Breeding Week 2024: A refresher on sexed semen
With approximately 300,000 sexed semen straws expected to be used on dairy farms this spring, Dr Stephen Butler of Teagasc Moorepark provided a refresher on this technology and outlined best practice for its use as part of the recent Efficient Dairy Breeding Webinar.
Breeding strategies on dairy farms have been dominated by the use of conventional dairy and beef semen, typically resulting in a calf crop consisting of 27% female dairy calves, 27% male dairy calves and 46% beef-sired calves. However, by using breeding programmes to include the usage of sexed semen, the proportion of dairy male calves can be reduced significantly, potentially moving to just 3% of the calf crop, with the beef-sired proportion expanding to 70%, Dr Butler outlined.
Commenting on the effectiveness and the role of sexed semen, Dr Butler said: “We’ve had rapid growth in availability and usage of sexed semen. Sexed semen is a key technology for the Irish dairy industry. It is however a fragile product and requires careful use.
“It will deliver fewer male dairy calves. It will allow you to generate better EBI replacement heifers and also better DBI non-replacement calves and, collectively, this will improve the sustainability metrics of the entire dairy and beef sectors,” Dr Butler outlined.
On the fragility of the sexed semen product, Dr Butler reminded farmers of the key advisory messages in relation to its use.
Key advisory messages on sexed semen use:
- Pick highest EBI bulls available and use a large team of bulls;
- Pick the top 50% of herd based on EBI;
- Heifers must be at target body weight at a BCS of >/= 3.25 and cycling regularly;
- Select first to fourth calving cows, >50 days in milk on day of AI, with a body condition score >3, cycling regularly; and have no postpartum disorders or uterine disease;
- Use sexed semen in the first three weeks of the breeding season, within the first 10 days if possible;
- AI 14-20 hours after heat onset;
- Fixed time AI is an option, but its costly and mitigates risk and it facilitates targeted used of sexed semen on mating start date;
- Straw handing on day of AI
- Organise sexed straws into one goblet;
- Thaw two sexed semen straws at a time max;
- Thaw at 35-37 degrees Celsius for 45 seconds;
- Load straws into pre-warmed AI guns, keep warm;
- Deposit semen in uterine body;
- Complete inseminations within five minutes.
He also noted that sexed semen usage should be targeted at heifers, not only because these are the highest genetic group of animals contained within many herds, but due to their higher inherent fertility. Usage across both cows and heifers should also be targeted for the first round of AI to maximise the number of replacement heifers born at the very start of the calving season in the subsequent year.
Watch Dr Butler’s presentation to the Efficient Dairy Breeding Webinar, where he provides more detailed information on sexed semen, straw numbers and best practice use:
Sexed semen in dairy herds - guidelines
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