Ruminant Nutrition Simplified

1.       Market available feedstuffs through ruminants. Ruminants (cattle, sheep, goats, deer and elk) are a profitable way to market forages like grass and hay.

2.       Rumen microbes digest cellulose. Ruminants by themselves cannot utilize all the nutrients in forages. Some of the nutrients are contained within the fibrous portion of the plant (cellulose). Ruminants can utilize cellulose because of the microbes in their rumen. The microbes help to supply the energy and protein needs of the animal by breaking down the cellulose and other complex compounds of the feedstuffs to more simplified compounds.

3.       Both microbes and animals need all classes of nutrients, energy, nitrogen, vitamins and minerals.

4.       Microbial numbers are increased with adequate dietary nitrogen and minerals. Microbial numbers are proportional to the dietary nitrogen supplied by intact protein (cottonseed meal, soybean meal, feathermeal, etc.) or urea. Microbial numbers depend on an adequate supply of nutrients. If the feed does not supply enough nitrogen (protein) and minerals, the number of microbes declines. Fewer microbes mean that less forage and/or grain nutrients are available for use by the animal. Minerals and protein are needed to increase the number of rumen microbes and their activity.

5.       Sustained nitrogen release in forage diets is important. The rate at which nitrogen and energy become available to the microbes is important because release of nitrogen without enough energy available will result in fewer microbes (less microbial protein produced so the animal gets less protein). A sustained release of nitrogen or amino acids from intact protein ensures availability of a nitrogen source as the microbes work to digest the forage—a process that usually takes longer than digesting concentrates (grains).

6.       More microbes, more usable energy and more feed eaten. Increasing the microbial population results in greater use of that feed by the animal for its needs, so that 1 lb. of feed now provides more energy than before. Not only is that feed yielding more energy, the animal may eat 10—50% more of it (depending on the level of concentrate) due to the supplemental mineral and protein.

7.       Rumen microbes are either fiber or starch users. Some microbes can use starches (or non-structural carbohydrates) like corn, oats or wheat to produce energy and protein for the animal’s use; others thrive on forages. Feeds like wheat midds and soy hulls are considered to be soluble fibers (or structural carbohydrates). These feeds are easily digested and can be used by either fiber or starch microbes.

8.       To get the most out of either roughage or starch, feed mostly that feedstuff. What the microbial population (fiber digesters and starch digesters) is fed determines which group is more dominant. If forages are the main feed, then forage digesters are more prominent and vice versa. Diets that range from 30:70 to 70:30 concentrate: forage are inefficiently digested.

9.       Too much grain eaten at one time will result in acidosis (grain overload). When an animal eats more starch than its rumen can handle, a large amount of lactic acid is produced and rumen pH drops below 5. As a result of these conditions, the animal goes off feed (acidosis) 2—3 days later. This could happen when ruminants are not started on grain slowly or if feeding management is not handled properly. The end result could be just sore feet (laminitis) or death.

10.    Vitamins are required by the animal and the rumen microbial population. Dietary sources of A and E are required by the animal because it cannot make these vitamins. The microbes can make the B vitamins and vitamin K. A healthy, functioning rumen population will make enough of these vitamins to meet their own requirements as well as the animal’s needs, provided all other nutrients are adequate. Since the water-soluble vitamins (B and K) are contained within the microbial cells, vitamin synthesis is related to the size of the microbial population.

11.    Feed to optimize production (milk or growth). The animal and the microbes have to be fed what they need so that the animal performs to its genetic potential (so it will perform as well as its breeding will allow).

12.    Know what to feed and when. When energy, protein, vitamins and minerals are supplied to the animal and microbes in the right amounts and at the right time, everything works beautifully. But a deficiency of any nutrient hurts performance (weight gain, feed efficiency, conception rate, weaning weight, velvet production, etc.).