Buying feeds to stretch current supplies until spring and summer feeds are harvested can be a difficult and expensive experience. To minimize milk production drops and minimize expense make sure that the feeds purchased will supplement and extend the expected on farm feed supplies. To do this evaluate what will need to be replaced in the current ration on a nutritional basis. The following graph (Figure 1) illustrates the needs of the high producing dairy cow. Note the major requirement by far is for energy, followed by fiber, protein, minerals & vitamins.
FIBER. Cows have a physiological need for fiber and is actually the first consideration when trying to extend on-farm feed supplies. If this need is not met acidosis is the likely result, producing a marked drop in milk fat tests, sore feet, depressed feed intake and lower milk production. When short of feed often the most critical consideration is fiber. Most farmers try to grow enough fiber as shipping, trucking and handling fiber is expensive. If there is a feed shortage, first check to see if there is enough fiber to meet needs. If not, consider this need when purchasing either energy or protein. It may mean buying hay, haylage or corn silage as part of this supplemental feed supply. A high concentrate ration might just benefit from 3-5 lb. of average higher fiber hay. However, fiber levels in excess of basic needs may depress feed intake and milk production. Low energy rations will likewise suffer from unneeded fiber additions.
ENERGY. The next most important consideration is energy. As the chart above shows, energy is the largest requirement and , following fiber, the one most likely to be in short supply. While protein sources are the most expensive, energy costs are the greatest because about 4-5 times as much feed is needed to meet energy needs as to meet protein needs. If energy is short buy the cheapest energy sources that will fit the ration needs. Because concentrates have about 2X the energy content/lb. compared to forages they are worth about 2X as much per ton for energy. For example, ground corn has an NEl value of 0.80 Mcal/lb while timothy hay has a value of 0.50Mcal/lb. This suggests that if hay costs $130/ton then corn meal is worth nearly twice as much on an energy basis.
As you can see by the values it is not exactly 2X so some computing is needed to fine tune the relationship. The cost of one Mcalorie of NEl from timothy equals $130/ton divided by 0.50 X 2000 (Mcal/ton) = $130/ton divided by 1000 Mcal/ton = $0.130/Mcal.
Cost of one Mcal NEl from corn meal, if corn meal costs $170/ton delivered to the farm is $170/ton 0.80 X 2000 (Mcal/ton) which equals $170/ ton divided by 1600 Mcal/ton or $0.106/Mcal. Corn meal is clearly the best buy for energy.
PROTEIN. If protein is the nutrient needed, purchase protein as cheap as possible. Determine the relative cost of protein from different protein sources. Compare canola at $200/ton to soybean meal at $250/ton. Canola is 37% CP and soybean meal is 45% CP. One ton of canola contains 2000 X 37% or 740 lbs CP, thus $200/ton divided by 740 lbs CP/ton equals $0.270/lb CP. One ton of soybean meal contains 2000 X 45% or 900 lbs CP/ton, thus $250/ton divided by 900 lbs CP/ton equals $0.277/lb CP. The canola is only slightly cheaper per lb of protein and may not be enough of a savings to warrant changing the ration formulation at these prices. Note that this is near a break even price for each one, a price break from the value of each given above would favor that ingredient as a better buy for protein.
MINERALS AND VITAMINS. Careful comparison shopping is needed to evaluate mineral supplies. Understand that independent mineral suppliers may include a fair amount of ¡°service fees¡± in their prices. Use these services for which you are paying or choose another source.
Do not buy unneeded mineral vitamin supplementation. Today, one way to reduce the mineral load reaching the land through the manure is to avoid excess supplementation. Excess minerals in the ration end up in the field and then back into the forage grown on that field. This can lead to forages with high calcium and potassium contents, trouble for tail-end and dry cow rations. Nitrogen from excessive protein levels and phosphorus from feeding levels above requirements can also load soil content of these plant nutrients, increasing the possibility of surface and ground water infiltration. Most importantly, avoiding excesses can reduce costs as both protein and phosphorus sources are expensive.
MIDDLE FEEDS. Some ingredients do not fit clearly into a fiber, energy or protein category such as cotton seeds with linters, brewer¡¯s and distiller¡¯s grains and even high grain content corn silage. The best way to evaluate these ingredients is in a total ration formulation where each ingredient is given it¡¯s current price. A least cost or maximum profit ration can be calculated, allocating the contribution that feedstuff makes to each nutrient category.
FEED ANALYSIS. How do you evaluate a prospective feedstuff for purchase after determining what nutrients are needed to balance the ration? A feed analysis is necessary. An analysis will be needed to balance the ration, why not request one prior to purchase. Use this information to determine if :
1. this is the best feed available to balance the ration
2. the feedstuff is competitively priced with other sources and with other feedstuffs supplying the same nutrients?
3. the moisture content is greater or less than average for that feed. Adjust the price accordingly.
FEED QUALITY. In addition to feed analysis some added parameters should be considered, particularly spoilage. This will not be detectable in the routine analysis and a close visual inspection is needed. You should not pay for or receive spoiled feed. It should be removed and placed to one side.
Beware of previously loosened silage. It will start to heat in just a few hours and markedly reduce the ¡°bunk life¡± once on the farm. Silage should be loosened and removed and loaded into the truck in one operation. Silage is best if hauled daily, though it should keep for a couple of days if it was originally well fermented.
Hay should be free of dust and mold and not stored directly on the ground or cement floor. The two best indicators of quality are the date of cut and the closely correlated protein content. Grass hay testing 8 - 10 % protein will not support very much milk production. It will also be low in energy content and it¡¯s rate and extent of digestion will be low.
GUIDELINE VALUES. Corn silage will average 27 - 30% DM, and on a dry matter basis contain about 8% CP, and 0.72 Mcal NEl /lb. Hay is more variable but higher quality grass hays will contain 90% DM (in the barn, 80% DM in the field), and on a dry matter basis contain 14 - 16 % CP, and 0.58 - 0.62 Mcal NEl /lb. Higher quality alfalfa based hays may contain, on a dry matter basis, 18% - 20% CP, and 63 - 65 Mcal NEl /lb. Often haycrop silages are higher in quality than hays because they were cut at an earlier stage of plant maturity due to less dependence on weather at harvest.
Haycrop silage varies widely in dry matter content but should show evidence of having been wilted prior to ensiling. Bunker silage should vary between 35% - 45% DM with upright silos varying between 45% - 55% DM. On a dry matter basis protein and energy values will be higher by a couple of points in haylage than for a comparable hay due to better leaf retention during handling and storage.
Sidney J. Lyford, Jr
Dept. of Veterinary and Animal Sciences
University of Massachusetts Amherst
Crops, Dairy, Livestock News. Vol. 2:1, Spring 1997