Move Over, Milky Way— Our Cows Are Stars Too

BY R. P. NIEDERMEIER, G. BOHSTEDT, AND C. A. BAUMANN

Today's dairy cow is a fantastic producer. Like all mammals, a cow gives milk because she has offspring and must feed it. Since milk is such a nutritious food, she has been developed as a milk producer and today the average cow not only feeds her calf but also provides milk and dairy products for 19 people. Our Nation's 11Y4 million milk cows annually produce over 115 billion pounds of milk, thus providing 253 quarts for every person in the United States. In 1975, Mowry Prince Corinne, a registered 9%-year-old Holstein cow owned by Mowry Farms, Roaring Springs, Pa., completed the highest milk record ever produced in a single lactation by a cow of any breed. In 365 days she produced 50,759 pounds of milk. On her highest test day she produced 180.4 pounds of milk! In a single lactation she produced 23,609 quarts —a year's milk for 64 U.S. families. This new record dramatically demonstrates how the dairy cow has been developed as a producer of human food. The oldest written records of man show that dairying was developed as far back as 6,000 B.C. Through history the cow has been used as a beast of burden, an object of worship, and a source of meat and milk. Dairy cattle were not native to America; the first importation came to the United States in 1624. From colonial times to the 18 50's, dairying was a family cow business. All of the U.S. dairy breed associations were formed between 1865 and 1885, thus establishing herd books for the registration of cattle. The dairy industry has grown to provide nearly 15 percent

R. P. Niedermeier is Professor of Dairy Science, College of Agricultural and Life Sciences, University of Wisconsin, Madison. G. Bohstedt is Emeritus Professor of Meat and Animal Science. C. A. Baumann is Emeritus Professor of Biochemistry.

139 Left, an oldtime cream separator, usually turned by a husky farm boy with muscle-power to spare. Right, modern cream separators are in foreground at this dairy processing plant. of the total farm income in the United States, and in leading dairy States accounts for 50 to 60 percent of farm cash receipts. Add the cost of processing, storage, distribution and retailing and this agri-business annually represents a $14 billion industry—a big change since the first cheese factory was established in Oneida, N. Y., in 1851. Today's dairy industry is more than ever before concentrated in the Great Lakes area. Over half of the nation's milk supply is now being produced in the eight States touching the Great Lakes, with other major areas being the northeastern United States and California. Wisconsin is the leading milk producing State fol- lowed by California, New York, and Minnesota. Technology for the production and processing of milk is the result of many factors. The development of bacteriology beginning with experiments by the French scientist Louis Pasteur led to pasteurization, a process used to destroy harmful bacteria in milk. The centrifugal separator invented by DeLaval provided a fast, convenient means of mechanically separating milk and cream. The Babcock test, perfected by Dr. Babcock in 1890, made possible an accurate chemical test for quality that has been used for milk payment and production records.

140 Holstein cows at Utah State University Dairy Farm. Control of possible milk-borne diseases such as tuberculosis was essential. A test and slaughter program begun in 1920 has elimi- nated this disease from U.S. dairy cattle—the beginning of many health control programs that have assured us a safe, healthful milk supply. Agricultural research has been and continues to be the key to new technology and increased productivity. This began with the establishment of Colleges of Agriculture by the Land Grant Act of 1862, and the subsequent funding for research in agriculture by the Hatch Act of 1887. In 1914, the agricultural extension service established by the Smith-Lever Act added the dimension of taking information from research farms and laboratories to dairymen and processors. Extension has likewise provided a means of bringing problems from farms and milk plants to the researchers. Agricultural research in the State and Federal experiment stations is essential if we are to continue to increase our output of animal products from the limited resources available to feed the growing human population. Adding to a well established heritage of dairying brought by immigrants from Europe when this country was settled have been inventions; development of sciences such as bacteriology, chemistry, genetics and nutrition; the development of agricultural education, research and extension; industrial technology, trans- portation, and the development of marketing and promotional or-

141 ganizations. These have been important to our dairy industry. However, most of the credit is due the modern dairy farmer on whose farm the whole process must begin.

The Darkest Place The dairy cow's abiHty to convert feed energy and protein into food is outstanding. As a ruminant she is endowed with the abihty to thrive on forages such as pasture, hay, and silage. She converts fibrous material that people cannot eat into protein- rich milk. W. D. Hoard, founder of Hoard^s Dairy^nany once said, "The inside of a cow is the darkest place in the world," The more recent science of "ruminology" has helped turn on lights inside the rumen or first compartment of the four-compartment ruminant stomach. The rumen or fermentation vat which holds up to 50 gallons in a large cow is the home of billions of bacteria and protozoa that digest cellulose, produce many vitamins, and manufacture essential amino acids or excellent protein for the cow either from non-protein nitrogen present in forages or that fed as urea (urea is a cheap synthetic chemical). The ruminant also has the unique ability to digest many waste products of the food and feed industry. By-products from the manufacture of sugar, starch, flour, beer and alcohol are efficiently converted to nutritious foods. Population pressures have led to suggestions that we shall soon become dependent upon plants for our food supply. It is true that more people can be fed per acre if cereal grains and protein oilseeds are used directly for human food rather than converted by animals into products such as milk and meat. The following quote from one of the opening paragraphs in an article published in the Agricultural Science Review, Volume 5, Number 2, ''Ru- minant Livestock—Their Role in the World Protein Deficit," by L. A. Moore, P, A. Putnam, and N. D. Bayley aptly speaks to this issue. '^Although the emphasis on cereal and oilseed proteins has some basis, relegating animal agriculture to a passive contribu- tion to world food deficits indicates a failure to appreciate the full impact of feed inputs into livestock production. "We contend that generally accepted concepts regarding the efficiency of livestock production in terms of use of available resources are erroneous. We contend that because livestock use forages and other feeds inedible to humans, the use of limited amounts of cereals as livestock feeds can enhance the efficiency

142 of producing proteins for humans in term^s of total food re- source titilization, *Turthermore, there are promising research leads, which, if exploited, can markedly increase the efficiency with which animal proteins can be produced. We also contend that consider- ing the world food deficits solely in terms of amounts of protein or calories may result in answers which will make only the less desired diets available to the 'have nots' and may aggravate the serious sociological problems of the world rather than reduce them." About 70 percent of the protein of the average U.S. dairy cow is obtained from forages. Recent trends toward heavier grain feeding to high-producing dairy cows can be reversed. Heavier grain feeding is the result of new technologies which have made grains increasingly abundant and relatively cheap. But with feed grains and soybeans in world-wide demand, we are now experiencing a transition to higher priced corn and soybeans and the importance of forages in dairy cattle feeding will almost certainly increase. Research has shown that dairy cows can synthesize essential amino acids in the rumen from urea. A. I. Virtanen, Nobel Prize winning scientist in Finland, demonstrated in 1966 that cows on protein-free feed could produce reasonable quantities of milk. Today large amounts of urea are used in ruminant feeds, and research continues to determine methods to increase the levels of urea or other forms of non-protein nitrogen that can be used by high-producing cows. Research is also being done on the treatment of woody, poor quality forages—such as straw and corn stover (stalks and leaves after the ears are harvested)—to make the cellulose more available for milk production. Through cooperative efforts of sci- entists working in forestry research laboratories, wood has been treated to enhance its use by ruminants. Wood "molasses" and poor quality forage have also been used as a feed energy source.

Our Need for Milk A strong argument for a flourishing dairy industry, even in the face of greatly increased population pressure, is the high nutritive value of milk to man. High-quality protein, a generous supply of nearly all of the vitamins, and a rich source of most of the essential minerals make milk the ideal supplementary food. It is possible to devise a vegetarian diet adequate in protein,

143 but it is very much easier to do so with milk in the diet. With- out milk it is possible, but relatively difficult, to concoct a human diet adequate in calcium. With a reasonable amount of milk in the diet, calcium needs are usually met. Almost auto- matically milk contains satisfactory amounts of the fat-soluble vitamins, including vitamin D if the milk is fortified, and of the water-soluble vitamins. Since neither most homemakers nor hardly any of us who eat in restaurants are professional dietitians, private attempts at de- vising diets low in calories, for example, can lead to inadequate intakes of dietary essentials. But with milk and meat in the diet, our nutritional needs are much more likely to be met.

Are We Producing Enough? Nationwide, 8 5 percent of all dairy farmers have gone out of business since 1950. Frequently two or more smaller farms were merged so that the acreage devoted to dairy farming and number of cows was not correspondingly reduced. During this period, milk cow numbers declined 47 percent. In these same years, milk yields per cow doubled. The average U.S. cow produced 5,314 pounds of milk in 1950 versus 10,291 pounds in 1974. This made it possible to maintain total milk production despite the drastic decline in farm and cow numbers. Milk yields per cow have increased as a result of improved feeding, improved genetic ability, and better environmental conditions. Space permits citing only a few research findings, with most emphasis on nutrition, that provided the technology for modern milk production. A similar story could be told for research contributions that led to artificial insemination of dairy cattle, sire and cow selection programs, and improved management procedures. However, a rapidly increasing human population since 1950 coupled with decreasing cow numbers means that today in the United States there is about one cow for 19 people as compared to one cow for 7 people in 1950. Even with the doubling of production per cow, the population increase has reduced the available milk supply from 775 pounds per person in 19 50 to only 545 pounds today. A critical point has been reached in the supply of milk in the United States to assure adequate levels of nutrition since milk and milk products contribute so importantly to the Nation's food supply.

144 - , - ■^^&4X-■a're<»ví'îiT-î^.•'i>;Ft;■>,v'.;^.vv;v«^_l^

Guernsey heifers from an outstanding registered herd in Missouri. At the beginning of the 1800's, Httle was known about the chemistry or physiology of plants and animals. A farmer would feed his animals hay and grain, or their equivalents, without being aware of the chemical elements or compounds in them that nourished the animals. With the march of science and technology and the development of an appreciation of basic aspects of nutrition, feeding standards were advanced. These later standards were based on the chemical content of feeds, primarily the protein, carbohydrates and fat in feeds, but the total instead of the digestible basis was still used. It became apparent that there was a need for more information than the chemical content of feeds. In 1864 in Germany, Dr. Emil von Wolff presented the first table of feeding standards based on digestible nutrients rather than total nutrients. For every one unit of digestible protein there were to be from 6 to 9 or 10 units of digestible carbohydrates

145 Truck-mounted metering system for farm bulk milk was developed at Penn State, and is said to be first of its kind to commercially measure milk. Such meters are expected eventually to replace present use of calibrated gage rods immersed in milk. and fat equivalent. The ratio of digestible protein to digestible energy depends on the particular animal and purpose for which it was fed. The Wolff standards were first brought to this side of the Atlantic in 1874 by W. A. Atwater. In 1880, H. P. Armsby of Pennsylvania State College published a manual on cattle feeding, based on Wolff's work. Subsequently, Armsby refined these feeding standards with the concept of net energy, essentially re- flecting the nutritionally depressing effect of fiber or cellulose in feeds. The productive value of a feed or ration varied inversely with the amount of fiber in it. Despite the logic of balancing rations by digestible protein in relation to kilocalories or megacalories of net energy, this system was not widely used. By far the most prevalent system during the past century has been by the Wolif-Lehmann standard or its modification by F. B. Morrison. This system is based on digestible protein in proportion to digestible non-protein organic nutrients, the so-called nutritive ratio. This may be because of readily understood weighable amounts of nutrients instead of the seem- ingly abstract concept of calories that do not register on a scale. During the early part of the past 100 years, there was a fairly

146 Left, Colorado youngster enjoys a cone. Right, a South Carolina dairyman. general appreciation of the need for certain minerals by farm animals, such as salt (even the ancients found it indispensable), calcium and phosphorus to avoid rickets, iodine to prevent ex- ophthalmic goiter, and iron and copper for suckling pigs to avoid anemia. The need for other minerals was still largely unknown. Continuing research revealed the importance of supplementing farm rations with one or the other additional major minerals, and particularly with a still larger number of the minor or trace minerals. Mineral supplement needs varied with soil and climatic or management conditions. But feeding standards at the time did not specify either kinds or amounts of minerals to use, nor so-called accessory factors, later called vitamins. It was years before some of these micro- nutrients became farm or household words, as being essential for man and beast. In 1906, F. G. Hopkins stated: "No animal can live upon a mixture of pure protein, fat, and carbohydrate." At the University of Wisconsin, Stephen Moulton Babcock had even before the turn of the century doubted the nutritional adequacy of feeding standards then in vogue. There were princi- ples he felt that were not covered by their specifications. In 1906, as an approach to the problem, he was instrumental in setting up an experiment with four groups of young dairy heifers, growing into milking cows. Each of three groups was fed a ration from a single plant source, the corn, oats or wheat plant. The fourth lot was fed a mixture of all three cereals. In each

147 case, the forage part was fed along with the grain or concen- trate part of the plant, in this way satisfying the current requirements for a ''balanced ration". Salt and, of course, water were allowed free choice. During two gestation and lactation periods, striking contrasts showed up among the groups. Cows on the corn ration were sleek and fine, the quality of their calves and quantity of milk produced normal or as expected. Those on the wheat ration were in both respects inferior, even disastrous. Performances on the oat and mixed rations were intermediate between those on corn and wheat. The gross chemical analyses for protein, carbohydrate and fat of all rations had been closely identical. Why then the differences in performance? A ready answer at the time was not available. The experiments themselves had been carried out by Hart and Humphrey, with the cooperation of McCollum and Steenbock. Each of these men was destined to have a distiguished career in nutritional science and to spend a very long and very productive life studying problems that were foreshadowed by the single grain experiment. The list of their subsequent accomplishments (by no means complete) includes: • The use of small animals, particularly rats, as a model for determining the nutritional requirements of animals in general— including man • The recognition of fat-soluble and water-soluble vitamins • The separation of vitamins A and D • The identification of carotene as the source of vitamin A activity of plants • The discovery that vitamin D can be produced by irradiat- ing foodstuffs • The discovery that copper is a dietary essential To these must be added fundamental studies on most of the known vitamins and essential minerals, and on fats and proteins, as well as the systematic application of the newer findings (as they became available) to the better production of farm animals. Nearly all of this subsequent work was done within the frame- work of a College of Agriculture and the Agricultural Experi- ment Station system. Of course, many of the newer nutrients proved to be as important to man as to the experimental or farm animals, and the value of basic nutritional research thus was established beyond all question.

148