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Great expectations for dairy nutrition

John Hibma Published on 28 June 2012

There was a time when dairy farming in the U.S. consisted primarily of the neighborhood dairy farm milking a handful of cows, requiring a few acres for hay and pasture, producing just a few gallons of milk per cow per day.

If you would have told a dairy farmer at the turn of the 20th century that in 100 years a cow would be producing over 15 gallons of milk after she freshened, he would have looked at you like you were daft. About as ridiculous as a man flying in the sky with the birds.

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Well, today we have a behemoth industry in which the average dairy cow produces over 20,000 lbs of milk per lactation. We have better management, better genetics and better nutrition to thank for all that milk.

Dairy farmers are constantly faced with the conundrum of finding the most economical balance of feedstuffs – concentrates, supplements and forages – with which to feed their cows.

As feed prices fluctuate relative to each other, finding the correct combination of ingredients to maximize performance and profitability also becomes an ongoing challenge. And average mailbox milk prices have not maintained parity with inflation.

The chronic misbalance of dairy products in the U.S. has forced much of the industry to adopt management strategies and business models that have resulted in ever-more milk.

And while the dairy industry is multi-faceted with its myriad of markets and not every cow in the country must average seven gallons of milk per day, the tendency has been to make cows make more milk. Advancements in dairy cow nutrition have been at the center of ever-increasing milk production and milk components.

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The feeding of dairy cows today has become a science unto itself as we continue to increase our knowledge and understanding of how a cow’s rumen works and seek to improve feeding and economic efficiencies.

Balancing dairy cow diets has become a sophisticated task for computer programs as opposed to merely tossing the cheapest feedstuff available in the feed manger and seeing how the cow milks. Feedstuffs must be evaluated for their nutritional values before they are purchased and incorporated into a ration.

With a basic understanding of how a cow metabolizes nutrients, we’ve taken the different nutritional components of a feedstuff, defined them mathematically and developed equations that allow us to calculate an optimal outcome, producing a solution.

Those solutions will tell us how much milk we can expect from a particular diet, what it will cost and, now with even more sophisticated optimization programs, tell us what the next-best alternative is.

Recent advances in ruminant biology focus on improving the efficiency of the rumen by increasing the microbial population in the rumen and the efficiency of how those microbes ferment feedstuffs. The ultimate goal in ruminant research is to maximize the amount of microbial protein produced for each unit of carbohydrate fed to a cow.

It’s now recognized, as well, that there are specific amino acids and peptides that improve the efficiency of rumen microbes. Any improvement in microbial growth in the rumen has the potential to lower costly feedstuff inputs that are currently used to provide bypass amino acids to the small intestine.

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For dairy farmers, this will mean a more scientifically balanced ration that will be environmentally friendly and improve efficiencies and the financial bottom line for their operations.

Dairy nutrition and ration formulation has moved well beyond analyzing and balancing for the basic dietary components of protein, fiber, energy, vitamins and minerals. When feeding dairy cows and heifers, nutritional requirements must be met for the rumen microbes as well as the animal’s systemic metabolic needs.

The interaction of ammonia, simple proteins and carbohydrates essentially define the health of the rumen and the amount of fermentation that can be accomplished in it. The more microbes available to ferment feedstuffs in the rumen, the more energy precursors (VFA) produced.

When the microbes have finished their job, they become a protein source for the cow’s metabolism. Microbial protein is a very high-quality protein due to its amino acid profile, and research in recent years has focused on increasing the microbial population in the rumen so as to decrease the need for costly dietary proteins that must bypass the rumen.

It has been well known for years that rumen buffers and enhancers such as yeast and probiotics can improve the rumen environment, allowing for more efficient fermentation. Much of the research in dairy nutrition is now conducted in the laboratory, where scientists are investigating products such as essential oils and enzymes that may increase microbial growth.

Rumen-protected lysine and methionine are routinely used in diets to deliver the correct amount of those limiting amino acids to the small intestine. Uniquely formulated enzyme supplements are being formulated to improve fiber digestibility.

Organic minerals (those chemically bonded to amino acids, peptides and polysaccharides) are now being recognized as having relatively higher bioavailability compared to inorganic minerals. There are complex interactions between microminerals such as cobalt, manganese, copper and zinc with the enzymes that are instrumental for cellular function.

And all of this research isn’t being directed just toward milk cows. Products are being developed for close-up dry cows, heifers and calves, too.

Nutraceuticals derived from yeasts have been found to promote gut health and bolster immune systems. These compounds can bind with Salmonella and E. coli species, reducing the number of those pathogens in the gut.

Some may view the continued advancing science of dairy nutrition as a two-edged sword that causes as many problems as it solves.

However, if our industry expects to remain more competitive both nationally and globally in the face of increased environmental regulations and competition for land, water and feed resources, those who can increase feeding efficiencies – making more milk and milk components relative to feed costs with healthier cows – can expect to gain a decided advantage in the market place for dairy products. PD

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