Benefit of piglet PCV2 vaccination in a herd with subclinical PCV2 infection

Based on serological studies, it is assumed that PCV2 is ubiquitous in the pig industry across the world. The purpose of this study was to evaluate the benefit of PCV2 piglet vaccination on ADG and mortality rate from weaning to slaughter in a herd subclinically infected with PCV2.

The study was conducted in a farrow to finish farm located in Brittany, France, positive for PRRSv, PCV2, APP, Mycoplasma hyopneumoniae, and Lawsonia intracellularis. The mortality rate from weaning to slaughter was below 5%. The ADG from weaning to slaughter puts the farm in the upper third among Brittany swine farms. Before the start of the study pigs of 120 and 140 days of age (doa) were tested positive for PCV2 by PCR. In total 929 piglets from 4 farrowing batches were included in the study. At 20 doa, one day before weaning, piglets were individually weighted, ear tagged and randomly allocated to either Group V (Vaccinated Group, N=465) or Group C (Control group, N=464). Piglets from Group V were injected with 1 ml Ingelvac CircoFLEX® by the intra-muscular route. Piglets from Group C did not receive any vaccine. The farm staff was blinded to treatment. To determine the course of PCV2 infection ten randomly selected pigs per group and per batch were designated as sample animals. In total 80 sample pigs were serially bled at inclusion, end nursery, mid and end finishing. Samples were assayed by PCV2 quantitative PCR. The primary parameters of this study were ADG and mortality rate from weaning to slaughter. Individual carcass data were collected at slaughter. Live weight at slaughter was calculated back from the carcass weight and was used together with the individual slaughter age to calculate the wean-to-slaughter average daily gain (ADG w-s). Data were analyzed using the statistical software Mintitab® (version 17). Data from the groups were compared using a t-test.

PCV2 viremia was confirmed by PCR on serum samples in animals of treatment group C of all 4 batches. The level and duration of viremia varied from batch to batch. In total, 17 pigs died during the study, 9 in the vaccinated group and 8 in the control group. ADG from weaning to slaughter was significantly greater in Group V than in Group C, 719,11 vs 708,05g respectivly (p< 0.05).

This study demonstrates the benefit of PCV2 piglet vaccination on ADG in a farm having already good technical results and in which PCV2 infection was not suspected to impair the performances. In the present study it was not able to determine FCR but it could be speculated that it can also be improved by vaccination as Correge et al. showed.

Disclosure of Interest: None Declared.