E. Rautiainen et al., Varying effects of infections with Mycoplasma hyopneumoniae on the weight gain recorded in three different multisource fattening pig herds, J VET MED B, 47(6), 2000, pp. 461-469
Citations number
30
Categorie Soggetti
Veterinary Medicine/Animal Health
Journal title
JOURNAL OF VETERINARY MEDICINE SERIES B-INFECTIOUS DISEASES AND VETERINARYPUBLIC HEALTH
Pigs in three specialized fattening herds were studied with respect to the
effect of infection with Mycoplasma hyopneumoniae on weight gain. Individua
l pigs were weighed four times at 4-week intervals during the fattening per
iod and their daily weight gain over the rearing period was calculated. A b
lood sample was collected on each weighing occasion and analysed for the pr
esence of antibodies to M. hyopneumoniae. The lungs of the principals were
inspected at slaughter and the extent of pneumonic lesions was registered b
y a specially developed technique that has been proven to warrant a high de
gree of repeatability. No serum antibodies to M. hyopneumoniae were detecte
d in one of the herds, and no pneumonic lesions were recorded at slaughter
in that herd. In the other two herds, the prevalence of pigs with serum ant
ibodies to M. hyopneumoniae increased from 6 to 54% and from 31 to 81%, res
pectively, during the fattening period. The prevalence of pneumonic lesions
at slaughter in these herds was higher the later the pigs seroconverted. O
n the other hand, the extension of the lung lesions tended to be higher amo
ng pigs that seroconverted early during the rearing period. Infections with
M. hyopneumoniae acquired early during the rearing, presumably strengthene
d by secondary infections and environmental errors, was found to decrease t
he daily weight gain of the pigs. However, even non-complicated M. hyopneum
oniae infections acquired late in the fattening period were associated with
reduced daily weight gain. That growth reduction was estimated to be at le
ast 60 g (about 6%) after adjusting for herd, pen, initial weight and sex.