A PILOT-STUDY OF ELEVATED ABORTION AND STILLBIRTH RATIOS IN CATTLE INTHE FOOTHILLS OF THE EASTERN PLAINS OF COLOMBIA

Health and production monitoring of around 80 commercial cattle enterp rises in the foothills of the Eastern plains of Colombia showed that a bortion and stillbirth ratios exceeded 0.10 in about one-quarter of th e farms. A case-control approach comparing three farms with elevated a bortion/stillbirth ratios (at least 0.10) with six farms with low rati os (0.03 or less) was adopted for an initial appraisal of the possible role of various infectious as well as non-infectious causes. The abor tion histories and estimates of the age of the aborted fetuses were co mpiled from the available records. Management practices and environmen tal variables were assessed using a questionnaire. Laboratory examinat ions were carried out on a sample of 30 female cattle from each of the nine farms (serology for Brucella abortus and Chlamydia psittaci, fiv e serovars of Leptospira interrogans, and infectious bovine rhinotrach eitis virus) and the breeding bulls (isolation attempts of Trichomonas fetus, Campylobacter fetus, and Haemophilus somnus). The prevalence o f antibodies to Chlamydia psittaci was significantly lower and the ser oprevalence of Leptospira interrogans serovar hardjo was significantly higher on the case farms while no distinct differences were found for any of the other variables examined. On two of the case farms, 28.3% of the cattle had titers of at least 1:400 to serovar hardjo as oppose d to 2.2% of cattle on the control farms (P < 0.01). On these two farm s 36% (10/28) of the abortions occurred in the second trimester of ges tation while on the third case farm most abortions occurred around ter m at the end of the dry season.