IMPROVEMENT OF REPRODUCTIVE PERFORMANCE IN SOWS AFTER CIRCOVAC^® VACCINATION

Hayden J. ¹, Neto R. ², Joisel F.³

¹Integra Veterinary Services, Mundford, Thetford, UK, ² Merial Animal Health Ltd, Woking, UK,

³ Merial S.A.S., Lyon, France

Introduction

Recent studies have shown that PCV2 is involved not only in PMWS, but also in several other disease presentations, including reproductive disorders, deteriorating sow performance (1, 2). The objective of this study was to assess the impact of CIRCOVAC® on the reproductive performance of a sow breeding unit weaning pigs on-site and selling them at 35kg.

Material and Methods

A 1000-sow outdoor breeding unit started vaccinating the breeding animals in May 2007 with a PCV2 inactivated vaccine, CIRCOVAC. The first vaccinated sows farrowed in July 2007. PCVD has been clinically diagnosed on the nursery and finishing units. The number of pigs born alive per litter and weaned per litter was routinely recorded using herd management software.

Historical data, since 2005 were collected. The data were divided into blocks of 6 months from the start of vaccination for the periods before and after. The data were also compared for a period of 1 year before and after PCV2 vaccination was implemented. Statistical analyses were undertaken using the two sample t-test with unequal variances and a two-factor (month and year) analysis of variance. Tests were carried out using proprietary statistical software.

Results

Live born piglets per litter after CIRCOVAC vaccination were increased by 1.425 pigs, p<0.001 (t-test) compared to the period before (2004 to July 2007).

Analyzing the data before and after July 2007 by a t-test shows that there is an improvement in the mean number of pigs of 1.066 pigs weaned per sow per litter after CIRCOVAC vaccination started.

Regarding pigs weaned per sow per litter, (Table 1) there was no significant difference between the first 6 months of 2005, 2006 and 2007 (before vaccinated sows started farrowing) but these were significantly different to the first 6 months of 2008 and 2009 (CIRCOVAC vaccinated sows started farrowing in July 2007), p<0.001.  Similarly that there was no significant difference between the second 6 months of 2004, 2005 and 2006 (before vaccinated sows started farrowing) but these were significantly different to the second 6 months of 2007 and 2008.

The use of CIRCOVAC on sows resulted in an improvement of 0.8 pigs born alive between the 6 months before the use of vaccine and 6 months after, from 10.27 to 11.07 respectively.

Table 1: Six month periods with mean number pigs born alive per litter

The number of piglets weaned per sow per litter was significantly different between the first half of the years 2005, 2006, 2007 and the first half of 2008 and 2009, the mean number of pigs weaned per litter for the periods of July to December 2004 and 2006 was significantly different to the same periods in 2007 and 2008, Table 2.

Table 2: Six month periods with mean number pigs weaned per litter.

Discussion and conclusion

This study shows the benefits of using CIRCOVAC on the reproductive performance of vaccinated sows.

Improving the number of pigs weaned per sow per litter optimizes the sows’ performance. This increase reduces the cost of production and considerably increases profitability (3).

The constant number of pigs born alive and weaned per litter during the post vaccination period indicates that the improvement achieved with CIRCOVAC vaccination resulted in a stable and sustained increase of the number of piglets born alive and weaned per litter.

References

1. O’Connor B. et al, (2001) Can Vet J; 42:551 – 553

2. West K.H. et al., (1999) J. Vet. D. Inv, 11, 6:530-532

®CIRCOVAC is a registered trademark of Merial in the European Union and elsewhere.