Growth rate, scrotal circumference, sperm characteristics, and sexual behavior of mixed-breed goat bucks fed three leguminous trees

Abstract

Aim of study: To investigate the effect of feeding foliage of leguminous trees on growth rate, semen characteristics, and sexual behavior of bucks. Area of study: Northeastern Mexico. Material and methods: Twenty-two young goat bucks were randomly allocated to one of four treatment groups: 33% alfalfa hay (dry matter basis), 33%; Acacia farnesiana; Leucaena leucocephala; or Prosopis laevigata foliage (n=4 for alfalfa; n=6 for the rest of groups). Main results: Average daily gain (ADG) did not differ between bucks fed alfalfa, A. farnesiana, or L. leucocephala (120 ± 26, 134 ± 37, and 103 ± 29 g/d, respectively), but ADG of bucks offered P. laevigata was the lowest (72 ± 8 g; p<0.05). Bucks fed alfalfa had the highest feed efficiency (6.59 ± 1.25 kg of feed consumed/kg of gain; p<0.05) and bucks offered leguminous trees had the lowest (average 9.85 ± 2.3). Bucks offered alfalfa, and A. farnesiana had increased (p<0.05) scrotal circumference (26.6 ± 0.4 and 25.8 ± 1.5 cm) than bucks fed L. leucocephala, or P. laevigata (24.3 ± 1.2 and 24.1 ± 2.0 cm). Mean ejaculate volume was two-fold higher in alfalfa-fed bucks than all other dietary treatments. Sexual behavior did not differ among bucks fed the different legumes. Research highlights: Foliage of both A. farnesiana and L. leucocephala could totally replace alfalfa hay for rearing growing goat bucks in confinement without affecting daily weight gain, most semen characteristics, and copulation ability. P. laevigata reduced body weight and reproductive function.