The effect of age of dam on adjusted 210 day calf weaning mass was estimated by the Least Squares method for 5 dam types on 2 farms. In the 12 models used the age of dam significantly (P < 0,01) influenced weaning mass. Heifers produced calves of significantly (P < 0,05) lower weaning mass than dams of other ages. The British and Bos indicus type dams reached peak production in terms of weaning mass at an earlier age than the Charolais, Simmentaler and Dual Purpose types. This was probably due to their rate of maturity. These results indicate that when the average dam-age is low in a herd, the early maturing types can be more productive than later maturing types. Extrapolating this data to extensive conditions, where cows tend to be culled at a younger age due to teeth disfunction, it seems that the later maturing breeds would have a low level of productivity because these cows would be eliminated in their potentially prime productive years. The results should be considered in determining the suitability of breeds to various environments.
"Experientia docet" - Experience is the best teacher