REPRODUCTION ABILITY OF BULLS BY VARIOUS BODY CONFORMATION TYPES AND EXPRESSION OF MEAT FORMS

Abstract

In the complex of measures of beef cattle improvement, essential in breeding is the choice of the desired body conformation type, which corresponds to certain direction of productivity. Reproductive traits of the Prydniprovskii breed type (PM -1) sires in ALLC "Volia", Zolotonostha district, Cherkasy region were evaluated depending on the body conformation types and development of meat forms. Conformation types were studied by the method of model deviations in rump height and body length from points of shoulders to pin bones. Body measurements were determined with a measuring stick at 18 months of age. By spitting the distribution of frequencies of deviations of the variation series over the measurements, large frame animals (big height and long bodied animals) and compact (low height and short bodied bulls) types of body conformation have been segregated. The development of the meat forms was determined by testing of the bulls’ own performance. It has been proved that greater volume of ejaculation, bigger number of spermatozoa in ejaculation with straight progressive movement, higher fertilizing ability of spermatozoa were associated with the bulls of large frame type as compared to compact type contemporaries. Under the pure breeding methods of selection, cows bred by large frame sires, have had easier calving. The offspring from compact-type bulls had larger forehead width, head depth, width at points of shoulders, and hip width, and lower body lengthas compared to the offspring from large frame sires. Survival rate of calves born from large frame sires until 8 months of age was higher. Bulls with better developed meat forms tend to have lower volume of ejaculation, concentration, and fertilizing ability of spermatozoa. Cows fertilized with their semen were more likely have difficult calving, which affected calves’ survival rate from birth to weaning. According to the results obtained, compact type bulls and bulls with better expressed meat forms have lower reproductive ability.