The experience of obtaining and evaluating sperm from repair bulls in the post-puberty period

Modern methods for assessing the bulls breeding value allow for the prediction of their offspring's performance early in life. However, a bull's own reproductive performance can only be assessed after reaching physiological maturity at 1.5 to 2 years. Evaluation methods and markers that can objectively characterize the reproductive performance of potential breeding bulls are constantly being sought. Three experiments were conducted to collect semen from 11- to 12-month-old bulls (n=10) using electroejaculation and transrectal massage. Individual characteristics of the bulls were identified. In the group with a positive response to the manipulations, 13 ejaculates were collected, from the group with an unsatisfactory response – 9 (4 of which were secretions with a concentration less than 100 million / ml). The concentration of spermatozoa in the ejaculate of the group 1 bulls was 380.6 million / ml and was higher in comparison with the indicators in the group 2 bulls (P<0.05), the total motility was 72.6% (P < 0.01), respectively, progressive motility – 66,7% (P < 0.01), the proportion of viable cells – 75.2%, spermatozoa with normal morphology were 83.4% (P < 0.001). Research has shown that systematic training of replacement bulls to produce semen post-puberty can allow for an assessment of their reproductive potential. This predictive assessment may be necessary for selecting candidate bulls for breeding operations.

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