Abstract 338

Erasmus,JA; Barnard,-HH

Dohne Agricultural Research Institute, Stutterheim 4930, South Africa.

South-African-Journal-of-Animal-Science. 1985, 15: 4, 162-164; 13 ref.

In 2 breeding seasons, Shorthorn and Bonsmara-type heifers were allocated to a high, medium or low level of nutrition after weaning at 7 months of age. These feeding levels were applied for 145 days to 57 heifers in 1972 and for 118 days to 42 heifers in 1973. The high- and medium-level groups received supplementary maize leaf-cob meal, maize meal, maize silage and/or lucerne hay to achieve daily growth rates of 0.68 and 0.34 kg resp. All groups received a protein-energy lick. Body weight gain was significantly higher in the high- and medium-level groups than in the low-level group. With min. mating weights set at 275 and 300 kg in the 2 yr resp., the percentage of the 3 nutritional groups achieving mating weight was 100, 95 and 58 resp. in 1972, and 79, 71 and 36 in 1973. The overall percentage of heifers calving during the 1st breeding season was 63.5, 55.0 and 33.5 in the 3 nutritional groups. During the 2nd-5th breeding seasons, the calving percentages were 75.2, 74.4 and 82.9 resp.