Mandibular cheek tooth eruption and development in Hereford cross Friesian steers as a means of age determination.

The development of the mandibular cheek teeth was examined, both visually and by radiograph, in a group of 76 Hereford cross Friesian steers, of which all but one were slaughtered at the same weight - 464 kg (1020lb). The age of the youngest animal was 1 year 0.3 months whereas the slaughter ages of the others ranged from 1 year 3 months to 1 year 8 months. The first molar was fully erupted and crown and root formation complete in all but the youngest steer. In the other five cheek teeth there were one or more significant differences between the mean ages of tooth development stages as assessed by radiograph. Cattle of 1 year 3 months could not be absolutely distinguished from those of 1 year 8 months by intra-oral second molar eruption. Examination of stages of development seen radiographically gave a maximum age range of 4 months before differentiation. In this study, development of the first two molars was in advance of the three permanent premolars and in these latter teeth the second premolar was the most developed.