Performance, body development and ingestive behavior of Nelore and crossbred heifers finished in a grazing system.

Abstract

The aim of this experiment was to evaluate growth, body development and ingestive behavior of Nelore and crossbred heifers. Twenty-two contemporary heifers (eight Nelore, seven Nelore × Angus (½ Angus) and seven Nelore × Pantaneiro (½ Pantaneiro) crosses) were evaluated. The variables evaluated were weight, subcutaneous fat thickness [assessed by ultrasound in the longissimus dorsi (SFT) and biceps femoris (SFTP8)] morphometric measures and ingestive behavior (determined between 7 am and 5pm). The daily gain differed between the breeds (P < 0.05), being greater for the ½ Pantaneiro than Nelore and equal to ½ Angus at the end of the study. The ½ Angus heifers differed (P < 0.01) from the other breeds for SFT (4.36mm), with no difference between Nelore (2.77mm) and ½ Pantaneiro (3.38mm). The SFTP8 was greater (P < 0.01) (5.36mm) in ½ Angus heifers than t others crossbreed, and greater in ½ Pantaneiro than in Nelore (4.28 vs 3.29mm). The heart girth and rump width between the ilia were larger (P < 0.01) for the ½ Angus than ½ Pantaneiro and Nelore (169cm; 41.6cm, respectively). Substernal height was greatest (P < 0.01) for the Nelore (69.1cm), reflecting the greater anterior and posterior height. The ½ Angus spent the longest time (P < 0.05) walking and less time grazing. Idleness also differed (P < 0.05) throughout the day. Crossbred heifers exhibited better performance and development than Nelore. The grazing pattern of ½ Pantaneiro heifers was identical to Nelore, but walked less, gained more weight, and exhibited better carcass finishing.