FACTORS IN YIELD OF DAIRY COWS

Manawatu Times, Volume LIV, Issue 6812, 16 January 1929, Page 10

FACTORS IN YIELD OF DAIRY COWS

Some external factors affecting the vicld of dairy cows have been investigated by Professor Tuff, of the Nor wegian College of Agriculture. Questions of age, live weight, length of lactation, service period, etc., had been considered by means of flic herd of 180 cows at the Norwegian College, where, it is interesting to learn, milk records have been kept every tenth day since IS9O, states an English journal. In regard to the age of cows in relation to their productivity, Professor Tuff found there was a comparatively large increase in the quantity of milk up to eight years, and then the rise was less until there was a. maximum of 10 years. On the question whether there was any influence on the milk vield due to the live weight- of the cow, he could, according to a paper presented at the w r orld’s Dairy Congress, find no correlation. The average lactation period worked out at 315 days, or 45 weeks. It was found that the correlation between the previous dry period and the milk yield was very small, but there was a slight balance in favour of a dry period of over six w'eeks. Eighty-three milk records of first lactations showed that the daily milk yield rapidly increased during the first four weeks after calving to a maximum, and then TCgularly decreased. Closer investigation showed that the time for maximum daily yield varied greatly —from 10 to SO days after calving. Most cows have their maximum yield after 30 days, and 75 per cent, of the cows have their maximum daily yield between 20 and 40 day. l ; after calving. The quantity of milk given in the first lactation period was found to bo an uncertain measure of the lactation capacity. On the other hand, a greater correlation was shown between the second lactation and the subsequent milk yield.