Towards an understanding of the concept of genotype-dietary interaction

Abstract

Die begrip genotipe-voerinteraksie is van besondere belang by veral twee fasette van die vleisbeesbedryf: prestasietoetsingv an bulle en die seleksie- of ontwikkeling van geskikte genotipes vir bepaalde produksiestelsels. Ten opsigte van prestasietoetsing het die resultate getoon dat genotipe-voerinteraksie die merieterangorde van bulle kan wysig. Gevolglik is dit wenslik dat bulle verkieslik binne die voedingsmilieu waarin hulle aangehou word, getoets moet word. Ten opsigte van die begrip soos moontlik van belang in produksiestelselsb lyk 'n herevaluasie van sommige resultate in die literatuur iungewese te wees. Wat moontlik as genotipe-voerinteraksie geihterpreteer is kon bloot die gevolg geweas het van onvoldoende begrip van die invloede van skaling vir grootte, die  multiplikatiewe (kromlynige) aard van groei en die differensiele grootte van metingsfout by verskillende voere of voedingspeile.

(Sleutehvoorde: genotipes,k ragvoer,r uvoer, interaksie

The concept of genotype-dietary interaction has considerable bearing on especially two aspects of the beef industry: performance testing of bulls and the matching of most suitable genotypes to particular production systems. With regard to  performance testing the results imply that the order of merit betwcen bulls could be altered due to genotype-dietary interaction. Therefore, it is preferable that bulls sltould be tested within thc nutritional environment in which they are kept. With regard to the concept as possibly applicable to p roduction sy sl cms, it would appear that som e results in the literatu re need re-evaluation. What is possibly being interpreted as genotype. dietary interaction could be a function of inadequate apprehension of the impact of the effects of scaling for size, the multiplicative (curvilinear) nature of growth and the differential size of measurement error with different feeds and feedine levels.

(Keywords: genotypes,c oncentrote,r oughage,i nteraction)