A study on energy metabolism in dairy cows around parturition under field conditions

“A study on energy metabolism in dairy cows around parturition under field conditions” This thesis topic was carried out under the supervision of Professor E. BRYDL of the Department of Animal Hygiene, Herd-Health and Veterinary Ethology, Faculty of Veterinary Science, Szent István University, Budapest, Hungary. The thesis is based on a Metabolic Profile Test performed on a herd of dairy cows on a farm east of Budapest in February 2010 and September 2011. Metabolic profiling of herds was first carried out in Compton, England in the 1960s, it is a test based on the concept that the nutritional status of an animal can be estimated by the chemical measurement of some of the components of the blood. The tests measure metabolites which reflect the animals energy balance e.g. non esterified fatty acids (NEFA), beta hydroxyl buterate (BHB), protein status (blood urea nitrogen (BUN), albumin), liver function (various enzymes, cholesterol and triglycerides) and macromineral’s (e.g. potassium, magnesium, calcium ect.) homeostasis. In addition micromineral’s and vitamins can be tested. Energy metabolism is the ability to break down feed nutrients and turn it into energy. The energy requirements of dairy cows vary depending on the production levels during pregnancy, lactation and dry period. It is important to monitor the energy intake, as it can significantly improve milk production and foetal health while reducing illness. Energy is generated from the breakdown of carbohydrates (glucose, glycogen), secondary products of pyruvate (acetic, propionic and butyric acid), fats and proteins (amino acids) through the metabolic pathways in the cells. By performing a metabolic profile test and comparing a herd’s status against known reference values a herd health profile can be created. However, Metabolic Profile Tests should only be used as one component of a health investigation and not as the sole measure of identifying potential problems. With the number of large scale farms increasing, research on energy metabolism and herd health has been demonstrated to increase the profits of the farmers by; increasing production, quality and calving rate and reducing animal loss and veterinary call outs. With improvements in vaccinations and quality farm management it has been proven that prevention is better then treating clinically sick animals. Two metabolic profile tests were performed on a dairy cattle herd in Hungary in February 2010 and September 2011. The review of the metabolic profile test results demonstrate that certain parameters for example BCS, BHB, NEFA, Urea and AST were outside the physiological range. These parameters are important to ensure a balanced energy metabolism for dairy cattle to maximise the milk and reproduction performance to ensure a profitable business. Veterinarians play a key role in the life cycle of the dairy cow from birth to death offering not only treatments but also nutritional advice with metabolic profiling, vaccination and ongoing health care. The recommendations given were to monitor the BCS in the months before parturition and improve the feeding technology by giving the correct energy: protein ratio, include bypass proteins, carbohydrates and limiting amino acids. Use hepatoprotective and antilypolytic ingredients and monitor the mineral content of the feed especially sodium and potassium By decreasing inorganic buffers and replacing them with yeasts the acid base balance will be corrected