PERFORMANCE OF THREECROSS AND HEREFORD COWS. III. CHARACTERISTICS RELATED TO THE CALF

Abstract

The performance of six groups of threecross and straightbred Hereford cows was studied during a period of six years. The crossbred cows were produced by 1/2 Charolais (C) — Hereford (F1), 1/2 Holstein (Ho) —Hereford (H) or 1/2 Sta. Gertrudis (SG) — Hereford (H) dams mated to Nelore (N) and Angus (A) bulis. The six groups of threecross and the straightbred Hereford cows were artificially inseminated with semen from Hereford bulis. The experiment was conducted at Estação Experimental Zootécnica de Uruguaiana, RS. Birth weight was not affected by the genetic group of the dam (P>0.05) and ranged from 32.9 to 37 kg for the calves produced by the 2/4 N 1/4 SG 1/4 H and 2/4 A 1/4 Ho — 1/4 H cows, respectively. Straightbred H calves had 33 kg at birth. The average weaning weight of the crossbred calvas was 166.7 kg, ranging from 147.2 to 183.1 kg for the calves produced by the 2/4 A 1/4 C 1/4 H and 2/4 N 1/4 Ho 1/4 H cows, respectively. The smallest weaning weight (128.8 kg) was from the straightbred H calves. Age of the calf at weaning was not affected (P > 0.05) by breeding group. Birth weight was higher (P<0.05) for the calves whose grandfathers were of the Angus breed (33.3 vs 33.5 kg), while the calves whose grandfathers were of the Nelore breed had a (P> higher 0.05). (P<0.05) weaning weight (180.7 vs 155 kg). Breed of calf s great grandfather did not affect any of the traits studied