OUR I N D U S T R Y TODAY 4 4 9

become available many modified basic chem- icals and blended detergents which have highly functional uses for specific operations, among which might be cited: detergents for low-tem- Deraturc operations, such as bulk milk tanks; for high-temperature operations such as vac- uum pans or pasteurizers; and for different types of soils as mineral, fat, protein, and complexes. The knowledge of the behavior of the detergents in normal systems has enabled completely programmed sanitation programs both on farm and in plant operations. Further improvements in detergent and sanitation chem- istry are bound to come, especially with the continuing consilidation of dairy plants.

During the past several years there has been continued increase in production of Grade A- caliber milk, not all of which is utilized in Class 1 product. There has been, then, a rather marked improvement in the quality of milk used for manufacturing purgoses. This effect is continually bringing to the forefront the consideration of a single grade of milk. There appears a constant increase in marketing order areas, which also affects the uses of milk.

One of the factors affecting the improve- ment of milk quality standards throughout the nation has been the expansion in use of the Agreements of the National Conference on Interstate Milk Shipments. Tremendous amounts of milk are presently being shipped

in interstate commerce through the Certification program provided for in the Conference Agree- ments now participated in by some 34 states and covering nearly 750 rated shippers. Con- current with this has been the development of a system of Certification of laboratories which appraises milk for the interstate shipments. In a recent annual period, 516 state-approved laboratories were utilized in evaluation of inter- state milk. The development of a Conference Agreement on an interstate basis has been matched by a Conference Agreement on an intrastate basis, as in Wisconsin, with tre- mendous benefit.

There appears to be an increase in the inci- dence of bovine tuberculosis. This certainly must have immediate attention. The incidence and nature of the infection of bovine mastitis is fully as great, and more serious, as at any time in the history of dairying. A National Mastitis Council has been organized to con- solidate efforts in every possible way to better meet this urgent problem. Continued effort in control of these, as well as other animal diseases, is mandatory for the industry.

The development and use of 3A Sanitary Standards and the 3A Symbol as administered by a 3A Symbol Council by the Dairy Industry has been a highly successful venture. New standards are in process of development and should become available in the future.

F O R T Y Y E A R S I N R E T R O S P E C T 1

J. G. ARCHIBALD 2

Dairy and Animal Science Department, University of Massachusetts

Forty-year review of progress in agricultural science. Turn back with me in memory for a few minutes to the year 1921, the beginning of the third decade of this century, and see if we can recall in part at least the situation as it existed then, paying special attention to dairy husbandry. Because my own special field has been dairy cattle nutrition, I think first of the contrast between our knowledge of the subject today and what we knew or thought we knew then. The concepts of an adequate ration in those days dealt only with protein, carbohy- drates, and fat. The vitamins were just be- ginning to be heard of; only two had been iden- tified, A, and B1, better known today as thia- mine. All the others were unknown.

Specific examples. Mineral nutrition was an unexplored field. Farmers knew from long ex-

1 Paper presented at the Dairy Farmers' Sem- inar, January 26, 1961, University of Massachu- setts, Amherst, Massachusetts.

2 Present address: 491 West 32 Place, ttialeah, Florida.

perience that salt must be supplied to their animals, more especially to cows and sheep, but possible deficiencies of phosphorus, iodine, or cobalt were unheard of. Amino acids, the building blocks of proteins, were a laboratory curiosity, and the concept of biologically com- plete proteins was in its infancy. An interest- ing sidelight here is that when the idea of com- plete and incomplete proteins was definitely established, dairy cattle specialists hopped on the band wagon and preached for years the necessity for great variety in the components of mixed feeds for dairy cows. I t was only after careful research in this country and abroad within the past two decades that we came to realize that protein quality is not of significance for dairy cattle, young calves ex- cepted. The myriads of nficroorganisms in the rumen take care of the task of furnishing their host with proteins adequate in this respect.

Perhaps of most significance from a nutri- tional standpoint is our present understanding of the importance for the dairy cow as a source

4 5 0 JOURNAL OF DAIRY SCIENCE

of energy of the so-called short-chain fatty acids, notably acetic, propionie, and butyric acid, which result from the fermentation in the rumen of cellulose, that very important con- stituent of forages. Forty years ago there was some doubt as to whether cellulose was of any value as a nutrient. We realize today that a cow's ability to digest cellulose (woody fiber) through the medium of the microorganisms in her rumen is of prime importance to the wel- fare of the human race.

Changes in practical agriculture. Look now for a few moments at some of the developments in agricultural practice that were unheard of forty years ago. Fertilization of pastures and rotational grazing were introduced in this coun- try a little over 30 yr ago, more recently elec- tric fencing has made strip grazing practical, and now with the improvements in machinery, we have arrived at zero grazing. The making of grass and legume silage was a development of the mid-thirties; barn-drying of hay crone along in the forties. The green-hay loader, the field chopper, the field baler, the corn har- vester, all have appeared in the past 20 or 25 yr. Mechanical refrigeration has superseded the annual chore of harvesting ice, and now also we have bulk tanks and stainless steel truck tanks. Barn cleaners, milking parlors, loose housing, and automatic feeding devices recently have come into the picture.

Herd improvement. Improvements in pro- ductive capacity of cows through record keep- ing, culling, use of proven sires, artificial in- semination, and better feeding and management are so obvious as hardly to need mention. Forty years ago the only form of official testing was Advanced Registry; DHIA and HIR were unknown.

The battle against elimination of disease had only just begun in 1921. Area testing for T.B. was just getting under way. Control measures for brucellosis and mastitis were not yet de- veloped; vibrio, leptospirosis, and trichomo- mares were still unidentified.

A few contrasts. These are some of the im- portant developments that might be mentioned. They represent the labors of a host of patient, persistent research workers all over the world. I t is of interest to speculate on how these ad- vances in knowledge and technology may have affected milk production and cow numbers, both in this state and in the country as a whole. Census data for the period are not comparable, because the basis of reporting milk production is not the same from one deeennimn to another. However, the Crop Reporting Service of USDA has published some data of interest on the subject. Comparisons are drawn between pro- duction in 1959 and the average of 1951-55.

Their data show that in Massachusetts there were only 82% as many cows in 1959 as in the 1951-55 period, but that this somewhat smaller number produced 97% as much milk, produc-

tion per cow being 119% of what it was in the earlier period.

For the country at large, the corresponding figures are 90, 105, and 116, respectively, i.e.: 90% as many cows produced 105% as much milk, whereas production per cow was 116% of the earlier period.

There are, of course, other factors which have influenced this improvement, but undoubtedly the examples I have cited have had a lot to do with it.

Another interesting quotation from a recent issue of an agricultural journal states that "one farmer can take care of 50 milking cows today, whereas he could handle only 15 to 22 in 1939."

Our contribution. At this point, you may be wondering what contribution the Massachusetts Experiment Station may have made to these nmrked improvements in dairy husbandry. With due modesty, I wish to cite some of the results of our work during the years that I have been here. Time and your patience do not permit a complete list, so I shall mention only those that, to me at least, seem of most significance. In so doing, I must first of all acknowledge the able assistance and cheerful cooperation I have had from colleagues too numerous to mention. Here are some of the conclusions we have reached :

1. Under conditions of practice, cattle seldom suffer from calcium deficiency. They utilize the calcium of their rations very efficiently.

2. They are much more likely to suffer from phosphorus deficiency; this is especially true of young stock on poor pasture when no grain is being fed.

3. Skimmilk powder, plus a mixture of half as much yellow hominy meal and low-grade flour, makes an excellent ufilk replacer for young calves. Average daily gain was 1.7 lb when this combination was fed.

4. The amounts of calcium and phosphorus in milk are not influenced by the amounts of these elements in natural feeds, or by the feed- ing of mineral supplements containing them. They are influenced by breed of the cow and stage of lactation, and to a small extent by season of the year.

5. On the other hand, the amounts of the so-called trace elements in milk can be increased by feeding compounds of them as supplements. The greatest increase we have been able to show has been with the element molybdenum, but cobalt, manganese, and zinc also have been significantly increased. As a result of our work with cobalt, an international authority on the subject stated in a recent textbook that "the nmmmary gland readily permits cobalt to pass its barrier" and that "such treatment represents an easy practical means of raising the cobalt intake of suckling calves in cobalt-deficient areas."

6. Nitrogen fertilizer applied to grass crops markedly increases the yield, whether for pas-

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ture or hay. I t also increases the protein con- tent by about a half, and nearly doubles the carotene content. Complete fertilizers also have a favorable effect in these respects.

7. The water content of grasses in the vege- tative stage is a good indication of the feeding value of their dry substance. In other words, the more succulent they are, the higher is the content of protein, minerals, and carotene in their dry substance.

8. Application of fertilizer does not increase the calcium content of grasses to any significant extent; a change in the botanical character of the forage by using more legnmes in seeding mixtures is the most practical means of increas- ing the calcium content of forage.

9. Orchard grass and timothy kept in the vegetative stage by clipping or grazing give higher yields and are relished more by cows than are red top, bluegrass, or the fescues.

10. When pastures are of good quality and grazing is proper ly controlled, maximum econ- omy in cost of milk production can be achieved with grain-to-milk ratios as high as 1 to 6. Be- yond that point, cows tend to lose weight unless they have access to some dry roughage.

11. The making of grass or legume silage is an excellent practical alternative to the making of hay, especially for first cutting and in un- favorable haying seasons.

12. High-nmisture levels in the crop (above 72-75%) result in poor-quality silage unless the condition is corrected. This may be done by wilting or by the use of additives.

13. The most satisfactory additive from all standpoints has been hominy feed applied at the rate of 150 lb per ton. Certain chemicals such as Kylage and sodium metabisulfite also have merit, but they do not control run-off nor do they add feeding value to the silage, as does hominy.

14. Barn-drying of hay either with or with- out heat is another alternative to field curing that makes the farmer 's operations just that much more flexible. Too much should not be expected of a dryer; without heat the safe upper level of moisture in the hay going over the dryer is around 35%; with heat, the safe maximum is around 45%.

15. The value of poor-quality hay for milk production can be considerably improved by the addition to the grain mixture of a supple- ment consisting of molasses, urea, and a min- eral mix containing phosphorus, iron, and co- balt.

16. Cows need supplemental carotene or vita- min A in winter rations that consist only of hay and grain. The best practical source is grass or legume silage.

17. As much milk can be produced on high- quality mixed grass hay as on hay containing 40-50% of alfalfa. This means grass hay con- taining 10 to 14% of protein and around 30% of fiber. Such hay is produced by judicious use of fertilizer, and by early cutting and proper curing.

18. Individual cows vary greatly in the effi- ciency with which they convert coarse fodder into milk. Their abili ty to do so is of more importance than the type of roughage they eat, provided that the roughage is of good quality.

19. Citrus pulp compares favorably with beet pulp as a hige-energy supplement for milking cows.

20. Animal proteins such as tankage and fish meal are satisfactory substitutes for such stand- ard protein concentrates as soybean meal and cottonseed meal when prices warrant their use.

21. When prices warrant it, urea can take the place of par t of the standard protein con- centrates in grain mixtures. The upper limit appears to be around 40% of the nitrogen in the grain mixture, or 25% in the total ration.