ALTERNATE TESTING PROCEDURES AS ALTERNATI VE FOR OFFICIAL MILK RECORDING

Objectives of this study were to investigate the accuracy of alternate testing plans of milk recording. From 20 herds enrolled in official m ilk recording, data were collected monthly: yield of evening, morning and daily milking and start of milking in the herd. Milk samples were analysed for fat and protein content. The correlation coefficients bet ween the a.m. or. p.m. milking and daily yields were in the range of 0 .90 to 0.98. Accuracies for estimating total daily yield from a.m. or p.m. tests were more than 95% (fat yield more than 90%). Bias in depen dence on cow average or herd average of milk yield for the test were f ound. Standard error for predicting daily yield was not reduced by usi ng multiple regression factors. Nevertheless accuracy of estimating of lactations yield by alternate recording is high. The mean deviations between the two recording plans were lower than 0.3%.