Replacement Heifer Selection in A Beef Cattle Herd

The relationship between a heifer's weaning weight and her fertility and weaning weight of her calves was studied. Also investigated was the effect of dam amount of fat (DAF=dam weaning weight/weaning height) on heifers' ability to breed and rebreed. This is similar to Body Mass Index (BMI) calculated for humans. The relationship of dam's average daily gain from birth to weaning and from weaning to finishing and DAF to calf weaning weight was studied also. These determine which heifers should be kept as replacements. Data were collected from 816 heifers. Heavier animals had higher conception rates. Average daily gain of the dam from birth to weaning and DAF had adverse effects on calf weaning weight. This suggests that over-conditioned heifers are likely to have lighter calves. In addition, the cubic model of dam weaning weight showed that after a weight of 272 kg, calf weaning weights no longer increased with increasing dam weaning weights.