G. Schramm et A. Aragon, THE EFFECTS OF ENZOOTIC BOVINE LEUKOSIS O N THE ECONOMICS OF CATTLE PRODUCTION IN COSTA-RICA, Tierarztliche Umschau, 49(1), 1994, pp. 26-31
A herd of Jersey cows, located in Cartago, Costa Rica, was studied to
determine the effect of enzootic bovine leukosis (EBL) infection on pr
oduction, reproduction and mastitis. The prevalence and incidence of i
nfection of EBL were for the period 1986 to 1992. Preventive and contr
ol measures, investigated by the herd owner, reduced the incidence of
disease in the herd during this period. No associations between the oc
currence of bovine leukosis and variables representative of production
and reproduction were found. The prevalence of mastitis in cows, with
and without leukosis, was similar. It was concluded that infection wi
th bovine leukosis virus did not have any adverse effects on productio
n, reproduction or the incidence of mastitis in animals with no clinic
al signs of EBL.