To establish food rations: the recommended food intakes depend on the live weight of the animal. To monitor the growth of foals. To adjust the doses of drug treatment, in particular antiparasitic and to monitor the state of health in general. From measurements that are easy to take such as the height at the withers (HW), the thoracic perimeter (TP), baryometric formulas are available according to the type of animal. To take measurements of height at the withers and thoracic perimeter, place the horse upright on its 4 limbs on a flat ground, held in the hand and upright, head supported. Place a tape measure to the withers, taking as a mark the upper point to the right of the shoulder (scapula) vertically to the strap passage. Make sure the tape is flat and well positioned on both sides. Read the measurement in cm on the tape adjusted but without tension. Put on a halter + lanyard. Wear suitable (safety) shoes. Carry out the measurements with 2 people (handler, helper) or even 3 for young horses. Warning, these baryometric formulas will no longer be valid for horses of extreme sizes (for which equations have not been established) : pony < 1 m, horse > 1,80 m.