BUTTER FAT YIELDS.

Shannon News, 4 March 1924, Page 3

BUTTER FAT YIELDS.

REASONS FOR VARIATION IN RETURNS.

The tendency on. the part of farmers to expect a close correspondence between the amount of 'butter-fat supplied to the factory and that indicated by the herd-testing results was the subject of comment by Mr H. O. Huse, secretary of the New Zealand Co-operative Herd-testing Association (states the New Zealand Herald). Mr Huse said that when two sets of returns agreed v it was merely a coincidence, for several factors operated to prevent close correspondence. - In the first place,, it was extremely unlikely that the feeding for the whole 30-day period should, be exactly similar to the feeding on the day when the herd-testing official obtained* his weights and samples. Yet it was well known that the feeding influenced the .yield materially, both in respect to quality and quantity. The factory calculations took into account the daily performance of the (herd, whereas the herd-testingi figures were based on one day's production as representative of the whole month. Variations from day to day throughout the whole month were reflected in the factory returns, but this was not the case in fie herd-testing returns. Continuing, Mr Huse said that feeding alone must be regarded as a potent factor in causing differences between , factory and herd-testing returns. The weather also affected the, returns, and caused variations wnich could not be accurately, noted in the herd-testing figures. ■ There was a tendency to overlook the loss that took' place during the process of separa-' , tion. Taking as a, basis that wellskimmed milk contained .01 per cent, of butter-fat, the amount of butterfat left N in the milk after separation would be considerable for a herd of cows throughout a 10 months' season. Mr Huse also referred to the milk * and cream used for household puri poses and the cream used for making butter in the ihouse. These losses wfere frequently overlooked when comparing! WenWtesffcing and 'factory figures. The quantity of milk consumed by calves and pigs and spilt about the milking shed would have a ! bearing oh tJie question. Then again, at the. commencement of a cow's test the yield was always calculated out for ,a 30-day period, although some of the cows of the herd might only have commenced their lactation period 5, 10, 15, or 20 days before the samples of' the whole herd were taken* Further, the end of tihe factory periods and the end of the herd-testing periods did not coincide, and this was. another factor to be considered. Cows were periodically out of normal condition, and were often suffering from bad quarters, lack of good drinking water, and other troubles which, dis- < turbed the quality and quantity of their milk flow; '

The testing officers under theV group system weighed the est half-pound, and in a herd of 50 cowi the quantity of milk shown would probably be greater thani it should be.