Lungworm data highlights need for prevention
Lungworm data highlights need for prevention
A RECENT survey on 10 Cheshire dairy farms showed nearly all yearling heifers had been exposed to lungworm.
This demonstrates that prevention planning is vital to avoid potentially large financial loss, says the vet practice which carried out the survey.
Final year vet student Sally Wilson blood sampled five heifers from each of 10 dairy clients of Cheshire-based vet practice Lambert, Leonard and May. Heifers were at the end of their first grazing season.
In nine out of 10 herds, all tested heifers had antibodies to husk showing they had consumed larvae which can bring about the disease while grazing. In one, three animals had antibodies and two were negative, says Miss Wilson.
"In the case where three animals were positive and two negative, this showed husk was on the farm and the negative animals were clearly at risk, making it easy to advise him to vaccinate."
But in herds where all tested animals had antibodies to husk, this did not necessarily mean they were immune to the parasite, she adds. "Although antibodies show animals are likely to be immune to husk at the time of testing, immunity is only short lived. Cattle need constant exposure to husk larvae to generate antibodies and may not cope with a sudden high larval challenge."
Level of challenge from husk also varies from year to year, warns Miss Wilson "We still do not completely understand the disease."
The consequences of infection in heifers and adult cattle can be devastating, she says. "An outbreak sets back young heifers. For infected adults – in herds that do not vaccinate – milk yield falls and having to treat with anthelmintics can lead to financial loss through having to observe long withdrawal periods. Cattle may also die in severe cases."
Den Leonard, of the practice, advocates worming heifers well in their first grazing season and vaccinating against husk before turnout in the second. "Most farms worm frequently in the first grazing season and only occasionally in the second. Frequent worming will protect cattle against husk in the first season. Vaccinating in the second, allows them to develop immunity to the disease, particularly when worming is less frequent." *