In this month’s Vet Viewpoint, vets warn of increasing cases of mastitis and fluke and explain how to accurately diagnose and treat cases.
Hannah Fletcher from Warwickshire also sheds some light on what may be causing poor growth rates in lambs.
And with resistance to triclabendazole now widespread, vet Ken Wilson explains how farmers can check their drench is working.
Rosevean Veterinary Practice, Penzance, Cornwall
We have been dealing with several herds over the past few months that have had increased numbers of mastitis cases. Mastitis is caused by either environmental or contagious pathogens.
The control programmes for each type are different, so it is important to identify what is causing the mastitis on your farm.
We find the two most useful tools for identifying the cause of mastitis are milk samples from clinical cases and accurate mastitis records. It is best to take a sample from each clinical case of mastitis and freeze it.
This means if any investigations are needed there are suitable samples ready for immediate analysis. To get mastitis cases into a format that is easy to analyse, it is best to submit the cases each month at milk recording. It is then easy for your vet to carry out any analysis required.
Fenton Vets, Haverefordwest, Pembrokeshire
Recently, we have seen a few cases of black disease in lambs and the Wales Veterinary Science Centre has reported three cases in the past two months, including a beef heifer that was found dead and a nine-year-old Friesian cow which died after a short period of illness.
Black disease is caused by Clostridium novyi. It causes illness in a similar way to other clostridial diseases by taking advantage of damaged tissues.
In this case, it is associated with damage caused to the liver by migrating liver fluke larvae.
This has been another wet year following a mild winter, so we are seeing a significant fluke challenge earlier than we would expect.
To control black disease it is important to have a plan for fluke control, focusing on tackling immature flukes and considering a clostridial vaccine that protects against Clostridium novyi.
DS McGregor and Partners, Thurso, Caithness
Autumn sees the annual increase in acute liver fluke in sheep.
Triclabendazole drenches are widely used to control acute liver fluke, but resistance to triclabendazole is becoming increasing widespread.
This can have very severe consequences if treatment fails. To prove that triclabendazole works in your flock every year before it is required, a group of 10 ewes are tested as follows:
1. Confirm via dung sample that they are currently infected with liver fluke.
2. Take individual dung samples from 10 ewes before treating with triclabendazole.
3. Submit samples to your vet for testing of fluke coproantigen.
4. 14 days later the same 10 ewes’ dung is sampled again.
5. Again, submit samples to your vet.
If the test indicates triclabendazole resistance, it is critically important to review your fluke control strategies with your vet.
Midshire Veterinary Group, Nuneaton, Warwickshire
A number of farmers have complained of lean lambs and poor growth rates this summer.
Cobalt deficiency is a common cause and is often underdiagnosed. Cobalt is needed for the production of vitamin B12, which is necessary for energy production, fleece and body growth.
If the soil is low in cobalt then the grass will have low levels too and lambs will be deficient.
Lambs present in poor body condition and are unable to fatten despite good grazing. Other symptoms include an ocular discharge, poor fleece, scouring and anaemia. Lambs will die if not treated correctly.
Cobalt deficiency is also a cause of poor fertility in ewes. Blood sampling six to 10 lambs will ascertain whether cobalt supplementation is required.
Oral supplementation of cobalt in the form of a bolus or drench is required in areas with low cobalt levels. B12 injections may be needed in severe cases.