The Rumen

As farmers, we have been led to believe that cows are ruminating machines that are able to digest everything from grains to by-products to grass. We need to make the best saleable product we can for the least amount of cost, which includes feed and veterinarian bills.

The term “feed efficiency” in the dairy industry has been shipped out with the cull cows. A vast majority follow the belief that “more feed = more milk” even though they probably have cows of their own that prove this to be untrue. So we not only need inexpensive feed, but we also need to use it wisely so we do not have to buy our herd average. What is the most abundant and cheapest source of feed we have available as producers? Grass and forages. Here is how to make the most of your forages:

1. Water.
First, realize that cows have the ability to overeat as much as 50% to make up for dietary deficiencies. For example, if you have little or poor water, cows will overeat on high moisture feeds, such as pasture or corn silage, while refusing to eat dry hay. Therefore, little or poor water → slow fermentation → fewer bacteria (ruminant microflora) → little or poor milk production and quality.

2. pH.

Next, the correct pH in the rumen is needed for the ruminant microflora. The proper proportion of protein to energy in the ration controls the pH of the rumen. Grasses and legumes contain high amounts of protein and insufficient amounts of energy to balance the dietary ration, resulting in an animal with poor fill, health, and breeding. One way pasture problems have been dealt with is to feed corn to animals on pasture. This provides energy to help balance the protein excess of green grass, but poses another interesting problem...

3. Food Source.

The next requirement for bacterial growth: a sufficient food source. Different bacteria require different food sources to grow. Two different cultures of bacteria are required to digest grain (proteolytic bacteria) and grass (cellulytic bacteria). Every time a dietary ration is changed the proportions of these bacteria also change (which takes 7-10 days). While these cultures are capable of coexisting, they do compete in the rumen. Thus, even though feeding grain on pasture improves herd health, breeding, production, and feed efficiency, it is not the most efficient situation from the bacterial point of view. A high or all forage diet, for example, would be more efficient because only one culture of bacteria (cellulytic) would be doing most of the work. Thus, when supplying energy to a source, promoting only cellulytic bacteria would be necessary. This means feeding limited or no grain. If we cannot feed grain, we could do the next best thing and supply products that result from the fermentation of grain such as fatty acids, amino acids, and alcohol to initiate the process of forage fermentation.

Promoting cellulytic fermentation allows animals to do the same job on 25-30% less feed. Acetic acid production is promoted, increasing butterfat. These active and thriving bacteria allow the animal to consume poorer quality forages with little change in milk production or health. This would be beneficial for those who do not have enough or have poor quality pasture. Producers could have the option of milking more head, farming less ground, or buying less hay. What would that be worth?!

Thus, increasing the energy of the forage ration through forage management and supplementation with energy will improve herd health, breeding, and production.