Relationship of weight gain with infrared temperatures in Nelore and F1 (Nelore × Angus) heifers reared in two forage production systems1.

Intensive production systems require high-yield genetics as obtained in Bos taurus × Bos indicus crossbreeding. Generally, high-producing taurine cattle are more susceptible to parasites and heat stress. This study evaluated animal performance, heat-stress measurement (infrared temperatures), and internal parasite infection with daily weight gain in heifers from 2 genetic groups (Nelore and F1-Nelore × Angus) reared in 2 forage production systems (with or without crop-livestock system) during 1 yr.