Javad Habibizad, Ahmad Riasi, Hamid Kohram and Hamid Reza Rahmani

(Small Ruminant Research. 132: 37-43)

Abstract

This study was conducted to compare the effect of high energy or high energy-protein diets in long-term(16 days, flushing) or short-term (6 days, focus feeding) supplementation period on ovarian performanceand serum metabolites and hormones of ewes. For this purpose 40 cyclic Naeini ewes (40 ± 1 kg BW and2–3 years of age) were randomly assigned to experimental groups: 1—Control (CON), 2—long-term highenergy diet (LE), 3—short-term high energy diet (SE), 4—long-term high energy-protein diet (LEP), and5—short-term high energy-protein diet (SEP). Ewes were housed in the individual pens with free access tofood and water. The estrous cycle of ewes was synchronized with insertion of intravaginal progesteronesponges for a 12-day period. Follicular development was observed by ultrasound four days before toone day after sponge removing (−4 to +1) and blood was sampled once a day during this time. Resultsshowed that LE and SE groups had more large-size (>5 mm) follicles (P < 0.05) than those the other groupon day +1. Double ovulation rate was high in ewes fed with high energy diets. The LE and SE groups hadhigher (P < 0.05) serum glucose, cholesterol and insulin, but lower urea concentration compared to theother groups. Feeding high energy caused low serum oestradiol before the sponge removing. However,the LE and SE groups had the highest (P < 0.05) oestradiol concentration before the estrus time. Resultsof the present study revealed that change in dietary energy levels for a short-term or long-term periodjust before ovulation could improve the blood metabolites and reproductive performance of the ewes.

Key words: Feeding program, Energy, Protein, Folliculogenesis, Blood metabolites, Ewes