Effects of energy source in milk replacer on glucose metabolism of neonatal dairy calves

Milk replacers (MR) formulated to contain more lactose than whole milk could potentially reduce insulin sensitivity in dairy calves. This study evaluated how partially replacing MR with fat on a weight/weight basis affects glucose–insulin kinetics neonatal calves fed high quantities of MR. Thirty-four Holstein bull were blocked by dam parity (1.6 ± 0.3) and randomly assigned 1 2 treatments (n = 17): high-lactose (HL; 46.1% lactose, 18.0% crude fat, 23.9% protein dry matter basis) or (HF; 39.9% 24.6% 24.0% basis). Calves individually housed pooled colostrum at 1.5 h 12 postnatal 18 9% metabolic body weight (BW0.75), respectively. From 24 until the end (d 7), transitioned (prepared 150 g/L) 18% BW0.75 twice daily 0700 1900 h. On d 4, an insulin-modified intravenous glucose tolerance test was conducted 8 after morning meal infusion (0.54 g/kg BW0.75, min 0) (3.9 µg/kg 20). During postprandial sampling 6, abomasal emptying assessed dosing acetaminophen (0.13 BW0.75) measuring its appearance within plasma. Sequential blood samples collected analyzed for plasma glucose, insulin, concentrations. killed 7 liver pancreatic tissues histomorphological analysis. Partially increased gain (679.6 vs. 462.0 69.68 g/d) gain:metabolizable energy intake (186.6 120.5 20.21 g weight/Mcal) compared feeding HL Furthermore, rate reduced HF Calculated variables based concentrations, such as maximum concentration area under curve, tended be lower Postprandial HF, although estimated from not different. showed enhanced glucose-stimulated secretion. In conclusion, resulted smaller fluctuations concentrations increase but fasting