The effect of subclinical experimental Cowdria ruminantium infection on the health and reproductive performance of breeding ewes

This study documented the effect on the productivity of Dorper-Merino cross ewes when they became infected with Cowdria ruminantium as would occur in an endemically stable state. A flock of 152 breeding ewes was randomly divi ded into two matched groups. One group was infected on multiple occasions w ith C. ruminantium; the other group remained uninfected. The ewes were bred and monitored for one breeding/lambing/weaning cycle. Hematological, repro ductive, and health parameters were recorded at regular intervals. Statisti cally significant differences in hematological values between the two group s were infrequent and transient. No significant differences in weights, mor tality rates or reproductive parameters were detected between the two group s. Subclinical C. ruminantium infection did not negatively affect health an d reproductive performance of breeding ewes; endemic stability would be a s uitable alternative method of controlling heartwater. (C) 1999 Elsevier Sci ence B.V, All rights reserved.