Risk factors relating to helminth infections in cows during the peripartum.

The aim of this study was to investigate whether season, lactation number, breed standard and milk production were risk factors relating to occurrences of gastrointestinal nematodes in dairy cows during the peripartum period. Eighty-four cows were randomly selected through proportional stratified sampling. In order to analyze the fecal egg per gram (EPG) count, the data were subjected to the Spearman test, Kruskal-Wallis test at 5% significance and linear regression. At the time of calving, the cows showed high EPG counts in relation to all variables analyzed. Among the animals studied, we observed that purebred Holstein cows at their first lactation and with high milk production showed high EPG counts (600) and comprised the group most at risk within the herd studied. In this group, the animals showed moderate EPG during the prepartum period (300) and a significant increase (p < 0.01) in EPG count from the time of calving (900), i.e. an increase of the order of 300%. Selection of animals for milk production in tropical countries should be based not only on productive potential, but also on adaptive features.