Technical note: Evaluating nuclear magnetic resonance spectroscopy for determining body composition in Holstein dairy calves using deuterium oxide dilution methods

Abstract

Deuterium oxide (DO) dilution methods have been used to assess body composition in live animals. Estimated body water content can be used to predict body fat and protein, and thus, the amount of energy reserves. It is an alternative method to direct chemical analysis and considered a noninvasive technique that is economical and repeatable. Deuterium oxide use is considered easy, safe, and accurate; however, the traditional methods of analyzing DO are expensive, tedious, and time consuming. The objective of this study was to evaluate the potential for using nuclear magnetic resonance spectroscopy (NMR) to determine body composition in Holstein dairy heifers. Nuclear magnetic resonance is less expensive and requires minutes to calculate the percentage of DO in the blood. This study used 24 newborn dairy heifer calves blocked by birth and randomly assigned to 1 of 3 treatments: (1) 446 g dry matter (DM) of a conventional milk replacer (MR) [CON; 20% crude protein (CP), 20% fat], (2) 669 g DM of a moderately high protein MR (MOD; 26% CP, 18% fat), or (3) 892 g DM of a moderately high protein MR (aggressive, AGG; 26% CP, 18% fat). All calves had free-choice access to starter and water. Both MR and starter were medicated with decoquinate. During weaning (d 43 to 49), the morning MR feeding ceased. On d 50, all MR feedings ended but starter and water intakes were continuously recorded until d 56. When calves were 50 d of age, a baseline blood sample was taken followed by injection of 300 mg of DO/kg of body weight in sterile physiological saline (0.9%). The syringes containing the DO in physiological saline were weighed before and after administration to record the actual dose of DO injected gravimetrically. After injection, the DO was allowed to equilibrate with body water for 1 h. Six blood samples were taken over 6 d (1/d) at 1630 h to estimate the dilution of the tracer. The plasma was aspirated and stored at -20°C until further DO analysis. This new method was validated using 4 calf plasma samples that were sent to an outside laboratory for measurement using an independent validation method. We detected no differences in total body water, protein, fat, or mineral content in calves fed CON, MOD, or AGG; however, results demonstrated that the DO dilution technique and analysis by NMR is an appropriate and easy method to estimate water, protein, ash, and fat in young heifers.

Nutrition and feeding of dairy cattle

“…Water makes up between 56% and 81% of total body weight in the dairy cow 25 and between 68% and 72% in the preruminant calf. 26 Water is essential for the transport of substances around the body, temperature regulation, insulation, and removal of wastes. As described earlier, water is essential for rumen microbial development in the preruminant calf and ultimately critical in the conversion of the calf from non-ruminant to ruminant (see calf and heifer section).…”

The effect of meloxicam on neonatal dairy calves: Immunoglobulin G uptake and preweaning performance

“…The amount of MR fed remained consistent throughout the entirety of the experiment, and refusals were measured at both a.m. and p.m. feedings. Feeding rates were based on previous research conducted at our university ( Guindon et al, 2015 ; Chapman et al, 2017a , b ; Aragona et al, 2020 ). While some studies at our institution have indicated that calves fed MR at a higher rate present with greater gains and feed efficiency during the preweaning period ( Guindon et al, 2015 ; Chapman et al, 2017a ), these studies have also revealed lower starter intakes during the preweaning and weaning phases ( Guindon et al, 2015 ; Chapman et al, 2017a ), poorer nitrogen efficiency ( Chapman et al, 2017a ), and greater cortisol levels at weaning, suggestive of more stress due to removal of MR ( Guindon et al, 2015 ), compared with the control group.…”

Energy and protein requirements for Nellore steers estimated with the deuterium oxide marker

“…The requirement of net protein for weight gain (NPg) was estimated by regression equation of retained protein in shrunk weight gain (g/kg of daily EBW 0.75 ) on protein intake (g/kg of daily EBW 0.75 ) (CHIZZOTTI et al, 2007).…”

“…The use of deuterium dilution for beef cattle began in the 1980s (ARNOLD et al, 1985;LEME et al, 1994;GOMES et al, 2012) and also has been used for studies with swine (ZHANG et al, 2017), sheep and goats (AL-RAMAMNEH, et al;2010),dairy cattle (CHAPMAN et al, 2017;SCHAFF et al, 2017) and equine (DUGDALE et al, 2011;FERJAK et al, 2017).…”