Gastrointestinal nematode infection in Purunã heifers raised in conventional and integrated livestock forest systems

Abstract

ABSTRACT The objective of the study was to evaluate the resistance of Purunã heifers to nematode infection in two different production systems. In this study, 29 heifers were divided into eight pickets, four in an integrated livestock forest system (ILF) and four in a conventional pasture system (CPS). Feces were collected monthly to perform the fecal egg count (FEC), evaluate the degree of infection caused by gastrointestinal nematodes in cattle, and carry out coproculture, to identify the genus of the parasites. In addition, animal body weight was determined to evaluate performance. On the same day as the measurements, forage samples were collected to determine the number of infective larvae per kilogram of dry matter (L3/kg DM) in each picket. There were no statistical differences in FECs between the treatments. Although no significant differences were observed in the recovery of L3/kg DM, the contamination was higher in the ILF compared to CPS in December (344 and 37.7 L3/kg DM, respectively) and January (312 and 0 L3/kg DM, respectively). In March, the CPS (321 L3/kg DM) presented higher contamination than the ILF (80.7 L3/kg DM), but with no statistical difference. The weight of the animals was higher for the CPS compared to the ILF treatment throughout the whole experimental period, with a significant difference in December (343.30 kg and 314.08 kg, respectively). The present study demonstrated numerically that greater numbers of L3 were recovered from pasture of the ILF, which could have resulted in higher contamination and lower performance of the animals.