Estimation of equations relating fat and protein contents in milk of farmers of milk collecting centers

Abstract

The relationship between fat and protein content was studied in milk of farmers of Milk Collecting Centers (CAL) in the city of Valdivia, Chile, during autumn- winter and spring- summer 2000 and 2001. The objective of this research was to study the relationship between these parameters.
The milk samples were obtained from 10 farmers associated to Milk Collecting Centers and sample of milk tank.
Milk fat was determined by the Gerber method and protein contents by the Kjeldhal method. The data obtained from this study were statistically analysed through the software Statgraphic Plus 2.0.
Statistically significant differences of milk fat  (p<0,05), between samplings and farms were found in both seasons. With respect to protein contents  this parameter was similar in the season autumn- winter, but different in the season spring- summer. According to the average of fat and protein contents there were no differences between seasons.
The data of both parameters were analysed by linear regression  and second order polinomial models.   The best model studied was the polinomial regression to relationship of these parameters.
With a general equation for the autumn- winter season it is possible to calculate protein through the fat content of milk. But in spring- summer season it is necessary to obtain a particular equation for each CAL.