Document Type

Dissertation - Open Access

Award Date

2025

Degree Name

Doctor of Philosophy (PhD)

Department / School

Animal Science

First Advisor

Amanda Blair

Abstract

The objective of this study was to evaluate the influence of maternal nutrient restriction during mid-gestation on the performance of the dam, feeding performance, carcass composition, and genetic expression in the offspring. Cows (n = 46) were randomly assigned to one of two treatments based on global nutrient intake: 1) fed to achieve and/or maintain a BCS of 5 or 6 (Positive Energy Status [PES]; n = 24) or 2) fed to lose one BCS during 99 days of mid-gestation (Negative Energy Status [NES]; n = 22). Cows in NES had greater decreases (P < 0.05) in body fat stores and muscle mass, elevated NEFA concentrations, and displayed decreased (P < 0.05) DMI, HP, and GHG emissions. There were no differences in milk components or volume produced between treatments (P > 0.05). There were no differences in birth weight (P > 0.05) or average daily gain (ADG; P > 0.05) between treatments from birth to weaning. Measures of calf feeding performance and body composition were collected from weaning to harvest. There were no differences (P > 0.05) in offspring feeding performance during the receiving period or the backgrounding phase. There was a tendency (P = 0.09) for PES calves to have a greater ADG throughout the finishing period. There was an interaction (P < 0.05) for REA during feeding with PES calves having a larger REA at weaning and at finishing but a similar REA to the NES calves during backgrounding. There was a trend (P = 0.11) for marbling score to differ at the completion of the backgrounding phase and the finishing phase with NES calves having greater intramuscular fat. There were no differences in hot carcass weight, dressing percentage, 12th rib fat thickness, marbling score, yield grade or quality grade. However, calves in the PES treatment had larger rib eye areas. There was a trend (P = 0.15) for NES calves to have more favorable fat deposition. Genes for bone, muscle, and fat growth were differentially expressed (P < 0.01) between treatments. Maternal nutrient restriction during mid-gestation altered gene expression and influenced economically important tissues in the offspring.

Publisher

South Dakota State University

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Rights Statement

In Copyright