Measures of Crainal Angles to Predict the Homozygous Polled Condition in Beef

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Kae Dee Rinderknecht and Jennifer Payne.
Dr. Glenn R. Wehner, Faculty Mentor, 1999.

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Anecdotal evidence concerning the apparent line of sight differences between horned heterozygous polled (without horn), and homozygous polled beef cattle prompted this research as to the quantification of these differences. Thirty-seven polled and twenty horned Gelbvieh cattle were crainly photographed in profile while under mild restraint. Physical markers of tip of nostril and lowest proximal jaw point served as a baseline and the line bisecting at the tip of the nostril through the center of the eye was utilized as the experimental treatment. Data revealed significant (P<.10) difference of 3.3 degrees with horned cattle having more oblique angles (ang. 45.4 degrees) than polled cattle (ang. 48.7 degrees). It appears that there is enough difference to warrant further investigation into this phenomenon since no DNA marker has been determined to identify homozygous polled cattle which is a very desirable trait.