COMPARISON OF DIFFERENT HOLSTEIN X ZEBU CROSSES IN GROWTH TRAITS UNTIL 300 DAYS

Growth data from 343 carves of the base population and the first inter - se mating of the Siboney (5/8 IIo 3/8 Z)and Mambi de Cuba (3/4 IIo 1 /4 Z) projects, born during 6 years and reared as future sires under t he same feeding and management conditions for their comparative evalua tion, were used. The traits studied were liveweight at 90 (W-90), 180 (W-180) and 300 (W-300) days of age, as well as weight For age at the same ages (WFA 90, WFA 180 and WFA 300). Data were analysed by tile le ast squares method according to a linear model of foxed effects which included as sources of variation: genotype (4), year (6) and bimester of birth (6), as well as the interaction year x bimester. General mean s obtained were 101.7; 206.2, and 324.5 kg for W 90, W 180 and W 300, respectively and of 1.13; 1.14 and 1.07 kg/day for WFA 90, WFA 180 and WFA 300. Results indicate that there are significant differences betw een genotypes due to the superiority of the 3/4 IIo 1/4 Z with respect to the rest at: the initial stages, although this is lower as age inc reases. The year significantly influenced all the measurements with an increasing trend in the years studied. Results indicate that these ge notypes have an adequate growth potential which guarantee their use as future sires.