Horse body mass
The horse body mass is highly variable, depending on breed, model, physiological state, condition, owner's purpose and usage of the animal.
Thinness is associated with mistreatment, but owner-independent factors such as age and illness can cause dramatic weight loss in horses.
[6] The purpose of breeding and the animal usage also call for different body conditions:[7] for example, a horse destined for sport should always be as close as possible to its ideal weight, to remain a top performer.
On the other hand, a pregnant or nursing mare will be in better shape if she has a higher than average body mass, with some fat reserves.
[13] In summer, changes in light levels lead to an increase in appetite and changes in metabolism,[14][15] which generally result in weight gain.
In winter, on the other hand, appetite is reduced and the efficiency of energy conservation is increased, as the food available is generally scarcer.
[16] This particularity seems to stem from the horse's long evolutionary history in an environment that does not always offer the same quantity of food from one season to the next, nor from one year to the next.
Consequently, this is the method used by professionals in everyday conditions, without excluding the use of weighing in special situations, notably to monitor animal growth.
On the other hand, breeders and professionals in the horse market often acquire them,[3] not only for the precision of the measurement, but also to perfect their judgment, through visual appreciation.
Tape weighing is the method of estimating an animal weight using mathematical formulas based on body dimensions.
[3] These formulas have generally been developed for adult, mesomorphic animals in a normal state of maintenance and with an average level of digestive tract replenishment.
The values collected must therefore be interpreted according to age, body proportions (brachymorphic, mesomorphic or dolichomorphic), state of maintenance and estimated replenishment of the digestive tract.
The tape weighing, placed around the body between the withers and the girth area (corresponding to the thoracic perimeter, TP on the diagram), gives an estimate of weight.
A formula specific to draft horses was developed in 1990 by William Martin-Rosset, researcher in charge of equine nutrition at INRA: Weight = 7.3 × (TP) - 800.
The system is based on both visual and tactile assessment of the fat present on six points of the body, as shown in the illustration below.
Studies have shown that it is active tissue, particularly in the secretion of hormones and inflammatory proteins (cytokines), the presence or absence of which can severely affect the animal's health.
[35] Numerous cases of mistreatment have involved owners who have fed their animals poorly (or not at all), with the result that they have been found in a state of emaciation that is sometimes considerable.
Between 1998 and 2005, the National Animal Health Monitoring System (USA) estimates that the obesity rate rose from 1.5 % to 3.5 % of the equine population.
[43] In France, although no equivalent study has been carried out, obesity is common in Percheron, Boulonnais, Bretons and Comtois draft horses when destined for the meat market.
This explains why foals, which expend a great deal of energy during their growth, are much more rarely obese than adult animals.
[46] Cultural factors also come into play, as people with little knowledge of horses' body condition tend to compliment owners of fat animals, and find obese ponies "cute".
There are indeed genetic causes, with certain breeds of hardy ponies (such as the British Mountain and Moorland) being predisposed to put on weight if they have free access to rich food.
[44][51] Generally speaking, people who come into contact with horses on a daily basis seem to get so used to seeing overweight animals that they come to regard this body condition as the norm.
[58][59] The recommended treatment for obesity is to adapt the horse's diet to the equestrian work or exercise required of it, as in the case of pathology (locomotor apparatus, cardiological problems, etc.
[62] Lighter at birth, but not recognized by the Guinness Book of World Records, Einstein is a miniature foal born weighing 2.7 kg, with a height of 35.5 cm, who is not affected by dwarfism.
[64] In August 1989, the Canadian Thoroughbred Tritonis was recognized as the world's tallest and heaviest non-draft horse, measuring 1.98 m at the withers and weighing 950 kg.
