Wilbur (12) found that dairy cows utilize ground corn and oats more 

 efficiently and economically than whole corn and oats. These two grains 

 when ground medium fine produced more milk and fat per 100 pounds of 

 grain fed than pulverized or coarsely ground grain. Darnell and Copeland (6) 

 found that when corn, oats, milo, and barley in the ground state were fed 

 to dairy cows, they were consumed in larger quantities than when fed whole. 

 Greater milk production was obtained in all the experiments when ground 

 grains were fed. Wallis and Olson (10) studied the effect of fineness of 

 grinding on corn and oats. They concluded that nothing was gained by fine 

 grinding and that it made little difference whether the grain was coarse or 

 fine. The medium grinding of grain, which was just sufficient to break up 

 the kernels into several portions, was considered to be the best practice. 

 They also found that more benefits were derived from grinding corn than 

 from grinding oats. 



Olson (8) concluded from two feeding trials that the coarsely ground 

 grain was equal or superior to finely ground grain. Ward (11) found in 

 palatability, milk, and butterfat production trials with dairy cows that 

 the cows showed slight preference for the coarse feed but the fine feed gave 

 slightly more milk and butterfat. He concluded that conventional rations 

 were as satisfactory as the coarse but due to the price difference the conven- 

 tional fine feeds were much more economical. 



Preliminary reports on most of the studies summarized here were pre- 

 sented in mimeographed form (3), (4), (7). 



Experimental 



This investigation was carried out in four different experiments. The na- 

 ture and time of each is given below. The digestion and utilization studies 

 were carried out in the Metabolism Laboratory of the Department of Dairy 

 Husbandry according to procedures as given by Benedict et al. ( 1) ; Colovos 

 et al. (5) ; and Ritzman and Benedict I 9) . The feeding experiment was carried 

 out at the Nutrition Research Barn uf the Department of Dairy Husbandry. 



Digestion and Utilization Experiment 1951 



A coarse-textured concentrate mixture and a medium finely-ground 

 mixture of similar composition were compared in eight complete nutritional 

 balance studies with four purebred dairy heifers. These heifers weighed 

 between 540 and 600 lbs. at the beginning of the experiment and included 

 two Guernsey, one Jersey, and one Ayrshire. Each animal was fed a daily 

 ration of 6 lbs. of chopped hay plus 8 lbs. of ground or coarse-textured feed 

 on all balances. The experiment was planned so that the two feeds could be 

 compared when fed to each animal. The concentrates used were obtained 

 from a local feed manufacturer in the form of a coarse-textured mixture 

 containing 700 lbs. cracked corn, 600 lbs. crimped oats, 300 lbs. wheat bran, 

 100 lbs. pea-size soybean oil meal, 200 lbs. brewers 1 grains, 40 lbs. pea-size 

 linseed oil meal, 20 lbs. iodized salt, 20 lbs. steamed bone meal, and 20 lbs. 

 pulverized limestone supplemented with cobalt and manganese. The ground 

 feed was prepared by grinding in a hammer mill fitted with a 3/32-inch 

 screen 100 lb. bags of the coarse-textured feed selected at random. It was 

 only slightly finer in texture than the so-called "fine feeds" sold throughout 

 the New England area. The hay used was from a lot of field-cured, prebloom 



4 



