Tendencia y estacionalidad de la presentación de estros en vacas lecheras

Estrus seasonal behavior and tendency in dairy cows from Camaguey province, Cuba, were determined. Information on estrual females observation from January 1989 to December 2005 was collected from monthly records kept by six dairy production centers. A seasonal detaching procedure based on a serial time analysis was applied. A decreasing general tendency showing fluctuations in estrous cycle stability with a distinctive seasonal bahavior pattern was detected.This pattern was characterized by a marked decrease of estrual females between January and April, a recovery from June onward reaching peak values in July and August, and relatively high values between September and November. Such a seasonal behavior was associated to a higher grassland availability due to an increase in rainfall levels during the rainy season, which allowed females recovery after a food deficit stage. Taking into account Camaguey province conditions, these results prove the validity of similar investigations and also the dependence estrus cycles have on grassland availability more than on other factors.