| Popis: |
Prepubertal crossbred gilts (avg. initial BW of 109 kg; age 169 d) were used in two experiments to determine N retention, ovulation rate, and hormonal profiles. In Exp. 1, 43 gilts were used to determine apparent N and energy digestibility and ovulation rate. In Exp. 2, 14 gilts were used to measure hormonal profiles and plasma urea N. In both experiments, gilts received 1.8 kg/d of a corn-soybean meal based diet containing either 606.6 g (high) or 228.6 g (adequate) CP. Diets were formulated to be isocaloric, providing an average of 5,306 kcal/d DE. Gilts were fed their respective diets from d 3 of second estrus until d 10 after third estrus. Energy and N balance and plasma urea N were determined during the second estrous cycle. Hormonal profiles were determined during the second estrous cycle and at third estrus. Ovulation rate and ovarian characteristics were determined on d 10 after third estrus. Mean estrous cycle lengths were 2 d less for gilts fed high-protein than for those fed adequate-protein diets ( P P >0.85) energy balance but increased N retention ( P P P P |
