Evaluating the Effects of Glutamine Supplementation in Preweaned Holstein Heifer Calves Managed in Production Conditions

Guadalupe Ceja, Purdue University

Abstract

Calf management practices in the dairy industry have an important role in improving calf health and welfare to maximize production performance in later stages of life. However, certain stressors that are a byproduct of management practices, such as varied quality and timing of colostrum feeding, housing conditions, transportation, exposure to temperature stress, and weaning, impose negative effects on calf development and health. Additionally, these stressors are occurring during a time where calves have a developing pre-ruminant digestive system and an immature immune system reliant on maternal antibodies. These stressors negatively alter immune function, feed intake, growth performance, intestinal health, and behavior. As an outcome, the stress responses can make calves highly susceptible to disease, with enteric disease greatly increasing calf morbidity and mortality during the preweaning period. With there being producer interest in finding nutraceutical products that can be applied in a production setting to alleviate the effects of production stressors and disease on heifer calves, current research is looking at the potential use of L-glutamine (L-GLN) supplementation for combating the negative effects of physiological stress during the preweaning period. Glutamine research in monogastric nutrition has demonstrated the potential benefits of L-GLN on intestinal health, production performance, and behavior during a catabolic period. However, little is known about the benefits of dietary L-GLN supplementation on health and production parameters in preweaned dairy heifer calves. In the first study (Chapter 2), a urinary catheterization procedure for accurate, precise, and in vivo urine collection in preweaned heifer calves was developed for the evaluation of intestinal permeability in neonatal heifers. A second study (Chapter 3) was then performed to investigate the effects of dietary L-GLN supplementation on growth performance, disease scores, rates of therapeutic treatment, post-absorptive metabolic biomarkers, stress, and immune function markers, and intestinal permeability. In the first study, the urine collection method was effectively applied for evaluation of intestinal permeability using Cr-EDTA, an indigestible oral marker, demonstrating the applicability of the procedure in 1-week-old and 6-week-old neonatal heifer calves (n=15 calves). Calf health observations were recorded during the entire urinary catheterization process and collection period to evaluate any negative health reactions to the procedure, or localized reactions.Proportion of localized reactions were analyzed, and the proportions did not exceed 20% for the calves catheterized at either 1 week or 6 weeks of age. In the second study, the developed catheterization procedure and urine collection method was applied using Cr-EDTA as an oral marker to investigate if L-GLN supplementation would offer improvement to intestinal permeability. In this larger study, 30 Holstein heifer calves [1.5 ± 0.5 days old; 37.1 ± 0.86 kg body weight (BW)] were blocked by serum total protein, BW, and age, and randomly assigned to 1 of 2 treatments: GLN [24% crude protein (CP)], 17% fat milk replacer (MR) +10 g L-GLN/kg MR powder) or NS (24% CP, 17% fat MR). MR was reconstituted to 12.5% solids with warm water and fed 3.8 L/calf/d until weaning. Calves were weaned at 56.4 ± 0.5 days of age, and had ad libitumgrain (17% CP, 2% fat) and water access throughout the experimental period. During the preweaning period, calves were individually housed in hutches and health observations, which included respiratory and fecal scores, were assessed daily.

Degree

M.Sc.

Advisors

Johnson, Purdue University.

Subject Area

Physiology|Endocrinology|Food Science|Immunology|Neurosciences|Pharmaceutical sciences|Veterinary services

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