2 April 1999

Improve cow fertility by reducing time with calf

RESTRICTING a suckled calfs access to its mother to once or twice a day from five weeks old can improve cow fertility.

This can help keep a tight calving pattern, ease management and improve profit, said SAC Aberdeen researcher Kevin Sinclair at the BSAS meeting.

He believes that suckler herds which maintain a tight calving pattern are most profitable. When a cow doesnt calve every 12 months output is reduced.

"Improving fertility will stop a cow slipping back though the calving period. It is easier to manage an even batch of calves; they may be healthier, can be sold together and will weigh more at sale, increasing profit."

But many beef cows have long calving intervals because they ovulate too late after calving. This is undesirable because pregnancy rates increase in subsequent ovulations. There is a better chance of pregnancy when serving a cow on its second or third ovulation, said Dr Sinclair.

Achieving a 365-day calving interval gives 84 days to get a cow in calf. By 30 days after calving the uterus should have repaired and regenerated. Silent heats in this period are normal. The aim must be to serve cows at 65-66 days to allow a second service before 84 days.

Cows need to ovulate earlier, but not too early. "When a beef cow is sucking a calf it stops her ovulating too early. Then when the calf is five weeks old, allowing it to suckle once or twice a day and keeping it out of sight and smell, but within sound of its mother, reduces the maternal bond, allowing the cow to ovulate quickly.

"Thats providing she is on a high level of feeding and was in good condition at calving." Aim for body condition of 2.5 to three at calving, and feed well before calving, he advised.

Restricting calf access may be impractical for those calving outside, but in summer fertility tends to be higher naturally.

"But in winter months when animals are housed the technique can be used. Calves happily live in a creep area by five weeks old and feed seven times a day on many units.

"These calves could be put in a pen further away and allowed out twice a day."

Now many small producers in Sardinia and northern Spain who collaborated in this EU study are using these practices to induce ovulation without drugs.

RESTRICTEDACCESS

&#8226 Calf suckles twice a day.

&#8226 Induces ovulation.

&#8226 Improves fertility results.