Farming Magazine - November, 2012
Dairy Nutrition: Athletic Cows
I always enjoy watching some of the Olympics. The thrill of victory and the agony of defeat. Amazingly talented athletes run, jump, launch, tumble, swim, bicycle, row, play volleyball and soccer, and shoot guns and arrows. The process of training to be an Olympic athlete is a science in itself. Specific muscle groups are targeted and exact diets are consumed. These athletes dedicate much of their lives to preparing and training for their events.
I consider the high-producing dairy cow to be something of an athlete as well. For cows to perform well, they have to be at the top of their game. Being the domesticated animal that they are, cows depend on us to help them reach top production. The high-producing dairy cow is "in training" her entire life, and the measure of performance excellence for a dairy cow is how much milk and milk components she produces during a lactation or a lifetime. Diet, environment, management and genetics have the most influence on whether a cow can ever get a medal.
In order for a cow to perform well and stay healthy, the rumen has to be functioning efficiently. At the heart of rumen health are the rumen microbes, and they too must be at the top of their game. They are responsible for converting feedstuffs into energy and glucose through the process of fermentation. A cow without glucose is a cow that can't perform.
When carbohydrates - both structural (neutral detergent fiber) and nonstructural (sugars and starches) - undergo microbial fermentation, they produce volatile fatty acids (VFA), which are the building blocks for glucose. The three primary VFAs are acetic, propionic and butyric acids. These three VFAs provide most of the energy for a cow.
Just like the human athlete, a cow's diet must be balanced with the correct types of feedstuffs to ensure that the rumen bugs are healthy and can proliferate so they can go about their job of fermenting feeds and making VFAs for energy. Just like a human athlete who is training to run the mile wouldn't dream of eating all junk food to maintain strength and endurance, the dairy cow needs highly digestible feedstuffs that maximize rumen efficiency.
The "training regimen" must continue every day, even when the cow is in the dry pen. Even though milk production has ceased for a couple of months, the cow is still in need of a proper diet as a fetus grows and develops inside of her and she's preparing for the next lactation. We all know how easily and quickly we get out of shape when we stop exercising or don't eat right. The same thing holds true for a dairy cow. We can't expect her to be at the top of her game on the day she freshens if she hasn't been fed correctly while a dry cow. While feed intakes are greatly reduced during the dry period, the rumen must be prepped a few weeks before freshening so the bugs are ready to "race" when they're called upon to do so.
The cows at all of our dairies represent a considerable investment, since it takes two years or more to get a baby calf into the milking parlor and producing revenue. Unfortunately, the economic environment in which the dairy industry currently finds itself, with historically high feed prices, makes keeping our cows at the top of their game incredibly difficult. The milk price to feed price ratio has never been as low as it is now. A pound of feed ration on a dry matter basis costs nearly the same as the price received for a pound of milk. When the feed bill consumes more and more of the milk check, it's easy to look at cows and heifers and calves as a liability rather than an asset.
As the economic uncertainty lingers, each dairy farmer must make a decision as to where they might cut back on feed costs while doing the least amount of harm to the long-term productivity of the herd. Focusing on efficiencies has become a mandatory requirement of dairy farm management. Diets must be balanced with great precision so that rumen fermentation is optimized.
With purchased commodities and grains becoming more expensive nearly every month this year, in many cases forages are becoming a better value, especially high-quality grass and legume forages. High-quality forages are essentially defined as forages with a low fiber level and a high protein level. The lower the neutral detergent fiber (NDF) fraction of forages, the more digestible they tend to be. If the NDF is too low, then the forage will act more like a low-fiber grain or byproduct, which tends to result in dysfunctional rumens that may lead to acidosis. The trick with getting the best use out of high-quality forages is maximizing their available energy while maintaining fiber effectiveness that will promote and sustain microbial health.
Producing high-quality forages in New England isn't always an easy undertaking. Timeliness of forage harvesting has the greatest management influence on producing good forages. In hay crops there's a negative correlation between NDF and the digestibility of the NDF: The more mature a forage becomes, the less digestible it will be. For grasses, the optimal time for harvest is in the midvegetative to boot stage. In legumes, the indigestibility of fiber rises at a slower rate than grasses. Blooms in legumes should be kept to a minimum. All hay crop forages, once they flower or go to seed, rapidly decline in their ability to provide high levels of dietary energy. The farmer must learn to weigh the advantages of high-quality forage and the milk it will produce against trying to maximize tonnage per acre.
The dairy industry has yet to fail in rising to face new challenges and continuing to maintain record-breaking production. Just as the science of training athletes has evolved over the years so that records can continue to be broken, the dairy industry must never stop looking for new options for maintaining the most efficiency in producing milk, even when the economy is bleak.
The author is a dairy nutritional consultant and works for Central Connecticut Farmer's Cooperative in Manchester, Conn.
Farming Named Official Publication of Vermont Farm Show
Farming, The Journal of Northeast Agriculture, has been named the official publication of the Vermont Farm Show. Our staff is working with the farm show committee to put together a program that will be handed out at the three-day event. The Vermont Farm Show takes place January 29-31, 2013. For more information about the show, contact Jackie Folsom at 802-426-3579 or email firstname.lastname@example.org.