Математический способ оценки репродуктивной функции крупного рогатого скота

The reproductive potential of females is one of the determining factors of profitability of dairy cattle breeding, so the fertility of animals is a necessary criterion for evaluating different breeds of cattle. The paper describes and gives a comparative assessment of various methods of determining the reproductive potential of cows using a mathematical model. It is established that the existing methods of monitoring reproduction do not always fully characterize the biological potential of the female in certain conditions. Thus, the coefficient of reproductive ability shows only the reproductive qualities of cows, without taking into account the age of the first calving of the heifers, and the fertility index can not be calculated for the first calves. The reproduction coefficient reflects the number of offspring received during the life of the animal, but its values are always minimal for the first-born, and grow as the age of the cow increases. In connection with the identified shortcomings, a method for determining the "fertility coefficient" is proposed, taking into account the interbody intervals and the age of the first calving, which allows for a more objective assessment of the reproductive potential of animals. With the use of the developed method, the analysis of reproduction indicators of cows of the Kholmogorsky breed with a different share of Holstein of one of the farms of the Komi Republic was carried out. It is established that with the growth of blood on improving breed fertility coefficient in this economy increases. So the difference between animals with blood more than 50%, was significantly higher by 0.04...0.05 (P<0.001), compared with purebred Kholmogorsky cattle, which is associated with the earlier first calving in crossbreed cattle.