Some Effects of Differences in Dietary Energy and Protein Levels on the Ovary and the Anterior Pituitary Gland of the Ewe

Abstract

Ninety-eight mature white faced ewes weighing an average of 60.4 kg. were used in 2×2 experiment to study the effect of two levels of digestible energy (5.2 and 3.2 meal.) with two levels of digestible protein (272 and 68 gm.) on ovulation. The rations were pelleted using casein, starch, alfalfa and timothy hays as the feed ingredients. At the end of the feeding period of approximately 55 days the numbers of corpora lutea determined at autopsy and laparotomy were 1.83, 1.92, 1.52 and 1.32 for high energy-high protein, high energy-low protein, low energy-high protein groups, respectively. The percent multiple ovulations and the weight gains in the same order were 78.0, 88.0, 48.0 and 28.0, and 5.3, 3.0, 0.4 and 0.3 kg., respectively. Significant increases in number of corpora lutea and percent multiple ovulations were observed with both high energy treatments. Pituitary gland hypertrophy accompanied the increase in ovulation rate in ewes fed high energy rations. Increase in pituitary gland size was associated with greater percent of solids, higher protein and higher ratios of protein/DNA and gland weight/DNA. Copyright © 1969. American Society of Animal Science . Copyright 1969 by American Society of Animal Science