黒毛和種発育不良子牛の血中成長ホルモン，IGF-1，甲状腺ホルモンおよびビタミンA濃度

鹿児島大学農学部（〒890-0065　鹿児島市郡元1-21-24）

（1998年3月17日受付・1999年3月18日受理）

要　　　　　約 　下痢・肺炎の罹患率が高く，コクシジウム・乳頭糞線虫などの感染が観察された黒毛和種発育不良子牛の血中成長ホルモン（GH），インスリン様成長因子-1（IGF-1），甲状腺ホルモン（T3，T4）およびビタミンA濃度を測定して内分泌学的要因の解析を行った．GH濃度は発育不良子牛（23例; 14.3±9.5ng/ml）では高く律動性分泌を示したのに対し，対照正常発育子牛（6例; 2.9±1.0ng/ml）では低く律動性分泌は認められなかった．IGF-1濃度とビタミンA濃度は発育不良子牛（それぞれ30.1±15.7ng/ml，15.7±7.7μg/dl）では，対照子牛（それぞれ120.5±64.9ng/ml，29.2±5.4μg/dl）に比較して有意に低かった（p＜0.05）．甲状腺ホルモン濃度は両者間に差はみられなかった．発育不良子牛の血中IGFh1濃度の低下は下痢，肺炎あるいは寄生虫感染に伴う低栄養状態により引き起こされたと推測されたことから，予後判定には血中IGFh1濃度測定が有用と考えられた． ―キーワード：発育不良子牛，成長ホルモン，IGF-1，甲状腺ホルモン，ビタミンA． --------------------日獣会誌　52，427〜430（1999） Blood Concentrations of Growth Hormone, Insulin-Like Growth Factorh1, Thyroid Hormone and Vitamin A in Japanese Black Calves with Retarded Growth Mizuho ISHIBASHI, Kanji USHINOHAMA, Syunichi KAMIMURA and Katsumi HAMANA Factulty of Agriculture, Kagoshima University, 1-21-24 Khorimoto, Kagoshima 890-0065, Japan SUMMARY 　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±9.5 ng/ml) showing a rhythmical change as compared with that in clinically healthy ones (6 cases; 2.9±1.0 ng/ml) showing no rhythmic secretion. Plasma IGF-1 and vitamin A concentrations were significantly lower in calves with retarded growth (30.1±15.7 ng/ml and 15.7±7.7μg/dl, respectively) as compared with those in clinically healthy ones (120.5±64.9 ng/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 IGFh1 concentrations might be useful for prognosis. ―Key words : calf with retarded growth, growth hormone, IGF-1, thyroid hormone, vitamin A. --------------------J. Jpn. Vet. Med. Assoc., 52, 427〜430 (1999)