Equine nutrition

how long are horses designed to spend eating and why is this important?

• 16-18 hours/day

• mental and physical health

what are the 4 parts of horse diets?

1. forage

2. roots, succulents and by-products

3. oils

4. concentrates

why is it important to consider the way an animal is fed?

• psychological stimulation

• feeding on the ground is better but obvious concerns if trying to restrict diet

what water access should horses have?

• ad lib

what should be the main component of horse’s diet

• forage

• roughage

can forage/roughage be used as a complete diet?

• yes if used with appropriate vitamin + mineral supplement

what is forage required for?

• psychological fulfillment

• healthy digestive system

what is the nutrient composition of hay?

• high fibre

• low digestible energy

• low starch

• high Ca, K

• low P

• vit A, E, K (maybe D if sun cured)

• variable protein

what should the water content in hay be to prevent mould?

• <20%

why may we soak hay?

• causes variable amounts of nutritional leaching

• for horses on restricted diets

how long should we soak hay for?

• 2 hours max

why may we steam hay?

• reduces mould, dust and spore content

what horses may we use steaming for?

• horses with respiratory issues

what is haylage

• grass cut and stored in O2 limiting facility - minimises dust and spores, good water intake

why is mouldy haylage so dangerous?

• risk of botulism! will kill the horse

what should we do with mouldy haylage?

• get rid of it!

why may we ‘roll’ concentrates before feeding?

• helps digestion by making access to starch store easier

outline some nutritional components of concentrate feed

• low fibre

• high digestible energy + starch

• low Ca and vitamins

when should we feed concentrates?

• when more energy is required

what are balancers

• commercially formulated vitamins and minerals for different life stages

• provide essential micronutrients that might be lacking in current diet

what is the average DM content of:

1. hay

2. haylage

3. concentrates

4. spring grass

1. 85-90%

2. 60-75%

3. 85-90%

4. 20%

what are the 2 processes CHO undergo in the horse digestive tract

• bacterial fermentation

• hydrolysed by digestive enzymes

where is starch broken down?

• in small intestine

• in the hindgut - fermented

why are large quantities of starch bad for horses?

• rapidly fermented in the hindgut which can cause upset

what are example CHOs that are fermented, why do they need this?

• cellulose/hemicellulose/pectin/fructan

• non-digestible by mammalian enzymes

Is hemicellulose easily fermented and what is a good source of it

• yes but slow in the hindgut

• grasses and bran

pectin:

1. what is it

2. digestible/fermentable?

3. found in what?

1. heteropolysaccharide

2. fermentable, almost completely in the hindgut

3. in sugar beet + apples

what must we do with sugar beet before feeding, why?

• soak it

• if we don’t, it will rapidly expand in the stomach potentially causing issues

fructan:

1. what is it

2. what do we find it in

3. how is it digested

4. risk of digestive upset?

1. polymer of fructose and sucrose

2. storage in many cool grass species

3. not by enzymes, but fermented to VFA + lactic acid

4. if consumed in large quantities

what is an NSC?

• non-structural carbohydrate

what makes up NSC

1. water soluble cabs

2. ethanol soluble carbs

3. starch

why is NSC analysis useful?

• calculates portion of plant CHO that can be directly analysed, following water/ethanol extraction/enzyme hydrolysis

how do the following environmental conditions affect sugar conc in grass;

1. <5 degrees C

2. >5 degrees C

1. more photosynthesis but slower growth = increase conc

2. equal photosynthesis and growth = ± sugar conc

what are 2 key water solubl eminerals for horses

• vitamin B

• vitamin C

what are key fat soluble vitamins for horses

• A

• D

• E

• K

how does a horse obtain the following vitamins:

1. D

2. A+E

3. B+K

4. C

1. when exposed to sunlight by skin

2. variable amounts in pasture + hay

3. synthesised by microbes in LI

4. horses snythesise themselves

what are 7 key macro minerals

1. Ca

2. P

3. Na

4. K

5. Cl

6. Mg

7. S

what are 6 key trace minerals

1. cobalt

2. copper

3. zinc

4. selenium

5. iron

6. iodine

how do we assess mineral intake?

• mineral analysis of pasture

• look at labels on commercial feeds

why do we recommend giving salt licks?

• commercial diets and forage usually low in Na + Cl

what can the wrong Ca:P ratio, with more P lead to?

• severe bone abnormalities

what’s the ideal Ca:P ratio?

• 2:1

which animals are Ca:P most relevant to?

• pregnant mares

• lactating mares

• young, growing horses

what can the wrong Ca:P ratio in young growing horses lead to?

• OCD (osteochondrosis dessicans)

what are the 6 steps for equine ration calculation?

1. BW + BCS

2. assess workload/activity level

3. adjust to suit individual

4. assess dry matter requirements

5. formulate for forage requirements

6. digestible energy requirement

what can we use to assess BCS?

• 5 point system

• 9 point system

what are the 5 categories of work

1. maintenance

2. light

3. moderate

4. heavy

5. very heavy

what is the mean resting heart rate for the following work categories:

1. maintenance

2. light

3. moderate

4. heavy

5. very heavy

1. 28-44

2. 80

3. 90

4. 110

5. 110-150

what are example types of events for the following work categories:

1. maintenance

2. light

3. moderate

4. heavy

5. very heavy

1. not in ‘work’

2. recreational riding, beginning of training

3. school horses/recreational riding, polo, show horses

4. polo, show horses, low-med eventing, race training

5. racing, elite 3-day event

what is the recommended DMI?

• 2% bodyweight per day

what DMI should we never go under, unless supervised by a vet

• 1.5% BW

how do we assess forage requirement?

1. work out DMI of the horse (2% BW)

2. divide by the (estimated DM of feed/100)

how do we work out digestible energy requirement?

Maintenance requirement x factor of work

• maintenance = 0.1393 x BW

what is the work factor used for digestible energy requirement for the following group:

1. light work

2. moderate work

3. heavy work

4. very heavy work

1. 1.2

2. 1.4

3. 1.6

4. 1.9

what are donkeys very good at in terms of digestion?

• extracting energy from poor quality fibre

what is the E requirement in DMI of a donkey?

• 1.3-1.7% BW/day

what should we provide to donkeys for their digestion?

• poor quality feed

• access to branches to chew on

• sparse paddock + hedges and bushes

• mineral and vitamin provision via daily balancer

what can we suggest to an owner to help manage their obese horse?

1. feed 1.5% BW for 4-6 weeks + balancer

2. increase exercise (5 × 30 min is ideal)

3. reduce pasture turnout if possible

4. turnout on to a sand/wood chip paddock

What can an owner do with their hay to help manage weight in a horse?

• double net wrap

• soak it

• smaller but more frequent hay

• non edible bedding

Is there a risk of gastric disease with fasting ponies overnight?

• no

how can we help reduce the risk of gastric disease in ponies we’re fasting overnight

• small but frequent meals before fasting

• small weave haynets so it takes longer

• double hay net

• multiple nets

• hang nets away from a wall

what should the DMI be if we’re trying to lose weight:

1. dry forage

2. soaked

1. 1.5% BW

2. 1.8% BW

what percentage body weight do we expect ponies/horses to lose per week?

1%

if a horse/pony isn’t losing the weight we want, what steps do we need to take?

1. check compliance

2. see if we can change any management

3. reduce feed by 0.25% - but do not go below 1% BW DMI

4. if none of these work, consider drug usage

what drugs can we use as a last resort to help manage weight loss

• levothyroxine

• metformin