Yard tools
Dose & withdrawal calculator
Turn a prescribed mg/kg dose into millilitres, and a published detection time into a date you can defend. Pure arithmetic — no accounts, nothing stored, nothing sent anywhere.
Dose to volume
Convert a prescribed mg/kg dose into the millilitres to draw.
Draw
5.5ml
500 kg × 2.2 mg/kg = 1100 mg ÷ 200 mg/ml = 5.5 ml
Withdrawal planner
Work forward from the last administration to a date you can defend.
Pick the date of the last administration.
Getting it right
- 1
Weigh the animal
Not eyeball it. Under-dosing an antimicrobial or an anthelmintic drives resistance, and over-dosing an NSAID causes ulceration. A weigh tape is the minimum; a weighbridge is better.
- 2
Take the dose from the prescription
The mg/kg figure comes from the attending veterinarian for this animal and this presentation — not from a product page, a forum, or what worked last season.
- 3
Read the concentration off the label
Same molecule, different strengths. A 5% and a 20% solution of the same drug differ four-fold in volume, and this is where most dosing errors actually happen.
- 4
Plan the withdrawal before you treat
Work the detection time forward to a date, add a margin, and check it against the race calendar. Discovering the conflict afterwards is not a plan.
The arithmetic
total dose (mg) = weight (kg) × dose (mg/kg)
volume (ml) = total dose (mg) ÷ concentration (mg/ml)
clear date = last dose + detection (h) + margin (days)
Why volume errors dominate
The dose is usually right on paper. What goes wrong is the conversion — a 20% product treated as a 5% one, or a 650 kg camel dosed on a 450 kg assumption. Both produce a four-fold error, and neither looks wrong in the syringe.
This tool performs arithmetic on figures you supply. It is not a prescribing tool and it does not recommend a dose or a withdrawal period. Both must come from the veterinarian attending the animal, and the withdrawal must be confirmed against your racing authority's current rules.