected cows increased as somatic cell counts increased with greater infection rates above 400 .times. 103.