Bovine leukosis (BL) is a lifelong disease of dairy cattle caused by the bovine leukosis virus. Although most infections appear to be subclinical, a proportion of cows over 3 years old (30 – 50%) develop persistent lymphocytosis, and a smaller percentage (5%) develop malignant tumors (lymphosarcomas) in various internal organs.
At calving, calcium requirements are quadrupled, which results in cows experiencing variable degrees of subclinical to clinical hypocalcemia. Subclinical hypocalcemia (SCH) is normally defined as calcium concentrations in blood lower than 2.1 mmol/L (8.5 mg/dL). Previous research conducted in Holsteins…
Salmonella enterica serotype Dublin is an important cause of illness among dairy calves younger than 2 months of age. Infection with S. Dublin can occur when susceptible calves ingest the bacteria in milk or manure from infected animals. In addition to diarrhea, the most common manifestation of S. Dublin in calves is pneumonia.
Insulin is an anabolic hormone that allows body cells to absorb glucose, amino acids, and fatty acids circulating in the blood and increases the synthesis of fat and protein. At the beginning of lactation insulin levels in blood are very low to support milk production.