Determinación de la composición química de la leche en vacas holstein mestizas según el tercio de lactancia en la estación experimental Tunshi.

Abstract

This research animed to determine the chemical composition of the milk obtained from the crossed bred Holsetein cows`, at Tunshi`s Experimentel Station, in the Academic and Research Unit for dairy cattle, that belongs to the livestock Sciences at ESPOCH. This, whit a duration of 60 days 8 cows were part of the research form one third of breastfeeding from a total of 24 animals, the experimetal units were modelled under a bifactorial system in a combined arrangement. For the statistical analysis as study factor, A one third of the breastfeeding in milk production (first, second and third), and as a B factor, the cows were milked twice a day, in the morning and in the afternoon , and the interaction of the third of breasfeeding at milking time. The results shows that the chemical composition of the milk, presented the highest percentual of fat (1,80%), solids not fat (8,74%), density (32,85 g/cm3), protein (3,29%), freezing point (-0,59Cº) and lactose (4,96%) in the mik sample from the first-therd of breasfeeding. On the other hand , the evaluation oh the milk according to the milking time presented the hogher number in relation to conductivity (5,38mS/cm), pH (7,79), water (1,48%) y production/milking (8,24 l) in the sample collected during the morning. It was conluded that for the chemical composition oh the milk, the best third was the first-third obtained during the morning , It is recommended to use the necessary methods for the analysis and determination of ther main chemical and physical parameters for natural milk quality, that guarantees the safety of the producto.