556 Scientific Proceedings, Royal Dublin Society. 



about one pint in volume was drawn daily from March 28th to June 17th, 

 inclusive, and from it the specific gravity of the milk was ascertained by 

 means of a lactometer. 1 



The cows were fed as follows : — 



In house from February to May 11th: 

 61b. of concentrates. 

 6 stone of roots, 

 oat straw or hay ad lib. 



From April 28th roots were replaced by | cwt. rye. 



May 3rd rye was „ „ vetches and rye. 



,, May 7th vetches and rye „ „ rape and hardy greens. 



To grass on May 11th— pasture: 



' From October 19th, cabbage on pasture. 

 „ „ 25th, hay on pasture. 



Into house on October 28th : 



61b. concentrates. 



cabbage and hay. 



Table 3 gives the measured and calculated results for cow 155. Similar 

 data were accumulated for each of the twelve cows. Diagrams were drawn to 

 represent the total daily milk, total daily fat and per cent, fat for each cow. 

 Two of these are appended, one— Plate LII — for cow 155, which did not calve 

 nor become in calf during the period, and another — Plate LIII — for cow 159, 

 which was served on February 20th, and calved on September '20th. This 

 group of cows exhibits variations in the daily returns similar to those 

 observed in the 1915 lot. When the four-consecutive-day method of 

 sampling for fat percentage is put to the test, it is found that in every case 

 it gives the approximate average for a period of about one month extending 

 equally on both sides of the date of sampling. From the tables and graphs 

 the following observations also can be made. 



(1) There is a pronounced variation in the daily fat percentage both when 

 the cows are in the house and on pasture. 



(2) The milk and total fat decline gradually before the cows go on to 

 the grass, but because the milk declines more quickly than the fat, the 

 percentage of fat rises slightly. 



( ; 3) Green feeding in the house does not materially alter the yield either 

 of milk or fat. 



1 Required for the second part of the experiment. From specific gravity and per 

 cent, fat the total. solids have been calculated. 



