To the same effect speaks the following table giving the results of an experiment with a ration of corn and cob meal, in contrast with one of sugar meal. Each cow had a common ration of 12 lbs. corn fodder and 4 lbs. clover hay, in addition to the test diet which was 12½ lbs. corn and cobmeal in the one case, and 10 lbs. sugar meal in the other. To avoid the misleading effects of a sudden transition from one food to the other, each special ration was fed for seven days before the commencement of each test period.

Animal and Ration. Milk. Lbs. Fat. Per Cent. Solids Fat. Lbs. Solids Lbs. Ratio of fat to solids not fat.
Grade Shorthorn Cow:
1st 21 days: Corn and cob meal 631.25 3.43 11.57 21.67 73.02 422. :1000
2d 21 days: Sugar meal 641.50 4.04 12.53 25.93 83.38 476.2:1000
3d 21 days: Corn and cob meal 559.00 3.22 11.86 17.97 66.32 371.7:1000
Grade Shorthorn Cow:
1st 21 days: Corn and Cob meal 604.75 3.57 11.95 21.56 72.28 425.1:1000
2d 21 days: Sugar meal 582.00 3.91 12.37 22.74 72.57 456.3:1000
3d 21 days: Corn and cob meal 527.00 3.37 12.05 17.78 63.48 389.1:1000
Grade Shorthorn Cow:
1st 21 days: Sugar meal 753.50 3.97 12.43 29.94 93.67 469.8:1000
2d 21 days: Corn and cob meal 601.50 3.15 11.45 18.97 68.89 380.0:1000
3d 21 days: Sugar meal 560.50 3.85 12.16 21.58 68.16 463.3:1000
Grade Shorthorn Cow:
1st 21 days: Sugar meal 487.50 4.15 13.27 20.25 64.69 455.6:1000
2d 21 days: Corn and cob meal 379.00 3.51 12.00 13.30 48.09 382.3:1000
3d 21 days: Sugar meal 374.50 3.72 13.01 13.95 48.74 401.0:1000

Here we find a material increase of the solids and particularly of the fat whenever the sugar (gluten) meal, rich in fat and albuminoids was furnished. It is interesting to note the relative amount of fat and albuminoids in the corn and cobmeal mixture as compared with the sugar meal.

Constituents. Corn and cob meal. Sugar meal.
Per Cent. Per Cent.
Water 13.37 6.10
Salts 1.43 1.17
Fat 2.81 11.16
Carb-hydrates 65.99 52.66
Woody fibre 8.03 8.64
Proteids 8.37 20.27
—Bulletin: Iowa Agricultural Experiment Station.

Such variations in the quality of the milk under different rations, occasionally affect the weak stomach of the new born, and as the same constitution is likely to predominate in the same herd, a number may be attacked together as a result of some change in feeding.

Other conditions, however, lead to variation in quality. Hassall found that the morning milk of the cow furnished 7.5 per cent. of cream, while the evening milk gave 9.5 per cent. Boedecker found that morning milk had 10 per cent. of solids and evening milk 13 per cent. The first drawn at any milking is poorer in cream than that which is drawn last. The first may have only one-half or in extreme cases one-fourth of the cream that the strippings have. When the cow is in heat the milk not only contains more of the solids, but has granular and white blood cells like colostrum and often disagrees with the young animal. The milk of the young cow with her first calf is usually more watery than that of the adult, and that of the old one has a greater tendency to become acid. The longer the period which has elapsed since calving the greater the tendency to an excess of salts. Certain breeds like the Channel Island cattle produce an excess of butter fat (4–5 per cent.), whereas others like Holsteins, Ayrshires and Short Horns have less on an average (3–4 percent.), the casein and, it may be, the water predominating. Hence Jersey and Guernsey milk will scour calves which do well on that of one of these other breeds.

Overkept, fermented and soured food tends to produce acidity and other changes in the milk. Old brewers’ grains, swill, and spoiled gluten meal, or ensilage, especially such as has been put up too green, are especially injurious to the milk. The milk of cows fed on raw Swedish turnips or cabbage acquires a bitter taste and odor.

The milk of different genera of animals offer such strong contrasts that it is always dangerous to attempt to bring up the young of one genus upon the milk of another. The following table giving the composition of the milk in woman and each of the domestic mammals serves to illustrate this and to furnish a basis for adjustment:

Woman. Cow. Goat. Ewe. Camel. Mare. Ass. Sow. Bitch.
Density 1032.67 1033.38 1033.53 1040.98 1033.74 1034.57 1041.62
Water 889.08 864.06 844.90 832.32 904.30 890.12 854.90 772.08
Solids 110.92 135.94 155.10 167.68 134.00 95.70 109.88 145.10 227.92
Butter 26.66 36.12 56.87 51.31 36.00 24.36 18.53 19.50 87.95
Casein and extractive matters 39.24 55.15 55.14 69.78 40.00 33.35 35.65 84.50 116.88
Sugar 43.64 38.03 36.91 39.43 58.00 32.76 50.46 30.30 15.29
Salts(by incineration) 1.38 6.64 6.18 7.16 5.23 5.24 10.90 7.80
Becquerel and Vernois.

Not only does the milk vary so widely with the genera, but that of the ruminating animal with its great excess of casein coagulates in the stomach into large dense clots which are not easily penetrated and digested by the peptic juices while that of woman or soliped forms loose clots, easily permeable by the gastric fluids and therefore much more readily digestible. Indeed the milk of these monogastric animals often form loose floating flocculi only, instead of solid clots. As cows are usually selected for foster-mothers to the orphaned animals of other genera this becomes a source of danger to the young and must be obviated by modifying the milk more in keeping with that of man or soliped.