Sire breed and breed genotype of dam effects in crossbreeding beef cattle in the subtropics. 2. Calving interval and cow productivity

Abstract

The influence of sire breed and breed genotype of dam on calving interval (CI) and cow productivity (CP) in Afrikaner, Hereford, Simmentaler and Bonsmara cattle, as well as in F₁, and two- and threebreed rotational crosses between Afrikaner, Hereford and Simmentaler were investigated. Cows bred to Afrikaner and Bonsmara bulls exhibited longer (P < 0.05) calving intervals than cows bred to Hereford and Simmentaler bulls. Cows bred to Afrikaner bulls were less (P < 0.05) productive than cows bred to other Bos taurus sires. An increase in proportion Afrikaner breeding in dam resulted in longer calving intervals and a decline in cow productivity, but these differences were not always significant. A breeding strategy for the retainment of superior performance is discussed.

Die invloed van vaderras en genotipe van moeder op kalfinterval en koeiproduktiwiteit by Afrikaner-, Hereford-, Simmentaler- en Bonsmarabeeste, asook twee- en drierasrotasiekruise tussen Afrikaner, Hereford en Simmentaler is ondersoek. Die gebruik van Afrikaner- en Bonsmarabulle het 'n langer (P < 0.05) kalfinterval tot gevolg as wanneer Hereford- en Simmentalerbulle gebruik word. Koeie met kalwers van Afrikanerbulle was minder (P < 0.05) produktief as koeie met kalwers van die ander Bos taurus-bulle. 'n Toename in persentasie Afrikanerteling in die koei het 'n langer kalfinterval en verlaagde produktiwiteit tot gevolg gehad, alhoewel die verskille nie altyd betekenisvol was nie. 'n Kruisteeltstrategie om prestasie op hoë vlakke te handhaaf, word bespreek.

Keywords: Calving interval, crossbreeding, dam breed genotype, productivity, sire breed.