Table 1.

Description of various bull traits used to define bull fertility

Trait	Abbreviation	Description	Units
Production traits
Concentration	CONC	Relative amount of spermatozoa per ejaculate, measured by a colorimeter	millions/mL
Number of spermatozoa	NSP	Calculated by multiplying spermatozoa concentration and semen volume; expressed in millions	millions
Volume	VOL	Total amount of the ejaculate, measured by weight	mL
Quality measures
Mass activity	MASS	Score from 0–5 with 0 being no activity and 5 being rapid, distinct swirls/ rapid swirling, slower swirling, generalized oscillation, and sporadic oscillation, similar measurement to motility score	score
Motility	MOT	Movement and swimming of sperm	%
Motility score	MOTSC	Score which scale varies depending on study.	score
Progressive motility	PROG	Swimming in a mostly straight line or large circles, measured by computer-assisted semen analysis	%
Morphology
Percent normal spermatozoa	%NORM	Percentage of morphologically normal spermatozoa	%
Percentage of living spermatozoa	%LIV	Percent of living spermatozoa with an intact cytoplasmic membrane after thawing	%
Abnormalities
Percentage of spermatozoa with an abnormal cytoplasmic droplet	DROP	Percentage of spermatozoa with a cytoplasmic droplet defect	%
Percentage of spermatozoa with an abnormal head	HEAD	Percentage of spermatozoa with a defect to the head of the spermatozoa	%
Percentage of spermatozoa with an abnormal tail	TAIL	Percentage of spermatozoa with a defect to the tail of the spermatozoa	%
Primary abnormalities	PRIM	Generally, defects of the head of the spermatozoa	%
Secondary abnormalities	SEC	Slight defects of the tails	%
Total abnormalities	ABNO	Percentage of abnormalities in the total ejaculate sample	%
Scrotal circumference
Scrotal circumference	SC	Circumference measured at the widest point of the scrotum with both testes fully distended	cm