The relationship between management practices and estimated weight for age of Friesian heifers in north-eastern New South Wales

Abstract

The weight of 2659 Friesian heifers was measured electronically on 41 farms in north-eastern New South Wales during autumn 1992. The 41 producers involved were surveyed on their heifer management practices. The relationship between liveweight and age was determined from these measurements. This provided a base line against which improvement in heifer weight for age could be measured subsequent to a planned extension program. In 1992, 2 management practices were found to be associated with significantly higher weights for age. These were feeding more than 1 kg of concentrate to heifers prior to weaning and grazing heifers on fertilised pasture between weaning and 12 months of age. An extension program promoting improved heifer management was conducted, using adult learning principles, from 1992 until 1995. Nineteen of the 41 farms were revisited in winter 1997 when the heifers were again measured and management practices surveyed. Heifer weight for age had increased by a small but significant amount between 1992 and 1997. Management changes which occurred between 1992 and 1997 were: increased vaccination rates; decreased use of antibiotic injections for treating calf illnesses; increase in feeding over 1 kg of concentrate per day to preweaned heifers; and increased use of silage to feed weaned heifers. There was also a decreased percentage of producers who considered calf diseases to be a problem. Between 1992 and 1995, 14 farmers began monitoring their heifers regularly, either by measuring weight electronically or by using a weigh tape.