Tsonev P, G'l'binov G, Kamburov G
Vet Med Nauki. 1975;12(8):21-4.
Studied was the milk productivity (milk yield and butterfat percent) of 255 normal and 255 diseased cows with subclinical mastitis, both groups pertaining to the Bulgarian Brown breed within the region of the Sofia Pedigree Breeding Inspection. All animals were examined at one and the same time during the period of their third lactation, and the milk productivity data obtained referred to the same period. It was established that there were no statistically significant variations between milk productivity data of the healthy cows and those of the cows with subclinical mastitis for a 300 day period. The relative number of cows with subclinical mastitis showing a milk yield of up to 4000 kg was lower as compared with the same number of the negatively reacting cows. On the other hand, cows showed yields of more than 4000 kg milk manifested reverse trends.
研究了索非亚纯种繁育检验区内255头正常的和255头患有亚临床型乳腺炎的保加利亚褐牛品种奶牛的产奶性能（产奶量和乳脂率）。所有动物均在第三个泌乳期的同一时间进行检查，所获得的产奶性能数据均指同一时期。结果表明，在300天的时间里，健康奶牛和患有亚临床型乳腺炎的奶牛的产奶性能数据之间没有统计学上的显著差异。与相同数量的阴性反应奶牛相比，产奶量高达4000千克的患有亚临床型乳腺炎的奶牛相对数量较少。另一方面，产奶量超过4000千克的奶牛则呈现相反的趋势。
