A case study: Oral Pro Vitamin D3 plus E to aid in control of PRRS virus circulation in three sow farms

摘要

Porcine reproductive and respiratory syndrome virus (PRRSv) has been infecting sows and pigs on farms for decades. Sometimes a producer will decide to eliminate it by depopulating, cleaning the premises, and starting over with a source of negative gilts. Unfortunately, this negative herd is just as susceptible as the previous herd. Sometimes it is better to just learn how to live with the virus. Being infected by one strain of PRRSV may not provide much protection when a different strain infects theanimals. For some producers, the goal is not to eliminate PRRSV. Rather, the goal is to live with it and wait for herd immunity to develop resulting in production of PRRSV-negative offspring. Instead of waiting, the producer may want to intervene in an attempt to shorten the time-to-negative-pig (TTNP) interval. A recent study looked at TTNP using herd closure and intervention with virulent resident virus (LVI) or MLV vaccine.1 Measuring from the first day that intervention was administered, researchersfound the median TTNP was 27 weeks across both interventions and the range was 12 to 43 weeks. Herds using LVI reached TTNP significantly (P < 0.05) earlier than those using MLV (median 25 weeks and 33 weeks respectively). Additionally, herds with a history of previous outbreaks reached TTNP about 9 weeks sooner as compared to naive herds breaking for the first time. It can take a long time between PRRSV outbreak in a sow herd and producing negative pigs. Any intervention that will help reduce the TTNPrepresents real economic gain for the producer and an improvement in the health and welfare of the animals.