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A Profilometer for Studying Head Form of the Bovine^{1, 2,}

University of California³

Abstract

During the investigations at our laboratory concerning the physical manifestations of the dwarf gene in cattle, it became imperative to develop more refined methods and techniques to aid in identifying the different genotypes associated with the dwarf locus. The limited data of Johnson et al. (1950) indicated that this anomaly is conditioned by an autosomal recessive gene, and this is confirmed by more extensive data collected by Gregory et al. (unpublished).

Observations upon the dwarfs indicated that their heads were consistently different from those of normal animals in both proportion and conformation. Therefore it was suspected that an instrument which would record the head profile with precision might be of value, not only in studying the dwarfs, but in separating homozygous normal animals from the heterozygous normal (carriers of the dwarf gene), on the assumption that the two genotypes possess slight but consistent differences with regard to head shape.

The instrument described in this report was first visualized by the senior author. The problem of construction was placed in the hands of the junior author who was responsible for most of the engineering details. It required several months to develop a model that was successful in meeting all the demands in the field, and improvements are continually being made. The instrument is referred to as a profilometer and is shown in figure 1.

¹ This work was supported by the Kellogg Fund for the application of Genetics to farm mammals.

² This study was in cooperation with the Bureau of Animal Industry, USDA and the State Experiment Stations under Western Regional Project W-1 on Beef Cattle Breeding Research.

³ Davis, California.