Produksiepotensiaal van verskillende eerstekruising Afrikanerbeeste

[摘要] English: In the development of crossbreeding systems in beef productionunder South African conditions, more information on the combination ability of various types of exotic beef breeds with theindigenous Africander is of primary importance. For this reasonfour breeds of bulls namely Brahman, Charolais, Hereford andSimmentaler were used on purebred Africander cows in this study.These breeds represented a Zebu type, large frame lean meat type,small frame fat meat type and a large frame dual purpose type ofcattle respectively. Simultaneously purebred Africanders wereproduced as controls. The progeny of the five bull breeds (838in total) were evaluated in respect of duration of gestation,birth and weaning mass. Postweaning growth and development ofsteers as slaughter animals were studied under two productionsystems while the female progeny were evaluated as breedinganimals. Special attention was given to the occurrence ofinteractiombetween sire breed and production system as wellas sire breed and production function.It is apparent that the choice of a breed/type of bull for theproduction of Africander F1-calves is of utmost importance dueto the effect thereof on birth mass. and dystocia. As a resultof the extreme size of the Charolais-Africander calves at birthand the extent of dystocia, the production of this crossseemed not to be of any merit. Furthermore, although this combination of breeds performed very well in a semi-intensive productionsystem, it was found that the female progeny lack in motheringability and cannot be recommended as replacements in herds.The crosses of Brahman, Hereford and Simmentaler bulls, however,proved to be of excellent potential for exploitation underspecific conditions. The Brahman progeny has a dual purposeproduction potential in an extensive production situation as astore animal as well as a replacement heifer. Likewise theSimmentaler cross has a multi-purpose production function interms of replacement heifer and slaughter animal. For the latterpurpose it became apparent that this cross is equally efficientas a fodder animal or store, keeping in mind that it only becomesmarketable at an advanced mass especially under extensive grazingconditions. Hereford crosses proved to be extremely suitable asSlaughter animals, regardless of the production system, althoughit performed especially well under intensive management.

[发布机构] University of the Free State