Jaylor: TMR Corner Troubleshooting Total Mixed Rations

Published on Mon, 11/03/2014 - 3:54pm

In previous articles, we have talked about factors that affect the uniformity and consistency of Total Mixed Rations (TMR). In this article we present methods for compensating for the most common mix uniformity problems, namely uneven distribution across the feedbunk, excessive amounts of long material, and sorting behavior.

Uneven distribution across the feedbunk
There are two basic types of uneven distribution, each with its own cause and potential solution:
1. High to low concentration of grain
along length of feedbunk:
a. Improper ingredient sequence (Vertical mixers): This can occur in vertical mixers if grains, rather than forages, are added first, which is the normal practice with horizontal type mixers; the opposite sequence (i.e. forage first) is correct for vertical mixers. Vertical mixers mix predominantly by gravity. If the denser grains are added first they will tend to circulate and remain in higher concentration beneath the lighter forages, and then be delivered first during feedout. Always add forages first and grains last with vertical mixers.
b. Dry mix: If there is not enough moisture in a TMR, the smaller, denser particles are not held as easily in suspension and will form a gradient of higher to lower concentration from the bottom to the top of the tub within the mixer. This gradient will then be reflected in the feed-bunk at feedout since the majority of mixers deliver from the bottom. Furthermore, this effect will be enhanced as forage particle size increases. The most effective control method for dry mixes, which is responsible for much of the sorting that is seen during eating, is to add liquid to the mix (see below).
2. Variation along the feedbunk:
a. Fluctuating ingredient concentrations: Non-uniformity of the mix along the feedbunk, such as in forage to concentrate ratio, can be an indicator of inadequate mixing, either due to insufficient time, over-filling, or because of a malfunctioning or worn mixer. Most TMR mixers are designed to require from three to five minutes of mixing at full PTO RPM after the last ingredient has been added. Often this does not occur because of underestimation of time required, routine operation at lower tractor speeds, inclusion of time spent driving at lower RPM or lack of understanding. Final mix times need to be substantially increased when mixers are run at lower speeds or are overloaded, and as they wear, to achieve comparably uniform mixes to those operated to specifications. If overloading is common, it may be cost effective to make an additional load, or even buy a larger mixer to better meet your needs.
b. Forage clumps: The presence of clumps of forage along the feedbunk within an otherwise well mixed ration indicates an inability of a mixer to incorporate long forage, or clumps of silage, into the TMR. Overall, this will most likely be related to a particular machine’s inherent ability to process long forage, in that some machines are more capable than others. That said, this problem may be minimized by ensuring that knives are replaced regularly and remain sharp, especially those on the bottom of the augers of vertical mixers, which do the majority of the actual cutting. With vertical mixers, it is also helpful to first add to the mixer only the forages that require processing, including frozen and clumped silages, plus any chopped silage or other ingredients that are used to help the long material flow within the mixer. Then run the mixer at full PTO RPM until the majority of the processing has been completed and most of the clumps have been broken up. This will minimize the time required for processing, as well as make it more efficient by maximizing the exposure rate of the long particles to the lower blades. Adding baled or other long forages on top of processed forage or a partially completed mix will dramatically increase the time required for processing and the appearance of unprocessed clumps in the mix.

The ability of cattle to sort TMR rations comes primarily from two sources, the differences in physical characteristics (size, shape and density) between forages and concentrates, and the moisture content of the ration. Solutions for minimizing sorting thus usually revolve around more extensive and uniform processing of long forage, and addition of surface moisture to increase entanglement and the adherence of small particles to longer particles.
1. Increasing processing: Excessively long forage particles particularly enhance sorting by enabling animals to ball them together and nose them out of the way to get to the concentrated smaller grain and supplement particles beneath. The most effective way to decrease sorting is to ensure that the majority of forage particles are reduced to below two inches (2") in length. This will result in a particle size distribution comparable grass haylage chopped at a one-half (1/2) to three-quarter (3/4) inch theoretical length of cut. If forage processing is inadequate, ensuring knives are sharp, adjusting the processing method as described for forage clumps above, and/or increasing processing time may help. Otherwise, it might be best to consider alternative forage processing, or consider buying a vertical mixer that is capable of creating a more uniform mix with a smaller particle size, such as a Jaylor TMR mixer.
2. Addition of liquids: Regardless of optimal particle size, a TMR will separate or be able to be sorted if it does not contain an adequate amount of moisture, and especially moisture on the surface of the particles. The easiest and most effective way to add moisture to TMRs is simply to add water, and it can take a surprisingly large amount of water to yield optimal results. Regardless of starting moisture content, if the cattle appear to be sorting (making holes in the feed and eating the concentrate first), start by adding 10% water by weight (as-fed) to the final mix, slowly, over the duration of the final mixing period. Wait 4-5 days to observe the results; if there appears to be improvement in eating behavior, intake, and/or manure consistency, add another 5% water by weight and observe the results. Then, continue adding water in 5% increments and observing results for about 4 days between additions, until there is no further perceived benefit, then decrease the water addition by one step. I once worked with a dairy herd that made its ration from dry alfalfa hay and grain, and then added water until the ration was about 50% dry matter, with impressive results. If you do the math, this means they added almost the same amount of water to the mix as they did dry ingredients. In the end, any source of palatable moisture will work, this includes moisture from haylages or corn silage, or even wet by-products if they are available, and sufficient is added.
The creation of a uniform ration that holds together so that each animal gets it share is a process that benefits from consideration of the physical characteristics of the ingredients and their collective moisture content, as well as the capabilities of your TMR mixer. It is equally important that these are tuned and work together to get the most out of your TMR feeding program — “Because Nutrition Matters.”

Dr. Alan Vaage is a Ruminant Nutritionist with over 30 years of experience in the beef industry, and currently provides technical support for Jaylor, in Orton, Ontario. Dr. Vaage can be contacted by email: nutrition@jaylor.com.