Testing TMR Provides Useful Report Card

The January 2022 newsletter that I received from Mercer Milling Company opened with the quote “The (mineral) market is seeing some stability, seeming to be quiet. Per the ‘new normal’ we seem to be getting used to, freight and logistics are the troubling factors; finding trucks and logistics for deliveries are very time consuming. COVID, China’s ‘Blue Sky’ initiative (to clean up that nation’s air before the February Winter Olympics) and plant shutdowns are all having an impact and look to be a big issue in the first and second quarters of the new year.” It also stated that urea prices have leveled off (still at around $825/ton – an increase of 195% in the last 22 months!). One producer of dicalcium phosphate (dical) has raised its price, but other dical suppliers are holding prices steady. Quoting the letter directly: “Fertilizer is still driving the dical and urea boat.” In addition to seriously impacting urea production, “the rolling power outages in China, to prepare for the Olympics, will likely affect B vitamins the most.”

Most of my readers know that I am a serious advocate of testing soils, forages, livestock performance, etc. Not knowing what nutrients are present – or lacking – in soils is a case where ignorance is anything but bliss. Typically, a farmer might call me to ask why a pasture is being overrun by Russian knapweed. I answer their question with a question: What do your soil tests tell you? My question is normally followed by loud silence on the part of the non-testing caller. This lavender-flowered perennial pest tolerates moderately acid soils, low phosphorus and excessive potassium. Another common weed opportunist is horse nettle (wild tomato), which likes higher pH, low phosphorus and poor soil biology. Complete soil tests (including base saturation percentages) would provide the crop person very useful information. Most of the time, giving the desirable plants the soil nutrient package they need helps chase away undesirable plants.

Testing forages is very important, even more so if the soils growing those roughages were not tested. Intuition only goes so far in tying together feed programs. I take testing one step further, beyond soils and forages – namely testing total mixed ration (TMR) blends, for folks using this management tool. TMR programs have at least three advantages (compared to separate ingredient feeding). They can ensure that every mouthful ingested is nutritionally balanced; they enable the cattleman to introduce dietary changes gradually (minimizing off-feed issues); and TMRs generally increase total dry matter intake. Here’s a fourth benefit: TMR analyses provide a report card, grading the ration balancing skills of the dairyperson.

TMR analysis data arrived in my inbox on Jan. 3. They came from Kenny, a “grass-fed” dairyman whom I advise in both crop and feeding programs. Such results from the Dairy One Lab in Ithaca offer 30 values, expressed on a dry matter basis. On his TMR analysis report were a few values that concerned me. First, total dry matter percentage was 45.3%. Generally, when total diet dry matter drops below 50%, increasing dry matter intake beyond present levels becomes quite a challenge; particularly in cold weather, soggier TMRs are colder and may freeze. Adding two to three pounds of chopped hay per head per day (PHPD) will dry up the TMR and not depress intake of the other feeds. As total pounds of dry matter intake increase generally so does milk production.

The second point concerning me was a protein solubility of 41%. We try to keep that figure closer to 30% (definitely not over 35%). Wetter forages tend to have higher protein solubilities, with a greater proportion of their nitrogenous compounds showing up as non-protein nitrogen (NPN). More carbohydrates are needed to feed to rumen microbes, which couple these energy sources with NPN to synthesize more complete proteins needed for producing meat, milk, calves, etc. Adding a pound of molasses (approved for grass-fed) PHPD will provide these microscopic workers the carbs they need to perform this vital task. The third point of concern is a net energy for lactation of 0.57 mcal/pound. We’d like that value over 0.60 mcal/pound. That pound of molasses helps meet that need. The presumed total PHPD dry matter intake is 40 pounds.

Point #4 is a calcium reading of 0.70%. We’d like that upped to at least 0.80%; adding one ounce of feed grade limestone (35% calcium) will bump that up toward that target. Point #5 is a phosphorus test of 0.36%, which we’d like to be 0.40%. Adding one ounce of dical PHPD will nudge phosphorus toward that 0.40% target and also provide a few more grams of calcium to her diet. Dical is the main source of phosphorus for American livestock diets. We don’t want to underfeed it, but since its cost has increased from $0.24/lb. to $0.42/lb. in the last five months, we don’t want to overfeed it either.

The last figures that concern me on Kenny’s TMR analysis are magnesium (Mg) and potassium (K) readings of 0.24% and 2.72%, respectively. Although the Mg reading isn’t terribly low, it does tend to be “bullied” by the very high K reading, causing an imbalance between these two cations (positively charged particles). In a dry cow diet, that imbalance can predispose her to a milk fever. Adding 0.1 pound of Epsom salt (magnesium sulfate) PHPD goes a long way toward restoring the balance between Mg and K, thus heading off most milk fever threats at the pass.

I should point out that grass-fed diets tend to run lower in phosphorus than more normal diets with grains – and that a phosphorus deficiency can also spawn milk fevers. On average, grains bring about twice as much phosphorus onto the farm as do forages. Let me also point out that a little over one pound of actual phosphorus accompanies every thousand pounds of milk leaving the farm.

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