Date of Award

Fall 2014

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

First Advisor

Peter D Constable

Committee Chair

Peter D Constable

Committee Member 1

Jonathan R Townsend

Committee Member 2

Lawrence A Horstman

Committee Member 3

Wayne L Singleton

Abstract

Dystocia is a major problem in the dairy industry as it causes livestock and economic loss. It is more frequently seen in primiparous cattle compared to their multiparous counterparts due to their smaller stature and the slow maturation of pelvic dimensions. In some instances, human intervention of the parturition process is imperative to avoid pain, injury, and mortality of the neonate and the dam. The ability to accurately predict dystocia and the time of parturition will ensure that timely assistance can be given to animals that are of high risk of dystocia.^ The present thesis contains four studies that explore methods to predict dystocia and the time of parturition as well as factors that influence the presentation and outcome of cesarean sections. The first study, presented in chapter three, evaluated the clinical utility of measuring the circumference of the calf front and maternal intrapelvic dimensions to predict the incidence of dystocia in late gestation Holstein-Friesian cattle. The ratio of the calf hoof circumference to the maternal intrapelvic area was identified to have clinical utility in predicting the calving difficulty score. The second study, presented in chapter four, assessed the changes in plasma progesterone concentration, rectal temperature, sacrosciatic ligament relaxation, and feed intake to predict the time of parturition in dairy cattle. Results indicated that plasma progesterone concentration had the highest accuracy in predicting the time of parturition. The third study, presented in chapter five, explored the clinical utility of blood and plasma glucose concentrations in predicting parturition as well as their relationship with hypercortisolemia and clinical signs associated with the activation of the sympathetic nervous system namely heart rate, respiratory rate, mean arterial blood pressure, hematocrit, and rumen contraction rate. Blood glucose was determined to have the potential to predict parturition due to its accuracy, practicality, and cost effectiveness. In the fourth study, presented in chapter six, a retrospective study was conducted to examine the clinical presentations and outcomes of beef cattle that were admitted into a teaching hospital with dystocia and had cesarean sections performed. Results indicate that cesarean section was a useful method to resolve dystocia with high dam survivability but delays in admitting cattle to the hospital could result in increased calf mortality.^ Collectively, the results presented in this thesis provide methods to predict dystocia and parturition in late gestating cattle as well as highlight factors that help ensure favorable outcomes from cesarean sections.

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