A mass screening programme of angus cattle for the mannosidosis genotype — A prototype programme for control of inherited diseases in animals

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Abstract
Extract Recent research has shown that the gene frequency for mannosidosis (pseudolipidosis) may approximate 0.05 in pedigree Angus herds (Jolly, unpublished data). As epidemiological studies suggest an equal frequency in commercial non-pedigree herds, the disease is elf economic importance to the national beef industry. Mannosidosis is an inherited lysosomal storage disease associated with a defect in catabolism, of the heterosaccharide fractioln of glycoproteins ( Whittem and Walker, 1957 Donnelly, W. J. C. , Sheahan, B. J. and Rogers, T. A. 1973a. GM1 gangliosidosis in Friesian calves. J. Path., 111: 173–179. [Google Scholar] ; Jolly 1971 Donnelly, W. J. C. , Sheahan, B. J. and Kelly, M. 1973b. Bet α-galactosidase deficiency in GM1 gangliosidosis of Friesian calves. Res. vet. Sci., 15: 139–141. [Google Scholar] ; Hocking et al., 1972 Hocking, J. D. , Jolly, R. D. and Batt, R. D. 1972. Deficiency of α-mannosidase in Angus cattle. Biochem. J., 128: 69–78. [Google Scholar] ; Phillips et al., 1974 Jolly, R. D. 1971. The pathology of the central nervous system in pseudolipidosis of Argus cattle. J. Path., 103: 113–121. [Google Scholar] ). Whereas animals with mannosidosis have negligible tissue sand plasma levels of α-mannosidase, heterozygotes having one normal gene and one defective gene have approximately half the normal level of enzyme in their tissues and plasma. This observation forms the basis for a control programme in which heterozygotes are identified by their plasma α-mannosidase 1evels ( Jolly et al., 1973 Jolly, R. D. , Tse, C. A. and Greenway, R. M. 1973. Plasma α-mannosidase activity as a means of detecting mannosidosis heterozygotes. N.Z. vet. J., 21: 64–69. [Taylor & Francis Online] [Google Scholar] , 1974a Jolly, R. D. , Thompson, K. G. , Tse, C. A. , Munford, R. E. and Merrall, M. 1974a. Identification of mannosidosis heterozygotes — factors affecting normal plasma α-mannosidase levels. N.Z. vet. J., 22: 155–162. [Taylor & Francis Online] [Google Scholar] , b Jolly, R. D. , Thompson, K. G. and Tse, C. A. 1974b. Evaluation of a mass screening programme for identification of mannosidosis heterozygotes in Angus cattle. N.Z. vet. J., 22: 185–190. [Taylor & Francis Online] [Google Scholar] ).