Growth of Holstein calves fed 3 nutritional programs and weaned at 42 d of age

Abstract

Our objective was to determine effects of 3 nutritional programs on growth of Holstein calves from birth to 20 wk of age. Calves (30 female, 45 male) were assigned at 3 d of age to 3 treatments in a randomized block design: (1) low (LOW) milk replacer (454 g/d, 21.2% CP, 21.2% fat, DM basis) and starter (20.4% CP, DM basis), (2) moderate (MOD) milk replacer (908 g/d, 27.1% CP, 18.8% fat, DM basis) and starter (23.3% CP, DM basis), and (3) high (HIGH) milk replacer (1,124 g/d, 29.2% CP, 21.0% fat, DM basis) and starter (25.8% CP, DM basis). The LOW, MOD, and HIGH milk replacers were reconstituted to 11%, 14%, and 18% solids, respectively. All calves were weaned on d 42. For all treatments, the respective starter was available for ad libitum intake from d 3 through wk 13. From wk 13 to 20, all calves were fed a maximum of 4.5 kg/d per calf of LOW starter and ad libitum hay. Before weaning (wk 6), ADG of BW (0.42, 0.55, and 0.62 ± 0.02 kg/d) was greater for MOD and HIGH than for the LOW treatment (P < 0.0001) and greater for HIGH than MOD (P = 0.02). Gain-to-feed ratio (0.36, 0.59, 0.62 ± 0.03) to weaning was greater for calves fed MOD or HIGH treatments than for those fed LOW (P < 0.0001). Calf BW at 20 wk (185, 190, and 181 ± 1.1 kg) was greater for calves previously fed MOD than for those previously fed HIGH (P < 0.01) but did not differ for LOW compared with the average of MOD and HIGH. Calves fed MOD had increased starter intake and maintained growth rate at weaning relative to calves fed HIGH when calves were weaned at 42 d of age. At 20 wk of age, calves fed MOD were heavier and longer than calves fed HIGH. Greater growth rate before weaning for calves fed HIGH was not maintained across and after weaning relative to calves fed LOW. Cost per kilogram of BW gain was greater for calves fed MOD or HIGH than for those fed LOW.