Effect of mortality rate, breed type and breed on total herd efficiency

Abstract

The influence of two scenarios of mortality rates (assumed average and observed) on total herd efficiency of the four main breed types in South Atrica (SangafZebuc, omposite,B ritish and European),a s well as all the individual breedsp articipating in the National Beef Performance Testing Scheme (1980-1985), was investigated by means of a computer simulation program. Simulation runs were done for an 18/18 month production system (all market animals sold at 18 months of age) in the case of the evaluation of breed types and for an 8/18 month (steers sold at eight months of age / surplus heifers sold at 18 months of age), as well as an 18/18 month production system in the case of the evaluation of the individual breeds. Mortality rate had a marked influence on ranking of breed types as well as individual breeds in terms of relative income per hectare. Composite breed types normally performed well, indicating that use of such breeds in a variety of environments is a good choice. This study also indicated that bio-diversity does exist between breeds and further research is needed on breed characterization, since no framework currently exists for the charucterrzationo f breeds for bio-economic important traits.

Die invloed van twee scenariosb etreffendem ortaliteitsyfers( verondersteldeg emiddeldee n wuurgenomem ortaliteitsyfers) op die totale kuddedoeltreffendheidv an die vier hoof rastipesi n Suid-Afr*a (Sanga{Zebuk, omposiete,B ritse, Europese) asook van al die individuele rasse wat aan die Nasionale Vleisbeesprestasietoetsskem(1a9 80-1985) deelgeneemh et, is ondersoek met behulp van 'n rekenaarsimulasieprogramS. imulasie-opiesi s vir 'n 18/18 maande produksiestelsel( alle markdiere op l8 maande bemark) gedoen in die geval van die vergelyking tussen rastipes en vir 'n 8/18 maande (speenkalwers op agt maandeb emark/surplusv erse op 18 maandeb emark) sowel as 'n 18/18 maandep roduksiestelseli n die geval van die vergelyking tusseni ndividuele rasse.M ortaliteitsyfersh et'n drastiesei nvloed gehado p die rangorde van rastipes sowel as individuele rassei n terme van rdlatiewe inkomste per hektaar.K omposietrastipesh et normaalwegg oed presteer, wat aandui dat die gebruik van komposietei n 'n verskeidenheido mgewingsg ewoonlik 'n goeie keusei s. Hierdie studieh et ook aangeduid at bio-diversiteit wel tussenr asseb estaane n dat verderen avorsingt en opsigte van raskarakteriseringn odig is, aangesien geen raamwerk tans in Suid-Afrika bestaan vir die karakterisering van rasse ten opsigte van bio-ekonomies belangrike eienskappe nie.

Keywords: Breed, breed type, mortality rate, total herd efficiency.