02082naa a2200301 a 450000100080000000500110000800800410001910000210006024501390008126000090022052012250022965000080145465000170146265000110147965000100149065000220150065000170152265300280153965300110156765300100157865300100158870000210159870000190161970000230163870000240166170000250168577300700171018096712017-03-30       2001    bl ---       0--  u    #d1 aSERENO, J. R. B.  aPrecocidad sexual de novillas de la raza pantaneira frente a las razas nelore y mestizas pantaneira x nelore en el Pantanal brasileno.  c2001  aThe objective of this work was to estimate the age at the first mount in heifers of Pantaneira (P) and Nelore (N) breeds and crossbreeding Pantaneira x Nelore (PxN). A total of 98 females was used, with 51, 24 and 23 from P, N and PxN heifers, respectively. All of heifers were born and growth up in typical native pastures of Brazilian Pantanal. They were weighted in the start and the end of season breeding, occasion where it takes place the pregnant diagnosis by rectal palpation. The variance analysis showed no significant difference (p=0.307) of age between breeds, showing 3.5, 3.4 and 3.2 years to P, N and PxN heifers, respectively. The results showed significant difference (p=0.0001) between ages and pregnant, showing that the older females (n=69; 3.5 years) became pregnant, while younger females (n=24; 3.0 years) were not pregnant. As the interaction between breeds and pregnant was significative (p=0.015), we studied the age in the pregant and observed significant difference (p&lt0.05) between no pregnant heifers: Pantaneira heifers (3.5 years) were older than Nelore (2.9 years). However, the pregnant N heifers (3.7 years) only showed significant difference (p&lt0.05) with PxN heifers (3,2 years).  aage  areproduction  aBovino  aIdade  aRecurso Genético  aReprodução  aAnimal genetic resource  aBovine  aMonta  aMount1 aPELLEGRIN, A. O.1 aLARA, M. A. C.1 aABREU, U. G. P. de1 aSERENO, F. T. P. S.1 aCHALITA, L. V. A. S.  tArchivos de Zootecnia, Cordobagv.50, n.189-190, p.153-157, 2001.