Equine Nutrition Midterm

lime

this may be spread on pastures to raise soil pH

alfalfa

a common legume forage

lysine

the first limiting amino acid in horses

-only amino acid with known requirements

• soybeans and soybean meal

• animal sources (whey protein)

-grasses and many grains are generally low in lysine

forage

a horse should eat at least 1.5% of its body weight per day in ______, on a dry matter basis

volatile

microbial fermentation of fiber produces _____ fatty acids, which are used as an energy source by the horse

laminitis

overload of sugar and starch in the diet can cause this if it is not digested in the small intestine

esophagus

the long muscular tube between the horse’s mouth and its stomach

lignin

indigestible fiber that passes through the horse and is not utilized

fat

if we want to increase the body condition score of a horse, we could consider feeding a diet higher in this energy source

iodine

a micromineral found in higher concentrations in grasses than legumes

small intestine

site of protein digestion in the horse

stomach

because it is designed to be eating throughout the day, the horse’s ______ is relatively small, compared to some other species

net energy

the fraction of gross energy used for maintenance and production

soil sample

this should be performed every three years to determine soil pH and fertilizer needs

cecum

a large component of the hindgut in which forage is fermented by microbes

2:1

an appropriate calcium:phosphorus ratio would be _____

niacin

another name for vitamin B3

calcium

a macromineral important for bone strength and muscle contractions

glucose

a major form of carbohydrate stored in the muscle and liver as glycogen

vitamin A

a fat-soluble vitamin whose precursor, beta-carotene is found in green leafy plants

structural

fiber is an example of a ______ carbohydrate

energy

body condition scoring is a measure of the _____ status of a horse by determining how much fat cover it has

gall bladder

an organ in the digestive tract of a horse that humans have but horses do not

salt

a feedstuff that should always be available to horses

biotin

a B vitamin that is well-known for its role in hoof growth and repair

modified monogastrics

horses are _____ ______

-fermentation in the cecum

-able to utilize large amount of roughage in the diet

mouth

part of the body that performs prehension and ingestion

mastication

alteration of physical form

-reduces particle size, which improves digestibility

-greater number of chewing movements for roughage than concentrate

long

_____ stem forage promotes more even dental wear

99%

saliva is greater than _____ water, contains almost no digestive enzymes

10-12

how many liters of saliva does an average horse produce in a day?

bicarbonate

what does saliva contain that acts as a gastric pH buffer?

angle

the sharp ____ of the esophagus at the attachment to the stomach is the reason why horses cannot belch or vomit

7.5 to 15

how many liters does the average stomach hold?

non-glandular

the upper mucosal surface of the stomach is lined with ____ (squamous) epithelium

glandular

the lower region of the stomach is lined with ____ mucosa

hydrochloric acid, pepsin, bicarbonate, mucus

what 4 things does the stomach secrete 24/7

pepsin and lipase

what two enzymes begin to digest proteins and fatty acids in the stomach?

hind gut

where microbial fermentation of fiber and water absorption occurs

foregut

where enzymatic digestion of sugars, starch, most protein, fat, vitamins, minerals occurs

small intestine

site for digestion of many vitamins, some minerals

-relatively short (about 35% of the digestive tract)

-rapid passage (45 minutes to 4 hours)

-very little microbial fermentation of fiber

amino acids

pancreatic and SI enzymes digest protein into _____

fatty acids

pancreatic and SI enzymes digest fats into _____

glucose, simple sugars

pancreatic and SI enzymes digest soluble or hydrolysable CHO (sugars and starch) into ______

duodenum, jejunum, illeum

what are the three sections of the small intestine

villi

the presence of these in the small intestine help to increase the surface area

monosaccharides

simple sugars that are digested in the small intestine

oligosaccharides

short chain monosaccharides joined together, also sugars

-digested in the small intestine

polysaccharides

usually starch and cellulose

-long chains of 100s to 1000s of monosaccharides

starch

subject to enzymatic digestion in the small intestine

cellulose

requires microbial cellulase in the hindgut

small intestine

sugars and starches are non-structural carbohydrates and are digested in the _____

hindgut

dietary fibers are structural CHO and are digested in the ____

hindgut

term for the combination of the cecum and colon (large and small)

-largest portion of the GI tract (~60%)

-rate of passage is 50-60 hours

-no mucosal enzymes

-where water is absorbed

cecum

one of the most important parts of the GI tract!

-8 gallon volume

-microbial digestion by bacteria, fungi and protozoa

• create volatile fatty acids that horse can use as an energy source

B and K

what vitamins does a horse synthesize themselves in the cecum?

large colon

10-12 feet in length, 21.5 gallon capacity

-nutrient absorption, continued fermentation

small colon

10-12 feet in length, 5 gallon capacity

-water and mineral absorption, fecal ball formation

water, energy, protein, vitamins, minerals

what are the 5 main nutrient classes

water

the most important nutrient, often overlooked

-responsible for

• maintaining body fluid balance

• digestive functioning

• gastrointestinal health

62-68%

total body water in adult horses is about ____ of body weight

drinking, moisture in feed

2 examples of direct water intake

metabolism of fats, CHO, protein

what is an example of indirect water intake

urination, defecation, respiration, lactation, cutaneous

5 examples of water loss

water-holding

fiber has a high _____ capacity

urinary

horses consuming excess protein, potassium, or sodium will have an increased renal solute load, and thus higher ____ water loss

digestible energy

gross energy minus feces energy

metabolized energy

digestible energy minus urine and methane energy

net energy

metabolized energy minus heat increment

-used for maintenance and production

calorie

amount of heat produced by oxidation that raises one gram of water one degree celcius

1000 kcal

1 megacalorie equals ____ kcal

-used for horses

-not included on feed labels

digestible energy

total digestible nutrients

-affected by gross energy content of feeds

-can be determined from feeding trials

-also can be determined from prediction equations from the NRC

BCS 1

Poor. Animal extremely emaciated. No fatty tissue can be felt. Bone structure very noticeable. Ribs projecting prominently. Shoulder is sharp and protruding. Tailhead, point of hip and point of buttock projecting prominently.

BCS 2

Very Thin. Animal emaciated. Ribs prominent. Noticeable bone structure. Vertebrae prominent. Neck is obviously thin. Shoulder is noticeable. Ribs easily discernible. Points of hip and buttock prominent. Tailhead very prominent.

BCS 3

Thin. Slight fat cover over ribs. Ribs easily discernible. Neck, withers and shoulder accentuated. Hip is rounded with some filling, but easily discernible. Point of buttock slightly distinguishable. Tailhead prominent, but individual vertebrae cannot be visually identified.

BCS 4

Moderately Thin. Faint outline of ribs with some fat filling between ribs. Negative crease along back (backbone sticks up). Neck, shoulder and withers slightly thin. Point of hip still discernable. Point of buttock rounded and not distinguishable. Tailhead slightly prominent.

BCS 5

Moderate. Ribs not visible but are easily felt. Backbone is level. Shoulder blends smoothly into body. Withers rounded. Hip and buttock rounded. Fat around tailhead beginning to feel spongy, and tailhead blends smoothly with rump.

BCS 6

Moderately Fleshy. Fat beginning to be deposited. Fat over ribs feels spongy. Ribs are not visible, but can be felt with slight pressure. Slight positive crease (gutter appearance) may appear down backbone. Shoulder blends smoothly into body. Withers rounded. Fat beginning to be deposited around tailhead.

BCS 7

Fleshy. Fat deposited along neck, withers, area behind shoulder and on either side of tailhead. Neck may begin to become cresty. Individual ribs can be felt with pressure, but noticeable filling between ribs. Fat is beginning to fill in the flank. Back has positive crease (gutter appearance).

BCS 8

– Fat. Fat deposited at withers, area behind shoulders, and along either side of tailhead. Thickened and somewhat cresty neck. Difficult to feel ribs. Positive crease (gutter appearance) down back. Flank is nearly filled flush. Fat deposited along inner buttocks. Fat around tailhead feels spongy

BCS 9

Very Fat. Bulging fat. Patchy fat appearing over ribs. Difficult to palpate ribs. Area behind shoulder is filled with fat. Obvious positive crease (gutter appearance) down back. Fat along inner buttocks may rub together. Flank filled in flush. Tailhead appears sunken due to fat deposits along either side

body condition index

method of assessing body fat similar to BMI in humans

-not as subjective as BCS

one month

usually takes at least _____ to increase or decrease a BCS score

carbohydrates, fat, protein

where do horses get DE

-the energy containing nutrients

-energy from these nutrients can be

• immediately available after a meal

  • stored for future use

ATP

major source of chemical energy used in cells

-adenosine triphosphate

-generated from metabolism of carbs, fats, and proteins

glucose

the major form of CHO used to generate ATP

-can come from circulation, or from body stores

-stored primarily in skeletal muscle and liver

fat

the most abundant energy source in the body

-broken down into fatty acids, which are then broken down to generate ATP

long chain fatty acids

come from food digestion or from stored fat (adipose tissue) in the form of triglycerides

short chain fatty acids

come from bacterial fermentation of structural carbohydrates in the hindgut

-aka volatile

-can meet most of energy requirements at maintenance

-can also be metabolized into long-chain fatty acids or glucose

carbohydrates

the most common form of energy in equine diets

-come from forages and concentrates

structural

type of CHO that consists of fiber

non-structural

type of CHO that consists of sugars, starches and pectins (sometimes a soluble fiber)

amylase

the enzyme that is missing in the small intestine to be able to break down fiber

glycogen

the storage form of glucose in liver and muscle

fiber

the most important ingredient in equine diets

-usually provides sufficient energy required for maintenance

crude fiber

crude assay related to structural CHO in the feed

-on feed labels

-somewhat indistinct

-most of cellulose, but only part of lignin

-always underestimates actual fiber content of a forage

-generally the higher the CF, the lower the DE and digestibility it will have

pectin

a water-soluble fiber that is found in the cell walls of fruits, tubers, and stems of plants

-in presence of low pH, these turn into a gell

neutral detergent fiber

percentage of the plant material in the forage made up of structural fibers

-higher it is the lower the intake, more wastage

acid detergent fiber

percentage of the plant material in the forage that is difficult for the horse to break down

-cellulose and lignin

-higher it is, the lower the digestibility and lower nutrient availability

water soluble

this kind of CHO includes simple sugars, disaccharides, oligosaccharides, and some polysaccharides