Autumn is here, so it’s time for parasite issues to flare up again.
Liver fluke is a parasite that is pretty common on the West Coast. The life cycle of the parasite (properly called Fasciola Hepatica) is slightly different from other parasites as it involves a small snail as a host.
The adult fluke ‘graze’ on the lining of cattle and sheep bile ducts and livers, creating an inflammatory reaction and scarring. This results in protein loss and anaemia, which can cause chronic wasting.
Fluke snails live in areas with reasonably clean, slow-moving water sources that typically do not dry up in summer. The snails predominately thrive from late summer through to early winter, and this is when the most juvenile flukes are ingested by livestock as they graze in the areas where the snails live. Fluke infections are often worse after dry summers, when normally wet snail habitat is grazed!
Photo 1: Liver fluke damage in liver slices.
Credit Ridgeway Research.
Ostertagia is the most significant parasite in cattle in New Zealand. It is a stomach worm that survives across a range of environments. Larval numbers peak in autumn, so disease is often seen at this time of year.
Ostertagia can cause considerable harm to the fourth stomach by reducing nutrient absorption, which leads to a significant decrease in milk production.
Photo 2: Ostertagia damage in the fourth stomach – this sample is from a sheep.
Credit Farmer’s Weekly.
Heading towards late autumn and winter, feed is getting less abundant and farmers are calculating feed budgets. To ensure your animals are not sharing their food with either of these internal parasites, we recommend testing your bulk milk for antibodies. If antibody levels are high, treatment is strongly recommended. As all liver fluke treatments have a milk withhold, treating after drying off is your best option to remove these
extra ‘eaters’.
If you want to do the annual bulk milk test for Ostertagia and liver fluke this autumn, get in touch with the clinic. We then provide recommendations specific to your farm, depending on results.
