36 . ILLINOIS STATE DAIRYMEN'S ASSOCIATION 



time the milk produced returns to its original solid content. 

 As the pasturing season advances the effect on the composition 

 of milk will depend largely upon how nearly the pasture main- 

 tains the cow and furnishes in addition food sufficient for the 

 amount of milk being given. In looking over our records I 

 find that the effect of giving four cows, having been fed a ration 

 of alfalfa hay and corn silage, access to rye pasture for three 

 weeks is as follows : ^ 



Average Percent of Fat in Milk. 



Three weeks before Three weeks on Three weeks again 



turning into pasture pasture on dry feed 



3.16% 3.35% 3.11% 



A heavy producing cow if fed no grain in addition to 

 pasture will in time draw upon her body weight, and a lowering 

 of the percent of solids may result. Again, during a period of 

 drought when cows are subjected to a partial starvation diet the 

 solid content of the milk has been known to become lowered. 

 During July and August, which were the dry months of a pastur- 

 ing season, the milk from herds sending to creameries in New 

 York lowered in fat as well as solids not fat.. 



It is the writer's belief after studying the data at hand that 

 the important point in connection with pasturing is whether 

 or not the pasture furnishes enough feed to keep the cow from 

 losing w^eight in addition to supplying food for milk produc- 

 tion. There are several instances which indicate that it is the 

 physical condition of the cow that affects the solid content of 

 the milk. Analyses made of many samples of milk coming to 

 creameries in Sweden show that from January until spring the 

 solids in the milk tend to lower, which is due to the fact that 

 the winter feed supply is usually exhausted in January, and 

 from that time on the cows depend largely on old hay stacks as 

 a source of feed. 



The effect of silage on the composition of milk has been 

 observed in several instances. Reports have indicated that silage 

 in the ration as compared with dried fodder plus the corn tended 

 to raise the fat content of the milk slightly. Such a comparison 



