Risk Factors for and Treatment of Ketosis in Lactating Dairy Cattle
This thesis was conducted to investigate risk factors for ketosis development in lactating dairy cattle and evaluate treatments for affected animals. Four main studies were carried out. A systematic review of the ketosis treatment literature was performed to analyze the current body of literature available and provide guidance for treatments to be used in future studies. Secondly, a randomized clinical trial was performed on seventeen commercial dairy farms to determine the effectiveness of a combination butaphosphan cyanocobalamin product, insulin, and propylene glycol for ketosis treatment. A second randomized clinical trial was performed on nine commercial dairy herds to further evaluate the usefulness of a combination butaphosphan cyanocobalamin product and two durations of propylene glycol treatment on ketosis resolution and early lactation milk production. Finally, records from five commercial dairy farms were analyzed to evaluate individual cow risk factors associated with ketosis development. Evaluation of the ketosis treatment literature revealed the lack of well-designed ketosis treatment studies and the need for further investigation to determine an effective treatment regimen. Both treatment trials showed an effect of blood glucose concentrations at the time of enrollment on the efficacy of study treatments that had not been previously described in the literature. Animals that had blood glucose < 2.2 mmol/L at the time of ketosis diagnosis were more likely to cure and produced more milk when treated with insulin, butaphosphan cyanocobalamin, or extended duration of propylene glycol than untreated controls with blood glucose < 2.2 mmol/L. Treatment benefits did not extend to animals with blood glucose > 2.2 mmol/L at the time of enrollment. Older age at first calving, extended days open in the previous lactation, longer dry period, and increased parity increased ketosis risk. Also, animals that were ketotic during a lactation were more likely to become ketotic in the subsequent lactation. The information contained in this thesis helps increase understanding of ketosis risk and proper treatment. The novel interaction of the level of blood glucose and ketosis sheds light on previous inconsistent results on ketosis impacts and will change approaches to understanding and treatment of the condition in the field.