By Ben Strugnell
Specialist vet with the Eblex/John
Warren ABP post-mortem project

WEATHER conditions have continued to be good and beef and sheep at grass have continued to do well.

Recent wet weather has resulted in a spike of parasitic gastroenteritis cases in sheep, the small intestinal Trichostrogylus may be one of the worms responsible now, or later in the year.

These worms have a habit of developing resistance to wormers. When dosing lambs, don’t miss the opportunity to screen for resistance by doing a worm egg count at suitable intervals after treating (seven days after a yellow drench, ten to 14 after a white drench and 14-16 days after a clear drench). For more information consult your vet or visit the SCOPS website at scops.org.

uk/anthelmintics-testing-forresistance.

html During this project, several cases of the important “iceberg’”

diseases of adult sheep, such as Johne’s disease and Ovine Pulmonary Adenocarcinoma (OPA) have been diagnosed. Usually, affected flocks have taken steps to address or further investigate the problems. OPA is caused by a virus that leads to slowly growing tumours in the lungs, which cause poor breathing and weight loss.

They are called “iceberg” diseases because by the time you see signs of them they have already been present in that sheep (and probably others) for some years. Weaning time is a good opportunity to further investigate whether they are present.

Johnes can be screened for by taking a pooled faeces sample from ewes and sending them off for a test (PCR) which detects the causal bacterium.

OPA is more difficult to screen for and although some progress has been made with ultrasound scanning, post-mortem examination remains the best way to confirm a diagnosis.

Although it may seem a waste and loss of return, postmortem examination of some of the thinnest cull ewes, which may not be worth much as culls, could be cost-effective in the long term to assess your status for these diseases.

Weaning time is another opportunity to think about Border disease, especially if you have had any hairy shakers or are disappointed with lamb performance. Lambs which are poor for no apparent reason can be screened for Border disease.

Other sheep related things to look out for include pasteurellosis in hoggs intended for overwintering, which has just started to crop up as a cause of death. Diagnoses in suckler calves out at grass have been varied with no major themes although, as mentioned before, trace element status is important, particularly in cattle due to be housed. Now may be the time to blood sample a few calves to ensure that no supplementation is required prior to housing. For project details and post-mortem prices, contact Ben Strugnell on 07899 950372 or Warrens ABP, Hamsterley, County Durham.