The authors report an altered geometrical configuration of some basal body cylinder in a normal, apparently healthy cow. Defective basal bodies of the so-called 'half-centriole' are described. Only one microtubular pattern is composed of ten triplets encircling an apparently symmetric lumen. In medical literature there are a few documented cases of basal body cylinder defects. Most of them have been described in ciliary pathology. This paper deals with the first cases of basal body abnormalities observed in a healthy domestic animal.