DAIRY FARMING. History reveals that many species of mammals have been used as a source of milk for human consump tion. The most common references to sources other than that of the human mother were to the cow, ewe, goat, and the mare. Today the ewe and the goat are extensively used in many coun tries. In France Roquefort cheese is produced from ewe's milk. In Italy many varieties of cheese are produced from goat's milk. Almost every city in the United States has a limited supply of goat's milk, the result of a demand created by physicians who recommend its use for those who cannot assimilate cow's milk. When milk is mentioned, however, the reference is to cow's milk unless otherwise specified.
Meat and milk products have been used abundantly by most of the European countries. Butter and cheese are mentioned in the earliest recorded references to human food products. The animals used as a source of meat and milk by the people of the old world were as varied as the history of the people themselves. The in fluence of immigration, conquest, and environmental conditions such as climate, topography, and fertility of the land has resulted in the development of a large number of types of animals of the same species. Up to the 17th century little attention had been paid to the improvement of livestock or to the development of breeds for special uses. The year 1770 is mentioned as the beginning of livestock improvement. It was around this time that interest was aroused in Great Britain in the improvement of cattle and other domestic animals. The demonstrations of im provement by selection of livestock were so striking that the movement spread rapidly throughout the world and formed the beginning of improved breeds of livestock. This interest in im proving livestock was timed to be of greatest benefit to livestock development in the United States. It made possible improved and specialized breeds of livestock for this new market. The early colonists had brought some livestock with them, but few of these survived. The foundations of most of the American breeds of livestock were brought to the United States early in the 18th century from Europe.
It can be said for dairy farming that when properly managed it will maintain or increase fertility to a greater extent than most systems of livestock farming. It is for this reason that dairy farming is followed on some of the oldest and highest priced land in the world. The dairy farmer not only feeds most of the crops produced on his farm, but he also purchases feeds which are high in protein and thus enriches the manure produced by his animals. A dairy cow fed properly will produce about 12 tons of solid and liquid manure in a year. This manure when properly handled will increase farm crop yields sufficiently so that a farmer can realize from $2 to $6 per ton for manure. A dairy farmer by feeding his crops to his cows sells less fertility from his farm than when he sells crops. The value of fertilizing elements—nitrogen, potash, and phosphoric acid—in a ton of butter is about 32c and in a ton of milk $1.46. In a ton of alfalfa hay the value of fertilizing elements is $6.68, in a ton of corn $4.88, and in a ton of wheat $6.16. This is based on a price of 1 oc per pound for nitrogen, 6c for phosphoric acid, and 5c for potash. Dairy farmers in recent years have taken advantage of research in crop improvement and are using high yielding clovers and alfalfa to the exclusion of non-legumes. This plan also is conducive to maintaining soil fertility and reduces the need of purchasing pro tein supplements to feed their animals.
The dairy cow has an advantage over some types of livestock in her ability to consume large amounts of roughage. High pro ducing cows are generally fed all the roughage they will consume and grain supplements to make up the nutrients required. In the European dairy countries the dairy cows are fed mostly on hay and pasture, while in the United States dairy cows are fed more liberally on farm-grown grains. An efficient dairy cow will return more edible food nutrients from food eaten than will other classes of livestock. For each 10o pounds of digestible nutrients in her feed she will return 18 pounds of edible milk solids.
In spite of the many factors favourable to dairy farming, the amount of labour and the daily routine of painstaking labour involved are objectionable to many farmers. Perhaps this condi tion is an advantage in that it limits the number of dairy farm ers. The milking machine and labour saving barns and equip ment have made dairy farm labour less irksome on many farms. Because dairy farming is a year round job, labour is utilized to better advantage than on some other types of farms. Dairy farm ing is generally a safer type of farming because it means a daily income for the farmer. On most dairy farms the world over the labour involved in handling dairy cattle becomes a family enterprise, and labour may be used that would not otherwise be used to advantage. The extent to which dairy farming is followed in the United States may be indicated by the fact that, of a total of 6,800,00o farms in 1937, 5,232,000 reported cows were kept for milk production. Almost every farmer keeps a few cows. When their production becomes more than the needs of the family, the surplus is sold. The United States census defines a dairy farm as one where more than 40% of the income is from dairy cattle. This reduces the number of specialized dairy farms to about 600,000 in the United States. The leading States in total milk production in the United States are Wisconsin, Minnesota, New York, and Iowa.
The term "dairy cows" refers to dairy cows two years old or over kept for milk production. By "dairy cattle" is meant dairy animals of all ages and both sexes. The term "pure bred cattle" refers to animals whose ancestry came from the original home of the breed mentioned and whose record of descent has been re corded in the herd books of the breed.
A grade or unregistered animal may show the characteristics of one of the breeds, but its ancestry has been mixed with unregis tered animals or for other reasons it cannot be registered. Most of the dairy animals in this country are classed as grades. Less than 4% of dairy cattle are pure bred.
Pure bred dairy cattle registered in the United States during 1937 were: Ayrshire, 14,103 ; Guernsey, 50,312 ; Holstein-Friesian, 79,110; Jersey, 43,682; Brown Swiss, 8,566.
In the United States more than one-fifth of the total annual agricultural income comes from dairy cows. A big proportion of our farms not only keep cows for milk production but they sell dairy products. The degree to which a farmer engages in dairy farming is subject to a large number of ever changing conditions. It is common knowledge that the most productive type of farming over a long period of time is the type that utilizes most of the crops produced on the farm in producing livestock or livestock products. The type of livestock used will depend upon the oper ator. The specialized dairy farmer will probably keep either grade or pure bred cattle of one of the special breeds of cattle. Even the general farmer may have dairy cattle, the number de pending upon the extent to which he engages in dairy farming.
Some factors that may determine the extent to which a farmer engages in dairying are : nearness to special markets; the size of his farm; the kind of land; availability of labour; and type of farming in the locality.
A dairy farmer generally chooses one of the following markets: (I) sell to a pasteurizing plant for use as fluid milk; (2) bottle and sell his own milk either raw or pasteurized; (3) sell milk to a condensery, cheese factory, or creamery; (4) separate the milk and sell the cream to a creamery or other dairy plant ; (5) churn the cream and sell butter in a nearby town.
Most of the specialized dairy farmers have a special market for their products. By far the greatest amount of cream for butter is produced by the farmer who separates his milk on the farm and sells cream. This leaves the skimmed milk, nutrition ally the most valuable part of the milk, for feeding livestock on the farm. To utilize the skimmed milk to advantage, a farmer should have some hogs and chickens, in addition to the calves he raises for replacements, to consume this by-product. It is this type of dairy farming that encourages a diversified system of farming and has made pork production and poultry raising a valuable adjunct to dairy farming. It is for this reason that dairy farming is so generally followed in the agricultural section of the United States. The dairy stock may consist of 12-15 cows in milk, 5-6 heifers, a herd sire, and a few young calves. To house these cattle a rectangular barn with a cement floor and stalls for the cows in milk is desirable. The hay is commonly stored in a mow above the cattle, and a silo is located near the barn for con venience in feeding. On the specialized dairy farms certain re quirements must be met in housing the animals and handling the milk. It is common to build a milk house near the milking barn but distinctly separate from it, with facilities for cooling the milk and washing utensils. Regulations covering the production of milk for the fluid milk market are formulated by State laws, city ordinances and special conditions specified by the purchaser. In the case of the producer of cream, the regulations are less rigid but it is desirable that he too have a milk room for separating the milk, cooling the cream, and washing the utensils. The cream should be kept cool and delivered to the creamery sweet or only slightly sour. Cream is generally delivered or picked up by trucks at the farmer's door, twice a week in winter and every other day in the summer.
The cream is paid for on the basis of its butterfat content as determined by the Babcock method. Cream testing 3o-35% butterfat is desired. Each delivery of cream is tested for butterfat and in some States laws specify that a differential in price will be paid for cream of different grades of quality. Low grade cream is rejected. One hundred pounds of milk when separated will pro duce between 82-85 pounds of skimmed milk and 15—i8 pounds of cream, depending upon the per cent of fat in the milk and the per cent of fat in the cream. A comparison of normal milk and skimmed milk is given below: Not only is most of the protein of milk left in the skimmed milk, but this protein is of the highest quality for human or livestock feeding.
The butterfat removed from the milk is valuable commercially, but as a feed for livestock it can be replaced by corn at a material saving. In feeding calves between one month and six months of age, two pounds of corn are equal to a pound of butter fat as a source of energy. Skimmed milk is a valuable food for human consumption since it contains everything in milk except the butterfat and the accessory elements in the butterfat. Skimmed milk becomes valuable commercially only when it is dried. The development and use of dried skim milk may eventually cause more milk to be delivered to creameries where the milk can be separated and dried. The utilization of skimmed milk on a general dairy farm may determine the profit or loss of the dairy herd. The management of the dairy herd has an important bearing on the production of the herd, the use of labour, and the success of the entire venture. In most of the dairy States in the United States outside of the milk shed, the cows are bred to freshen in the fall of the year. This means that the cows will produce best during the winter months when butterfat is highest in price and when the farmer has more time to spend with the herd. This also means that many of the cows will be dry during the busy crop season. This plan of winter dairying is not suitable when milk is sold and a constant supply throughout the year is necessary. It is common knowledge that fall freshening cows turned to grass in the spring will produce more in the year than spring freshen ing cows.
The specialized breeds of dairy cattle in the United States are: Jersey, Guernsey, Ayrshire, Holstein-Friesian, and Brown Swiss. The Milking Shorthorn, Red Polls, and Polled Durhams are listed as dual purpose or milk and beef breeds. In England and in some herds in the United States, the Milking Shorthorns have all the characteristics of the special dairy breeds. The advantage a dairy farmer has in using a specialized dairy breed is that he gets the benefits of years of selection for the characteristics of a special dairy animal. There is no one breed that is especially better than another in efficiency of production. The breeds vary in colour, size, per cent of butterfat. and amount of milk produced. When it comes to efficiency of production, it is a matter of individual animals.
The only sure way to measure a cow's ability is to use some means of estimating the amount of milk she produces and the amount of feed eaten. This may be done by weighing the milk from each milking or by weighing the milk one day of each month and using this as a basis for estimating the milk for the period. The feed eaten may be estimated in a like manner. This may be done by the owner, by a representative of the Cow Testing Asso ciation, or by a representative of the breed association.
In the United States at the present time less than 3% of the cows have any records of production, and records were kept on more cows in 1938 than for any year to date. In Denmark some districts have as many as 5o% of their cows in cow testing asso ciations.
A cow testing association, or dairy herd improvement associa tion, as used by the United States Department of Agriculture is an organization of dairy farmers, 25 or 26 in number, who employ a man to spend one day of each month with each herd. While at the farm he estimates the milk produced by each cow and the feed consumed during the same period. A sample of each cow's milk is tested for butterfat by the Babcock method. Using this day's production as the average for the month, the estimate for the month can be determined by multiplying by the number of days in the month. At the end of a year a summary may be made on each cow. The tester also helps the farmer with his feeding and man agement problems. Cow testing associations originated in Den mark and are very common in all dairy countries. In the United States each dairy breed association, in addition to recording the ancestry and issuing registration certificates on pure bred animals, has a system of advanced registry for supervising and recording records of production. The records are supervised in co-operation with the agricultural college in each State at the request and expense of the breeder.
Some exceptionally high records have been made by representa tives of each breed. These records are important to the end that they show the possibilities of maximum production without regard to economy of production. The cows are liberally fed, milked three or four times a day, and handled to produce to the maximum. The records in Table II. were made under the uniform rules adopted by the breed association in the United States. Two of the records were made in Canada, but under supervision similar to that in the United States.
The average butterfat production of the cows kept for dairy purposes in the United States was 1691b. of butterfat in 1938. It is generally assumed in the United States that a cow should produce 2oolb. of butterfat in a year to pay for her feed. United States cows in co-operative cow testing associations in 1938 pro duced an average of 7,8311b. of milk and 3171b. of butterfat. In unselected herds of dairy cows in the United States, or in most any State of the United States, one-third of the dairy cows are kept at a loss, another one-third will about pay for their feed, and the remaining third will produce profitably if properly fed and cared for.
A dairy cow should be bred in the third month after calving. This will permit her to milk ten months and be dry two months before giving birth to a calf. During this ten-months' period, a cow should produce at least a pound of butterfat per day to pay for her feed, labour, and overhead costs. It cost about $70 per year to feed the average cow testing association cow in this is only one-half of the total cost of keeping a cow.
The chances of getting high producing animals can be increased by carefully selecting the ancestors of our cows. The ability of a herd sire is reflected in the progeny of every cow in the herd. Here again we cannot measure a sire's ability until his daughters have freshened. In a study of 992 pure bred bulls proved in United States cow testing associations in 1938, the results demonstrated that with cows averaging 3641b. of butter fat, less than half of the bulls sired heifers that produced as much as their dams. With the present plan of handling dairy sires, only one sire out of five is alive when his value is known. The method of measuring a bull's ability is to compare the records of at least five of the bull's daughters with the records of their dams. The average production of a bull's daughters may be used as a basis for an index of the bull's ability. As yet, record keeping in dairy herds is not common enough to make mass selection possible.
The control of disease in dairy herds is one of the problems of management. In the United States, Federal and State funds have provided funds for payment of farmers for animals known to be tubercular. As the result of an intensive campaign in all of the States, this disease has been practically eliminated. A similar campaign is about to be launched to combat Bang's disease. Mastitis, or garget, is another disease that is troubling dairy farmers.
A typical daily ration for a 1,000lb. dairy cow giving 251b. of 5% milk would be 1olb. alfalfa hay, 3olb. of corn silage, and 6-81b. of a mixture of farm-grown grains. As the cow's production is decreased the grain may be eliminated until at 121b. of milk daily the hay and silage will be sufficient.
The above distribution of milk indicates the large amount used for fluid consumption. It also indicates that a large proportion of milk or the products of milk pass through processing or bot tling plants. Condensed and evaporated milk are increasing in use in the United States, and a larger proportion of skimmed milk and whey is being used for casein, dry skimmed milk, and other by-products of milk.
In the use of fluid milk Switzerland leads the other countries with a per capita consumption of 232 quarts per year. The United States is second with 153 quarts, and Denmark is third with quarts per person. In butter consumption New Zealand is first with 381b. per person for the year. Canada is second with 311b., and Australia is third with 291b. per year. The United States ranks seventh with 17 pounds. In cheese consumption Switzer land leads, followed by the Netherlands and Germany with 19, 14, and 13 pounds, respectively. The United States is tenth in the countries listed in cheese consumption. The per capita consumption of dairy products and oleomargarine in the United States for 1937 was: butter' 16.7lb. ; cheese 5.31b. ; evaporated and condensed 14.81b. ; ice cream 2.01 gal.; fluid milk 38.o gal.; all products reduced to milk equivalent 800lb. ; oleomargarine 3.1 pounds.
To stress the wholesomeness of dairy products it has been neces sary to carefully regulate the conditions under which milk and dairy products are produced. Two important factors in the pro duction of high quality dairy products are (1) to produce them under clean conditions and (2) hold in clean cold rooms.
Dairy products are generally sold on the wholesale market on the basis of a score that will give the trade a guide as to quality. In the case of butter the score is determined by flavour, body and texture, colour and package.
Milk is now commonly sold on grade. The grade is determined by the requirements met as indicated by its bacterial content and delivery temperature and the farm conditions where the milk originated. In the sale of milk, rapid strides have been made in the United States in uniform laws and regulations covering the production, processing, and distribution of milk. The United States Public Health code is used as a guide. More than half of the cities over i oo,000 in population have between 90 and of the milk pasteurized. In some cities all milk is re quired to be pasteurized except certified or grade A milk. Pas teurized milk as defined on most markets is milk that has been heated to 143° F. and held at this temperature for 3o minutes and then cooled, or milk that has been heated to 160° F. for 15 seconds and then cooled. These are the minimum temperatures required to kill disease-producing bacteria.
Certified milk is milk produced and handled under conditions specified by the American Association of Medical Milk Commis sions. This is the highest quality of raw milk offered for sale. In 1937 the pasteurization of certified milk was approved. The high price of certified milk and the abundance of high quality grade A raw and grade A pasteurized milk at a much lower price has minimized the importance of certified milk. Grade A raw milk, as defined on most markets, complies with most of the re quirements of certified milk but some of the more elaborate re quirements have been eliminated to reduce the price to somewhat near the regular market milk. Usually the market requires grade A raw milk to contain less than 50,00o bacteria per c.c. Grade A pasteurized milk has about the same requirements as grade A raw except that after pasteurization it must have a bacterial content of less than 30,00o per c.c.
Other market grades are used, but they are so variable that they cannot be discussed here. A few definitions of different kinds of milk as given in the U. S. Public Health Code follow: Milk. Milk is hereby defined to be the lacteal secretion obtained by the complete milking of one or more healthy cows, excluding that ob tained within 15 days before and 5 days after calving, or such longer period as may be necessary to render the milk practically colostrum free; which contains not less than 8% of milk solids not fat, and not less than 3a% of milk fat.
Cream and sour cream.—Cream is a portion of milk which contains not less than 18% milk fat. Sour cream is cream the acidity of which is more than o•20%0, expressed as lactic acid.
Skimmed milk.—Skimmed milk is milk from which a sufficient portion of milk fat has been removed to reduce its milk-fat percentage to less than 3a%o.
Buttermilk.—Buttermilk is a product resulting from the churning of milk or cream, or from the souring or treatment by a lactic acid or other culture of milk, skimmed milk, reconstituted skimmed milk, evaporated or condensed milk or skimmed milk, or milk or skimmed milk powder. It contains not less than 8% of milk solids not fat.
Homogenized milk.—Homogenized milk is milk which has been treated in such manner that after a storage period of 48 hours tests of the ioocc. portion decanted from the top of a quart bottle of milk will not show a difference in fat content over tests of the remainder of the milk after thorough mixing exceeding 5% of the total fat content. For example, on 4% milk the difference shall not exceed o.2%. In homogenized milk the globules of butterfat are more finely dispersed than in normal milk. This condition is brought about by forcing the milk under high pressure through a specially designed homogenizer valve.
Vitamin D milk is milk in which the vitamin D content has been increased. Three methods are commonly used: (I) by direct irradia tion of the milk, (2) by feeding irradiated yeast to the cows, (3) by the addition of vitamin D concentrates. The present standard is 430 U.S.P. units of vitamin D per quart of milk.
Colostrum milk is the milk secreted by a cow during the first three or four days after calving. It is especially designed for the use of the young calf. It is high in vitamin A and contains more than twice the amount of total solids found in whole milk. This difference is due in a large part to the increased amount of globulin in the colostrum milk.
In recent years the dairy breed associations have exploited the milk from their cattle. For example, we have the following trade marked breed milks: (I) Golden Guernsey Milk produced from herds of which at least one-half are pure bred Guernsey cattle and which meets the local requirements for raw milk ; (a) Jersey Creamline Milk pro duced by pure bred Jersey cattle and which also meets the local ordinance for raw milk ; (3) Ayrshire Health Milk produced by pure bred Ayrshire cattle and which also meets the local requirements.