By Heather Smith Thomas


with small testicles. Testicle size in bulls also tends to have an influence on fertility of their daughters. Te daughters of bulls with larger testicles tend to reach puberty sooner. Well-fed bulls generally reach puberty quicker than under- nourished bulls. Preparing young bulls for sale has focused on nutrition, oſten pushing them to grow quickly, so a num-


R 18 | TEXAS LONGHORN JOURNAL | HERD SIRE EDITION


esearch in the past several decades has shown that bulls with larger testicles tend to have more sperm and are able to settle more cows than bulls


ber of research studies have examined the role of nutrition in bull fertility. John P. Kastelic, DVM, PhD, Professor, University of


Calgary, has done a lot of research and studies on nutrition in bulls. “We started many years ago looking at beef bulls, and more recently with dairy bulls. In beef bulls historically, people focused on nutrition aſter weaning. Tere has been a lot of study on that, going back to the 1970s when Dr. Glenn Coulter (my former colleague at the Lethbridge Research


Eitan & Sandy Barhum photo


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