The ration MushMate by Skimate.eu shows you every morning is not a number carved in stone. It moves with the dog's weight, with what it ran this week, with what's scheduled for next week, and with the last body condition score taken. Here's how that number is calculated, and what it doesn't know yet.

The CAMT training model (fitness, fatigue, season phases) has its own article — How MushMate builds your plan — and why you stay in charge. This one is only about the bowl: how a dog's workload changes the number of grams it gets.

1. The formula: RER → daily need → grams

Three steps, in order, for every dog (the daily need is detailed in § 2):

  1. RER — resting energy requirement, in kcal/day. From the Merck Veterinary Manual formula: 70 × weight(kg)^0.75.
  2. Daily need — maintenance (1.5 × RER), plus cold, plus work by the kilometre (§ 2).
  3. Grams/day = (daily need × 1000) ÷ (the food's kcal per kg), rounded to the nearest 5 g.

The weight used is the last recorded weigh-in, or the reference weight if there isn't one — the ration sheet, the dog's profile, and the mobile app all read the same value today.

The formula hides no safety margin inside its grams. A margin does exist — but it sits alongside the number, spelled out under every calculated ration: "Veterinary estimate ±30%, adjust based on BCS." A warning to read, not an invisible factor baked into the calculation.

And one rule outranks everything: grams entered by hand short-circuit the entire calculation. What you typed is what shows, full stop.

2. One equation, no more tiers

The ration is no longer read from a table of five tiers (rest, light, training, race, long-distance race). It is now added up, in three parts:

daily need = maintenance + cold + work

Work is paid by the kilometre; it no longer "picks" a tier. That is what lets the ration climb beyond what the old table allowed: a 25 kg dog running 160 km a day in a long-distance race goes past 11 times its RER, where the old automatic calculation stopped at 3 (4 on a declared race day).

"Long-distance race" is therefore no longer a tier to force by hand: the amount comes from the kilometres, not from a label.

What the card shows

This equation is not hidden: the Ration card writes it out with your dog's own numbers. A stacked bar shows at a glance the share of maintenance, cold and work in the day's need. Under it, three lines, one per term: the figure in kcal and its reason ("1.5 × the resting need of a 22.6 kg dog", "2 kcal × 22.6 kg × 17.1 km/day on average over 7 days"). When the mean temperature is below the threshold, the cold line writes its calculation, for example "10 − (−6.3) °C"; while cold is switched off, the line says so instead of staying silent. A last line does the conversion: the need in kcal, divided by the food's energy, gives the grams (rounded to 5 g). On the website all of this sits in the card, with the week of kilometres that sets the work; on the phone, the week is behind "See the week".

3. Where the kilometres actually come from

The most counter-intuitive case. During the four maintenance weeks that follow a race, the plan drops back to a quarter of its peak volume. The calendar said "rest." But the dog just raced hard: its ration must not fall back along with the plan. That is why the kilometres counted are the largest of three figures, never their sum:

km of the day = max(
  per-day average of the km actually RUN over the last 7 days,
  per-day average of the km PLANNED over the next 7 days,
  the race's km, if today is a race day
)

The max can only push the figure up, never back down. The backward window, the last seven days, is the one used elsewhere in the app to judge the gap between plan and actual: the same question shouldn't have two definitions in one product. The forward window is symmetric for a simple reason: seven days is the unit in which the plan prescribes load.

Three clarifications that avoid surprises:

What the musher sees

Under the grams, the Ration card shows the breakdown: maintenance 1,174 · cold 0 · work 750 kcal (for a 25 kg dog), then where the kilometres come from ("15 km/day · logged outings", "planned km" or "race day"). If the dog has neither a run nor a plan, the screen says "no km logged or planned". Beyond 8 times the resting need, a notice reminds you that kibble alone is no longer enough: at that level, the ration is topped up with meat and fat.

The per-dog activity setting still exists, but its role changes: it becomes an imposed level. A dog that has one gets the old factor (1.5 / 2 / 3 / 4 / 7 × RER) instead of the equation, and the screen writes "Level imposed: …". Your existing settings keep their meaning; nothing was migrated. The 5 and 40 load thresholds no longer drive the ration (they still serve the plan).

4. Multiple foods in the same bowl

The calculation splits the day's calorie requirement in proportion to each food's share of calories, then converts each share into grams using that food's own kcal/kg. A 50/50 mix by calories is deliberately not a 50/50 mix by grams: raw meat and kibble don't share the same energy density. You can also set an explicit calorie target, which then replaces the calculated need — and the ±30% band that comes with it is the same figure as the on-screen warning, not a separate one.

Each kennel enters its own foods and can share one with the community (moderated before publishing). A duplicate within your kennel is rejected; a kcal/kg outside the plausible range warns you, without blocking the save.

5. The BCS nudge: alongside the grams, never inside them

When the last body condition score (BCS, on a 9-point scale) falls outside the ideal band, the Ration card adds a line under the grams, without touching them: "BCS 3 — thin: consider increasing by about 10% (≈ 770 g/day). Your call."

That 10% is flat, in both directions, and it is not a figure from the literature: it's a musher's prior, the product owner's own practice ("10% is roughly what I adjust rations by"). A proposal to make it configurable kennel by kennel was considered and explicitly turned down the same day: 10% is one constant for the whole product, not a setting you'll find in preferences.

Three details worth knowing: the nudge triggers as soon as a dog falls outside the ideal band (BCS 4-5: nothing shows, even on an old score), and the most extreme cases (BCS ≤ 2 or ≥ 8) get the same ±10% even though a separate gate has already put them on full rest — the nudge doesn't replace that gate; a stale score outside the ideal band shows only "re-score before adjusting the ration," with no figure; and a missing score, or a ration entered by hand, shows nothing at all.

6. The ration sheet, on screen and on the wall

/meute/rations shows the whole team at a glance (Dog, Ration/day, Weight, Activity, Food), each row carrying a three-level BCS badge — green, orange, red — always paired with its text, never color alone.

A dedicated printable poster exists too: A4 landscape, two columns of dogs, paginated so it can actually be posted on a wall. On paper, the Activity column disappears ("at feeding time you pour grams, you don't recompute a factor") and the food moves under the dog's name; BCS shows up as text, only for dogs that need watching or correcting — and for those, the ±10% nudge from § 5 prints right underneath, with its percentage and suggested grams: it was reserved for the screen at first, then put back on the poster when the owner noticed it vanished on print exactly where he relied on it to make decisions standing at the wall. A per-food total (kg/day, kg/week) counts dogs with a calculable ration, and counts the rest separately. A ration pinned by hand carries the label "entered," with the caption: "entered = ration set by hand: it does not follow weight."

7. What it doesn't know yet

So, what do you do with it?

The calculation does the bookkeeping nobody can hold in their head across twenty dogs and six months, and catches mismatches a calendar alone would have missed. It doesn't replace your own eye for a dog's coat, nose, and appetite on any given morning. The ration proposes a number, the BCS suggests an adjustment — you're always the one who pours the bowl.

A number that looks wrong to you? Write to us — these coefficients are meant to move, especially after a first full winter under this model.