Skip to content
AgridianDairy KB

TMR load accuracy

Definition

Section titled “Definition”

Load accuracy is how closely the amount of each ingredient loaded into the mixer, and the amount of TMR delivered to each pen, match the targets in the ration recipe. It is measured from the mixer scale and logged by feeding software for every load.

Accuracy is measured at two levels:

  • Per ingredient: actual loaded weight vs target weight for one ingredient in one load. Shows which ingredients, and which loaders or feeders, are missing the target.
  • Per load: total loaded vs total target, or a combined score across all ingredients in the load. A load can hit its total within 1% while individual ingredients are off by 10% in opposite directions, so the per-load total alone is not enough.

Delivery accuracy (pounds dropped per pen vs the pen’s call) is a third check. It matters most when one load is split across several pens.

A tolerance band is the error accepted before a load is flagged. Bands are usually set as a percent of target, tighter for large ingredients and looser (or as an absolute pound limit) for small ones.

Loading order

Section titled “Loading order”

Ingredients are loaded in a set order so they mix evenly and the mixer can process long forage. The right order depends on mixer type (vertical auger, horizontal reel or auger). A common pattern:

  1. Dry hay or straw that needs processing, first, run briefly.
  2. Grains, concentrates and premix (minerals, additives).
  3. Wet commodities and silages.
  4. Liquids last or near the end, with mixing time after.

Small-inclusion ingredients

Section titled “Small-inclusion ingredients”

Ingredients fed at a few pounds per load (minerals, buffers, additives, some protein supplements) are where percent-based accuracy breaks down:

  • A loader scale bucket or mixer scale may read in 5–20 lb increments, so a 15 lb target can’t be hit within ±5%.
  • Herds usually combine small ingredients into a premix or mineral mix made on a more accurate scale, then load the premix as one larger ingredient.
  • Track small inclusions with an absolute pound tolerance, not a percent.

Formula

Section titled “Formula”

Plain text:

Ingredient error (%) = (actual lb − target lb) / target lb × 100
Load error (%)       = (Σ actual lb − Σ target lb) / Σ target lb × 100
Load accuracy (%)    = 100 − Σ |actual lb − target lb| / Σ target lb × 100
Loads in tolerance (%) = loads with every ingredient within band / total loads × 100

LaTeX:

e_i = \frac{a_i - t_i}{t_i} \times 100
\qquad
A_{\text{load}} = 100 - \frac{\sum_i |a_i - t_i|}{\sum_i t_i} \times 100

where a_i and t_i are actual and target as-fed lb for ingredient i in a load.

The absolute-value version is the useful one: it doesn’t let over- and under-loads cancel. Feeding software products score accuracy differently (some weight by ingredient cost or DM), so state the method when comparing.

How to pull it in DC305

Section titled “How to pull it in DC305”

Load accuracy is not in DC305. Target and actual weights are logged by the mixer scale and feeding software (TMR management systems export load-level and ingredient-level actual vs target).

DC305 supplies the pen cow counts that set each pen’s call (pounds to deliver):

COUNT BY PEN FOR LACT>0          cows per pen, to check feed calls
SUM BY PEN FOR LACT>0            head count by pen (SUM with no items counts animals)

If the feeding software’s pen counts disagree with DC305, the calls are wrong even when loads are mixed perfectly.

Typical range

Section titled “Typical range”

Herd context: US Holsteins, freestall or dry-lot, TMR mixed in a scale-equipped mixer wagon, accuracy from feeding software logs.

Measure Common target
Per-ingredient error, major ingredients (forages, grains) within ±5%
Per-ingredient error, small inclusions absolute limit (e.g. ±5–10 lb) or ±10%
Per-load total error within ±1–2%
Loads with all ingredients in tolerance > 90%
Herd load accuracy score > 95%
  • Mixer scale calibration: scales drift; herds commonly check with known weights or a certified truck scale on a set schedule, e.g. quarterly.

Common mistakes

Section titled “Common mistakes”
  • Looking only at load totals. Errors cancel. Track per-ingredient error with absolute values.
  • Percent tolerances on small ingredients. They flag every load or none. Use absolute pounds or a premix.
  • Accurate as-fed, wrong DM. A load can hit every as-fed target while a wet silage means DM is 10% short. Accuracy and DM testing work together. See as-fed vs dry matter.
  • Overloading the mixer. Past rated capacity, mixing is poor even with perfect weights.
  • Changing loading order or mixing time between feeders. Weights are right but the ration cows sort through is not.
  • Uncalibrated scales. Every number, including DMI and shrink, inherits the error.
Section titled “Related”