1) This case report describes a 120-sow farm in Japan that implemented PCV2 vaccination of sows in 2008 and saw a reduction in post-weaning mortality without vaccinating piglets. 2) After sow vaccination, the farm's post-weaning mortality rate decreased substantially from around 20% to an average of 5.2% in 2012, though it fluctuated due to other disease issues. 3) Testing showed that PCV2 viral loads decreased after sow vaccination such that the virus was not detected in pigs of any age three years after vaccination began. Continued sow vaccination provided strong immunity and global protection across the farm.

1. Abstract accepted for 6th Asian Pig Veterinary Society congress, Ho Chi Minh City, Vietnam, September 23-25, 2013
IMPORTANCE OF CONTINUATION OF PCV2 SOW VACCINATION: A CASE REPORT
Mitsuo Kagawa1, Yu Endo2, Fumio Miyagawa3, Tetsuo Kikuiri3, Rie Nagasawa3, Shoji Ogino3
1Kagawa Livestock Clinic, Gunma, Japan; 2Merial Japan Limited, Tokyo, Japan;
3 Nippon Zenyaku Kogyo Co., Ltd., Fukushima, Japan
yu.endo@merial.com
Introduction
It has been shown that PCV2 vaccination of breeding herds protects their piglets against the development of porcine circovirus diseases (PCVD) 1, 2. However, vaccination of piglets has been more widely practiced than that of sows in Japan. This report describes a case of a farm which has continued PCV2 vaccination of sows for almost 5 years, and where PCVD has been successfully controlled without ever vaccinating piglets.
Materials and Methods
The farm is a single-site, 120-sow farrow-to-finish operation, managed under a continuous flow production system, located in Kanto district, Japan. PCV2 vaccination of sows was implemented as of September 2008. Sows were initially mass-vaccinated with CIRCOVAC® (Merial, Lyon, France) twice 4 weeks apart, since then sows received a booster shot 2-4 weeks before farrowing at every subsequent gestation. Piglets were never vaccinated against PCV2. The post-weaning mortality rate was recorded monthly, and blood samples were examined for PCV2 viral load by real-time PCR, before vaccination, and 1 and 3 years after vaccination.
Results and Discussion
As shown in Figure 1, the post-weaning mortality rate was around 20% in the first half of 2008, and the implementation of PCV2 sow vaccination substantially decreased mortality. Although mortality fluctuated due to management problems and other diseases such as porcine reproductive and respiratory syndrome (PRRS) and colibacillosis, average mortality rate was improved year by year, and was 5.2% in 2012. Before vaccination, PCV2 DNA was detected from all pigs apart from suckling piglets, but 1 year after vaccination, it was not detected up to 90 days of age. Moreover, no PCV2 DNA was detected from pigs of all stages (Figure 2).
To make vaccination of sows work, quality and amount of colostrum intake and satisfactory management level are required, and it takes more time to gain beneficial results than vaccination of piglets. The longer vaccination is continued, the stronger immunity breeding herds acquire, which provides global protection of the farm up to slaughter. This case clearly indicates the benefit of continuation of PCV2 sow vaccination.
Literature cited
1. Opriessnig T. et al., 2010, Vet Microbiol 142: 177- 183.
2. Pejsak Z. et al., 2010, Comp Immunol Microbiol Infect Dis 33(6): e1–5
® CIRCOVAC is a registered trademark of Merial in the United States of America and elsewhere
Figure 1. Evolution of mortality rate from weaning to slaughter, before and after vaccination
Figure 2. Mean PCV2 viral load in serum in 2008 (A: before vaccination), 2009 (B: one year after vaccination) and 2011 (C: three year after vaccination); PCV2 DNA was not detected from any serum samples of 2011.
13.9%
6.9%
7.9%
6.1%
5.2%
(A) 2008 (B) 2009 (C) 2011
Sow vaccination start