CHURNING 281 



power of coalescence is greatly reduced and the formation of 

 butter granules is retarded. When cream containing butterfat 

 of this character is held at a low temperature for a considerable 

 length of time and is churned at that low temperature, the dif- 

 ficulty of churning becomes very marked and the churning pro- 

 cess may require several hours. On the other hand, in the case 

 of cream containing butterfat which is made up of a relatively 

 large portion of fats with a low melting point and has a soft 

 texture, the cream will churn quickly because the coalescence 

 of the soft fat globules is facilitated. 



Individuality, breed, age and length of milking period exert 

 some influence on the melting point and mechanical texture of 

 the fat. Thus the Channel Island cows produce butterfat with 

 a higher melting point and of firmer texture than the Holsteins 

 and Ayrshires, Quite often cows which have been in milk for 

 an abnormal length of time produce a very firm butterfat that 

 churns with great difficulty. But these factors must be con- 

 sidered rather incidental and of material influence only in the 

 case of butter that is made on the farm and from a small num- 

 ber of cows. 



The most important and decisive factor affecting the chem- 

 ical composition, melting point and mechanical texture of the 

 fat and the churnability of the cream is the feed. Experimental 

 investigations 1 have conclusively brought out the following facts 

 with reference to the influence of different feeds on the melting 

 point and mechanical firmness of the butterfat: 



Feeds which increase the per cent of olein usually tend to 

 make a soft butter. To these belong feeds rich in vegetable oils, 

 such as germ oil, corn oil, linseed oil, linseed meal rich in fat, 

 cottonseed oil, soya bean oil, soya bean meal, gluten feeds rich 

 in fat when fed in large quantities and blue grass pasture. 



Feeds which decrease the per cent of olein, such as feeds 

 low in vegetable oils, and rich in carbohydrates and sugars, tend 

 to make a firm butter. To these belong potatoes, corn meal, 

 corn silage, sweet corn fodder, wheat bran, sugar beets, etc. 

 Cottonseed meal also tends to make a firm and crumbly butter. 



It is obvious from the above results, that in winter, when 

 the cows are on dry feed and especially if the grain ration con- 



iHunziker, Spitzer and Mills. Purdue Bulletin No. 159, 1912. 



