How TMR Dead Spots Impact Herd Health

The science of feeding the perfect TMR (Total Mixed Ration) does not end with a ration on paper – this is just the beginning. Precision feeding requires measuring each ingredient exactly and then mixing those ingredients uniformly and consistently to produce the TMR your nutritionist has prescribed. Any mixer can weigh ingredients, but will every mixer blend a TMR properly? A TMR is formulated to give animals the energy and nutritional value needed to produce and perform at optimal rates in every bite. The ingredient ratio in each handful should equal the ration on paper.

Feed mixes when particles fall together simultaneously and unobstructed. When feed stops moving, you start losing – fiber, fuel, time, and steel, costing you milk, meat, and money. In high-performance mixers, the action of mixing occurs at the tub ends, processing feed along the sidewalls.

In non-performing mixers, feed movement slows and then stops first at the cyclical transition from the tub end to the sidewall, visible as “dead spots”. As the mixer fills, dead spots expand into the mixing tub ends to restrictors. When vertical mixing fails, ingredients separate into 3 different rations. The bottom ration (1) is 40% nutrient-dense fermentable carbohydrates while the top 60% (2) is high-fiber feed with low energy floating on the top. Forages trapped in the middle (3) processing zone are pulverized by knives rotating at 24 RPM, reducing particle length below the recommended theoretical length of cut (TLC). Looking inside the mixer reveals a floating feed mat undulating with auger rotation but not mixing. The resulting TMR is under-mixed and over-processed.

Dead spots can be a rumen killer. When vertical mixing blends improperly to form layers, the ration is inconsistent and ingredients are not uniformly delivered to the animal. Over-processing reduces physically effective fiber (peNDF), which forms the rumen mat and stimulates cud production (known as the tickle effect or scratch factor). Energy-dense nutrients concentrated in the bottom 40% of the mixer tub feeds the first 1/3 of the herd at the top of the feed rail. Low fiber, high-energy intake causes hot ration over-eating, leading to a condition known as acidosis (rumen pH falling below 5.8).

Early symptoms of acidosis include reduced feed intake and rumination, lethargy, high body temperature, and diarrhea. The over-mixing loss of peNDF reduces cud chewing for a loss of natural, neutral saliva production to buffer hot rations. Prolonged and frequent acidosis conditions lead to permanent loss of rumen motility, ulceration of rumen lining, liver abscesses, and laminitis. In acute acidosis, the cow is off-feed, suffering increased heart and breathing rate, and eventually death.

When vertical mixing stagnates, so do lactation curves. The lower 1/3 of the herd at the bottom of the feed rail is also negatively impacted when limited to a high-fiber, low energy diet. Not enough dry matter intake (DMI) means the animals are not getting the caloric energy needed to produce milk efficiently. Energy is first utilized for survival needs (NEm), secondly for gain and reproduction (NEg), and finally for lactation (NEL) – leaving milk production adversely affected.

Dead spots destroy machines. When static and sorted, TMR ingredients are most abrasive. If the operator observes the feed is not mixing, they often mistakenly attempt to compensate with longer runtime. Longer, non-mixing efforts are wasting time and fuel while creating excess machine wear and adding up unwanted tractor hours, without improving nutrition.

Mixing a true TMR requires a machine engineered to eliminate obstacles and dead spots without sacrificing mixing performance. What we now call vertical mixing is actually design-controlled correlation of vertical mixing and horizontal processing. Feed is processed horizontally while lifted up the sidewalls and mixes when falling into the mixing cavity of flared tub-ends.

This Golden Ration of vertical-to-horizontal flow is not 1:1, but a delicate balance of the exact right mixing consistency for cows to get the same bite every time. Once the balance starts shifting, health and production are impacted. Just a 1lb. deviation in daily milk production translates into $5,200 per 100 cows per lactation on $17.00 milk. Over-process and under-mix and lose rumen efficiency and risk acidosis. Under-processing results in increased sorting, decreased DMI, and loss of rumen performance.

Patz Balanced Flow™ Technology works to create the perfect ration of vertical mixing and horizontal processing. Precision fitted AR400 component screws create high-volume mixing cavities at the flared tub ends. Tru Taper™ and Vortex ® screws in proportional, vertical relief tub design with patented contoured baffles create the signature Patz “rolling boil” to balance vertical and horizontal feed flow.

Knowing the importance of unimpeded mixing, Patz also created a patented tub-mounted magnet. This magnet has a two-stage retention system that follows the contour of the tub for non-restrictive feed flow and maximum hardware protection in your rations.

Know your flow! Try the carrot test. Take one bag of baby carrots and toss them into the full mixer. The carrots should move to the sidewalls and tub ends and disappear in less than one minute, re-emerging in 2 to 3 minutes. Work with your veterinarian or nutritionist to conduct routine shaker-box tests (Penn State Particle Separator) to monitor mixer performance regularly.

See the applied science of mixing in action with Patz Balanced Flow™ Technology in this video:


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