The effect of supplemental feeding on the reproductive behavior of Canchim young bulls. III. Traits of the semen

Abstract

The objective of this work was to evaluate the effect of supplemental feeding during the dry period of 1982 and 1983 on physical and morphological traits of the semen in Canchim young bulls. Thirty weaned (eight-month-old) male calves were randomly alloted to the following treatments: T₁ - control, on Brachiaria decumbens pasture; T₂ - pasture plus 1.0 kg/an./day of a balanced concentrate; and T₃ - pasture plus 2.0 kg/an./day of concentrate. In the second dry period (year 2) the amounts of concentrate of T₂ and T₃ were increased to 2.0 and 4.0 kg/an./day. Semen was collected every 15 days up to puberty and monthly thereafter through 30 months of age, by eletroejaculation. The results indicated that treatments had no effects on the traits studied. The least square means of the traits at 30 months of age, for all treatments together, were: 7.1 ml for semen volume; 1.9 for gross motility; 42.6% for individual motility 3.8 for vigor 504.2 x 10³/mm³ for sperm concentration; 18.4% for total major defects; and 9.4% for total minor defects. There was a significant improvement on all traits as the animal aged. There were tendencies of improvement of the trails with increased scrotal circumference and testicular volume, within age groups; however, just a few of the correlations were significant, as the ones for sperm concentration at puberty (0.44 and 0.36).