PSVI-10 Effects of lipid and starch supplementation on total water intake of Holstein bull-calves

Abstract

Water intake of dairy calves is often overlooked by most nutrition models which can be associated with the misconception that dairy calves meet their water requirements with milk or milk replacer (MR) alone. The goals herein were to investigate the effect of two isoenergetic supplements fed in a MR diet on total water intake (TWI) and fresh water intake (FWI). Twenty-three Holstein bull-calves (94.67 ± 12.07 kg) were distributed in a completely randomized design and received one of three supplements for 68 days: control (CON; n = 7), carbohydrates (CHO; n = 8), and lipid (FAT; n = 8); on top of a MR-based diet. The CON was composed of ad libitum MR alone. The FAT was composed of a supplementation of menhaden fish oil on CON (3%); and CHO was composed of corn starch supplementation on CON. All animals were provided free access to mineral mix, 200 g daily dried brewer’s spent grains, and clean water. Data were analyzed with orthogonal contrasts for pre-specified treatment comparisons using R statistical software [R Core Team (2019)]. No significant differences were observed for MR intake, 3.13, 3.05, and 3.14 kg, final bodyweight, 208.75, 200.94, 202.64 kg, and average daily gain, 1.74, 1.60, 1.64 kg, for FAT, CHO, and CON, respectively. TWI in a metabolic bodyweight (MBW) basis was different (P < 0.05) amongst treatments; lower TWI intake was seen for FAT than CHO than CON (0.363 and 0.388 vs 0.423 L/kg0.75, respectively). TWI without MBW resulted in similar results (P < .05) with average TWI of 15.69, 16.08, and 18.00 L; FWI differences (P < .05) were seen alone 1.51, 2.59, and 3.77 L, as well as in MBW basis 0.033, 0.060, and 0.088 L/kg.75 for FAT, CHO, and CON. These data could potentially show that metabolic water production in early ruminant animals can significantly decrease water intake.