ojxnriioxs aii-'ixtix(; the ciiukXAUii.i i \ oi ( ki:AAi 



Sectional view of Disljrow. 



containing a larger proportion oi' the softer fats than do tliose nf 

 any of the other Ijreecls. 



3. The period of lactation also affects the melting-point ot 

 l)utter-fat. When a cow is fresh she fields a larger proporticjn 

 of the soft fats than she does 

 later on in the lactation period. 

 Just how much this change in 

 the liardness of the fat is due 

 to advance in the lactation 

 jicriod and how much to 

 change from succulent to dry 

 feeds is not dcfinitel}' known, 

 since the two parallel each 

 other so closely, it being the 

 common practice in this coun- 

 try to have the cows freshen 

 in the spring. According to 

 investigations conducted at the Purdue Statinn,' the melting 

 point of the fat lowers as a cow ach'ances in her lactation period, 

 pro\'ided she is fed the same feeds throughout the year. If 

 these findings be correct, they mean that the influence of the 

 feed is much greater than that of the stage of lactation, since the 

 broad truth still remains, that under our conditions the propor- 

 tion of hard fats increases as the lactation period advances. 

 Witn this increase in the proportion of the hard fats in the 

 advancement of the lactation period, the fat-globules become 

 smaller. This, together with the increased hardness of the fat, 

 causes difficult churning at times. It readily can be seen that 

 the larger the fat-globules are the greater are the chances for 

 these globules to strike each other during agitation in the churn- 

 ing process. 



4. The nature of the food fed affects the melting-point of 

 butter to a considerable extent. Cotton-seed and its b_\--products 

 have been demonstrated thoroughly b)' se^•eral investigators to 

 cause butter to become hard. When a large amount of cotton- 

 seed is fed, the butter assumes a crumbl)-, tallowy, hard condi- 



' Purdue Kulletin 159, 



