Prenatal androgenization of lambs: I. Alterations of growth, carcass characteristics, and metabolites in blood.

Eight ewe lambs (TE) born to ewes implanted with testosterone propionate between d 40 and 70 of gestation and 10 ewe lambs (CE) and 10 wether lambs (CW) from non-implanted ewes were used to measure the effects of prenatal androgenization on growth and metabolism. Starting BW (approximately 60 d of age) were not different among treatment groups. Finishing BW of TE and CW tended to be greater (P < .10) than those of CE; ADG of TE was 13% greater (P < .05) than ADG of CE. The DMI tended to be greater (P < .10) for TE than for CE but feed efficiency did not differ among treatments. Carcass weights were greater (P < .05) for CW than for CE. Subcutaneous fat, internal fat, and longissimus muscle area were not affected by sex or prenatal androgenization. Increases in glucose concentration in plasma from prefeeding to postfeeding were greater (P < .05) for CE than for TE or CW. The concentration of NEFA in plasma decreased (P < .05) from growing to finishing stages for TE and CW but remained constant for CE. Plasma glycerol concentration decreased more (P < .05) after feeding for TE and CW than for CE. Average concentrations of insulin (P < .01) and the increase of insulin after feeding (P < .05) were greater for TE and CW than for CE. The average concentration of urea N in plasma tended (P < .08) to be greater for CW than for TE or CE.(ABSTRACT TRUNCATED AT 250 WORDS)