Nutrition

THE IMPORTANCE OF GOOD NUTRITION

Ensuring working equids have an adequate diet not only impacts on their longevity and ability to carry out the required work but also to resist and recover from illness/disease/wounds, their reproductive ability, body condition, comfort, and overall welfare state (1,2).

HOW MUCH FOOD DO EQUIDS NEED?

• Natural appetite/intake rates vary between equid species
• Intake rates depend on the type of food provided as well as the climate/season and availability/access (including water) as well as dental health
• Energy and protein requirements will vary depending on the equids’ age, reproductive state and maturity as well as with the intensity of work expected

	When donkeys are fed on fibrous forages, natural appetite limits for maintenance have been shown to be around 1.3 - 1.8% bodyweight (in dry matter) per day and energy requirements have been estimated at around 0.08 – 0.095 MJ DE/Kg bwt/day (3,4). As workload increases so will the requirement for energy and protein.
	Dry matter intakes for horses have been estimated as 2 – 2.5% of bodyweight/per day depending on the level of work (5). The maintenance DE requirement for horses has been estimated at around 0.58 MJ DE/ Kg bwt/day. Horses in heavy work may have energy requirements in the order of twice those of maintenance (6).
	The nutritional requirements of mules have not been fully established but are thought to lie between those of donkeys and horses (7).
	Donkeys can be at an increased risk of developing hyperlipaemia as a result of a negative energy balance (8,9).

WHAT TYPE OF FOOD SHOULD BE PROVIDED?

• Pasture and/or other forages should form the bulk of the diet.
• Diet choice/selection should take into consideration the specific nutritional needs of the animal(s).
• The type of food should be appropriate for the animals’ dental status and health.
• Any supplementary feeds should ideally be based on fibre or fat (in limited quantities).
• If supplementing with cereals/grains, attention should be paid to ensure that the starch content is not excessive: combined sugar and starch levels should ideally be kept under 10% across the whole diet.
• Care should be taken to ensure the proper provision of micronutrients (vitamins, minerals, and essential amino and fatty acids) that are essential for good health and welfare.
• All equids should be able to access food resources without fear of conflict/competition from other companions.
• Food should be palatable, of good hygienic quality and free from contaminants e.g. toxins, chemicals or infectious agents

	Donkeys are extremely efficient at digesting fibrous, low nutritional quality plant material and have a superior digestive efficiency compared with horses when fed highly fibrous forages such as straw (10). Additional consideration must be given to the risk of obesity if fed diets with excessive energy content particularly during a non-working period.
	Donkeys (and mules) need opportunities to access woody shrubs and trees in order to satisfy their natural browsing behaviours (11).
	Although relevant for all equids, additional consideration should be given to bonding between donkeys. If bonded companions need to be separated for short periods due to different dietary needs, they should still be kept within sight of each other (12).

HOW OFTEN SHOULD FOOD BE PROVIDED?

• Under natural conditions equids will typically spend multiple sessions totalling around 14 – 18 hours a day foraging for food; it may increase as forage quality decreases.
• Eating little and often is most beneficial for digestive health and for reducing the risk of health issues such as gastric ulcers and colic.
• Time spent foraging serves additional important welfare needs for equids beyond nutrition e.g. free movement.

	Equids should ideally not be left longer than 4 hours without access to feed and foraging (13). Food resources should be made available at frequent and regular intervals throughout each 24hr period, including freely during rest periods, to encourage natural trickle feeding behaviours.
	Working equids should be allowed to forage whenever possible and an adequate number of breaks should be given in an appropriate environment to allow them time to eat.

WHAT AFFECTS DIETARY REQUIREMENTS?

Whilst all equids have basic maintenance requirements, their exact nutritional needs will also depend on other factors:

INTENSITY OF THE WORK

Energy and protein requirements will vary with work intensity. For hard working equids, additional energy will be required in line with physical activity and increased protein intakes will help support muscle maintenance/repair.

CLIMATE

Cold or extreme weather conditions can result in higher energy demands to enable equids to maintain body temperature and weight/condition. Hot weather may lead to a reduced feed intake (14).

LIFE STAGE AND REPRODUCTIVE STATUS

Foals, youngstock and pregnant and lactating equids will all have different dietary requirements. Demands for energy and protein increase significantly in late pregnancy and lactation (5).

DENTAL HEALTH AND STATUS

An equid’s ability to pick up and chew food can have significant impacts on digestion and overall health. Those with poor dentition may struggle to eat fibrous forages and may require alterations to their diet (11).

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

MALNUTRITION AND REDUCED WORK:

Poor performance/poor working ability is often one of the earliest indications of nutrient imbalances and malnutrition (15). Work will likely be compromised due to reduced energy levels, decreased stamina and potentially a higher likelihood of health issues.

POOR HEALTH & INCREASED SUSCEPTIBILITY TO DISEASE:

Imbalances or deficiencies in essential nutrients can weaken the immune system making animals more vulnerable to infections/diseases. Poor diets can also lead to the development of digestive problems including colic, musculoskeletal issues, poor hoof health and/or metabolic disorders.

DECREASED WATER INTAKE:

If animals are inappetant or the amount of food provided is insufficient, their water intake is likely to decrease. This can have negative implications for their health with an increased risk of dehydration and colic e.g. due to impactions (16,17).

ABNORMAL BEHAVIOURS:

Insufficient opportunities to express natural feeding behaviours may result in a poor welfare state including animals displaying abnormal behaviours, such as apathy, repetitive behaviours, wood chewing, aggression and increased reactivity (13,18).

EARLY RETIREMENT OR DEATH:

If animals are unable to carry out the work or role required of them, they will likely be retired, abandoned or destroyed posing a financial loss and significant risk to their welfare.