Effects of transportations, a high lactose diet and ACTH injections on the white blood cell count, serum cortisol and immunoglobulin G in young calves.

Twelve calves were subjected to 5 different, consecutive treatments considered to induce stress. These included a) transportations for 4–8 h at temperatures just above or well below 0°G at the start of the experiment and 6 and 11 weeks later, b) feeding a high lactose diet and c) ACTH injections. The transportations resulted in a transient suppression in the level of serum IgG, and increase of Cortisol, blood neutrophils and lymphocytes. One and 2 weeks after the first transportation, the lymphocyte count was suppressed. Intramuscular injections of ACTH also resulted in temporary increases in serum Cortisol, blood neutrophils and lymphocytes, but no obvious changes in IgG. Thus, the suppressed levels of IgG which were seen after the transportations did not appear to be directly related to the increased level of Cortisol. The high lactose diet was not accompanied by a significantly higher frequency of diarrhoea and lower mean weight gain. The IgG level did not appear to be influenced by the lactose level of the diet, and calves fed a high lactose diet responded similarly to transportation as calves fed a normal type of milk replacer. Apart from some diarrhoea, no health problem occurred.