FACTORES AMBIENTALES Y GENÉTICOS QUE INFLUYEN SOBRE LA EDAD AL PRIMER PARTO EN HEMBRAS DE LA RAZA ROMOSINUANO

Objetive. To Objetive study the enviromentals and genetics factors that influence on the age and the first delivery of romosinuano females bovines. Materials and methods. Materials and methods. From the age Materials and methods. to the first calving of native cattle of Colombia romosinuano, 932 data were studied from a herd at the Turipaná Experimental Station of CORPOICA, Cereté, Colombia, between 1980 to 2001. For the study of the environmental factors the variance analysis was used by means of lineal models using the GLM of SAS procedure (1995). Results. esults The age to the first calving was of 1162.3±4.2 days, with a coefficient of variation of 11.19%. The variance analysis revealed that the year and month from calving were statistically significant causes of variation of the age to the first calving. The heritability, calculated by the correlation intra class between half-sibs was of 0.16±0.08. Conclusions. Year Conclusions and month of birth influenced over the age in the first delivery of romosinuano cows. However, age heredability at first calve and the calf sex it appears to be no important.