Abstract #M155

# M155
Evaluation of milk replacer feeding rates on Holstein calves via a meta-analytical approach: 1. Effect on digestion and growth from 0 to 2 months of age.
W. Hu*1, T. M. Hill1, T. S. Dennis1, F. X. Suarez-Mena1, J. D. Quigley1, 1Nurture Research Center, Provimi, Cargill Animal Nutrition, Brookville, OH.

The objective of this study was to evaluate the effects of the milk replacer at 2 feeding rates on growth performance of dairy calves via a meta-analytic approach. A database was developed from 10 studies conducted at the Nurture Research Center, Provimi (Brookville, OH) from 2014 to 2016. Male Holstein calves (n = 491; 42.8 ± 4.9 kg BW initially; < 1 wk of age) were randomly assigned to 1 of 2 treatments: total milk replacer intakes of 29.7 ± 0.6 kg DM (MOD) and 48.8 ± 4.5 kg DM (HIGH). Meals were divided into 2 equal a.m. and p.m. feedings; during weaning half the allotment per d was offered for 3–7 d in the a.m. feeding only. Calves were weaned at 6–7 wk. Milk replacer ranged from 24.8 to 28.6% CP and 17.6–20.2% fat; starter ranged from 17.3 to 22.2% CP and 3.0–4.3% fat on a DM basis. Statistical analysis was conducted using mixed-effects models. From 0 to 35 d, calves fed HIGH had greater ADG (0.642 vs. 0.447 kg/d; P < 0.001) and gain/DMI (0.537 vs. 0.490 kg/kg; P < 0.001) but consumed less starter (0.104 vs. 0.208 kg/d; P < 0.001) compared with calves fed MOD. From 0 to 56 d, feeding HIGH resulted in greater ADG (0.634 vs. 0.545 kg/d; P < 0.001), gain/DMI (0.491 vs. 0.469 kg/kg; P = 0.001), and hip width change (0.069 vs. 0.064 cm/d; P = 0.001), but lower starter intake (0.467 vs. 0.690 kg/d; P < 0.001) compared with calves fed MOD. Apparent digestibility of DM (73.3 vs. 78.4%; P < 0.001), OM (74.1 vs. 79.0%; P < 0.001), CP (74.8 vs. 78.9%; P = 0.001), and NDF (40.8 vs. 53.9%; P < 0.001) were lower for calves fed HIGH vs. MOD when estimated during a 5-d period in wk 8. Feeding calves more than 0.681 kg/d (as-fed basis) of milk replacer improved BW gain and structural growth in the first 56 d of life; however, digestibility of DM, OM, CP, and NDF was depressed after weaning. Growth advantage from feeding more milk replacer was partially lost during weaning transition, which could be due to the reductions in nutrient digestibility.

Key Words: calf, performance, digestibility