Keywords: rams, breeding value, quality of descendants, estimation methods, growth rate, preservation, newness factor
The results of evaluating the breeding value of rams of different genotypes by a wide range of productivity indicators of their descendants are presented. Tribal rams of the Kharkov interbreed type of Prekos breed of 2-3 years of age, as well as crosses from the introductory crossing of Prekos sheep with the Romanov breed and Merinolandsheep, were evaluated. The resulting offspring were grown under the conditions of one production flock. The evaluation considered the indicators of the reproductive ability of ewes, sex and type of birth of the offspring, the safety of lambs from birth to 20 days of age, the dynamics of the average daily growth of daughters in the uterus and at the age of birth to 20 days and from 21 to 90 days, live weight indicators were considered, cutting and length of hair of daughters at the age of 14 months.
Studies have established that the average yield of lambs throughout the sample was 115.3 % per 100 ewes, with significant differences between the estimated producers – from 105.1 to 131.3 %. This indicator did not have a definite relationship with the genotype of the estimated sheep.
Among the offspring of all rams, males slightly prevail over females in the ratio of 1.09 to 1. This advantage is due to the large number of rams born among same-sex twins. Their part exceeded 28 %, while only 23.4 % turned out to be similar in type of birth.
By the sum of the ranks that were put to individual sheep for the indicators of the average daily growth of daughters at different periods of their growth, the best cross-breed sheep No. 1625 and No. 9953 are distinguished. On the whole, there is a fairly clear tendency for a positive relationship between the ranks for the growth rate in the embryonic period and the same indicator for posterity aged 21-90 days.
According to both the ranking and the probity-based evaluation results, ram No. 1625 (a created line based on crossing with the Romanov breed) is assigned to complex improvers. The rest topping ram out to be improvers of individual traits, and the producer of the breed Prekos No. 1823 was an improvement in production of wool and length of staple. Ram No. 1960 turned out to be a complex deteriorator in the quality of offspring.
The descendants of rams No. 4464 and 9953, derived from the breed of Merino landscape, reliably (p≤0.01), by 18.6-20.8 % in terms of wool coefficients, are inferior to the daughters of ram No. 1823, breed Prekos, which is an unconditional evidence of the strengthening of their characters meat productivity over wool one.
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