Studies of the permanent incisor eruption, and body development, of the large East African Zebu (Boran): 1. The ages at first appearance of the incisors, lengths of the incisor eruption period, and source of variation

Abstract

Observations were made of the ages at first appearance of each pair of permanent incisors (‘eruption age’), and the time from first appearance to full eruption of each pair (‘eruption’), for Large East African Zebu cattle (Boran). For females the eruption ages were found to be 108.5±9.9 weeks, 137.2±12.9, 165.7±15.8, and 200.9±18.2 for incisor pairs one to four respectively; for steers the figures were 104.3±7.9, 130.3±10.6, 154.6±13.2, and 180.9±14.0; and for bulls 103.3±8.6, 127.6±11.2, 151.0±12.9, and 181.2±15.7. Females were significantly different from steers (p