Evaluation of three-breed composites alongside Angus controls for growth, reproduction, maternal, and carcass traits

摘要

Angus cows at two locations were used to generate purebred controls and three three-breed crosses, as a result of inter-mating two-breed (halfbred Angus) crosses. The three-breed crosses were: 25 Simmental, 25 Friesian, 50 Angus (SiFA) from reciprocal matings between SiA and FA crosses; 25 Maine Anjou, 25 Jersey, 50 Angus (MaJA) from reciprocal matings between MaA and JA crosses; and 25 Blonded' Aquitaine, 25 Jersey, 50 Angus (BaJA) both from matings between JA bulls and BaA cows, and from matings between BaJ bulls and A cows. Breed crosses for this experiment were selected as potentially contributing to productive crossbred cows, based on the early years of two-breed cross data. After producing the first generation (F1) of three-breed crosses, each cross was subsequently interbred to produce F2 and F3 calves (202 sire groups overall). There were overlapping generations and contemporary controls, to compare crosses for growth, reproduction, maternal and carcass traits. The three three-breed crosses had greater yearling weights as F1s than contemporary A animals, by an average of 7.5. Calf survival of the breed-types and generations was similar to A, except for SiFA Fl calves which experienced more difficulty and 17 greater birth weights than A calves. Three-breed cross cows were, on average, 7 heavier than A cows as Fls and their calves were 11 heavier at weaning than A calves. On average, the Fl cows showed a 12 advantage over A in calves weaned per cow joined, 24 in productivity, and 16 in productivity adjusted for cow weight (efficiency ratio). For carcass data (BaJA and A only), the BaJA calves were heavier and leaner than A controls. The breed types varied in their advantages in efficiency ratio, relative to A, and this appeared to depend on the pathway and dam genotype used to breed them. The efficiency ratio of contemporary two-breed crosses was similar to that of the three-breed crosses on average. The best breed types were two-breed crosses, so the three-breed crosses were likely to be less favoured by the farmer.