Exploratory field study on the effects of porcine circovirus 2 (PCV-2) sow vaccination at different physiological stages mimicking blanket vaccination

Abstract

Background The objective of the present study was to explore the benefits of Porcine circovirus 2 (PCV-2) blanket vaccination in a sow herd on productive parameters, PCV-2 infection and immune status in sows and their progeny. For this purpose, 288 sows were distributed among four balanced experimental groups. One group remained as negative control group and the other three received 1 mL of PCV-2 Ingelvac Circoflex® intramuscularly at different productive cycle moments: before mating, mid gestation (42–49 days post-insemination) or late gestation (86–93 days post-insemination); phosphate buffered saline (PBS) was used as negative control item. Reproductive parameters from sows during gestation and body weight of their progeny from birth to weaning were recorded. Additionally, blood was collected from sows at each vaccination time and piglets at 3 weeks of age. Moreover, up to 4 placental umbilical cords (PUC) per sow were taken at peri-partum. Sera from sows and piglets were analysed for PCV-2 antibody detection using an enzyme-linked immunosorbent assay (ELISA). Sera from sows and PUC were tested to quantify viraemia using a real time quantitative polymerase chain reaction (qPCR) assay. Results Globally, results indicated that vaccinated sows showed heavier piglets at birth and at weaning, less cross-fostered piglets, lower viral load at farrowing as well as in PUC, and higher antibody levels at farrowing, compared to non-vaccinated ones. When all groups were compared among them, sows vaccinated at mid or late gestation had heavier piglets at birth than non-vaccinated sows, and lower proportion of PCV-2 positive PUC. Also, cross-fostering was less frequently practiced in sows vaccinated at pre-mating or mid gestation compared to non-vaccinated ones. Conclusions In conclusion, the present study points out that PCV-2 sow vaccination at different time points of their physiological status (mimicking blanket vaccination) offers benefits at production and serological and virological levels.

Descriptive analyses of maternally-derived antibody levels against porcine circovirus 2 (PCV-2) in 3- and 21-day-old piglets from farms of four European countries using different vaccination protocols in sows

“…In line, the results reported in the present study suggest the number of animals with very high PCV-2 titers elevated enough to interfere with vaccine efficacy in terms of AWDG would not be negligible when the sows are vaccinated. Obviously, this situation will depend on the gestational time of vaccination, since it would not be the same to vaccinate early during gestation or during late gestation [ 20 ] and, probably, on the vaccine used. In the present study, information on the exact moment of gestational time of vaccination was not available as sow PCV-2 vaccination was mostly done in a blanket fashion in Italy and Spain; in the case of France sow vaccination was mainly applied before farrowing (range of 2–12 weeks pre farrowing) while in Germany the time of sow vaccination was variable depending on the farm.…”

“…Further studies comparing the level of MDA in piglets coming from sows vaccinated at early or late gestation would be required. Nevertheless, in a blanket fashion vaccination, all possibilities may be represented [ 20 ]; in any case, sow vaccination close to the farrowing time would result in the highest MDA titres in piglets.…”

“…In line, the results reported in the present study suggest the number of animals with very high PCV-2 titers elevated enough to interfere with vaccine efficacy in terms of AWDG would not be negligible when the sows are vaccinated. Obviously, this situation will depend on the gestational time of vaccination, since it would not be the same to vaccinate early during gestation or during late gestation [20] and, probably, on the vaccine used.…”

Revisiting Porcine Circovirus Disease Diagnostic Criteria in the Current Porcine Circovirus 2 Epidemiological Context

“…While the outcome of PCV-2-SI in postweaning pigs is well-established and measurable, no solid data exist regarding subclinical infection on the reproductive side. Some studies tried to determine the impact of such intrauterine infections in farms with no overt reproductive clinical signs, but unequivocal, conclusive and reproducible effects have not been sufficiently documented [ 25 , 26 ]. Therefore, the impact of the subclinical PCV-2 intrauterine infections is yet to be elucidated.…”

“…The use of qPCR has been expanded to other sample types such as oral fluids, placental umbilical cords, processing fluids or tissues and environmental samples [ 26 , 43 , 52 , 53 ]. This approach is excellent for monitoring, surveillance and epidemiological purposes, but it does not allow the establishment of disease diagnoses.…”