Clinical, haematological, metabolic and endocrine traits during the first three months of life of suckling simmentaler calves held in a cow-calf operation.

Newborn suckling Simmentaler calves (10 males and 9 females) in a cow-calf operation were examined from birth up to the age of 3 months. The average daily gain from 47 to 120 kg was 0.86 kg. Except for higher average daily weight gains and insulin-like growth factor-I concentrations and lower thyroid hormone levels in male than female calves, there were no significant sex differences. Plasma glucose, total protein and immunoglobulin G concentrations increased on day 1 of life, thrombocyte number and plasma triglyceride concentrations rose during the first 7 days, whereas lymphocyte and monocyte percentage and plasma inorganic phosphorus, phospholipid, cholesterol and albumin concentrations increased during the first 14 or 21 days and then remained elevated. Eosinophil percentage increased after 3 weeks and insulin-like growth factor-I concentrations increased over the whole growth period. There were transient elevations of plasma glucagon concentrations up to day 14, of the activity of alkaline phosphatase transiently up to day 7 and of gamma-glutamyltransferase, aspartate aminotransferase and lactate dehydrogenase activities on day 1 of life. Plasma iron concentration transiently decreased up to day 28 and creatine kinase activity up to day 7. Total white blood cell number, neutrophil percentage, packed cell volume and concentrations of haemoglobin, calcium, magnesium (after a transient rise on day 1), non-esterified fatty acids, bilirubin, creatinine, triiodothyronine and thyroxine decreased from birth up to days 42, 56, 28, 28, 21, 84, 14, 14, 7, 14 and 7, respectively. Basophil percentage and concentrations of beta-hydroxybutyrate, urea and insulin did not exhibit significant age-dependent changes. The behaviour of most traits in the first weeks was the same in suckling calves under study as in non-suckling pre-ruminant calves. However, packed cell volume, red blood cell number, haemoglobin and plasma iron concentrations were higher, whereas glucose and insulin concentrations were lower than normally found in veal calves. On the other hand, concentrations of glucose, insulin and insulin-like growth factor-I in suckling calves in the third month of age were higher than can normally be measured in breeding calves.