Dairy Husbandry Department
Feed Grain, Milk Cows, Nutrition, Digestibility, Dairy
The ground beef bin on the Jones farm was empty. Mr. Jones pulled the switch and soon the little mill was humming a song that scarcely changed a note as the first few shovels of grain disappeared down its mouth.
Mr. Jones noted that the grain was scarcely more than cracked. He readjusted the mill to grind it finer, and soon it was spewing out an entirely different product. Did Mr. Jones make a mistake when he readjusted his mill to grind the feed finer for his dairy cows?
Results of an experiment conducted at the South Dakota Agricultural Experiment Station would indicate that Jones did make a mistake by grinding the grain fine – one that is common in the dairy industry. These are a few results of the experiment:
1. It made little difference in the case of milk cows whether grain was ground coarse or fine in relation to the food value obtained by the cow from the entire ration. Feeds need only to be cracked sufficiently to expose the kernel interiors to digestive juices.
2. More benefit was derived from grinding corn than from grinding oats. A total of 110 pounds of alfalfa hay and whole corn ration was required to equal 100 pounds of an alfalfa hay and medium-ground corn ration in food value. For whole oats the comparison was 102 pounds to 100 pounds.
3. After subtracting the food value of the alfalfa hay, it was found 119 pounds of whole corn were required to equal 100 pounds of medium ground corn in food value, and 105 pounds of whole oats were required to equal 100 pounds of medium ground oats. These figures may be used when combining these grains with o�her roughages in a ration. Little difference was noted in the food value of either grain when ground medium or fine.
4. Greater benefits were derived from grinding corn largely because greater amounts pass through the animal undigested when whole corn is fed. Nearly one-fifth (19.9 percent) of the whole corn fed was recovered from the feces (solid manure). For whole oats, recoveries in the feces ranged from 10.8 to 14.8 percent.
5. Ground grain rations were much more palatable than whole grain, and were more convenient for mixing with other ingredients in the ration.
Futhermore, it is generally understood that it costs more in time and money for fine grinding than for medium coarse grinding. The power cost is greater chiefly because of the greater length of time that the power must be used in grinding fine as compared with coarse. Calculations made from figures obtained from the South Dakota, Indiana and Ohio Stations indicate that it would take about 2 or 2Yz times as much power to grind the finely ground grain as for the medium coarse as used in this experiment. For instance, Indiana reported that it took 0.21 kilowatt hours (K.W.H. electrical power) for coarse grinding of 100 pounds of corn and oats and 0.57 kilowatt hours for fine grinding. If one were paying for electrical power from a highline the cost would be directly proportional to the kilowatt hours used. Essentially the same relationships would exist if tractors or gas engines were used as a source of power.
South Dakota State State College of Agriculture and Mechanic Arts, Agricultural Experiment Station
Wallis, G. C. and Olson, T. M., "How Fine should Grain be Ground for Milk Cows?" (1941). Agricultural Experiment Station Circulars. 31.