Abstract
Plasma growth hormone (GH), insulin-like growth factor-1 (IGF-1), thyroid hormone (T3 and T4), and vitamin A concentrations were examined in Japanese Black beef calves with marked retarded growth having diarrhea, pneumonia, coccidiosis or strongyloidiasis. Plasma GH concentrations were significantly higher in calves with retarded growth (23 cases; 14.3±9.5ng/ml) showing a rhythmical change as compared with that in clinically healthy ones (6 cases; 2.9±1.0ng/ml) showing no rhythmic secretion. Plasma IGF-1 and vitamin A concentrations were significantly lower in calves with retarded growth (30.1±15.7ng/ml and 15.7±7.7, μg/dl, respectively) as compared with those in clinically healthy ones (120.5±64.9ng/ml and 29.2±5.4μg/dl, respectively). There was no difference in plasma T3 and T4 concentrations between the two groups. These findings suggested that the retarded growth resulted from some endocrinological disturbances and malnutrition due to diarrhea, pneumonia or parasite infestations and that the estimation of plasma IGF-1 concentrations might be useful for prognosis.
