Degree Type

Dissertation

Date of Award

1993

Degree Name

Doctor of Philosophy

Department

Animal Science

First Advisor

Jerry W. Young

Abstract

Twenty-four multiparous cows were used to evaluate effects of body condition at calving on metabolic responses to induction of an experimental ketosis. The ketosis was induced by restricting cows to 80% of feed intake and including 1,3-butanediol, a ketone precursor, in the ration at 7% of dry matter intake from 15 to 49 d of lactation (FRBD). Obese and normal cows were assigned randomly to the control or FRBD diet after calving. Three normal and three obese cows developed signs of ketosis on the FRBD protocol. The FRBD protocol involved decreasing energy intake, and cows compensated by decreasing milk production. Energy balance, however, tended to be decreased by the FRBD protocol. Blood ketones were increased by the FRBD protocol, but they increased less in obese than in normal cows. The hepatic triglyceride to glycogen ratio was increased by the FRBD protocol; the increase, however, was greatest in cows of normal body condition. Hepatic gluconeogenesis, measured by increased in blood glucose after a propionate infusion, was delayed in obese cows, but tended to be greater than in normal cows. In cows that developed ketosis, in vitro glucose release was greater in obese than in normal cows. The FRBD protocol lessened the glucose increase after a propionate infusion, and there was no glucose increase at 26 d postpartum in cows that later became ketotic. Thus, obese cows were better able to compensate for the stresses of lactation and the FRBD protocol, yet they became ketotic more readily than cows of normal body condition.

DOI

https://doi.org/10.31274/rtd-180813-10055

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Terry Russell Smith

Language

en

Proquest ID

AAI9414021

File Format

application/pdf

File Size

155 pages

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