Outlines of dairy bacteriology, 10th edition / A concise manual for the use of students in dairying

by H. L. Russell; E. G. Hastings

Fig. 10.—Dirt from Milk.
The dirt adherent to each of the filters was obtained from one pint of milk. The milks tested were produced on different farms.

Much reduction as to the amount of dirt that finds its way into milk may be accomplished by improved stable environment. The fouling of the udder and flanks comes from wading in dirty water, muddy yards, and from improper type of stalls. Barnyards are often a disgrace through the accumulation of manure and seepage. Cows wading in such mire cannot but accumulate mud and filth to a material degree on the teats and udder. Greater care as to drainage of the barnyard and the paving of same with gravel, cinders, etc., will permit of its being kept clean, and so prevent the fouling of animals. But more important than the yard is the stall which the animal occupies in the stable. The essential feature is to have a stall of such construction as to keep the animal out of her own manure when she lies down. To accomplish this, it is necessary to have a manure drop behind the stall proper so that the feces and urine are kept out of the bed of the stall as much as possible.

Fig. 11.—The Model Stall.
A stall of this type keeps the animals clean, and thus aids greatly in producing good milk.

Most of the stalls widely advertised in the farm press seek to accomplish this in one way or another, usually by some arrangement by which the cow is forced back when standing and drawn forward on lying down. In Fig. 11 a type of stall is illustrated that accomplishes this most successfully; the essential feature being a 2×3-inch wood strip nailed to the stall floor immediately in front of the hind feet of the animal when in a standing position. When the animal lies down, she crowds forward to avoid lying on this strip, and thus is out of contact with the manure, except such as is carried onto the bedding by the hind feet. By the use of this stall it is possible to keep the animals free from all accumulations of manure.

Effort should be made to prevent fouling of the animals rather than in cleaning them after once soiled. It is very evident that where the cattle come to the milker with muddy udders, they will not be so cleaned before milking as to prevent a large amount of such dirt from entering the milk. However, when all that can be done towards keeping the cows clean has been accomplished, a small amount of grooming will greatly reduce the contamination coming from them.

The kind of bedding used in the stalls may have a marked influence on the contamination coming from the animal. If the straw is dusty, partially rotten and moldy, the bacteria and molds adhere to the coat of the animal and are thus introduced into the milk. In the case of cattle on pasture, no visible evidences of dirt are usually present but the hair is covered with the dust coming from the soil. There is very good reason to believe that the quality of milk is influenced by the type of pasture on which the cows graze, due to the difference in the types of bacteria in the surface soil. The milk from animals on low land is more likely to show undesirable fermentations than that from those grazing on higher lands. This is not due to the influence of the feed as is often supposed but rather to the dirt from the coat of the animal.

Washing the udder. If a surface is moist, dust and the adherent bacteria cannot be easily dislodged. The air over snow-covered mountains or over oceans is relatively free from bacteria. The udder and flanks of the animals can be carded to remove the loose hairs and the evident dirt; the fine dust can now be removed by wiping with a clean damp cloth just before the milking process. The actual washing and wiping of the udder and flanks still further reduces the contamination coming from the animal; experiments show a reduction of fully three-fourths of total contamination. Clipping the udder and flanks also aids in keeping the animal clean.