Scrotal circumference and testicular consistency of yearling beef bulls

Abstract

This study was conducted to: (a) determine scrotal circumference (SC) and testicular consistency (tone) of performance tested, yearling beef bulls of various breeds; (b) correlate these values with performance data; (c) attempt, by means of a buyer survey, to evaluate the fertility and overall desirability of the beef bulls sold through the Virginia BCIA Bull Test Stations; (d) study the relationship between several semen characteristics, scrotal circumference, and testicular consistency measurements of yearling beef bulls.

Final SC was correlated .60 (P < .01) with initial SC and -.31 (P < .01) with final weak spring tone. Final weak spring tone was correlated .87 (P < .01) with final strong spring tone.

Final SC was positively correlated with final weight .44 to .64 (P < .01) and age .40 to .52 (P < .01). Final weak spring tone was negatively correlated with final weight -.35 (P < .01) and age -.30 to -.34 (P < .01).

When the least-squares means were calculated for final SC, the final SC of the Angus breed was significantly different from the final SC of the Simmental and Polled Hereford breeds (both P < .01).

For the bulls placed on a collection regimen, SC was positively correlated with ejaculate volume, .53 (P < .01) to .57 (P < .05), and with sperm output .55 to .71 (P < .01). No significant correlations were found between the tone measurements and the semen traits.