Delayed feeding of first colostrum: are there prolonged effects on haematological, metabolic and endocrine parameters and on growth performance in calves?

To test the hypothesis that delaying first colostrum feeding of calves after birth exerts long-lasting effects on haematological, metabolic and endocrine traits and on growth performance, neonatal calves were fed first colostrum at 0–2 and 24–25 h after birth. Delayed feeding of first colostrum for 24–25 h after birth caused reduced plasma levels of total protein and globulin for up to 30 days and of insulin-like growth factor-I for up to 7 days, whereas concentrations of nonesterified fatty acids were elevated during the first day of life. There were no significant effects of delaying feeding for 24–25 h on leucocyte and erythrocyte number, packed cell volume and on haemoglobin levels and on plasma concentrations of albumin, urea, glucose, triglycerides, phospholipids, cholesterol, insulin, growth hormone, 3.5.3'-triiodothyronine and thyroxine and on growth performance. Thus, calves fed first colostrum with a delay of 24–25 h after birth were able to compensate rapidly for nutritional deficiencies on day 1 of life, i.e. there was no evidence for permanent imprinting of haematological, metabolic and of endocrine traits by starvation on the first day of life.