monogastric nutrition- horses

foregut

• what type of digestion

• how much percent crude protein

• 2 regions

• how long does digestion take

• what is secreted

• enzymatic digestion

• 3-4 hours

• 52-58 percent crude protein and all soluble carbohydrates

stomach

• rigid and small in size

• squamous upper region does not have protective coating

• glandular lower area has gastric juices and protective coating

• pepsin secreted into the stomach- break down proteins

• gastric lipase secreted by stonach and pancrease into si to break down fat

foregut- small intestine

stomach linked to small intestine by pyrolus

• duodenum- bile continuously trickles- fat digestion and absorption

• jejunum- absorption of starch, protein, fat and fat soluble vitamins

• ileum- connects to the large intestine

hindgut

• length

• 4 parts

• capacity

• how long

• what type of digestion occurs here

• 8m long

• caecum, large colon, small colon and the rectum

• makes up about 65 percent of the digestive system.

• more than 100l capacity

• can take up to 72 hours for digesta to pass through LI

• all undigested food end up here

• change from enzymatic to fermentation digestion

• microbial digestion of fibre occurs in cecum and colon

• most horses energy comes from this hundgut digestive process

large intestine

• caecum, large and small colon and the rectum

caecum including caecum capacity

• 25-35l

• large fermentation- micro organisma

• gut flora is present to break down cellulose

• sensitive to dietary changes

large colon

• length in feet

• capacity

• reabsorption of water

• 10-13ft long

• capacity 90-110litres

• folded into 4 regions with 3 sharp bends within the large colon

• sternal pelvic and diaphragmic

small colon

• length

• role

• long (10-13ft) narrower than the large colon

• role of the small colon continuation absorption of water, electrolytes and vfa not prev absorbed by the large colon

• litte to no vfa

rectum

• short 30cm straight tube connecting small colon to anus

• acts as a storage area for faeces ready for passing out body through anus

vfa in the hindgut

• where does microbial digestion of fibre occur

• where is protein absorption more efficient

• microbial digestion of fibre occurs i the cecum and colon

• vfa produced

• microbes require protein and carbs to produce these

• vfa absobred and converted to glucose or fat

• protien absorption less efficient process

• protien absorption more efficient in small intestine

overview of digestion

• how many days

• what is the foregut sensitive to

• what are microbes sensitive to

• process of food from mouth to manure takes around 3 days

• foregut is more efficient and sensitive to feed volumes

• hindgut is necessary to cope with dietary fibre but mirobes are sensitive to rapid dietary change and must be kept healthy

• always provife plently of fibre

how much hours should horses graze

16 hours a day

body condition scoring

A- neck • B- wither • C- Behind the shoulder • D- Ribs • E- Top line • F- Tail head

Two scoring systems • 1 to 5 • 1 under weight → 3 ‘normal’ → 5 obese • 1 to 9 (Henneke et al., 1983) • 4 to 6 ‘normal’ → 9 obese

forage or roughage features

• high fibre

• contain large amouns of digestible and indigestible fibres

• fresh grass

• preserved hay or haylage

• alfalfa and chaffs, preserved by drying and grounding to use in mixed feeds

• main feed

• protein, vitamin and mineral content of forage is highly variable

what may be needed to add if main feed is roughage

balancer for correct vitamin and mineral

what do mixes contain

• oats, barley, maize, sugar beet, bran, peas and or beans which are soaked, boiled or extruded

• oil

• pre mixes

supplementation with minerals

• play critical role in the health of the horse

• amount supplemented to horse must be considered as minerals often influence absorption and metabolism of other nutrient

vitamin

risks in a high forage based diet

• organic substances that the body requires for various biological processes

• lack in diet- lead to deficiency- diseases

• nearly all vitamins are supplied by good quality pasture and usnlight

• horses with a high forage based diet which is rich in potassium can commonly lack sodium- salt supplementation

pther supplements

• electrolytes

• succulents (treats)- carrots, apples, parsnip

energy requirement

• Megajoules of Digestible energy (MJDE) measured in the UK

• MegaCals (Mcal) measured United states

• Convert Megacals to Megajoules multiple MegaCals by 4.186

• For example 16.7 Mcal X 4.186 = 70 Mjoules

guidelines from national research council animal nitriition

• appetite- how much percent of body weight

• maximum DM intake- how much percent body weight

• approx how much digestible energy per kg body weight

Appetite = 2% to 2.5% body weight •

Maximum daily dry matter (DM) intake 2.5% to 3% body weight

• Approximately 3.34 of digestible energy (DE) per kg of bodyweight

weight gain

• how much kg is one unit change in body condition score equivalent to

1 unit change in Body condition score (BCS) = 16 to 20 kg actual BW • Increase digestible energy 10

weight loss

Decrease digestible energy 10%

pregnancy

• common mistakes

• risk of a diet rich in concentrates during pregnancy

• common mistake is over feeding broadmares duirng early pregnancy and underfeeding during lactation

• a diet rich in conc during pregnancy can lead to increased incidence of osteochondritis dissecans

feeding for early growth

• how to populate the hindgut with bacteria

• too much protein

• foals and growing horses have undeveloped cecal and colonic digestion so little microbial digestion for less than 3 months

• coprophagia may be necessary to populate the hindgut with bacteria

• require a low fibre diet- needs to be digested in the foregut, early days rely on mares milk

• introduce creep feeding—-

• — gradually from a few weeks

• — too much protein can predispose them developmental orthopaedic disease

• — beware stealing mare feed

energy requirement for performance

500kg horse at maintenance requires 70 MJ DE

Digestible energy requirement Exercise (NCR, 2007) : Light Work = maintenance X 1.20

Moderate Work = maintenance X 1.4

Hard Work= maintenance X 1.9

feeding for high performance

including protein limits

• electrolytes

• increased protein

• limits of 2.5 percent bw/day protein

effect of over feed protein

• higher heart and resp rate

• strain kidneys

• higher rate of sweating and dehydration as body cannot metabollse but must secrete

under feeding protein

• decreased growth

• foetal loss in preg

• weight loss

• loss of muscle

• reduced appetite

• nitrogen is lost in sweat

maintenance protein requirement- formula to calculate

7-8 percent

serious issues caused by suboptimal nutrition and feeding practices

• colic

• gastric ulcers

• stables vices

• behaviour issues

• restricted feeding even in high BCS horses can cause colic, hyperlipidemia, laminitis

where could you auscultate with a stethoscope to assess colic

right: caecum

left: descending colon/ jejunum/small intestine

how could entrapment of the ascending colon affect the blood supply and impact the colon

branches of the caudal mesenteric artery can be twisted reducing passage of blood into the coon wall.

two important physiological functions of the large intestine include storage and absorption of fluid and retention of digesta for microbial digestion

in colic by entrapment, these functions would be compromised, impairing fluid and eletrolyte balance and reducing microbial digestion which is reguated by the the rate of passage of digesta through the large intestine.

why is manure management important?

• in general, horses do not have latrine areas ina field and will not eat where they have defecated

• therefore manure management is iportant to stop selective grazing and the development of lawns and roughs

• can be controlled by manual colleciton or harrowing

• may bealso important to discuss the importane of management relating to parasite management and the development of anthelminitic resistance.