DETERMINATION OF FERTILITY OF FIRST CALVING COWS UNDER DIFFERENT HOUSING

Abstract

The best fertilization rate of firstborns was established at the farm “Kutuzivka” under free housing, it was 11% times higher than at the farm “Agroprogres”, and 7% higher than the farm “Dekabrystiv”. The influence of the "farm" factor – 1.0% was probable (p < 0.001). In our opinion, the higher percentage of fertile inseminations of firstborns is explained by the use of an automatic system for determining sexual desire at the farm "Kutuzivka".The season of the year was the most influential factor in the fertilization of the first-born cows among the factors of the external environment. The largest number of inseminations of first-borns at farm “Agroprogres” was in the summer (28%), and the lowest in the winter (23%). On the farm of the farm “Dekabrystiv”, a greater number of inseminations were also carried out in the summer (30%) months, and the smallest share of inseminations – in the winter (21%). The nature of this impact is explained not by the state of the environment, but by the housing technology and feeding animals. During the first insemination after calving, a slightly lower percentage of fertilization of first-borns was observed in all studied farms. During the second insemination, it increased by 4% in the animals of the farm “Agroprogres”, by 7% in the farm “Decembrists”, by 3% in the farm "Kutuzivka". In the subsequent growth of the number of insemination of firstborns in the first two farms did not lead to probable changes in fertility. At the same time, the animals of the the farm "Kutuzivka", starting from the 5th insemination, were fertilized by 11–23% less than from the second insemination. The influence of this factor on the effectiveness of insemination of cows was improbable in the farm “Agroprogres” and amounted to 0.7%, in the farm “Dekabristov” and the farm "Kutuzivka" 0.8%. It was established that in all experimental farms, the number of artificial insemination after the first calving of cows is not the main factor that determines its fertility. The main factor related to the efficiency of insemination is the stage of lactation. Correlation coefficients of the lactation day with the number of artificial insemination in experimental farms ranged from +0.545 to +0.723 and with the daily productivity of first-borns equaled from +0.156 to +0.383. Low fertility in the first 90 days of lactation is primarily due to a high milk dominance, possibly a negative energy balance during this period of lactation.