Excessive intake of nutrients can result in decreases in the reproductive efficiency of goat bucks and increase production costs in goat e nterprises. In this study, the aim was to compare the reproductive features of young bucks fed diets for maintenance of growth or were fed ad libitum. Ten bucks were used (n = 5/group), with a completely randomized design. Blood and semen were collected from each animal every 2 weeks for nine collections. Semen was frozen and later analyzed using flow cytometry to compare reactive oxygen species, plasma membrane integrity, acrosome integrity, and membrane lipid peroxidation. Body condition score, sexual behavior, testicular biometry and histomorphometry of the testis, as well as oxidative enzymes and carbonylated proteins, were also evaluated. Animals fed ad libitum had a greater body condition score (3.32 + 0.08 × 2.88 + 0.05), sperm volume (0.68 + 0.04 × 0.52 + 0.03 mL), and testis circumference (25.2 + 0.21 × 24.5 + 0.24 cm) and volume (121 + 5.83 × 107 + 4.38 cm³, left testicle; 116 + 5.26 × 100 + 3.75 cm³, right testicle). Ejaculates of the bucks fed diets to maintain growth rate had a larger number of minor and total sperm morphology defects. There were no differences in testosterone concentrations and sexual behavior. In conclusion, there can be feeding for growth rate maintenance instead of ad libitum feeding, for the reduction in production costs of young bucks without compromising semen quality and reproductive functions.
Keywords: Ad libitum; Feed amount; Flow cytometry; Goat; Semen quality.
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