Organic calf growth associations with sire breed and with milk and component yield in later life

A relationship has been established between calf growth rate and milk production in conventional dairy herds, but not in organic herds. This study was designed to evaluate the effect of sire breed on body weight (BW) and average daily gain (ADG) of organic calves and to evaluate the effect of calf BW and ADG on first lactation production. Records from 114 calves with 944 BW from 1 to 9 weeks of age were retained for determination of BW in week 1 (BW1), BW in week 8 (BW8), and average daily gain (ADG). First lactation production records (305-d mature equivalent milk (M-305), 305-d fat (F-305), 305-d protein (P-305), average 305-d somatic cell score (SCS), fat %, protein %, and energy corrected milk (ECM)) were available from 83 animals. Calves were of 5 different sire breeds: Holstein (HO, N = 52), Jersey (JE, N = 11), Montbeliarde (MO, N = 9), Viking Red (VR, N = 7), and others (O, N = 4). MO, VR and HO sired calves were heavier and had higher ADG (0.76 kg/d, 0.73 kg/d and 0.71 kg/d, respectively) than JE sired (0.65 kg/d) calves. Regression on BW1 and BW8 were associated with increased M-305 (34.36 kg and 23.12 kg, respectively), F-305 yield (1.07 kg and 0.63 kg, respectively),P-305 (0.93 kg and 0.63 kg, respectively), and ECM (31.53 kg and 20.01 kg, respectively). Moreover, we found that each kg increase in ADG was associated with a 1580.39 kg M-305 increase during first lactation. These results indicate that the sire breed was associated with pre-weaning growth of dairy calves and higher growth was associated with increased production in the first lactation in organic herds.