Iliev I
Vet Med Nauki. 1982;19(2):3-10.
A study was carried out on the duration of the lactation period at different milk yield values and variable duration of the calving interval. It was found that the time period of lactation was influenced by the calving interval and the amounts of milk obtained. When the calving period was more than 365 days there was an unproportional lengthening of the lactation period which led to the respective lengthening of the dry period of cows. One day lengthening of the calving period brought about an increase of the dry period by 0.3 to 0.4 days. In the groups where milk yields amounted up to 4000 1 per cow the relative share of animals whose lactation period was below the standard was higher as compared to the groups with milk yields amounting over 4000 1 per cow. The higher the milk yield the higher the number of cows whose lactation period was within the norm. However, what is commonly observed is that with most of the cows the lactation period is below the standard, and this substantiates the fact that considerable amounts of milk are not really obtained.
对不同产奶量和不同产犊间隔时长情况下的泌乳期时长进行了一项研究。结果发现，泌乳期时长受产犊间隔和产奶量的影响。当产犊间隔超过365天时，泌乳期会不成比例地延长，这导致奶牛干奶期相应延长。产犊间隔延长一天会使干奶期增加0.3至0.4天。在每头奶牛产奶量达4000升的组中，泌乳期低于标准的动物相对比例高于每头奶牛产奶量超过4000升的组。产奶量越高，泌乳期在正常范围内的奶牛数量就越多。然而，常见的情况是，大多数奶牛的泌乳期低于标准，这证实了实际上并未获得大量牛奶这一事实。
