AI is making a return to the 370-cow suckler herd at Oteley Farm, Ellesemere, Shropshire, having been used in the 1990s to synchronise calving patterns between spring, summer and autumn-calving groups.

But this time producer Ian Mainwaring hopes targeted use of AI will achieve another objective – guaranteeing income from each suckler cow after removal of headage payments.

“It wasn’t so much of an issue when a suckler cow didn’t conceive immediately after calving and slipped between calving groups when we were receiving annual headage payments.

But that’s no longer the situation.

We need to ensure an annual income from each member of the herd,” he says.

With nine Limousin and Beef Shorthorn stock bulls covering most of the herd, sire:female ratios are at the upper end of industry recommendations.

“To relieve some of the pressure on sires and ensure a greater proportion of heifers – probably the most difficult group to manage in terms of synchronising fertility – are ready to calve-down as a block at the start of our calving season, we have decided to use AI,” says Mr Mainwaring.

Using Limousin AI sires from Genus’ catalogue for ease of calving and to add value to the resulting calf, 35-40 heifers were sponged by the unit’s vet on 24 April this year to synchronise heat 10 days ahead of service.

Sponges were removed and an injection of prostaglandin administered 72 hours later before the first of two doses of semen – inseminated 24 hours apart – was implanted by the local AI fieldsman on 5 May.

“According to work undertaken by SAC, this technique can help get the best out of a suckler herd.

It’s imperative today that each cow carries a calf and doesn’t slip between calving groups.

The loss of headage has taken away that safety net.”

Conception to first service among heifers was estimated at 40%, with those returning to heat three weeks later being AI’d again. A sweeper bull is left with the group to catch missed or late heat cycles.

“Overall, SAC results suggest 90-92% conception using this approach, so we’ll wait and see,” says Mr Mainwaring.

The AI programme costs 40 a head, allowing 10 for each semen straw and insemination fees.

“We will still have a nine-week spread in the heifer calving group, but at least most will calve at the start.”

Calving is expected to begin on 10 February next year, with most due before 16 February and the last group members by 20 April.

“We have to allow the heifer group some flexibility, but older cows missing cycles will be culled.

It is fortunate the market for these sucklers returned 82p/kg liveweight for the last batch we sent, weighing 660kg apiece.”

The rest of the herd is managed conventionally using stock bulls.

A batch of 45 cows will calve in May/June, having been served by a Beef Shorthorn sire, to rear replacement females to be retained for breeding.

An autumn calving group of about 130 cows will calve down outdoors from August to September.

These are served using a Limousin stock bull or AI’d to a Belgian Blue to improve the quality of beef calves kept for finishing.

About 400 cattle a year are reared and eventually sold through local livestock markets.

“The use of AI on the heifer group will make management easier.

With just one full-time herdsman and one part-time, it is not practical to keep bringing sucklers indoors to separate and inseminate a few at a time during cycling.

“The focus of AI will remain on synchronising the heifer group and improving the saleability of calves of some older herd members.

It will also relieve some pressure on service sires within our herd.

You cannot expect a bull running with 30-40 heifers to serve all of them successfully when they begin cycling together, as naturally happens,” adds Mr Mainwaring.

fwlivestock@rbi.co.uk