Page 6 - Turiroa Angus Sale 2021 ebook

REPRODUCTIVE FERTILITY IN HERD BULLS.

The most important factor influencing the profitability of a beef cow SEMEN QUALITY.
operation is the percentage of the calf crop weaned. The herd bull Semen quality is determined by the volume of the ejaculate and by the
influences overall herd fertility more than any other single animal. MOTILITY and MORPHOLOGY of the sperm cells.
Several factors influence a bull’s fertility. A bull must be developed Sperm MOTILITY is calculated by evaluating the percentage of spermatozoa
properly and have reached puberty to be fertile. Other determinants are with forward movement in a sample ejaculate. Semen MORPHOLOGY is
social dominance, Libido, good nutrition as well as physical characteristics calculated by evaluating the number of normal spermatozoa in a sample
such as SCROTAL CIRCUMFERENCE and SEMEN QUALITY. ejaculate in relation to sperm with primary and secondary abnormalities.
SCROTAL CIRCUMFERENCE. Semen MORPHOLOGY influences pregnancy rates therefore selection of
As scrotal circumference increases, so does the daily production of high bulls with better quality semen can help increase overall pregnancy rates
in a herd.
quality sperm. There is a positive correlation between a sire’s scrotal
circumference, the scrotal circumference of his sons and the pregnancy NOTE: Turiroa has been selecting for large scrotal size for many years
rate of his daughters. Bulls with a larger scrotal circumference are likely to and have listed the individual Morphology of each bull catalogued.
sire sons with large scrotals and his daughters are likely to reach puberty The standard is 75% or better for Morphology. Most Turiroa Bulls are
at younger ages and are more likely to be cycling at the beginning of the consistently achieving well over this. Also included is actual scrotal size (
breeding season and are more likely to become pregnant earlier when taken April 2021) and dams performance by way of calves born , eg 6/6
compared with the off-spring of bulls with a small scrotal circumference. . (Six calves born from six matings etc.) in a simple easy to read box.
All bulls scrotal measurement is an in - direct estimate of the mass of
testicular tissue, which is directly related to sperm quantity and quality
which is a measure of his capacity eg. Bull to cow ratio.