Herd health key to combating circovirus infections
Managing a herd’s overall health status is key to preventing the spread of potentially deadly circovirus between animals, say experts in pig health and nutrition.
Writing in Pig International, independent nutritionist Zoe Kay said that circovirus is associated with a range of pig health problems, and that improving health through biosecurity and nutrition is important in helping animals cope with infection.
Kay said there are a range of nutritional supplements that offer natural antioxidants, as well as botanical extracts that improve immunity.
“[These can] potentially make pigs less susceptible to secondary infections and ensure they recover faster,” she said.
Vaccination programs are also effective, but there are different options depending on the herd and its circumstances, said Brad Leuwerke from the US Swine Vet Center.
While some vaccines only require one dose, others need booster doses, with one-dose products given to piglets prior to weaning, and two-dose programs where the second dose given four weeks later.
“The aim is to create immunity in piglets before they come into contact with the field virus,” Leuwerke said. “If this is successful, then it will protect them for at least the following six months.”
Health and circovirus status will also influence decisions on how and when to vaccinate, as well as whether a herd is breeding or growing stock.
“All incoming replacement gilts should be vaccinated one to two months before entering the herd,” said Leuwerke. “If this is done, then the sows won’t need to be vaccinated again.”
If there has been a breakdown in this routine, a one-off, mass vaccination of the breeding stock is advisable, he added.
Producers can spot problems by reduced conception rates or weak-born piglets. Circovirus can also influence the pattern of disease in piglets.
Unlike some viruses, immunity to circovirus does not pass from the sow to the piglets, so it is essential to have effective strategies to build immunity in breeding and growing herds to reduce the virus’ circulation.
“If producers are seeing problems in growing pigs they should evaluate the effectiveness of their vaccination strategy in both gilts and piglets,” said Leuwerke. “Ensuring that the right dose is given at the right time is the best way to control the disease.”