Relationship between total spermatozoa per insemination and fertility of bovine semen stored in Caprogen at ambient temperature

Open Access
Publisher Website
Google Scholar
Abstract
A series of 4 trials was conducted to determine the effect of the number of sperm per insemination on fertility of semen diluted in Caprogen and stored at ambient temperature. Further objectives were: to test the effect of egg yolk concentration and catalase on response to dilution rate effects; and to determine the effect of semen age on the fertility of highly diluted semen. The combined results from the 4 trials showed no significant differences existed between the 2.5 × 106 total sperm per insemination treatment and any of the other treatment rates used. The differences between the total number of sperm per insemination relative to the 2.5 × 106 total sperm per insemination treatment were: 1 ± 0.64; + 0.28 ± 0.33; - 0.31 ± 0.54; and - 0.1 ± 0.66 for the 5.0, 3.75, 1.9, and 1.5 × 106 sperm per insemination treatments respectively. Dilution rate response was unaffected by egg yolk concentration or catalase. When diluted at 4 × 106 total sperm/ml (2 × 106 total sperm per insemination) semen could be stored for 60, and possibly 84 h, without loss of fertility. At this dilution, 100 000 inseminations per bull can be achieved from sires with the highest genetic value in the 10–12 weeks of the New Zealand spring mating season. The estimated advantage of using the Caprogen semen technology, compared to alternative semen dilution technologies, is 2–3 kg milkfat per daughter rnilked. This results from the greater selection intensity possible using this technique.