The growth and carcass characteristics of crosses of Hereford and Friesian with Angoni, Barotse and Boran cattle in Zambia

Abstract

Seven hundred and fifty purebred Angoni, Barotse and Boran cattle and their crosses sired by Friesian and Hereford bulls were compared for live-weight and carcass characters in Zambia. The cattle were born between September and December in three consecutive years and were reared on unimproved veld. In the first year all females and a random half of the males received supplementary feed in winter and the males were slaughtered at 2-5 years of age. The remaining males received the same total amount of winter supplementary feed prior to slaughter at 3-0 years of age. The males born in the second year were pen fed for a period prior to slaughter at 3-0 years of age. Males born in the third year were slaughtered at 3-5 years of age and received no supplementary feed.Genotype differences were important at all live weights and there were year of birth x genotype interactions at the 0-5, 1-0 and 1-5 year weights and a genotype x feed treatment interaction at the 2'0 year weight. Boran purebreds were heavier than the Angoni and Barotse purebreds; at 3-0 years the differences were +42-3 kg ( + 12-9%) and + 25-2 kg (+ 7-7 %) respectively. Cross-breds had heavier live weights than their corresponding purebreds with Boran crosses consistently heavier than the Angoni and Barotse crosses. The Friesian and Hereford sired Boran cross-breds were + 51-0 kg (+13-5 %) and + 43-0 kg (+ 11-6 %) heavier respectively than the purebred Borans at 3-0 years of age.There were large differences between the genotypes for all carcass characters with Borans having heavier carcasses than the Angonis and Barotses by + 20-3 kg (+10-6 %) and +19-1 kg ( + 10-0%) respectively. The average carcass weight advantages of Friesian and Hereford crosses with the Angoni, Barotse and Boran breeds over the corresponding purebreds were +40-3 kg ( +19-0%), +33-6 kg ( + 16-2%) and +31-0 kg ( + 14-0%) respectively. There were few important carcass differences between the corresponding Friesian and Hereford crosses.The mortality rate during the experiment was 8-2% with only small differences between genotypes.The interactions found in the experiment indicated that breed comparisons should be conducted over a number of years and at various management levels. For growth and carcass production under the conditions of the experiment the use of exotic crossbreds is clearly advantageous. reliable estimates of breed performance and compansons among breeds which would provide the Genetic improvement can be expected to play a basis for genetic improvement are seldom available, part in increasing the efficiency of cattle production In Zambia for example, published estimates are even in the absence of concurrent improvements limited to a study of the indigenous Angoni in management. Although these conditions often (Walker, 1964) and a comparison of the Angoni prevail in the developing countries of Africa, with exotic breeds for some reproductive charac-