equine revision - nutrition

Foregut

oesophagus, cardiac sphincter, stomach, pyloric sphincter, small intestine

hindgut

caecum, large colon, small colon, rectum

digestion time

72 hours

mechanical digestion

physically breaking down food into smaller pieces

where does mechanical digestion happen?

mouth, teeth and stomach

chemical digestion

breaking food molecules into smaller pieces

where does chemical digestion happen?

mouth (saliva), stomach and small intestine

microbial digestion

bacteria and protozoa breaking down complex carbs

where does microbial digestion happen?

caecum and large colon

Essential nutrients

water

energy - carbs (simple, complex), fat and protein (amino acids)

vitamins

macro minerals

trace minerals

electrolytes

water intake per day

30-70 litres

factors affecting water intake

weather, workload, moisture in feed (seasonal), cleanliness/ availability of water

factors affecting energy intake

reproduction, workload, seasonal/environmental factors

complex carbs

found in fibre, tough, stringy part of the plant

difficult to break down

most important part of horses solid diet

simple carbs (starch or simple sugars)

easily dissolvable, smaller carbs in the plant

product of photosynthesis

digestive system is not designed to cope with large amounts

sources of fibre

hay, beet pulp, grass, soyabean hulls

sources of starch

wheat, oats, grass, corn, grain

where is starch digested?

stomach

where is starch absorbed?

the small intestine

too much starch can cause:

laminitis, hindgut acidosis, tying up (RER and PSSM), colic, Equine Metabolic syndrome

too much fibre can cause:

hay belly, digestive build up

fat

slow release energy

2-3% in diet

balance fat with other nutrients

minimal dangers of overfeeding 

sources of fat

oils, copra, rice bran

where is fat digested?

small intestine

where is fat absorbed?

small intestine

protein

made up of amino acids

needs to be broken down to be absorbed

diet should be 8-16% protein

important amino acids

lysine, methionine, threanine

sources of protein:

legumes, lupin, clover, lucern, peas, beans

where is protein digested?

small intestine

where is protein absorbed?

small intestine

too much protein can lead to:

affecting growth rate in young horses, leading to developmental orthopaedic disease (DOD)

can put additional strain on kidneys

macro minerals

calcium and phosphorus, essential for skeletal system

bone growth and maintenance requires:

balance of calcium and phosphorus (calcium : phosphorus, 1:1 or 2:1 ratio)

a bit of vitamin D

calcium : phosphorus of a growing horse

1:1 ratio

calcium : phosphorus of a mature horse

2:1 ratio

high calcium : phosphorus feeds (3:1 or higher)

molasses, clover hay, lucerne hay, limestone

balanced calcium : phosphorus feeds (1 or 2:1)

vegetable oil, oaten hay/chaff, wheaten chaff, grass hay, native green, native dry

low calcium : phosphorus feeds (1:1.1 or higher)

oats, barley, corn, rice bran, lupins, tick beans, peas, soyabean meal, sunflower seeds, wheat bran, copra meal

trace minerals

iron (found in red blood cells)

manganese (necessary for cartilage)

selenium ( helps body deal with stress)

iodine ( reproduction and psychological function)

chromium (function of insulin tissue)

zinc (enzyme proteins)

copper (synthesis and maintenance of elastic tissue)

too much iron can cause:

tissue damage

too little iron can cause:

Anemia

too little manganese can cause:

enlarged joints and crooked limbs

too much manganese can cause:

interference of phosphorus absorption

too little selenium can cause:

weakness, impaired movement, difficulty swallowing

too much selenium can cause:

sweating, colic, head pressing, apparent blindness

too little iodine can cause:

lethargy, dull coat, hair loss, lack of appetite

too much iodine can cause:

enlargement of thyroid gland, eye tearing

sources of iron

any grass hay

sources of manganese

forage and unrefined grain

sources of selenium

hay and grains grown in selenium rich soil

sources of iodine

seaweed supplements, salt block

too little chromium can cause:

high blood sugar, hyperglycemia

too much chromium can cause:

weight loss, dermatitis, anemia, liver dysfunction

too little copper can cause:

liver/ kidney failure

too much copper can cause:

abnormal bone growth, connective tissue weaken

too little zinc can cause:

thickening of skin, hair loss, susceptibility to infection

too much zinc can cause:

decreased copper absorption

sources of chromium

forage, commercial feeds, supplements

sources of copper

molasses, brewers grains, soyabean meal

sources of zinc

wheat bran, wheat middlings, brewers grains, most forages

where are minerals digested?

stomach and small intestine

where are minerals absorbed?

small intestine

fat soluble vitamins:

vitamins A, D, E, K,

water soluble vitamins:

vitamins B1, B2, B5, B3, B6, choline, B12, B9, B7, C

electrolytes

sodium Na+, potassium K+, chloride Cl-, Magnesium Mg++

what do electrolytes do?

encourage the horse to drink

types of roughage

pasture, hay, chaff

amount of roughage per day (kg)

(1.5% / 100) x weight of the horse

concentrate of oats

starch

concentrate of corn

starch, vitamin A

concentrate of barley

energy

concentrate of sorghum

starch

concentrate of lupins, peas and beans

protein, fibre

concentrate of soyabean meal

amino acids, fibre, fat

concentrate of sunflower seeds

fat, protein

concentrate of linseed

protein, fatty acids, fibre

concentrate of canola meal

protein, fat

concentrate of cottonseed meal

protein, fibre

foals nutritional requirements

balanced diet

no more than 1.5-2kg of grain per day

needs to have:

-good source of protein

-suitable source of energy

-balanced cal : p ratio

-trace minerals and vitamins

growing horses nutritional requirements

needs to have:

-suitable energy source

-good source of protein

-balanced cal : p ratio

-trace minerals and vitamins

-good quality roughage

-receive 1% of body weight in roughage per day

-13-15% crude protein in diet

-access to salt

elderly horses nutritional requirements

old horses are more susceptible to laminitis

needs to have:

-easy to chew

-readily available nutrients

-high fibre = over 10%

-higher protein (12-16%)

-can be higher fat, if liver healthy

-higher vitamins and minerals

early pregnancy nutritional requirements

at this stage the foal is 20% of its birth size

needs:

-sufficient roughage

-balanced minerals and vitamins

late pregnancy nutritional requirements

needs to have:

-15% increase in energy

-increase in protein, calcium and phosphorus

-increase in trace minerals

-increase in vitamins A and E

-increase in selenium

-maintain a reasonable body condition (3/5 is okay, 3.3/5 is ideal)

lactation nutritional requirements

produces 1-4% of her body weight in milk each day

needs to have:

-energy

-protein

-calcium

-phosphorus

-vitamins

stallions nutritional requirements

balanced diet, must not be overweight

needs to have:

-10% more feed

-20% more energy, lysine, calcium, magnesium and phosphorus

-50% more vitamin A and E