November 2023 Newsletter
With the clocks going back last weekend, it seems as though Winter has crept up on us once more, with many stock now housed.
The winter housing season is always when we see an increase in the incidence of pneumonia. Both dairy and beef herds can find this challenging to manage at this time of year. High humidity and relatively mild temperatures allowing bugs to flourish plus mixing up of groups and weaning adds to stress and compromises immunity; a perfect storm. Trying to reduce the stresses are crucial to helping reduce the incidence of disease. We have a large armoury of vaccines at our disposal covering a multitude of viruses and bacteria. Unfortunately, there isn’t a one size fits all so it requires some thought as to which vaccine is most appropriate for a given situation. Diagnostics help us formulate a plan along with knowledge of the most likely bugs for a given group. If we use antibody tests then ideally we need a blood sample at the onset of a pneumonia case and another in around 3 to 4 weeks to see if the level of antibodies rise in response to disease. A dead calf gives us a valuable opportunity to take some lung tissue for PCR analysis and is often the easiest and quickest method of reaching a diagnosis.
Liver fluke can be a challenge diagnostically, unfortunately no test on its own will give us all the information we need at all times of year, so we need to use a combination of different tests and information from other sources. When we need to first treat for acute fluke in sheep, animals sampled will show no eggs on a faecal egg count because fluke need to be at least 10 weeks old to lay eggs; it is therefore, unhelpful to look at the muck. Antibody testing of lambs in the Autumn can be a useful tool to tell us about fluke exposure on farm when treatment is otherwise little better than guesswork. Cattle and sheep develop antibodies to liver fluke within a few weeks of being infected for the first time. Although these antibodies give no protection to the animal, we can use them to show that an animal has been infected. This is the test that will detect liver fluke earliest after infection, but as the antibodies last for months, they will still be present after successful treatment. It is therefore best reserved for new-season lambs as they can only have developed antibodies to fluke infection in the current year. A positive result in older animals is fairly meaningless due to previous exposure. The antibody test can detect antibodies from just 2 weeks after fluke infection, at the early immature stage. It is best used at the beginning of the fluke season to detect when the infectious stages (metacercaria) are starting to appear, and therefore, the risk of infection for cattle and sheep is starting. The test may need to be repeated as time progresses until a positive is seen. Once they test positive for fluke antibodies, there is a risk to all animals grazing those areas and treatment can be commenced. The results will not tell us how many liver fluke are there, only that the animal has met a fluke. If you need help with Fluke control please feel free to contact us for a chat.
We have a number of meetings coming up, please call to book your place. We would love to see you at any of these events.
BVD Control– Thurs 16th November, 7.30pm. Priddy Good Café, Townsend Farm, Priddy BA5 3BP.
Rearing ‘Beef from Dairy’ calves –Thurs 30th November, 7.30pm. The Surgery, Nates Lane, Wrington.
Dairy Cow Lameness with Nutrition – Weds 6th December, 11am. The Surgery, Nates Lane, & Pine Farm, Wrington.
Red Tractor Medicine Course – Weds 13th December 11-1pm, The Surgery, Nates Lane, Wrington.