AI pays off – when herd gets right feed balance

19 February 1999

AI pays off – when herd gets right feed balance

AI plays a vital part in

one expanding

Northumberland suckler

beef business.

Jeremy Hunt reports

EXPANSION and a switch to spring calving has strengthened commitment to AI in a Northumbrian suckler herd.

Cow numbers at Richard Greens beef and arable unit near Alnwick are increasing from 200 Simmental- cross autumn calvers and 60 autumn calvers to a totally spring calving herd of about 300 head.

As part of the streamlining of operations, the farms flock of 500 breeding ewes has been sold to enable the family to concentrate on beef and expand the arable side of the business by 80ha (200 acres). All calves from the familys farm at Heckley High House are sold through special Charolais-sired suckled calf sales at Wooler.

Some years ago the Green family paid 8500gns at Perth for a Charolais bull. The bull died prematurely after an accident, but a large supply of semen had been stored.

"We were devastated to lose a bull of such calibre, but decided to do more AI to ensure that we could continue to capitalise on his superior conformation," says Mr Green.

After several years of AI work in the herd, he believes it is an essential and cost-effective aid to management.

Although the greatest success with AI has been achieved with autumn calvers it has not deterred the Greens from using it as a big part of the breeding programme with the expanding spring calving herd.

No synchronisation is used. Over about eight weeks cows are checked each evening at 8pm for about an hour and any cows seen bulling are noted and drawn off at 8am the next morning to be inseminated by the AI man.

Any cows not seen bulling are examined after 21 days and those which have not come on heat or have not been seen to come on heat are examined by the vet and treated with Estrumate. Prids are used on cows which the vet says have not cycled naturally.

"This increased level of checking cows is not an arduous task and it also makes sure we pick up any cows that may need washing out."

But Mr Green believes the key to successful AI in suckled calf production lies in cow nutrition. "It is essential that cows are on a rising plane of nutrition," he says.

Autumn calvers, which start to calve on Sept 1 and finish in early November, are offered hay, silage or treated straw outside in ring feeders plus 1.5kg of barley with added magnesium before housing in mid-November.

At housing, the feed rate is increased to provide ad-lib silage and 2.5kg of a barley and maize gluten (20% protein) mix, but the mineral is changed to phosphorus, fed at 100g a head a day. This continues until three weeks after bulling is completed.

"Cows get a natural lift in condition when they are housed and benefit from a switch to ad-lib silage and the improved protein from maize gluten in the diet. It is a combined effect but it is essential to get cows cycling. You can see them improving in condition."

After the first three-week period any cows from the 170 or so autumn calvers which have not undergone AI are checked carefully. A conception rate to AI of over 55% has been consistently achieved and is considered quite acceptable.

The herd still uses sweeper bulls, which are introduced after three weeks. "We use one bull in each of the pens of 50 cows. We manage to AI 240 cows with three bulls; where we were relying on natural service we would have needed at least six."

Mr Green says the system does not demand a higher labour input. A strict routine is maintained and cows are fed silage and concentrate at about 5pm. After feeding, cows lie down, but by later that evening a walk through the sheds reveals any cattle on heat.

"We expect to see nine out of every 10 cows bulling. I am far more in touch with the cows – and the calves – because of the regular evening check. Cows are looked at again first thing in the morning and it is a simple job to draw cows off for the inseminator."

Although there will be more pressure on herd management, with all 300 cows calving from January to March, AI is still considered the most efficient breeding option .

"We will begin inseminating cows on Apr 10 with the aim of turning cows out on May 1, and calving starting Jan 20. We will go once through the herd with AI before we turn out and are aiming for a 10-week calving period.

Mr Green says he has synchronised cows on occasion and admits that it can bring the average calving date forward by about 10 days. "If it is impractical to check cows as we do, it is the only option, but I think it is very expensive."

Future management of the spring calvers will see cows fed ad-lib ammonia-treated straw and about 1kg of maize gluten during housing. Spring-born calves are creep fed during late summer and weaned as cows are housed in late October.

"It makes sense to concentrate the herd into spring calving. We have finished drilling crops by September-October, we can then start work on housing the herd and weaning calves and we are calved and inseminated by the time arable work starts to increase again.

"AI not only enables us to use semen from our superior bull, but we believe it is also the most efficient way of getting our cows in calf. We are achieving a conception rate that is certainly not less than 8-10% below what we would get using natural service," adds Mr Green. &#42


&#8226 Rising plane of nutrition.

&#8226 Observe herd closely.

&#8226 No synchronisation used.

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