The ram circle as a progeny testing method

Authors

• Jouko Syväjärvi Department of Animal Breeding, University of Helsinki, Finland
• Mikko Varo Department of Animal Breeding, University of Helsinki, Finland

DOI: https://doi.org/10.23986/afsci.71809

Abstract

Ram circles are used to obtain progeny from sire rams on a number of different farms in order that the effect of farm on progeny may be equalized and, concurrently, the selection of mate be a random one. The objective is the achievement of reliable progeny evaluations of the rams as a result of cooperation between farms. The Finnish experiment covered four farms, and four rams were used to service the four flocks containing a total of 66 ewes. In the spring, 163 lambs were born. In the autumn 40 male lambs were selected from this number at random and were slaughtered, dissected and evaluated. The results were analysed by covariance analysis, and the effects of the dam, the litter and the age of animal were eqalized. The effect of the farm on the early growth and the liveweight of the lambs was considerable, but it decreased with the ageing of the lambs. The effect of farm on the characteristics of the carcass was without significance. The variation between sires was greater than the variation due to error concerning almost all the characteristics, and in four cases the differences were significant at a probability level of 95 per cent. The differences will probably emerge more clearly if the number of farms and the number of rams in the circle are increased. In the experiment this time the number of progeny on the various farms was far from even. On the basis of slaughter results, however, estimates could be produced of the order of superiority of the sires.