Date of Award

12-2016

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Animal Science

Major Professor

Peter Krawczel

Committee Members

Janice Edwards, Gina Pighetti, Agustin Rius, Brian Whitlock

Abstract

Transition cows are the cows most susceptible to disease and prevalence has not changed over the past decade. However, increased physical activity during late gestation may represent a management option to improve transition. Therefore, the objectives of this study were to determine the effect of exercise, pasture turnout, or total confinement on 1.) physical fitness and cortisol concentrations during the dry period, 2.) neutrophil function and behavior during the dry period, 3.) horn growth and wear and sole thickness during the dry period 4.) calving behavior and cortisol concentrations at parturition, and 5.) calf performance, behavior, and cortisol concentrations at disbudding and weaning. Pasture turnout tended to reduce anaerobic metabolism 60 min after exercise and exercise and pasture turnout resulted in less variable heart rate during and after exercise compared with confined cows. Physical activity during late gestation may allow cows to maintain a certain level of fitness. Physical activity did not alter behavior or neutrophil function during the dry period. Exercise cows experienced greater hind hoof horn wear than confined and pasture cows but had more equal rates of horn growth and wear. Sole thickness was not altered with exercise or pasture turnout but tended to increase for cows in total confinement. Physical activity did not affect time for different periods within stage II labor; however, confined cows stood for longer periods during the days surrounding calving, which may be related to discomfort experienced when standing or lying. Cortisol did not differ between groups at calving or 3 days later. Maternal treatment did not affect calves’ ability to cope with the stress of dehorning, as calves displayed similar performance, behavioral, and physiological responses. However, calves from pasture cows displayed shorter lying time than calves from control and exercise cows while calves from exercise cows displayed more frequent lying bouts, potentially highlighting increased stress from weaning. Future research should investigate the impact of pasture turnout during periods cows are more active to increase the level of physical activity.

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