ABSTRACT
Fertility in Holstein Friesian and Black Pied Breeds. Population aspects

Santiago Urcelay V.1, M. Angélica Morales M.1 y Pedro Núñez G.1
 

Using de pure breed registers of the Sociedad Nacional de Agricultura and of the Asociación de Ganado Holandés de Chile, the fertility of these breeds was stimated from demographic indicators.
The general fertil ity rate was 48,35 and 44,97 per cent, in Holstein Friesian and Black Pied Breed, respectively. From 3 to 15 years of age, a Holstein Friesian cow calves 6.02 live offsprings, 3.19 being females; a Black Pied Breed cow, calves 5.99 live off prings, 3.02 being females. The age specific fertility rate showed its highest values at 3 to 9 years of age, with a peak at 4 years (58,44 per cent) in Holstein Friesian and at 6 years (53.95 per cent) in Black Pied Breed.

Keywords:
1 Méds. Vets., Facultad de Ciencias Agrarias, Veterinarias y Forestales, U. de Chile. Casilla 13, Correo 15, La Granja, Santiago, Chile.