Abstract:
BACKGROUND: Reproductive diseases limit the productivity of cattle worldwide and represent an important obstacle
to profitable cattle enterprise. In this study, herd brucellosis and bovine genital campylobacteriosis (BGC) status, and
demographic and management variables were determined and related to predicted calving rate (PrCR) of cattle
herds in Adamawa, Kaduna and Kano states, Nigeria. Serum samples, preputial scrapings, questionnaire data,
trans-rectal palpation and farm records were used from 271 herds. The Rose-Bengal plate test and competitive
enzyme-linked immunosorbent assay were used for Brucella serology and culture and identification from preputial
samples for BGC. A herd was classified as positive if one or more animals tested positive. The PrCR was determined
as the number of calvings expected during the previous 6 and next 6 months as a percentage of the number of
postpubertal heifers and cows in the herd. A multilevel linear regression model was used to estimate the herd-level
effect of Brucella abortus seropositivity, Campylobacter fetus infection and other factors on calculated PrCR.
RESULTS : The reproductive performance of the cattle herds was generally poor: Only 6.5% of the nursing cows were
pregnant and 51.1% were non-pregnant and acyclic; the mean annual PrCR was 51.4%. Brucella abortus and C. fetus
infection of herds were independently associated with absolute reduction in PrCR of 14.9% and 8.4%, respectively.
There was also a strong negative association between within-herd Brucella seroprevalence and PrCR. Presence of
small ruminants, animal introduction without quarantine and the presence of handling facilities were associated
with lower PrCR, whereas larger herd size, supplementary feeding, routine mineral supplementation and care during
parturition were associated with higher PrCR.
CONCLUSIONS : Brucellosis and BGC may be largely responsible for the poor reproductive performance of indigenous
Nigerian cattle. Farmer education and measures to improve the fertility of cattle herds are suggested.
