Reproductive and Hematological Effects of Feeding Diets Containing Gossypol to Mature Ewes

Abstract

The objectives were to determine what effects the short- or long-term feeding of diets containing gossypol to mature ewes had on reproductive and hematological variables. In Exps. 1 and 2, 29 Rambouillet ewes (avg wt, 128 ± 3.2 lb) and 35 Western white-face ewes (avg wt, 102.4 ± 3.6 lb), respectively, were randomly assigned to diets containing: (A) no cottonseed products (n=10, 12); (B) cottonseed meal and cottonseed hulls (n=9, 11); or (C) whole cottonseed and cottonseed hulls (n=10, 12, respectively). Ewes were fed 3.3 lb hd^-1 d^-1 of their respective diet for either 87 ± 3.9 d (Exp. 1) or 126 ± 5 d (Exp. 2). Free gossypol (FG; Exp. 1) or total gossypol (TG; Exp. 2) intake for diets A, B, and C were: 0, 0; 0.95, 2.87; and 2.42, 3.14 g d^-1, respectively. Embryos were surgically flushed from the oviducts of superovulated ewes 5 d post-estrus (d 0=estrus). Blood samples were taken from each ewe near the end of each experiment and serum hemoglobin and osmotic fragility of erythrocytes (RBC) were determined. Experimental data were analyzed by ANOVA and orthogonal polynomials. Controlled feeding of cottonseed products showed no effect (P>0.05) on ADG, estrous cycle length, interval to onset of estrus after synchronization, number of ovulations after superovulation, number of embryos recovered, quality score of embryos, or percentage of abnormal embryos. Serum hemoglobin increased in a linear fasion (P < 0.005, Exp. 1) and a quadratic fashion (P < 0.001, Exp. 2) as FG or TG intake increased, respectively. Erythrocyte hemolysis increased in a linear manner (P < 0.001, Exp. 2) as TG intake increased. Feeding cottonseed products to mature ewes resulted in no detrimental effects on reproductive variables measured. However, hematological evidence indicated that fragility of RBC increased as gossypol intake increased.