The objective of this work was to estimate the age and live weight at the first breeding in the Nelore (N), Pantaneira (P), and crossbreeding Pantaneira x Nelore (PxN) heifers. A total of 98 females was used for treatments, 51, 24 and 23 from N, P and PxN heifers, respectively. The statistical analysis did not show any significant difference (P = 0.3595) to live weight in the first breeding among breeds. The variance analysis did not show any significant difference (P = 0.307) of age among breeds, showing 3.5, 3.4 and 3.2 years to P, N and ½PxN heifers, respectively.The objective of this work was to estimate the age and live weight at the first breeding in the Nelore (N), Pantaneira (P), and crossbreeding Pantaneira x Nelore (PxN) heifers. A total of 98 females was used for treatments, 51, 24 and 23 from N, P and PxN heifers, respectively. The statistical analysis did not show any significant difference (P = 0.3595) to live weight in the first breeding among breeds. The variance analysis did not show any significant difference (P = 0.307) of age among breeds, showing 3.5, 3.4 and 3.2 years to P, N and ½PxN heifers, respectively.Esto trabajo tuvo como objetivo estimar la edad y peso a la primera monta de novillas de las razas Nelore (N), Pantaneira (P) y Mestizas Pantaneira x Nelore (PxN). Se utilizó un total de 98 hembras, siendo 51, 24 y 23 pertenecientes a las razas N, P y PxN, respectivamente. El análisis estadístico de los datos no reveló diferencia significativa (P = 0,3595) para el peso a la primera monta entre las razas estudiadas. El análisis de varianza no reveló diferencia significativa (P = 0,307) entre las edades a la primera monta entre razas, mostrando 3,5, 3,4 y 3,2 años para las novillas P, N y ½PxN, respectivamente
