IN BRIEF
Barren ewes not only cause of poor results
By Jessica Buss
INFERTILITY in sheep flocks is responsible for higher losses than most flockmasters realise and a high proportion may be due to toxoplasmosis.
Speaking at an Intervets launch of a new booklet Abortion and Infertility in Sheep, independent consultant Lesley Stubbings said there was scope to improve lamb output a ewe, helping profitability while lamb prices were low.
"When you look at the kg of lamb produced a ewe there is scope for improvement in most flocks. The average flock produces 27-28kg a ewe, but the top flocks produce 32-32kg a ewe at little extra cost," said Ms Stubbings.
She believes the high number of ewes failing to rear lambs is a big factor in reducing potential output.
Many producers underestimate infertility because they only count barren ewes. But they should also consider aborting ewes, lambs dying after birth and dead ewes.
In reality, she said 46% of lamb losses occurred after tupping, as abortions, stillbirths and losses before scanning.
These ewes are often culled. But when they have lost lambs because of toxoplasmosis, they may lamb normally if kept for another year. Identifying a high number of barren ewe lambs may indicate that toxoplasmosis is the cause of infertility.
"When a ewe is sold from a flock early, for infertility such as infectious abortion, flock replacement costs are high."
That did not give younger ewes a chance to recover some of their potential lifetime income, said Intervets vet Ian Mawhinney.
When a ewe had only had one lamb crop its lifetime gross margin was -£45 a ewe, but after three crops she had contributed £55, added Ms Stubbings.
But producers often blame poor fertility on nutrition, according to a survey of 100 flockmasters commissioned by Intervet.
Mr Mawhinney added that infertility was recognised by producers as the number of barren ewes in their flock, with over half of concerns attributed to poor nutrition. Abortion and disease was only seen as a big factor by 10% of respondents.
Most flockmasters also underestimated the % of infertile ewes, claiming about 3% were infertile a year, but that figure is only ach-ieved by the top 10% of UK flocks.
Most also put the cost of infertile ewes at under £50, far less than the true cost of £80.
Few producers thought lost pregnancies were the cause of barrenness, he said. "But they would be better off trying to control pregnancy loss, much of which is disease related, than focusing on nutrition at tupping."
Ms Stubbings said the comfort blanket of mineral supplements could be very expensive. "There is little evidence to support blanket use. Only a small number of farms need to use a specific mineral to improve their barren rate."
Mr Mawhinney added that four out of five flocks had either enzootic abortion or toxoplasmosis. A survey of toxoplasmosis showed that in 74% of flocks at least 20% of ewes had encountered the parasite, which is carried by cats, at some time.
But ewes could be vaccinated against toxoplasmosis using a single dose costing about £2.20 a ewe, he said. In most cases – unless the risk was high – no booster was required, so the average cost was 43p a ewe a year.
Some flockmasters only vaccinate ewe lambs because they are at highest risk of infection, building up protection in the flock over a number of years.
Ms Stubbing added that to be cost-effective, vaccination only needed to reduce the abortion rate by 0.5%.
• Abortion and Infertility in Sheep, A Practical Guide is available free from vets or from Livestock Marketing Services, Intervet, Science Park, Milton Road, Cambridge CB4 0FP. *
Spotlight on organic pigs
ORGANIC pig production is the focus of a new three-year project which aims to provide management advice tailored to different farm situations.
"We are looking at how best to optimise organic pig production – either for established organic producers or commercial producers keen to convert," says Sandra Edwards, a researcher at Aberdeen University and a joint partner with ADAS in the project which has funding from MAFF, PIC, and Tesco.
"Major supermarkets are seeing more demand for organic produce and say they cant source sufficient UK product – its a market available for people to move into."
Researchers will carry out a national survey to establish how organic pigs are being managed, and examine the effects of different breeds in these systems. *
Tup finding service
SHEEP producers purchasing high index rams will be able to use a new Signet service to help them find a tup to suit their flocks needs.
Signets Top Tup scheme will provide East Anglian producers with details of local flocks with high index tups available in their region, says Signets Samuel Boon.
"We will match buyers and sellers, and cut down the time and effort involved in finding good tups." *
CORRECTION
SLURRY at Alvis Bross Stepstones Farm is spread over 243ha (600 acres), not as stated last week. *
Pork pedal power pays off… Bob Beacroft, 73, cycled from Lands End to John OGroats in only eight days, and raised £15,000 for the Samantha Dickson Research Trust. He launched his appeal at the Pig and Poultry Fair (Livestock, May 21).
IN BRIEF
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• DRINKING milk produces stron-ger bones and the effect is long lasting, according to a Milk Devel-opment Council-funded project,
The Sheffield University study involving 80 adolescent girls concluded that drinking 330ml of milk a day increased bone density and mineral content. The results will be used by the National Dairy Council to promote milk drinking to adolescent girls.
• FORAGE additive users have switched to biological silage inoculants in the last six years according to a survey by additive manufacturer Alltech. But the proportion of producers using additives in the survey of 140 farmers has not changed, remaining static at 90%. However, 71% of additive users now prefer biological inoculants compared with 42% six years earlier. *