Total Mixed Ration Calculator
As noted for the "Basal Forage Supplemental Concentrate" calculator, in some cases goats are confined and fed a total mixed ration or diet alone (without access to any other feedstuffs, forage, etc.). In such cases, this calculator can be used.
Two types of information needed to use this calculator are nutrient requirements as concentrations and their concentrations in feedstuffs. For requirements, there are two considerations: absolute amounts and feed intake. An estimate of feed intake is needed to determine the required concentration of nutrients in the diet. This calculator has links to those for dietary requirements for metabolizable energy (ME) and metabolizable protein (MP). Those outputs can be sent to this calculator. The requirement for crude protein (CP) is based on the determined requirement for MP. This is done with an assumed relationship between the efficiency of conversion of CP to MP and the dietary concentration of ruminally undgraded CP (UIP) (NRC, 2000):
CP = MP / (0.64 + (0.16 x UIP, % of CP)), or
MP = CP x (0.64 + (0.16 x UIP, % of CP)).
For the estimate of feed intake, users may have previous knowledge about intake of a certain diet by a particular type of goat that can be used. Alternatively, one of the four "Feed Intake Calculators" can be employed to provide a predicted level of feed intake.
There are different options regarding concentrations of nutrients in feedstuffs. First, the user can input his/her own feedstuffs and composition values. Secondly, a feedstuff library can be employed by simply clicking on particular feedstuffs to be included in the ration. The feedstuff composition values of Preston (2000) are currently being used. It should be noted, however, that the actual composition of many feedstuffs can differ from values listed in feed composition tables. This is particularly the case for forages due to management practices such as stage of maturity at harvest, fertility, etc. By- or co-products can likewise vary in composition due to processing variation.
The two composition items of greatest concern for this calculator are concentrations of CP and energy (i.e., ME or total digestible nutrients (TDN)). Hence, the calculator also allows the user to click on a particular feedstuff and change one or more composition values while using the other library values. For example, a farmer may want to feed a barley hay, knows that the hay was harvested when fairly mature, and had the hay analyzed at a commercial lab. Rather than using 57% TDN and 9% CP, he/she can input actual lab values (e.g., 53% TDN and 8% CP) and still use other library values, such as 0.30% Ca and 0.28% P.
To Use This Calculator
To use this calculator, first click on the class of goat button below (Step 1). Once this is done, buttons will appear for requirements of ME (Step 2) and MP (Step 3), feed intake (Step 4), feed ingredients (Step 5), and input verification (Step 6). After using and closing each pop-up window from these buttons, the estimates will be saved for use in the ration balancer calculator. If you have already used the ME, MP, and feed intake calculators previously, you can proceed to Step 5. However, the common inputs for the the ME, MP, and feed intake calculators previously used must be identical. If not, you can now use the ME, MP, and feed intake calculators in Steps 2, 3, and 4, now. If you enter ME, MP, and/or feed intake calculators from the Total Mixed Ration Calculator Home Page, the ME, MP, and feed intake calculators will automatically close after you have entered the inputs and you have clicked on the Calculate Requirement button.
It is necessary to use a feed intake pop-up window even if one was already used with one of the previous pop-ups, since the feed intake pop-up will provide the estimate of feed intake on which the nutrient requirements in concentrations will be based for use in the ration balancing program.
For Step 5, Select Feed Ingredients, the dietary levels can be entered on a DM or as fed basis. It is necessary to enter feed ingredient cost if the least-cost balancing function of this program is to be used. Least-cost formulation can only be done on-line. These costs can be on any basis, such as $ per pound or ton. After clicking on the "Continue" button at the bottom of the window, you will be returned to the previous window that has all of the potential feed ingredients listed. At this point click on the "Return to Ration Balancer Home Page" button. Now, click on the "Verification of Inputs" button. This window checks to make sure that the same inputs were used for each of the previous steps. If one or more incorrect inputs were used, shown by a red "X", you can continue but with the realization that the requirements for ME and MP and the prediction of feed intake may not match. It would be better to go back and make the correction.
Another thing to be aware of is that the estimate of feed intake on which the ME and MP requirements on a concentration basis are based should be reasonably close to the ME concentration in the diet the user formulated. If they are not similar, then the user should go back to the earlier steps and enter a dietary ME concentration more similar to the one in the specified diet.
Sources used in this calculation method are:
NRC. 2000. Nutrient Requirements of Beef Cattle, Update 2000. National Academy Press, Washington, DC.
Preston, R. L. 2000. Typical composition of feeds for cattle and sheep. In: Beef 36(10), 10-20. Intertec Publ. Co. Overland Park, KS.