Composição do leite de cabras mestiças em diferentes condições ambientais.

Abstract

This study aimed to evaluate the composition of milk of crossbred goats maintained at shade and at sun and milked at morning and late during hot and humid season. Ten crossbred goats Anglo-Nubian were used, with average weight of 60 kg and average age of 36 months. The environmental variables were monitored throughout the experiment inside or outside of shed. Data were evaluated by F test analysis at 5% probability. The goats were distributed in a completely randomized design, in a factorial scheme 2 X 2 (two environmental factors, sun and shade, and two periods of milking, morning and afternoon) on days 0, 15, 30, 45 and 60. After fourteen- days of adaptation period, the animals remained grazing on the sun (five animals), and inside the shed on the shade (five animals). The goats were fed with bulky, commercial concentrate, water and mineral salt ad libitum. The environmental variables influenced the production and milk composition of goats. The growth was affected by the age of goats and lactation stage. The results obtained in this study indicate that sun exposition provoked higher discomfort to animals, because the production and milk composition decreased. The average NFDE of 6.6% was lower than recommended of 8.5% by the Brazilian current legislation. The SCC was changed by the period of milking, but wasn't by the environment, which can be justified by the inherent resistance of crossbred goats to infections of the mammary gland. Environmental variables had correlations with milk components (P < 0.01). Crossbreed goats must be maintained at shade during dry season, and milked at morning to higher production and milk composition.