INFLUENCE OF BULL’S BODY TYPES AND MEAT FORMS EXPRESSION ON THEIR SEXUAL ACTIVITY

Abstract

In beef cattle breeding, the reproductive capacity of bulls significantly affects the economic efficiency of production. Selection for the meat productivity can negatively affect the ability of bulls to reproduce, so it is necessary to consider the risks of such a connection when selecting them. The study determined the rate of manifestation of Ukrainian beef breed bulls sexual reflexes of different body types and severity of meat forms. According to the type of body structure of bulls divided into two groups: large (high and long-bodied) and compact (low and short-bodied). The distribution performed using the growth index. The severity of meat forms of bulls was determined at 15 months of age on a 60-point scale. The animals on meat forms divided into two groups compared with the average score of experimental bulls. The degree of sexual activity manifestation assessed by the duration of sexual reflexes from bringing the bools to the stuffed animal to the mating attempt. According to the manifestation of libido, animals divided into three groups: active – mating attempt to cage from 10 to 60 seconds, moderate – from 60 to 120 seconds and slow – the time before the mating attempt lasted more than 120 seconds. Subsequently, in experimental bulls recorded the duration of productive use period, the number of leads to the stuffed animal and mating attempts to it and the number of received and rejected ejaculates. It found that the tendency of the distribution of active moderate and slow manifestation of sexual reflexes in bulls of different body types and development of meat forms is similar. In bulls of different groups, moderate sexual activity most often observed, but specific tendencies observed within the groups. The share of high sexual activity was higher in compact bulls compared to large coeval animals. Among animals grouped by the development of meat forms, the share of high sexual activity higher in bulls with better expressed meat forms. In the future, large bulls tend to increase the duration of productive use, predominate in the share of mating attempt and are characterized by a decrease in the share of ejaculate culling. Bulls with better meat forms tend to increase the duration of productive use due to their higher breeding value in terms of meat productivity. No difference was found in the proportion of mating attempts and the percentage of culled ejaculates between animals with different manifestations of meat forms. The obtained results prove that for intensive use at a young age more suitable bulls of compact type, and in adulthood more effective large sires. Better development of meat forms somewhat reduces the sexual activity of young bulls. At a more mature age, the results of the use of bulls are practically unaffected by meat forms.