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A New Spin On Fertility

Article-A New Spin On Fertility

A bull's hair whorls may indicate his fertility, according to researchers at Colorado State University.

Research shows the location of hair whorls — the spiral of hair that occurs on the bovine forehead — is related to temperament (December 1995 BEEF, page 29). Cattle with a whorl above the eyes are more excitable than cattle that have a whorl located below the eyes.

Now, new research indicates that the configuration of the whorl — a spiral center opposed to a straight-line center — is indicative of a bull's fertility.

Colorado State University graduate student Melissa Meola found that Black Angus bulls bearing a spiral hair whorl with a round epicenter (Figure 1) had a higher percentage of normal sperm than bulls with an elongated hair whorl pattern (Figure 2).

A total of 150 Black Angus bulls were evaluated, and semen was collected from each during a routine breeding soundness exam (BSE). In addition, the bulls were classified by their hair whorl pattern.

About 100 sperm cells for each bull were evaluated under microscope using a staining technique. Each sperm cell was classified as either normal or abnormal, and defects such as bent tails and abnormal heads were counted.

Bulls with a normal spiral hair whorl with a round epicenter averaged 77.6% normal sperm. But bulls with the elongated abnormal pattern had only 69.4% normal sperm. To pass a BSE, a bull must have a minimum of 70% normal sperm.

In addition, the bulls were sorted into two extreme groups — those with either perfectly round spirals with round epicenters or those with elongated lines that were longer than the width of the bull's eyes. Of bulls with perfectly round spirals, 83% passed the BSE compared to only 50% of the bulls with abnormally elongated whorls.

The next group was sorted into all bulls that had a round epicenter compared to bulls that had an elongated epicenter that varied from barely noticeable to an extreme like that in Figure 2. Bulls that had no hair whorls were not used.

A total of 79% of the sperm cells were normal in bulls with round whorls with round epicenters, and only 71% of sperm cells were normal in bulls with non-round centers. Of bulls with round epicenters, 82% passed the BSE, while only 57% of the bulls with elongated epicenters passed.

How could a hair whorl be related to semen quality? Hair whorl patterns and gonad development occur at about the same time in the fetus. In humans, abnormal hair whorl patterns occur in children with Down's syndrome and Prader-Willi syndrome.

More research is needed to confirm these preliminary findings on hair whorls and semen defects. But remember that people thought it crazy when scrotal circumference was first introduced as a measure of bull fertility. Now it's an established part of a BSE.

Temple Grandin is a Colorado State University assistant professor of animal science and a livestock industry consultant on facility design, livestock handling and animal welfare. View her site at

Foreleg Size And Flightiness

I've observed in visits to packing plants that fine-boned cattle and other animals are more excitable. An Arabian horse, for instance, is fine-boned and nervous, but a workhorse is heavy-boned and calm.

To confirm these observations, graduate student Jennifer Lanier measured the foreleg bones (cannon bones) of feedlot cattle. The leg bones of 135 cattle were then collected at the slaughter plant.

The thickness and width of the foreleg, taken at the exact center of the foreleg bone, were measured. Temperament was measured by recording the animal's speed as it exited the squeeze chute, using a walk, trot or run designation. Australian research indicates exit speed is an efficient and objective way to assess temperament.

Cattle that walked out of the squeeze chute had significantly thicker foreleg bones than cattle that ran out. The foreleg bone was 9% wider and 5% thicker in cattle that walked out. The measurements were an average of 45.16 mm. (1.77 in.) in cattle that walked, and 42.52 mm. (1.67 in.) in cattle that ran.
Temple Grandin