T.J. TIERNEY1, W.J. TAYLOR2 and K.G. BEAN3
1Queensland Department of Primary Industries, Coolum Research Station, Coolum, Qld. 4573
2Queensland Department of Primary Industries, Rockhampton, Qld. 4700
3CSIRO, Tropical Cattle Research Centre, Rockhampton, Qld. 4700
Three successive calf crops from Hereford cows were used to record milk production, cow and calf liveweights to weaning, post weaning calf liveweights. calving dates and reproductive performance at Coolum Research Station in the coastal lowlands of south east Queensland.
Mean daily milk, total milk and lactation length were 4.5 kg, 1042 kg and 234 days respectively. Years had a significant effect on total milk yield while cow age and sex of calf had no significant effect.
Mean birth, 234 day (weaning) and 410 day liveweights of calves were 33, 195 and 270 kg respectively. Year, cow age, and calf sex significantly affected these liveweights.
Total milk production was significantly correlated with calf weaning liveweight (r = 0.41) but not with cow joining and weaning liveweights, calf birth weight, or cow day of conception.
Calf birth weight was significantly correlated with cow joining liveweight (r = 0.21), cow weaning liveweight (r = 0.17), calf weaning liveweight (r = 0.49) and calf day of birth (r = 0.28). Calf weaning liveweight was significantly correlated with cow joining liveweight (r = 0.26) and cow weaning liveweight (r = 0.25).
Repeatabilities of calving date (0.221), total milk adjusted for year, cow age, calf sex, year by cow age and calving date (0.346) and calf weaning liveweight adjusted for age (0.327) were significant.