Observation of normal and abnormal hair whorl patterning on the equine forehead

Journal of Animal Science, volume 72 Supplement 1 (1994) page 207

A.M.Swinker, M.J.Deesing, M.Tanner and T.Grandin
Colorado State University, Fort Collins, Colorado U.S.A.

In humans, scalp and hair pattern development have been linked to early fetal brain development. Patterning is determined at 10 to 16 weeks of early fetal life and is secondary to the growth and shape of tissues that underlie the skin, especially the brain. Anecdotal reports from horse trainers indicate that facial hair whorl patterns in horses are correlated to temperament.

The objective of this study was to observe the normal distribution of facial hair whorl positions. Observations were conducted on 423 horses consisting of 290 California racing Thoroughbreds and 133 Grand Prix jumping horses of varying breeds ( observed during the Masters at Spruce Meadows, Calgary, Canada).

Results indicated that hair whorls were categorized as:

*Abnormal whorls were defined as 3 or more on the forehead, or 2 whorls vertically placed on the facial area. Two horses had 3 whorls, one had 4, and the remaining (24 hd) had vertical placement.

A population bias of left sided whorls (47%) was noted. Traditionally, trainers handle horses from the left or near side. This population survey may possibly provide insight into handedness and temperament in horses.

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