Cow Tales: Ranch math of protein supplementation
December 4, 2012
A cow can stand next to a bale of feed and starve to death. Veterinarians are called out to examine down cows every year for this exact reason. In veterinary medicine we call it protein-energy malnutrition but more simply they are starving with full bellies. The problem is protein nutrition or lack thereof.
The second stomach of all ruminants is the rumen. It is a bacteria laden fermentation vat allowing cows to utilize poor quality feed stuffs. The bacteria do all the dirty work but require a few things as payment. Protein or nitrogen is one element they require. So, if the bacteria are starved of protein then digestion of roughage is reduced and the cow loses condition. If the deficiency is prolonged the animal can become recumbent and even die. In fact, once recumbent it can become exceptionally difficult to turn them around despite prolonged hand feeding.
Winter pastures, mature poor quality hay, straws, etc are typically deficient in crude protein. Cows consuming these feeds need additional protein to meet their requirement. In general, we recommend supplementing one pound of protein to each cow each day. Excess protein consumed will be digested and a large portion can be recycled through the blood stream back into the rumen to again be utilized by the bacteria, a rather ingenious bit of biology. Consequently, ranchers don't have to feed their supplements daily. The allotment required for two days can be fed every other day, for three days every third day, and so forth up to about once weekly. But not all protein supplements are priced equally.
The price of protein supplements should not be compared on a per ton basis. The price per pound of protein is the appropriate economic comparison. We need to know three things, the crude protein, the percent dry matter, and the price per unit. Crude protein concentration is available on every feed tag and should be reported on a dry matter basis. The dry matter may be reported or we might have to subtract the percent water from 1.00. And lastly, we need the price per unit of feed. The equation for determining the cost per pound of protein is $ per pound of CP = ($ per unit of feed) divided by (unit of feed x dry matter percent x crude protein percent). A quick call to the local feed store returned the following current feed prices. Dry matter percentages are estimated. Most hays are around 88 percent dry matter, I estimated lick tubs/barrels at 75 percent, and the liquid feed I looked at was 54 percent dry matter. The calculation for the first example would look like this: $125.00/(2,000 x .88 x .14)=$0.51.
The table can look drastically different when hay prices are closer to "normal" and not under the influence of severe widespread drought. Other factors to consider include ease of feeding, any additional equipment, storage, and delivery fees. Feeding hay can be as easy as unloading at the top of a hill, cutting the strings, and givin' her a good shove. On the other hand, it may require additional equipment such as a stack mover, bale processor, hydraulic bale un-roller, or a tractor. Transporting bales from hay ground to winter pastures can become a logistical problem for some producers. Others live in snowy ranges that require feeding for some period of the winter when grazing is no longer possible. Ranches that include productive hay ground will create opportunity to amass feed to be used on the ranch or possibly sold. Each ranch will have varying circumstances and so the solutions will be different.
Additionally, manufactured feeds create an opportunity to include vitamin and mineral supplements. Our recommendation has been to provide trace mineral from two months prior to calving through grass turn-out. This provides the nutritional requirements for the developing fetus but minimizes waste during the summer months when consumption wanes. The price of trace mineral supplementation can easily approach $0.15 to $0.25 per head per day and needs to be considered.
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The extensive regional drought will have many ranchers feeding less than optimal feeds this winter. Whether grazing dormant native grasses or offering a TMR, it pays to consider protein nutrition when balancing feed resources with cow requirements. The cost of protein supplements should begin with calculating the cost per pound of protein supplemented. Each rancher will have to weigh additional nutritional and logistical factors before procuring their feed resources. Be sure to contact your local feed supplier, representative, or veterinarian if you have questions.
Crude Protein – an estimation of the protein concentration of a feed stuff usually expressed as a percentage of the dry matter. Crude protein is a calculated number based on the measured concentration of nitrogen determined by the Kjeldahl method. In fact, the average protein molecule is 16% nitrogen. Many labs will use NIR in which light refraction is measured when it passes through a sample of feed. Data obtained from NIR technology must be standardized using "wet" chemistry or the Kjeldahl method.