Ewes were stratified by weight and randomly assigned into one of three dietary groups: maintenance control (C;N=16;100% National Research Council [NRC] requirements;2.4 Mcal of metabolizable energy per kilogram BW),overfed (O;N=16;200%NRC requirements) or underfed (U;N=16;60%NRC requirements) as described [14].
Diets were initiated 60 days before the onset of estrus (Day 0).
Ewes were fed their individual diets twice daily at 8 PM and 3 PM for the duration of the experiment, and every week ewes were weighed.
Individual diets were adjusted weekly to ensure the proper body weight (e.g., C, O, and U) was achieved at day 0 and maintained throughout the estrous cycle (s) and until completion of the experiment on Day 21 or 26 of saline (Sal) or Arg treatment.
Estrus was synchronized by insertion of a controlled internal drug release device for 14 days.