Thesis--Wisconsin. / Includes bibliographical references (leaf 87).

No description available.

Thesis (M.S.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

The mitochondrial utilization of a-ketoglutaric and pyruvic acids have been found to be depressed in guinea pig and bovine ketosis. Addition of sodium acetoacetate to the reaction medium resulted in depressed oxidation of pyruvate and 1-ketoglutarate of isolated normal rat liver mitochondria. / Ph. D.

Although the occurrence of ketosis is a postpartum phenomenon, recent studies have focused on the prepartum period as key in the development of the disorder. Indicators of prepartum energy status, such as depressed dry matter intake (DMI) and elevated plasma non-esterified fatty acid (NEFA) concentrations have been associated with the occurrence of ketosis. The objective of this study was to investigate the role of phosphoenolpyruvate carboxykinase (PEPCK) in the periparturient and ketotic cow. The enzyme PEPCK catalyzes the rate limiting step in gluconeogenesis in hepatocytes. Whereas, in adipocytes, it has been suggested that PEPCK functions in the synthesis of glycerol for the formation of triacylglycerol (TAG) when plasma glucose concentrations are low. Thirty-four pregnant multiparous Holstein dairy cows were fed a single prepartum ration that consisted of 50% oat hay, 18% corn silage and 32% grain mix (DM basis). The ration was formulated to meet or exceed NRC requirements of 14% CP and 1.6 Mcal/kg NE[subscript L]. At calving, cows were transitioned onto one of two postpartum diets: control (n=14) or 3.5% supplemental fat (n=20). The postpartum diets, fed from wk 1 to 3, were formulated to isonitrogenous and to meet NRC requirements. Both diets consisted of 25% alfalfa, 25% corn silage and 50% grain mix. The control and fat diets contained 17.2 and 17.6% CP and 1.67 and 1.74 Mcal/kg NE[subscript L] respectively. Liver biopsies from 28 cows and adipose tissue biopsies from 6 cows were collected at -14, 2 or 3 and 14 d relative to calving. Tissue samples were analyzed for PEPCK mRNA and activity. All results were analyzed by period: prepartum (-21 to -2 d), freshening (2 to 7 d) and postpartum (8 to 21 d). In a previous study in our lab, 25 and 75% cows on the control and fat diets, respectively, experienced ketosis. In the current study there a 40% occurrence of ketosis for both control and fat diet groups. The high occurrence in both diets may be attributed to the rapid transition from the dry cow ration (70:30 forage to concentrate ratio, DM basis) to the lactating cow ration (50:50 forage to concentrate ratio, DM basis). The cows on the fat diet had lower serum glucose at freshening. Cows with ketosis had higher prepartum body weights (788 kg) than non-ketotic cows (743 kg; P<.1). No prepartum differences were seen in body condition score, DMI, NE[subscript L] balance, NEFA, glucose or ��-hydroxybutyrate concentrations were detected between ketotic and non-ketotic cows. Expression of adipose PEPCK mRNA was not different between ketotic and non-ketotic cows. However, hepatic PEPCK mRNA expression was higher in non-ketotic cows at freshening when compared to ketotic cows. Cows that experienced ketosis had lower hepatic PEPCK activity prepartum (6.6 vs. 9.3 units /min/g protein) and postpartum (7.6 vs. 10.2 units/min/g protein; P<0.5) when compared to non-ketotic cows. Our data indicated that hepatic PEPCK is a useful prepartum predictor of a cows susceptibility to ketosis. / Graduation date: 1998

No description available.

Glucocorticoids are commonly used to treat cows with clinical ketosis and fatty liver disease. This study investigated the effects of 10 mg/mL of FlucortRTM and PredefRTM 2X on the day of calving on blood metabolites, immune function and milk composition on 30 transitional Holstein cows. Sample of blood and milk were analyzed for energy metabolites (glucose, NEFA, BHB and insulin), mineral metabolites (Ca, P, Na, K, Cl and Mg), energy function parameters (antibody, lymphocyte), milk compositional parameters (protein, fat, lactose, SCC). There were no differences in glucose, Na, Cl, Mg, antibody, lymphocyte and milk fat, were observed among treatments. FlucortRTM treated cows had significantly lower NEFA on D1, higher BHB on D21 and D28, lower insulin on D14, higher Ca on D1 and lower P on D1. PredefRTM 2X treated cows had significantly higher BHB on D21, higher insulin on D7, lower Ca on D1, higher SCC on D1 and higher milk protein on D1. With respect to the significant data in this study, the use of glucocorticoids FlucortRTM and Predef RTM 2X in a single intramuscular injection on d1 for the treatment of ketosis is not warranted.