12 April 2002

Breeders must

Keeping diseases out of

beef herds must start with

those breeding bulls taking

responsibility for diseases

their stock could pass to

commercial herds.

Jeremy Hunt reports

PEDIGREE beef breeders must recognise the important role they play in maintaining the health status of the national herd.

Scottish borders Limousin breeder John Logan believes pedigree producers should adopt a responsible stance over cattle health. "We should lead by example," says Mr Logan, who runs the Homebyres herd with his son John.

But sticking a sign over a bulls pen at a sale informing potential buyers that it has tested free from Johnes disease and Bovine Virus Diarrhoea (BVD) gives no guarantee to the purchaser, says Mr Logan Sr.

"Individual testing doesnt present potential buyers with a true profile of the animals health. It may be appropriate for BVD, but not for Johnes disease.

"Johnes disease is infectious. Cattle must be more than two-years-old before they are tested and the tests must be undertaken on a herd basis and not on individual animals."

Both pedigree breeders and commercial beef producers need to become more aware of how they can improve the health status of their cattle, he adds.

He would like to see a wider uptake of herd health monitoring among pedigree herds and for the benefits to be explained and promoted more vigorously among commercial producers.

The Logan family established their Homebyres Limousin herd in 1984. There are now 60 pedigree cows and 35 commercial sucklers on the 222ha (550-acre) mixed farm just outside Kelso.

The herd consistently produces top-class pedigree bulls for breed society sales and owns a full sister to Broadmeadows Cannon – the most influential Limousin sire of recent times. But the Logan family believes that joining SACs Premium Cattle Health Scheme has made a big impact on the their herds development.

"We felt we had to take a responsible approach to herd health. No pedigree breeder should sell a bull that could die of a disease that could have been prevented or pass on a disease to another herd.

"That was the driving force behind our initial enquiries about monitoring herd health more closely," says Mr Logan.

"At the first scheme meeting we attended someone questioned whether he could afford to join, when it could mean culling some of his best cows if they reacted positively to Johnes screening.

"The rhetorical reply from the SAC was simple: Can anyone not afford to join a herd health scheme? That brought the message home to us."

The two diseases monitored under the scheme are Johnes disease and BVD. Although the Logan family were aware that any positive reactors to Johnes disease would have to be culled, they decided to go ahead.

In the three years since joining the scheme, there have been no positive reactors in the Homebyres herd to either BVD or Johnes disease.

The annual test for Johnes disease is carried out on all cattle at two years old and older. Because there has never been a case of BVD in the herd, annual monitoring is now carried out by testing a randomly selected batch of 10 from each of the youngstock management groups. In addition all cull cows are tested for Johnes before leaving the farm.

"A negative test result for Johnes only shows that the animal will not develop the disease for 10 weeks. But providing the rest of the herd is clear and no other untested stock has been brought in, the risk of infection is kept low."

When a new animal is brought on to the farm, which is rare, it would be isolated and undergo a strict monitoring programme for Johnes disease.

"It costs us about £1000/year – thats about £10/cow. We carry this extra cost primarily for our own peace of mind and not because of any advantage it may give us when we sell bulls.

"Hopefully, were also promoting an image of good health in our cattle and can confidently sell our high health status stock into the herds of commercial producers," says Mr Logan Jnr.

He believes the restocking programme underway in many commercial beef herds hit by foot-and-mouth presents an ideal opportunity to set new standards for herd health. &#42

BULL HEALTH

Breeders to lead way.

Correct ways to monitor.

Johnes and BVD tested.

SAC disease notes

Johnes disease is a progressive wasting condition with the infectious agent spreading the disease rapidly through faeces, says SAC.

Youngstock are particularly vulnerable to contracting Johnes disease, but clinical signs such as weight loss and diarrhoea are most commonly seen in animals over 18 months old. This can lead to a high fatality rate of cattle between two and four-years old.

It adds that vaccination can be used to control the disease in badly affected herds, but it will only keep it under control and will not remove the infection.

Bovine Virus Diarrhoea (BVD) is another potentially fatal disease which affects the reproductive system and fertility and leads to mucosal disease. It can also cause embryo loss and reduce conception rates, warns SAC.

Embryos infected with BVD during the first third of the pregnancy can survive but will remain infectious. They will appear normal at birth and develop with no adverse reaction, but will spread the virus among the herd. Bulls infected with BVD can spread the virus through semen.

Individual bull testing for Johnes disease cannot give a guarantee to the purchaser – herd testing is the only option, believe the Logans.

&#8226 Breeders to lead way.

&#8226 Correct ways to monitor.

&#8226 Johnes and BVD tested.

Johnes disease is a progressive wasting condition with the infectious agent spreading the disease rapidly through animals faeces, says SAC.

Youngstock are particularly vulnerable to contracting Johnes disease, but clinical signs such as weight loss and diarrhoea are most commonly seen in animals over 18 months old. This can lead to a high fatality rate of cattle between two and four-years of age.

It adds that vaccination can be used to control the disease in badly affected herds, but it will only keep it under control and will not remove the infection.

Bovine Virus Diarrhoea (BVD) is another potentially fatal disease which affects the reproductive system and leads to mucosal disease. It can also cause embryo loss and reduce conception rates in cows, warns SAC.

Embryos infected with BVD during the first third of the pregnancy can survive, but will remain infectious. They will appear normal at birth and develop with no adverse reaction, but will spread the virus among the herd. Bulls infected with BVD can spread the virus through semen.

SAC disease notes