Sire breed and breed genotype of dam effects in crossbreeding beef cattle in the subtropics. 1. Birth and weaning mass of calves

Abstract

The influence of sire breed and breed genotype of dam on birth and weaning mass in calves of Afrikaner, Hereford, Simmentaler and Bonsmara cattle, as well as F₁, and two- and three-breed rotational crosses between Afrikaner, Hereford and Simmentaler were investigated. Afrikaner bulls sired calves with lower birth and weaning mass (P ≤ 0.05) than other breeds of sire. In terms of weaning mass, all the crossbreeding systems proved superior to purebred Afrikaner and Hereford breeding, but not to purebred Simmentaler and Bonsmara breeding. Simmentaler dams produced calves of heavier (P < 0.05) birth mass than other purebreds. An increase in percentage Afrikaner breeding in the dam led to a reduction in birth mass, while the reverse applied to an increase in Simmentaler breeding. Cows of predominant Simmentaler breeding tended to wean heavier calves than cows of predominant Afrikaner breeding.

Die invloed van vaderras en genotipe van moeder op die geboorte- en speenmassa van Afrikaner-, Hereford-, Simmentaler- en Bonsmarakalwers, sowel as F₁, en 'n twee- en drieras-rotasiekruising tussen Afrikaner, Hereford en Simmentaler is ondersoek. Afrikanervaders het kalwers met laer geboorte- en speenmassas (P ≤0.05) geproduseer as ander vaderrasse. Ten opsigte van speenmassa het al die kruisteeltstelsels beter as die suiwer Afrikaner en Hereford presteer, maar nie beter as suiwer Simmentaler en Bonsmara nie. Simmentalermoeders het kalwers met hoër (P < 0.05) geboortemassas as ander suiwer rasse geproduseer. 'n Toename in die persentasie Afrikanerteling het 'n afname in geboortemassa tot gevolg gehad, maar die teenoorgestelde is gevind vir 'n toename in Simmentalerteling. Koeie van oorwegend Simmentalerteling het swaarder kalwers gespeen as koeie van oorwegend Afrikanerteling.

Keywords: Birth mass, crossbreeding, dam breed genotype, sire breed, weaning mass.