Berning L M, Paape M J, Miller R H
J Dairy Sci. 1987 Jun;70(6):1302-6. doi: 10.3168/jds.S0022-0302(87)80145-5.
Quarter composite milk samples were obtained from five cows free of intramammary infection throughout an estrous cycle and after injection of corn oil and of estradiol benzoate (1 microgram/kg body weight) in corn oil. Samples were assayed for NAGase activity and somatic cell concentration. Least squares means for the enzyme were 1.46, 1.47, 1.43, and 1.41 natural logarithm nanomoles per minute per milliliter for control, estrus, corn oil, and estradiol benzoate, respectively. Milk somatic cell count means were 2.77, 2.71, 2.92, and 3.10 loge X 10(3) cells/ml. Treatment had no significant effect on enzyme activity or cell counts. Results suggest no adjustment of NAGase or cell count is necessary for stage of estrous cycle. When administered at physiological dosages, exogenous estrogen did not appear to influence either measure.
在整个发情周期以及在注射玉米油和玉米油中苯甲酸雌二醇（1微克/千克体重）后，从五头无乳房内感染的奶牛身上采集四分之一混合乳样。对样品进行N-乙酰-β-D-氨基葡萄糖苷酶（NAGase）活性和体细胞浓度检测。该酶的最小二乘均值分别为：对照组、发情期、玉米油组和苯甲酸雌二醇组每毫升每分钟1.46、1.47、1.43和1.41自然对数纳摩尔。乳体细胞计数均值分别为2.77、2.71、2.92和3.10 loge×10(3)个细胞/毫升。处理对酶活性或细胞计数无显著影响。结果表明，发情周期阶段无需对NAGase或细胞计数进行调整。以生理剂量给药时，外源性雌激素似乎对这两项指标均无影响。
