30 August 2002

Secret success of AI lies with grouping ewes

Speeding up genetic

progress through AI could

be vital to the future of

the sheep industry. But

money can be wasted

unless high conception

rates are achieved.

Jonathan Long visits one

Hants flock to find how to

keep conception rates

above 75%

ACHIEVING conception rates of up to 85% with laproscopic AI is possible when breeders pay attention to nutrition and keep management systems simple, believes pedigree Texel flockmaster Frank Moffat.

"Like all likestock management, with laproscopic AI it is the little things which make the difference, we aim to maximise conception by reducing stress," says Mr Moffat, who farms 67ha (165 acres) at East Meon, Petersfield in partnership with his son-in-law Simon Farmer.

Preparation of ewes for AI starts in June at weaning, with ewes put into sheds on a straw and water diet for a few days before being sorted into groups depending on condition score.

"While ewes are housed we carry out as many of the routine management tasks as possible, so we have to handle ewes less in the run up to AI," explains Mr Moffat.

Once grouped, ewes are turned out onto bare pasture. Replacement ewes are added to the main flock at this point to ensure the whole flock is managed identically before AI.

"We aim to have all ewes at the same condition score before sponging, this allows us to sort ewes into service groups, minimising stress immediately before and after AI."

Achieving a level condition score across the flock means some groups of ewes may require alittle supplementary feeding. Between 0.125kg/day and 0.25kg/day of concentrate may be fed for up to six weeks before AI. Concentrate is then fed for at least five weeks after AI.

"Supplementary feeding may not always be necessary, but it is good to have ewes on a rising plane of nutrition for about four weeks before AI, as it helps ovulation. Of particular concern, when using AI, is to ensure ewes are fertile. There is no point spending money on AI if ewes are going to return service," says Mr Moffat.

Trough feeding can also help with flock management. Any problems can be identified quickly and treatment for health conditions can be given without penning the flock. It also helps to keep an eye on which ewes have returned without having to put a dog around them.

Sychronisation of ewes is another key part of the AI process, Mr Moffat does this using using chronogest sponges. However, when sponges are used correctly they should be used to synchronise heat rather than induce a heat.

"To ensure ewes are cycling, we run them with a teaser ram for two to three weeks before sponging, promoting early cycling. When sponges merely induce a heat rather than synchronising heat it is possible that some ewes will return to anoestrus after the sponge is removed and their natural cycle may never kick in.

"We use AI to gain access to some of the top UK genetics by buying semen from other breeders, so we dont have the AI ram available as a chaser ram. But at least we avoid spending excessive amounts on rams," says Mr Moffat.

After AI ewes are fed for five weeks, to ensure they hold to service and keep those ewes that return on a rising plane of nutrition throughout tupping.

Management of ewes on AI day and immediately after is the most critical time, believes Mr Moffat. "Keeping ewes stress free at this time helps to ensure they hold to service and keeps returns to a minimum. With the expense of both AI and semen, ewes returning to AI can be costly."

Following AI, ewes are returned to their fields after having a few minutes to settle. Returning ewes to the same field is another factor in reducing stress. Ewes remain in the same field for at least two cycles after AI, to guarantee ewes have plenty of grass during this period.

The fields are split in two and ewes are given one half before AI and the second half after AI, this is again designed to minimise stress by keeping management changes to a minimum.

"Much of what we do is just following the advice of our AI contractor, CBS Technologies of Malvern. John Yates of CBS has provided us with clear and concise advice over the years, something which has helped us to achieve consistent results," explains Mr Moffat.

AICONCEPTIONRATES

&#8226 Management starts early.

&#8226 Feed if necessary.

&#8226 Keep ewes settled.