Feeding dairy animals in the 21st century
The University of Minnesota Extension is celebrating its 100th anniversary of providing education for the people of Minnesota this year. While Extension is very broad in its scope of subjects it covers now, providing information for educating farmers and dairy producers has always been one of the main missions of Extension. In 1885, W.D. Hoard commented on what a mystery it is that a cow can consume the feeds she does and end up producing milk. What goes on in a cow was truly mystery that the University of Minnesota as well as other land grant universities around the country have been working at solving ever since.
Before there was extension, T.L. Haecker published the first edition of “Feeding the Dairy Herd” in 1894. This has been followed by more than 30 editions and well over half a million copies of ‘Bulletin 218.’ Early editions provided information on requirements for vitamins and crude protein, different feeds and supplements, as well as winter fodder feeding. Feeding guides went up to 50 lbs of milk. The understanding of forage quality was the observation that cows went up in milk production when turned out on pasture and decreased in the winter. Such was the motivation for spring calving as well the promotion of ‘June Dairy Month’ to handle the spring flush of milk. On my book shelf is a book by Eckles and Warren from 1919 on dairy farming with a large section on feeding all dairy animals. Already then, forage quality and digestibility of protein and carbohydrates were addressed. Legumes were recognized as superior to grass for protein and minerals.
As we moved into the last half of the 20th century, new terms came into the vocabulary for feeding. Crude fiber was replaced by NDF and ADF. Crude protein was replaced by rumen available and by-pass protein. We also started feeding of buffers, added fat, a variety of additives and then by-pass fat. Feeding calves either whole milk or skim milk was exchanged for milk replacers. Dry cows were limited on the amount of calcium fed by changing forages in the dry period. Then we discovered that potassium was worse than calcium for dry cows and we needed to feed ‘transition cows’.
As we are now well into the 21st century, feeding of all dairy animals has truly become a science of physiology and biochemistry. We have computer models to balance for metabolizable protein and even metabolizable amino acids, three to five fractions of carbohydrates, fats and now fatty acids, amounts of NDF and lignin, effective NDF, digestible NDF, starch and sugars, as well as vitamins, minerals and specific trace minerals from organic and inorganic sources. This has occurred as we now mix a TMR of several ton at a time, use a payloader to fill the TMR with up to 10 ingredient combinations of forages, by-products, grains and liquid feeds.
So where do we go from here? Are there still new things to discover for feeding cows and other dairy animals? When I was in graduate school, I thought we were approaching a peak of what a cow could produce in milk production. Yet ways are found to still get a little more. When we think we have feeding figured out, the cow surprises us. Little differences are discovered we never knew existed. Recent work at the USDA Forage Center in Wisconsin has shown not all cows fed the same ration will have the same rumen bug population. No two cows are alike. Why do cows get loose manure when fed too much protein, especially rumen degradable protein? The same is true of rumen acidosis from too much starch. Is there a perfect combination or ratio of rumen available protein, carbohydrates, starch, sugars, NDF for a particular cow or a group of cows? What are the factors we need to determine to make that decision?
The next decade will challenge us even more. We are now given the task of feeding a world that needs more food while trying to minimize the environmental impact by reducing greenhouse gas emissions; gases which are normal emissions from belching by a ruminant such as methane and carbon dioxide. Can that be accomplished while still keeping milk production levels where they are? Can we alter rumen fermentation? It has proven difficult so far without decreasing milk production. Will the demand for grain to feed humans or to use as energy fuels price it out of cattle diets? What is the sustainable feeding of the future?
At the present, we do not have it all figured out. Researchers at the University of Minnesota as well as others around the world will be working on it. And, as they do, we in Extension will keep you informed.
Published in Dairy Star October 16, 2009