Effect of collection stress on serum growth hormone levels in pygmy goats.

Four experiments were conducted with mature female pygmy goats to determine the effect of blood collection stress and blood collection method on serum growth hormone (GH) levels and the nature of serum GH variability. Repeated blood sample collection via jugular venipuncture did not affect serum GH levels. Comparison of serum GH levels in blood samples collected via jugular venipuncture and jugular cannula indicated a lack of significant difference between methods, although GH levels in samples collected by jugular cannula were higher and more variable. Restraint failed to influence serum GH in cannulated goats. Variability observed in serum GH in samples collected without the goats' knowledge indicates that GH is secreted episodically at irregular intervals irrespective of the constraints of this experiment. The data in these experiments indicate that, in pygmy goats, release of pituitary GH was not increased when the animals were subjected to stressful stimuli. We have demonstrated the validity of a bovine GH radioimmunoassay system for quantitating GH in the pygmy goat. (