Age determination in crossbred calves using different techniques

The present investigation was carried out on 60 recently born crossbred cal ves up to 90 days of age to evaluate different methods of age determination , viz. visual observation of rostral teeth, teeth measurement and muzzle pr ints. The eruption of teeth from the gum line was faster during first and s econd fortnight. In the mapping method, the tooth area representing its gro wth was significantly different between genetic groups i.e. A ((1)/(2) Jers ey (1)/(4) Holstein Friesian and (1)/(4) Gir), B ((1)/(2) Holstein Friesian (1)/(4) Jersey and (1)/(4) Gir) and C ((1)/(2) Brown Swiss (1)/(4) Holstei n Friesian and (1)/(4) Gir), whereas, in the visual coding method, there wa s no significant difference in the growth of teeth between genetic groups. The mapping method used proved more efficient in determining the age. The d ifferent muzzle print characteristics namely ridged beads, clustered beads and converted beads indicated that number of beads was higher on the muzzle in the earlier age of calf. The association of age with various methods of age determination in crossbred calves up to the age of 90 days was signifi cant ( P < 0.01). Prediction equation indicated higher R-2 values for teeth area (62.41 to 92.10) followed by visual code (57.76 to 85.04) and muzzle print (40.96 to 44.89). The reliability for predicting the age varies betwe en genetic groups of crossbred as well as methods of age determination. The R-2 values indicated that teeth mapping was more precise method than teeth eruption and muzzle print for age prediction.