Water

The most important nutrient for the welfare of working equids is water (1). Working equids need regular and adequate access to palatable, safe water that meets their physiological and work requirements, which may vary.

THE IMPORTANCE OF WATER…

The consequence of insufficient hydration in working equids is that food intake becomes depressed (2) and leads to an apathetic animal incapable of performing its usual work duties at full capacity (1).

HOW MUCH WATER DO WORKING EQUIDS NEED TO DRINK?

  • Voluntary water intake will depend on hydration status, type of feed and opportunity to drink.
  • Working equids very rarely have unlimited access to water and estimating how much they need requires consideration of many variables.
  • Assumptions have been made in the referenced article (1) and expected requirements for daily intake of water are:
  • A working horse in a hot climate might need 40-60l/day.
  • A working donkey in a hot climate might need 20 l/day.
Donkey Research shows that ‘Donkeys are far more drought-resistant than horses (2). It is not uncommon for wild donkeys to go to water only once every 2-3 days’ (1).
Donkey The donkey is able to rehydrate quickly as it can drink 20-30l in a very short space of time (1). Horses are able to rehydrate quickly if given free access to water. There is no need to restrict water intake after a period of water deprivation (3).
All equines Repeated studies have shown no ill effects in allowing horses, donkeys and mules to drink their fill and return to work (1, 4).

WHAT AFFECTS PHYSIOLOGICAL AND WORK REQUIREMENTS?

Daily water intake depends on multiple factors. Hard work in hot, humid climates will lead to dehydration if equids are not able to access the water they require.

CLIMATE E.G. TEMPERATURE, WIND, HUMIDITY, ACCESS TO SHADE

Donkey and horse Daily water intake expressed in percent of live weight would be two-fold higher in the hot season than in the cool season that is 5% of BW per day in temperate climates and 9% under conditions of high ambient temperatures (5).

DIET

Donkey The water intake is related to the type and amount of forage which is offered and the environmental conditions (2). Water intake decreases in animals that are not eating either because they are in appetent or because of a lack of food offered (8). Horses fed a high forage diet drink more than those fed a grain based diet (6).

INTENSITY OF WORK

Donkey Water intake will increase when pulling with a force, according to the intensity of the work. Water intake can be predicted from work duration, climatic index and work intensity (2). Exercise increases water intake in horses (9).

STAGE OF LIFE

Horse e.g. foals, pregnant and lactating and elderly equids will have all have different requirements.

WHAT HAPPENS WHEN WORKING EQUIDS CAN’T ACCESS THE WATER THEY NEED?

DEHYDRATION

Donkey and horse Working equids often don’t get the volume of water they need. When skin hydration was checked in nearly 5000 working equids (10), 50% of horses and 37% of donkeys showed significant signs of dehydration (1).

SUPPRESSION OF APPETITE

Donkey Watering at every 48 or 72 hours decreases water intake by 42% compared to ad libitum, and consequently dry matter intake declines by 13% (2).
Donkey The donkey is able to manage temporary water deprivation without too high limitation of intake (2). Reducing water intake reduces horse appetite (11).

ILLNESS

All equines Dehydration can increase the risk of conditions such as impaction colic. This will impact on the work of the equid but may also prove to be fatal.

HOW REGULARLY DO WORKING EQUIDS NEED ACCESS TO WATER?

Donkey Regardless of evolutionary habits working donkeys should be provided water daily. In hot weather they should be offered water several times per day (1). Horses should be offered water daily, ideally 3 times daily as this has been shown to be no different In terms of volume of water consumed compared to free, continuous access (12).

WHAT MAKES WATER PALATABLE AND SAFE TO DRINK?

If water is too hot, cold or tainted equids may be disinterested in drinking and there will be a risk of dehydration.

All equids Stagnant water may be a breeding ground for infectious disease in southern Brazil, is the presence of leptospirosis in still stagnant water
Donkeys

KEY FACTS: DONKEYS


  • Donkeys drink 5% of their body weight per day in temperate conditions and 9% of BW in hot conditions.
  • This will vary according to diet and to intensity of work.
  • Water intake can be expressed per kg dry matter fed or per 100kg live weight.
  • Insufficient hydration depresses food intake and leads to an apathetic animal incapable of performing its usual work duties at full capacity.
  • Donkeys can rehydrate quickly and drink large volumes of water (20 – 30 l) in a short amount of time.
Horses

KEY FACTS: HORSES


  • Horses drink frequently if they have the opportunity (once every 1-2 hours on average). A total lack of water is more rapidly fatal to horses than a lack of feed.
  • Horses should be given access to water to aid rehydration after hard work or exercise. There is no evidence that the horse must have cooled down before water is given.
  • Transporting horses for long periods causes them to become dehydrated
  • Horses typically urinate every 4-6 hours and defaecate every 2-4 hours. Infrequent or abnormal urination/ defaecation are common indicators of dehydration, along with a strong desire to drink.
Info

Table of guidelines for watering the donkey. (Martin-Rosset, W. 2018)

A model for predicting water intake in the donkey at rest and working at different intensities. (Vall et al. 2003)

Factsheets and publications. ICWE www.icweworkingequids.org

  1. Camie, R.Heleski, McLean, A.K. and Swanson, J.C. (2015) Practical methods for improving the welfare of Horses, Donkeys and Mules and other working draft animals in developing areas. In: Improving Animal Welfare, 2nd edn: A Practical Approach. Grandin,T. editor .pp 328-348.
  2. National Research Council (NRC). (2007) Donkeys and other equids. In: Nutrient Requirements of Horses. The National Academy Press. Washington, DC.
  3. SUFIT, E., HOUPT, K.A. and SWEETING, M. (1985), Physiological stimuli of thirst and drinking patterns in ponies. Equine Veterinary Journal, 17: 12-16. https://doi.org/10.1111/j.2042-3306.1985.tb02028.x
  4. Pearson R.A. (2005). Nutrition and feeding of donkeys. In: Matthews, N.S. and Taylor, T.S. (eds.) Veterinary Care of Donkey
  5. Mueller PJ, Jones MT, Rawson RE, van Soest PJ, Hintz HF (1994). Effect of increasing work rate on metabolic responses of the donkey (Equus asinus). J Appl Physiol (1985). Sep;77(3):1431-8. doi: 10.1152/jappl.1994.77.3.1431. PMID: 7836149.
  6. Ellis J.M., Hollands T. and Allen D.E. (2002). Effect of forage intake on bodyweight and performance. Equine Exercise Physiology 6. Equine vet. J., Suppl. 34 66-7
  7. Donkey Nutrition and Feeding: Nutrient Requirements and Recommended Allowances – A Review and Prospect. J. Equine Vet. Sci.. 65, 75 – 85
  8. Freeman DE, Mooney A, Giguère S, Claire J, Evetts C, Diskant P. Effect of feed deprivation on daily water consumption in healthy horses. Equine Vet J. 2021 Jan;53(1):117-124. doi: 10.1111/evj.13259. Epub 2020 Mar 30. PMID: 32150657.
  9. Geor RJ, McCutcheon L.J. and Lindinger M.I. (1996) Adaptations to daily exercise in hot and humid ambient conditions in trained Thoroughbred horses. Equine Veterinary Journal, 22: 63-68
  10. Pritchard JC, Barr AR, Whay HR. Validity of a behavioural measure of heat stress and a skin tent test for dehydration in working horses and donkeys. Equine Vet J. 2006 Sep;38(5):433-8. doi: 10.2746/042516406778400646. PMID: 16986604.
  11. Houpt KA, Eggleston A, Kunkle K, Houpt TR. Effect of water restriction on equine behaviour and physiology. Equine Vet J. 2000 Jul;32(4):341-4. doi: 10.2746/042516400777032200. PMID: 10952384.
  12. McDonnell S.m., Freeman D.a. Cymbaluk N.F., Schott H.C. Hinchcliff K. and Kyle B. (1999 Behavior of stabled horses provided continuous or intermittent access to drinking water. American Journal of Veterinary Research, Vol 60, No. 11