Costly abortion losses prompt effective action

16 July 1999




Costly abortion losses prompt effective action

By Marianne Curtis

SHEEP abortion cost one Co Durham producer over £7000 last year, but he is now well on the way to cracking the problem.

Lamb losses had been creeping up on Brian Medds West Whorley Hill Farm, Barnard Castle, Co Durham. "Everyone gets the odd abortion. We grew from 100 to 600 ewes over five years. You do not notice numbers of dead lambs; I never counted them."

Based on the principle that you cant quantify lamb losses if you do not record them, vet Fiona Hatchell of Castle Vets, Barnard Castle, persuaded Mr Medd to try recording last year. This looked at lambs born alive and dead, abortions and lambs dying at less than a week old and more than a week old.

Identifying the extent of an abortion problem means attention to detail in record keeping is vital, says Miss Hatchell. "Abortion can be the cause of barren ewes, mummified foetuses, or weak live lambs which may die in the first few days of life. There may also be more singles than expected due to early death of an embryo."

At first, Mr Medd thought record keeping would just add to the work-load at lambing. "Keeping records is a minefield and I thought, no way. But if you want to save money you have to do it in the same way that you have to feed your ewes."

The results proved an eye-opener. There were 65 stillbirths, 37 aborted foetuses, 25 lambs deaths at less than a week old, 56 barren hoggs and 15 barren ewes in the flock.

"Assuming hoggs should have had singles and ewes, twins, the total losses which could be related to infectious abortion amounted to 213 lambs – 20% of the lamb crop," says Miss Hatchell. That amounts to over £7000 based on the MLCs 1998 average finished lamb price of 89p/kg liveweight.

Hogg performance last year was exceptionally bad. "We breed our own replacement Mule hoggs from bought-in Swaledales. "Last year, 56 of the 80 hoggs were not in-lamb. I thought they had not tupped properly but Fiona took blood samples from four and all were infected with toxoplasmosis.

"Even if they had only had one lamb each we would have made an extra £1900 from lamb sales, which is a lot of money."

The turning point came when Miss Hatchell advised Mr Medd to implement a vaccination programme. "We decided to vaccinate all ewe lambs with toxoplasmosis vaccine eight weeks before tupping last year, and with enzootic abortion vaccine four weeks later," she says.

Hogg performance rose considerably this year, according to Mr Medd. "Of this years 73 hoggs, all but two have lambed."

But hoggs are not the only susceptible group in a flock and buying in sheep poses a significant risk, warns Miss Hatchell. "Locally, the increasing prevalence of enzootic abortion is such that any farm buying draft ewes of unknown origin or enzootic abortion status would be lucky not to have introduced it by now."

As a precaution, all last years bought-in Swaledales were vaccinated with both vaccines simultaneously because there was no time to separate them before tupping. "This is not recommended, but is acceptable if vaccines are injected into different sides of the ewe."

Once a ewe has been infected with enzootic abortion she will continue to shed chlamydia – the bacteria causing the abortion – for up to six weeks, which can be picked up by other ewes or lambs, she says. "Some infected ewe lambs will abort during their first pregnancy. Gimmer lambs destined for breeding should not be fostered on to ewes which have aborted because they will abort their first lambs. Only lambs to be used as tups or finished should be fostered on to these ewes."

Because ewes infected with enzootic abortion continue to pose a risk to the whole flock, vaccinating every breeding ewe will minimise losses from the disease, she advises.

"Ideally, the entire flock should be vaccinated against enzootic abortion, but at £3.50 a dose the cost can be prohibitive. To reduce costs at West Whorley Hill Farm, we vaccinated the ewe lambs, shearlings and two shears four weeks before tupping."

In four years time, through continuing to vaccinate ewe lambs and bought-in ewes, Mr Medd reckons the whole flock will be protected against toxoplasmosis and enzootic abortion.

"From now on vaccination will be small money. Assuming you replace a fifth of the flock each season, the cost of vaccinating against toxoplasmosis and enzootic abortion works out at about £1 a head a year, but could save you thousands through reduced lamb losses," he says.

Recording losses will become part of the lambing routine at West Whorley Hill Farm and Castle vets will assist with the process by supplying record sheets at lambing time. &#42


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