English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Among the cows of milk production especially popular in our country the Holstein breed of cows, this was introduced by breeders in the 19th century in the USA. Herds of Holstein cattle have a high genetic potential of dairy production, and many animals have a record productivity [1, p. 2]. The highest average daily milk-yield in most cows is, as a rule, in the second month of lactation, and as lactation increase, they certainly decrease. The longer the period of lactation, the less specific gravity in it in the first months with a high average daily productivity of the animal [2, p. 15]. Increasing the duration of the service-period naturally leads to an increase of days of the dairy and the total lactation fee. At the same time, increased the milk-yield during the 305 days of lactation, and with the prolongation of the service-period increases the time a reduced productivity in cows as a result of pregnancy [3, p. 3]. In modern conditions of industrial production of milk, the service-period in high productivity cows is substantially lengthened, that's why the lactation period at 340-360 days is considered normal. In the conducted researches, the average duration of one productive period in Holstein cows from the first to the sixth lactation was at the level of 342.1-351.5 days. Taking into account the dry off time before the next calving, the duration of the period between calving of these experimental animals slightly exceeded the norm and amounted to an average of 400.2-410.5 days. Considering the level of milk productivity of Holstein animals for the entire period of lactation, it should be noted that it increase from the first-heifers of the first lactation, acquired the maximum value in cows on the third and remained practically identical in animals during the fourth, fifth and sixth lactation. Thus, 7747.7 kg of physical or 7532.6 kg of 4 % milk was obtained from the first-heifers, which inferior to the indicator of cows in the second lactation, in which the milk-yield was an average of 8597.8 kg and 8245.8 kg of 4% milk, respectively, at 10.9 % (P<0.001) and 9.5 % (P<0.001).

REALIZATION OF MILK PRODUCTIVITY OF HOLSTEIN COWS OF DIFFERENT AGE ON THE INDUSTRIAL COMPLEX OF MILK PRODUCTION