Expansion and distribution of the pedigree Jersey breed in Australia

Abstract

(i) The expansion of the pedigree Jersey breed in Australia has been due to extension of the geographical range, increase in number of herds, and increase in average herd size. The breed is at present doubling its numbers about every 10 years. (ii) Large fluctuations in population size from year to year have been observed. These could give rise to considerable random drift of gene frequencies. (iii) The approximate culling rate of pedigree Jersey females is calculated as 10-15 per cent. per annum. (iv) The extent of selective registration of bulls could be increased. Approximate calculations show that the number of bulls registered could be halved and the pedigree bull requirements of the breed still satisfied.