29 September 1995

Synchronisation brings all-round herd benefits

Heat synchronisation has benefits for both dairy and suckler herds. Jonathan Riley reports

SYNCHRONISED breeding programmes for suckler beef herds can improve profits by £60 a cow.

"This figure," says Judith Cochrane of Genus, "has been established in trials carried out by the Scottish Agricultural Colleges beef suckler unit over the last 10 years.

"Previously practical constraints have limited the use of AI in beef suckler herds – while the technique has made improved genetics available to dairy farmers for 30 years," says Mrs Cochrane.

Genus has introduced a synchronised breeding package and established a beef suckler herd at its Warren Farm research station, Berkshire, to demonstrate the benefits of using AI and proven beef sires.

"We want to produce calves by our own proven sires. So we are relying on synchronisation and have conducted three fixed-time AI programmes to get heifers in-calf. Only AI will be used in the herd. There will be no stock bull."

During May and June, 63 Simmental x Holstein Friesians were synchronised and AId with the Limousin Broadmeadows Tombola selected for his ease of calving, relatively short gestation length, and conformation.

Scanning confirmed a pregnancy rate after the third insemination of 95% of with cows due to calve within a seven-week period in March-April 1996.

Among the benefits of using top quality proven beef bulls through AI, Mrs Cochrane lists: Increased genetic gain, higher daily liveweight gains, reduced days to slaughter, good conformation and uniform calves, improved killing out percentage, improved carcass grades and ease of calving.

"In most beef finishing systems it is the final month that is crucial to profit," she says. "When a bulls progeny are known to have higher liveweight gains they will reach the required slaughter weight more quickly reducing feed costs. There can be up to 70 days difference in slaughter age between progeny of different bulls from any breed.

Superior conformation

"Also, though carcass premiums are relatively small, they can add up in large herds. So if a bull is known to consistently produce progeny of superior conformation, he must be worth using if all the other factors are right," she says.

"Having all cows in oestrus on the first day of the breeding season means all calves will on average be 12 to 13 days older than in naturally served herds – which means a higher average calf weight at weaning.

"A major hidden cost of suckled calf production is the cost of the bull. Normally the cow to bull ratio is about one to 35 cows. Trials have shown the bull to cow ratio for repeat services following synchronised AI is one bull to 60 cows, reducing the overall bull requirements," says Mrs Cochrane.

Lower calf mortality rates and reduced disease risk are further benefits. Vibriosis, IBR, IPV, BVD and leptospirosis are all transmitted via natural service sires and can have devastating effects. All these diseases are controlled in AI by regular testing of all bulls and semen," she says.

As for dairy cattle, Basil Lowman of the Scottish Agricultural College says that up to 10% of cows put forward for AI were showing a false heat and so semen – some costing £20 a straw – was being wasted.

"Synchronisation and AI effectively eliminates the need for oestrus detection and allows all heifers to be served on one day rather than as and when they come into oestrus.

"Heifers can be introduced to the parlour in a group before calving to acclimatise them without causing disruptions to the rest of the herd," says Dr Lowman.

There are management benefits too because heifers can be put into the right cycle for the calving pattern of the herd and labour can be tailored to match requirements.

"But," warns Dr Lowman, "producers must be careful that there is sufficient space, feed and straw to cope with a large number of calves born in a short period of time." &#42