Ohlson D L, Koch R M, Klindt J, Davis S L
J Anim Sci. 1987 Jul;65(1):63-7. doi: 10.2527/jas1987.65163x.
Six Hereford bulls from a line selected with an index of body weight and muscling score were compared with six bulls from a control line to determine if increased growth in the selected line was associated with changes in plasma levels of growth hormone (GH), prolactin (PRL) and (or) thyrotropin (TSH). The predictive value of sire hormone data for growth rate of progeny was also evaluated. Bulls of the index line were heavier at birth (P less than .02) and had higher postweaning daily gains (P less than .01) than bulls of the control line. Blood samples were collected from bulls (ages 2 and 3 yr) at 15-min intervals for 8 h. Overall plasma GH concentrations were higher (P less than .03) in the index bulls than those in the control line. All characteristics of PRL secretion examined tended to be higher in the index bulls, but only mean overall and baseline differences approached significance (P less than .10). There were no significant differences in measures of TSH secretion between lines. Sire differences in hormone characteristics accounted for significant amounts of variation in birth weight and postweaning gain of progeny, but not in gain to weaning. Also, when considered jointly, hormone characteristics generally added significantly to predictions that used sire growth rate alone. The results suggest that serum hormone characteristics in parents may provide additional predictors of growth rates of progeny.
选取了6头依据体重和肌肉评分指数选育的赫里福德公牛，与6头来自对照品系的公牛进行比较，以确定选育品系中生长速度的提高是否与生长激素（GH）、催乳素（PRL）和（或）促甲状腺激素（TSH）的血浆水平变化有关。还评估了父本激素数据对后代生长速度的预测价值。选育品系的公牛出生时体重更重（P<0.02），断奶后日增重更高（P<0.01）。在2岁和3岁公牛8小时内每隔15分钟采集一次血样。选育品系公牛的血浆GH总体浓度高于对照品系（P<0.03）。所检测的PRL分泌的所有特征在选育品系公牛中往往更高，但只有总体均值和基线差异接近显著水平（P<0.10）。品系间TSH分泌指标无显著差异。父本激素特征的差异在后代出生体重和断奶后增重方面造成了显著的变异，但在断奶前增重方面没有。此外，综合考虑时，激素特征通常会显著提高仅使用父本生长速度的预测准确性。结果表明，亲本的血清激素特征可能为后代生长速度提供额外的预测指标。
