Abstract

An economic appraisal was undertaken of female enriched dairy semen in New Zealand commercial dairy cattle. Artificial insemination (AI) scenarios were evaluated in cows (C) and yearling heifers (H) with normal (N-) or sex-sorted semen (S-) with a female enrichment ratio leading to 75% (S75) or 90% (S90) heifer calves at birth. In-calf rates with S-semen were 0.75 of normal. Scenarios examined were: cows inseminated with N-semen and yearling heifers naturally mated (CN); cows inseminated with S-semen (CS75 and CS90); cows and yearling heifers inseminated with N-semen (CN-HN); and cows inseminated with N-semen and yearling heifers with S-semen (CN-HS75) and (CN-HS90). These scenarios required 29, 24, 19, 20, 19, and 17 days of AI in cows, respectively. S-semen reduced six-week in-calf rate and final calving rate. The total costs, including reproduction losses, semen and insemination, of producing a four-day old AI heifer replacement calf in a herd of 400 milking cows were $70, $262, $292, $69, $129 and $143. Maximum genetic gain in the milking herd is achieved using S90 semen in the highest genetic merit cows, although this is uneconomic at current semen prices. S-semen has a limited role in New Zealand dairy herds.

WH, McMillan, and MG Newman

Proceedings of the New Zealand Society of Animal Production, Volume 71, Invercargill, 131-135, 2011