Forty eight cows of Holstein-Zebu crosses with at least one completed pregnancy were tested for antibodies to 20 disease agents. The testing was performed within one month (average two weeks) after calving when the IgG level constantly reaches its lowest value during the cows reproductive cycle. The results indicate that increasing levels of IgG against Leptospira interrogans serovar hardjo and Mycobacterium paratuberculosis may be associated with an increased calving interval. Increase in calving intervals could not be explained by age of cows or their genotypic characteristics.
A cohort of 125 cows (Zebu-Holstein crosses) were screened every two months during a period of two years for IgG antibodies to 20 viral, bacterial, rickettsial and parasitic agents. The screening was performed on sera using the ELISA procedure. The IgG levels fluctuated during pregnancy in a regular and similar way for all the antigens tested. IgG reached its lowest levels in the fourth and seventh month of pregnancy, a significant increase ocurred during the last month of pregnancy and this was followed by a precipitous decline during the first month post partum. The IgG fluctuations associated with the different phases of reproductive status may interact with seasonal changes in IgG levels. The changes in IgG levels during pregnancy may have the result that an individual animal oscillates between being seropositive and seronegative. This can have an important impact on serological studies of abortion epidemiology.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.