Date of Award

8-2015

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Animal and Veterinary Sciences

Advisor

Long, Nathan M

Committee Member

Andrae, John G

Committee Member

Higdon, III, H. Lee

Committee Member

Pratt, Scott L

Abstract

A study was conducted to evaluate late gestation maternal nutrient restriction with or without protein supplementation on endocrine regulation in newborn beef calves. This study utilized multiparous cows (4 and 5 yr of age, n = 57) randomly assigned to one of three treatments for the last 100 d of gestation. The control (n = 19) cows were fed to increase BCS while the nutrient restricted (NR, n = 19) and nutrient restricted with protein supplement (NRS, n = 19) cows were fed to lose 1.2 ± 0.2 BCS during the last 100 d of gestation. Control cows were allowed ad libitum access to tall fescue/crabgrass paddock and when grazing became insufficient, ad libitum hay was provided along with 1.3 kg of corn gluten feed 5 d/wk. Tall fescue paddocks were strip grazed to limit forage availability for NR and NRS. The NRS treatment were individually penned and fed 0.45 kg of soybean meal 3 d/wk. As forage became dormant the nutrient restricted paddocks received limited fescue hay. After parturition cow/calf pairs were moved to one common pasture and received ad libitum silage and 1.8 kg of high concentrate feed. Maternal nutrient restriction regardless of supplementation reduced cow plasma glucose and insulin concentrations during late gestation (P < 0.0001 and P = 0.0051 respectively). Calves from NR dams weighed less at parturition and the NRS calves were intermediate to control calves (33.4 ± 1.2, 35.0 ± 1.3 and 37.2 ± 1.3 kg respectively; P = 0.04,). Plasma glucose concentrations of unsuckled calves at parturition was reduced (P = 0.037) in NR and NRS calves compared to control (67.7 ± 6.5, 60.1 ± 6.9 and 83.7 ± 6.1 mg/dl respectively). At parturition, control and NRS calves had increased (P = 0.0037) plasma leptin concentrations compared to NR calves while calf plasma cortisol concentrations were greater for the nutrient restricted groups than the control (trt x day P = 0.0135). This research demonstrates that late gestation nutrient restriction reduces postnatal calf birth weight, plasma glucose and leads to reduced plasma leptin. Maternal protein supplementation appears to alleviate effects of late gestation nutrient restriction. This research demonstrates that maternal protein supplementation during late gestation nutrient restriction may alleviate effects of late gestation nutrient restriction.

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