Bulls with Perfect Hair are More Than Just a Pretty Face

Temple Grandin, Colorado State University animal behavior expert, and a graduate student have found a link between fertility and hair patterns on the heads of bulls.

Bulls with perfect hair spirals – or symmetrical hair whorls in the middle of their forehead – may be more fertile than bulls with abnormally shaped hair whorls, according to the research. The project, conducted by graduate student Melissa Meola, could help to predict which bulls may be more fertile and if the link is found in more studies it may help add up significant cost savings often spent on expensive fertility predictor tests, known as breeding soundness evaluations.

The research, released Thursday, suggests that hair whorls may be an indicator, but fertility predictor tests are still the best way to tell if a bull is fertile, cautions Meola. The effectiveness of a bull’s sperm has been proven to be connected to the sperm’s shape (normal or abnormal), known as sperm morphology. The tests were conducted on 150 black angus bulls.

Grandin and Meola believe that the link between fertility and hair patterns on bulls may be explained by the fact that hair patterns and reproductive systems generally develop in the womb at the same time.

"Our theory is that if there is some kind of disruption at that time of gestation, it may cause the hair whorl to take on an abnormal shape and also affect the reproductive system," said Meola.

For the study, Meola and Grandin classified facial hair whorls in the bulls as either having a round center or a non-round shaped center. Black Angus bulls with hair whorls with round epicenters had a higher percentage of morphologically normal sperm than bulls with non-round centered whorls. Eighty-two percent of bulls with round-centered hair whorls met the minimum threshold of 70 percent normal sperm; only 57 percent of the bulls with abnormal hair patterns reached that criteria.

"It is possible that facial hair whorl shapes could be used as a visual aid in determining the quality of sperm morphology during or prior to testing bulls for breeding soundness," said Meola. Breeding soundness evaluation tests play a significant role in determining the value of a bull to be used as breeding stock.

Grandin has studied hair whorls before, and found links between the placement of hair whorls on cattle’s heads and their temperament. In humans, abnormal hair whorl patterns on the scalp also are found in children with developmental disorders such as Down’s syndrome and Prader-Willi syndrome.