About Some Pecularities of Changing the Physical and Chemical Composition of the Cow Breast Secret

Abstract

Studies have shown the effect on the physical and chemical parameters of beestings and milk of metabolic correctors used by animals in accordance with the scheme developed by the authors. The experiment was carried out on 30 cows of the Holstein breed contained in the agricultural factory “Plemzavod im. Lenin” of Atninsky district of the Republic of Tatarstan. The content of the mass fraction of fat, the mass fraction of protein in beestings and milk was determined on “Laktan 1-4” milk quality analyzer, the content of trace elements in milk was determined on “Analist 200” atomic absorption spectrophotometer according to the manufacturer’s method. The use of vitamin-mineral premix P60-3/P in the final 15 days of the dry period in combination with metabolic correctors is accompanied by a maximum content of protein mass fraction in beestings (6.0%), and an increase in the use of this premix to the entire duration of the dry period allows increasing the mass the proportion of fat in beestings is up to 5.41%, however, these changes were not reliable. A significant decrease in the mass fraction of protein in the milk of cows of the control group (P <0.05) and a significant increase in the mass fraction of fat in animals of the third group to 4.13% (P <0.05) on the 30th day of lactation were found. On day 30 of lactation, a significant increase in the content of copper and selenium in the milk of individuals of the second (66.2% (P <0.01) and 65.2% (P <0.05), respectively) and the third (67.2% (respectively P <0.001) and 73.0% (P <0.01)) groups. On the 60th day of lactation in animals of the first group, the increase in the zinc content in milk was reliable and amounted to 6.9% (P <0.05). In cows of the second and third groups, the copper content was significantly higher than in animals of the first group by 60.3% (P <0.01) and 62.6% (P <0.01), respectively. In individuals of the third group, the selenium content was significantly higher than in animals of the first (control) group by 94.2% (P <0.01). This article was prepared as part of the state task AAAA-A18-118031390148-1.

Frequency of occurrence of k-casein genotypes and their effect on the milk productivity of Kholmogory cows

“…В отечественной литературе также наблюдается расхождение мнений по поводу влияния генотипов k-казеина на хозяйственно полезные признаки. Так, например, ряд авторов обнаружил, что удой молока, содержание жира и белка в молоке увеличивается у животных с генотипом АА CSN3 [9,10,11].…”