Genetic and environmental trends of growth and production in experimental herds under humid tropical conditions in Costa Rica

Abstract

Data for these analyses were taken from Dairy herds of the Department of Animal Industries, Tropical Center of the Inter-American Institute of Agricultural Sciences, Turrialba, Costa Rica. The maximum annual ranges in temperature and rainfall in this area are 17-23°C and 2.0-3.9 m., respectively. The average daily relative humidity is 86.94% with the absolute maximum during the day always 100%. These then are definitively tropical data. Body measurements (weight and withers height) of individual breed groups at different years were regressed on age using standard least-squares procedures. Breed group comparisons involving, Criollo (native breed), Jersey, Zebu, Brown Swiss and crosses of these breeds were made on the basis of the following traits: birth weight, average daily gain, average daily height, body weight predicted at 266 days of age, withers height predicted at 266 days of age, age predicted at 120 kg. of body weight, and milk production. ...