220 



Skimming Milk for Butter. 



to the end of the milking period ; but at no time does the 

 increased percentage of fat compensate for the loss in yield 

 of milk. In other words, a cow may generally be depended 

 upon to give a larger yield of butter-fat during the first 

 weeks of a milking period than at any subsequent time 

 during the same lactation. The following statement shows 

 the ratio of variation in yield of milk and percentage of fat 

 in periods of four weeks each. The first two weeks after 

 calving were omitted from the calculations because so many 

 abnormal conditions affect the flow of milk at that time. 

 The average for the first period of four weeks (commencing 

 from the third week after calving) is shown as 100, the 

 increase or decrease from that number representing the 

 variation in the succeeding periods. 



Average for 135 Cows. Xo. of Periods of four weeks, each after calving. 



1st 2nd 3rd 4th 5th 6th 7th Sth 9th iothnth 

 Milk - 100 96 93 89 85 81 76 71 67 62 55 



Fat - - - - 100 96 96 97 98 98 102 103 104 104 106 



The above table includes 135 yearly records, and it is 

 thought that such a large number must give a fair repre- 

 sentation of the average decrease in yield of milk and 

 increase of percentage of fat as the period of lactation 

 advances. The average decrease in yield of milk as lactation 

 advanced was about five per cent, from each period of four 

 weeks to the next. In percentage of fat there was an 

 average increase ot about one-half per cent, from month to 

 month. 



Sklmmixg Milk for Butter. 



Some experiments have been carried out at the Munster 

 Dairy Institute for the purpose of testing certain recommen- 

 dations in regard to the skimming of milk, which were con- 

 tained in a circular on butter-making issued by the Institute. 

 This circular advised that cream should be skimmed off at 

 the end of 12 hours, again skimmed at the end of another 

 12 hours, and finally skimmed after a third period of 12 

 hours had elapsed, or three times in 36 hours, special care 



