Heritability Estimates and Adjustment Factors for Yearling Testicular Size in DifferentBreeds of Beef Bulls

Relationship between Scrotal Circumference, Quantitative Testicular Traits and Growth Performance in Tropically Adapted Yearling Beef Bulls Differing in Age

Serving capacity of crossbred yearling beef bulls. I. Single-sire mating behavior and fertility during average and heavy mating loads at pasture.

Eighty crossbred, virgin, yearling beef bulls were subjected to three serving capacity (SC) tests. Ten low SC (LSC) and 10 high SC (HSC) bulls similar in weight (avg wt = 452 kg), testicular size and seminal traits but differing in average services were selected. Objectives were to evaluate the mating behavior and fertility of LSC and HSC bulls at pasture when exposed to an average and a heavy ...

Scrotal circumference in yearling Hereford bulls: adjustment factors, heritabilities and genetic, environmental and phenotypic relationships with growth traits.

Field data on 4,233 yearling Hereford bulls were analyzed using fixed and mixed model least-squares procedures to examine factors affecting scrotal circumference; determine appropriate adjustment factors; and study genetic, environmental and phenotypic relationships among scrotal circumference and growth traits. Scrotal circumference was affected by postweaning feed level; contemporary group/fe...

Age, season and breed effects on testicular volume and semen traits in young beef bulls.

A total of 218 yearling Hereford, Angus, Santa Gertrudis and Brahman bulls was evaluated for semen traits and testieular volume at average ages of 16 and 20 months in April and August, respectively, during 2 successive years. Brahman bulls reached puberty at a later age than bulls of the Santa Gertrudis, Hereford and Angus breeds. Santa Gertrudis bulls had the largest testes with the Brahman ha...

The Inheritance of Spermatozoan Midpiece Length and Its Relationship with Traits of Economic Importance in Cattle

approved: Redacted for Privacy William D. Hohenboken In two cattle populations; dairy and beef, the relationship between a bull's average spermatozoan midpiece length and production traits of economic importance was studied. In the first population involving 39 Holstein sires, variation in midpiece length between bulls and between ampules of semen from the same bull collected at least six month...