Animal Nutrition Test 2

How do these factors affect how much water is required? -Young vs Adult -Acitivity (nervousness)

- young require more water - nervous or active animals require more water

Horse esophagus

-50-to 60-inch long tube from the mouth to stomach on the left side of the neck -one-way peristaltic movements in the esophagus. The practical outcome of this is that it is essentially impossible for the horse to regurgitate

Horse large intestine

-60% of total gut capacity -cecum, large colon, small colon, and rectum and is 25 feet long -cecum and large colon contain a bacterial population similar to the rumino-reticulum -bacterial breakdown of cellulose and other carbohydrates producing VFAs -Absorption of VFAs does occur from the cecum. The horse on a forage diet will receive the majority of its energy from the large intestine. -Bacterial synthesis of water-soluble vitamins occurs and they are absorbed from the large intestine -Bacterial synthesis of protein occurs but the horse is not able to absorb this product because of the lack of enzymes and absorptive mechanisms. -cecum is the primary area of water reabsorption from intestinal contents, although more is absorbed from the colon. -large intestine is usually expanded with fibrous material. This is another source of digestive tract disorder in the horse. Impaction of the large intestine may easily occur and can be fatal

Gas is a major product of fermentation

-600 liters/day -65% CO2 7%N2 25% CH4 -O2, H2, H2S

Proventriculus

-Comparable to the glandular stomach in mammals or the abomasum in ruminants. -small in some species such as the chicken or pigeon. -large in some fish-eating species (i.e., those consuming highprotein diets). -site of gastric juice production (HCl and pepsin) and has a pH of 4. -Ingesta passes through rapidly ( approximately 14 seconds) so virtually no digestion takes place. Carnivorous birds are an exception to this. There is digestion in their proventriculus

Sources of NH3 include both degradable and nondegradable forms

-Dietary Protein -Nonprotein nitrogen (NPN)

Effects of differences in VFA forages

-Energetic efficiency favors grain diets because propionate production conserves more energy. When we increase propionate, we decrease acetate and methane. -Milkfat production favors forage diets because acetate is a necessary precursor of milkfat in the mammary gland. High grain dairy rations decrease acetate and, therefore, milkfat. Dairy rations are typically kept at least 40% forage to avoid "Low Milkfat Syndrome."

There are four major ways the body loses water

-Expired H2O -Vaporized from skin -Feces -Urine

Presume you are changing your lifestyle to become a desert nomad. You have the opportunity to develop a new animal for your use that is more water efficient. List the characteristics of this animal.

-Large ears and Light coloration -Nocturnal behaviors -No or underdeveloped sweat glands -Thermoregulatory circulation valves -Fat deposits localized and Oval-shaped blood cells -Hard, rounded feces. -Produces Uric Acid: -Young with minimum nursing times, becomes capable of eating "adult" diets relatively quickly -Aestivation capabilities: The animal can have the ability to go dormant -Scale covered eyes (no eyelid) -Digestive efficiency

Bird Ceca

-Located at junction of small and large intestine. -two in the avian. -size is influenced by type of diet. They are larger when the animal consumes high fiber. -Opens into the large intestine via the muscular ileocecal-valves. -Some water reabsorption -Some fiber digestion (perhaps as much as 18% of total fiber) and water-soluble vitamin synthesis -modem chicken does not need its ceca

micurition (urination)

-Nitrogen compounds (Urea in mammals, Uric acid in birds) -Sulfurous metabolites -Minerals: Cl, K, P, Na -Water

Saliva provides readily available nutrients for rumen microorganisms

-Nitrogen from mucin, urea secreted from blood -P and Na

Bird Large Intestine

-Relatively short (2-4 inches). -No distinct rectum or colon as in mammals. -main site of water absorption (not digestion). -Vitamin K synthesis and absorption does occur here in the chicken

Presume that your cattle herd is not drinking much water. It is your job to discover why. Develop a step-by-step plan for troubleshooting the problem.

-Track outside weather conditions -Examine feedstuff -Examine Distance between feed and water source -Analyze water quality --If the results showed high levels of a particular substance or TDS levels exceeding 3000 mg/L then I would work to either acquire a new source of water or clean the current source. -veterinary could run a toxic screen and disease tests to see if the problem is within the herd itself or they are being poisoned another way.

enzymes produced in the pancreas and their function

-Trypsin: initially secreted as trypsinogen and activated by calcium ions and the enzyme enterokinase found in the intestine. Trypsin breaks down protein into amino acids and peptides. -Chymotrypsin: secreted as chymotrypsinogen and activated by the action of trypsin in the intestine. It converts proteins into peptides and it has amino acids and a coagulating action on milk. -Carboxypeptidase: acts on peptides to amino acids. -Pancreatic lipase (steapsin): converts fats into fatty acids and glycerol. This action is most effective after the fats have been emulsified by the bile. -Pancreatic amylase (amylopsin or pancreatic diastase): converts starch to maltose. -Maltase: changes maltose into glucose. -Sucrase (invertase): changes sucrose to glucose and fructose. -Lecithinase: hydrolyzes the phospholipid lecithin

Nonprotein nitrogen (NPN)

-Urea. Feedlots use .25-.5% of total diet as urea. -Efficiency of urea utilization is largely dependent on the energy available in the rumen. The more energy available in the rumen the better it is used. -Feedlot 80-100% Efficiency -Range 25-50% Efficiency

If water is withheld, the following mechanisms kick in to alleviate the problem

-Urine excretion is reduced as is the water content of the feces. -animal oxidizes much of its tissue reserves to provide metabolic water. -Animals become sedentary, seeking shade whenever possible -reduction in feed consumption except for feeds that are high in moisture. -blood thickens, resulting in a decreased ability to transport nutrients and waste products.

microorganisms benefit from arrangement. They are provided with a near ideal set of living conditions, which includes

-Warmth. 101°-103°F. -Moisture. 75% water and 25% dry matter. -animal eats and thus replenishes the food supply of the microorganisms -pH is controlled by the animal by removal of the end products of digestion and by buffering mechanisms. -Ruminal contractions keep the contents mixed. -dark. Most of these microorganisms are killed by light. -Oxygen-free. The rumen microorganisms are anaerobic, some strict and some facultative. -end products of fermentation are removed by the animal through absorption, passage, and eruction so the environment of the microorganism is maintained in an acceptable state. -animal ruminates and masticates and thus reduces the particle size of the feed for easy access by the microorganisms.

Pig large Intestine

-about 16 ft. in length, has a capacity of 2.5 gallons, cecum and the colon that terminate as the rectum and anus. -cecum is about 9. 5 inches in length with a capacity of about 0.5 gals. -colon in the mature pig is about 16 ft. in length with a capacity of 2.0 gals. -functions are primarily to absorb water and to act as a reservoir for the waste materials that constitute the feces

Pig small intestine

-about 60 ft. in length, has a capacity of about 2.5 gallons -function is to continue the process of digestion by means of the pancreatic juice, bile, intestinal juice, and movements of the intestinal wall. -large amount of absorption of nutrients -pancreatic juice contains a number of enzymes that aid in the digestion of proteins, fats, and carbohydrates as well as sodium carbonate and sodium bicarbonate that neutralize acid from the stomach. -pancreas also produces insulin that plays an important role in carbohydrate metabolism.

Intracellular fluids account for the greatest amount of water in the body

-account for 40-45% or more of total body weight. -Most of this is in the muscles and the skin

Pancreatic juice

-alkaline secretion with digestive enzymes -Trypsin, chymotrypsih, carboxypeptidase, and aminopeptidase, all of which digest proteins. -Intestinal lipase, which breaks fats into fatty acids and glycerol. -Amylase that is specific for starch. -Other enzymes that work on dipeptides, disaccharides, etc.

Water and Metabolism

-all biochemical reactions require water -universal solvent -transports solids in gut, blood, tissue, cells, urine, and sweat -facilitates free movement of organics within and between body spaces -hydrolysis and oxidation

Bacteria can even convert nonprotein nitrogen (NPN) such as urea into bacterial protein that the animal subsequently uses

-bacteria pass out of the rumen and down the tract with the feed and are digested in the abomasum and small intestine. The amino acids released by the action of the animal's enzymatic digestion often meet the protein requirements of the animal. -microorganisms are about 50% crude protein with 3% lysine content. -quality is similar to soybean meal, which is an excellent quality feedstuff

Microbial species in rumen

-bacterial species range from 15-50billion/ml -protozoa species range from 20,000 to 500,000/ml -yeast and phages

In the horse's mouth the prehensile parts include teeth, upper lip, and tongue

-both vertical and lateral jaw movements. In addition the upper jaw is wider than the lower jaw. Because of this, mastication can occur on only one side of the mouth at a time. -saliva of the horse has no enzymes.

Enzyme action

-break bonds by adding water -some produced by accessory organs -some produced by microorganisms

Mastication

-chewing -carnivores: only to the extent needed to reduce the size of meat so it can be swallowed -herbivores: need thorough chewing of their feed (mostly forage) to allow bacterial enzymes access to cellulose by increasing feed surface area

Bloat is a common problem in ruminants if gas cannot escape the rumen

-creates a distention of the rumen that can actually be seen on the left side of the animal -most cases of bloat a stable froth or foam is produced in the rumen that cannot be eructated -Certain feedstuffs (especially legumes) are known to be more likely to cause bloat than others -Appropriate feeding strategies can help avoid but not totally prevent the problem -Bloating also occurs in feedlot cattle though it isn't as common -There is anecdotal evidence that there may be genetic tendencies of cattle to bloat.

Bile salts, which are derivatives of cholesterol, assist in digestion and absorption by two major actions

-detergent action that helps solubilize and emulsify fats, increases surface area of fat for lipase -forming a complex with fatty acids (products of fat digestion), which is easily absorbed

Vaporation of water from skin occurs in 2 ways

-diffusion when blood vessels dilate -sweating (perspiration)

Horse fat digestion

-digested and absorbed in the small intestine. -The absence of a gall bladder does not seem to cause any problem. The fats in rations of up to 20% fat are digested 90% or better

Crop

-dilation of the esophagus that is present in most species but not all. -functions as a food storage organ and moistening reservoir. -Size varies with the eating habits of the bird and between species. -doves and pigeons it produces "pigeon milk" or "crop milk," which is used to feed the young. -Fermentation occurs here in some species. -Surgical removal in the domestic chicken does not affect feed consumption or growth of the bird.

Treatments for bloat

-feed additives such as poloxalene (Bloatguard), which is expensive but effective, It is an anti-foaming agent that must be ingested at 12-hour intervals to be effective -short-term situations you can feed two to three ounces of laundry detergent per day. The detergent breaks down the foam by changing the surface tension so the foam disintegrates -In emergency situations, use a trocar and cannula, which is a device used to puncture the rumen and release the gas

Types of VFAs

-from carbs: acetate, proprionate, butyrate -from amino acids: isobutyrate, valerate, isovalerate

Herbivore Salivation

-horse 40 liter/day - cow 60 liters (16 gallons)/day -dairy cow 120-200 liters/day -sheep 10 liters/day

relative volume of each compartment is about

-rumen 80% -reticulum 5% -omasum 7 -8% -abomasum 8 -9%

Stomach of Pig

-simple stomach -capacity of about two gallons. -enzymes contained in the gastric juices are the ones you would expect in a monogastric except that rennin, the enzyme that coagulates milk, is not found in the pig's gastric juice. -about 24 hours to empty a full stomach.

On the average, elimination of water from the human body occurs by the following routes

1) lungs-15%, 2) skin-18%, 3) kidneys-60%, 4) intestines-7%.

In the animal kingdom, food is digested in two ways

1. Phagocytocally 2. Extracellularly before being absorbed by cells

How much saliva does the horse produce

10 gallons/40 liters per day

How many calories are lost from the body by evaporating five grams of water? Is this efficient

2,9000 calories are lost. It is extremely efficient

contents of the rumen generally equal about ____ of the body weight of the adult animal.

20%

How long is the collection period in a conventional digestion trial

4-10 days

How many animals per diet do I need for a digestion trial

4-6 animals per treatment

I fed a mouse 40g of protein. I collected 30g of protein in its feces for the corresponding time period. What is the apparent digestibility of the protein

40-30/40 = 25%

A typical dairy cow chews approximately _________ times per day

42,000: 4,700 movements for grain, 10,500 for forage and 26,400 for rumination

What is the "normal" ratio of water consumption to dry matter consumption for cattle? Sheep? Why do cattle need more

4:1 ratio for cattle, 2.5:1 and 3:1 for sheep. Cattle are not as efficient at conserving water as sheep

relative amount of dry versus wet material in the rumen is variable depending on what the animal has consumed and what has been absorbed

5 to 60 gallons of liquid and from 5 to 50 pounds of solid

Cattle and horses derive about _____ of total water from metabolic water

5-10%

Describe the extent of postgastric fermentation in the ruminant

5-15% of total digestion of feedstuffs by the ruminant occurs in lg intestine and cecum. VFAs will be produced and absorbed from fermentation

Describe how heat stress can affect water needs for animals. Give a concrete example

5-6% of body weight per day to 12% or more per day under heat stress. Feedlot steers consume about 29 L of water per day in winter, 31 L per day in summer

In some species metabolic water can contribute as much as _____ of the body water needs (desert animals). Hibernating animals survive on it during hibernating periods

50%

VFAs are absorbed through the rumen wall and supply about ___ of the energy requirement for the ruminant

50%

What is the relative quality of the protein manufactured in the rumen

50% crude protein with 3% lysine content. Similar to soybean meal, meaning excellent quality

Oxidation of each mole of glucose produces

6 moles of water

A normal adult human is ____ H2O (fat composition is a factor).

60 -65%

What is the composition of the gas coming off a ruminant fermentation

65% CO2, 7% N2, 25% CH4, some O2, H2, H2S

On a fat-free (lean) body basis, the water content of most species ranges from

70-75% (average 73%)

Air is ____ saturated when exhaled

90%

Individual tissue water concentrations are as high as

90%

Composition of saliva

97-99.5% water, electrolytes (mostly Na+ and K+ with some Mg++ and C-1), proteins (mucin, lysozyme, amylase, lipase)

Why must there be a preliminary period in a conventional digestion trial

A period of 3-10 days allows the GI tract to be cleared of pretest feed residues and provides time for the animal to adjust to the diet

What are the two basic functions of water in the body

Aiding the body in metabolism and temperature regulation

What are the advantages of using purified diets

Allow one to make quantitative changes in the concentration of a single nutrient without greatly affecting concentrations of other nutrients, determine quantitative requirement of nutrient for growth and functions, minimize present of unknown or undesired constituents

What is the point of fitting a cow with a rumen cannula

Allows direct access to the rumen so that the animal can be a donor of rumen fluid for experimentation or small bags of sample feed can be placed directly into the rumen

What is the function of the rumen

Anaerobic bacterial fermentation. Digest carbs and produce volatile fatty acids (VFAs) as an excretory byproduct

Postgastric fermentation in the ruminant

Approximately 5-15% ·of the total digestion of feedstuffs by the ruminant occurs in the large intestine and cecum

How does the water consumption of birds compare to mammals

Birds consume less water than mammals

List four problems with using external markers

Cannot be administered readily to range animals (must be mixed with food or given via capsule), irregular excretion, incomplete recovery, stained particles must be recovered from feces by tedious process of washing and sieving

What is the role of the stomach in digestion

Chemical, enzymatic and mechanical digestion: physical breakdown of food via churning, mixed with chemicals and enzymes, chemical HCL (denatures proteins, activates pepsin, provides acid pH for enzymes, kills bacteria), enzymes (rennin hydrolyzes milk protein, gastric lipase acts on fats). Food storage (allows animal to eat at faster rate, food metered to lower gut for sm. Intestine)

Why is the pig used as a model for human nutrition

Digestive system is similar anatomically and functionally to humans

What are all the sources of water to an animal

Drinking water, water in feed, metabolic water, water from body reactions, water in tissue catabolized from energy

What are the three portions of the small intestine and what are the functions of each

Duodenum (main site of food breakdown, has bile and pancreatic secretions), jejunum (some digestion but mainly absorption of end products of digestion), ileum (connection to lg. intestine, but some absorption occurs)

VFA concentrations in food

Forage: acetate (65), propionate (20), butyrate (12) Grain: acetate (45), propionate (35), butyrate (15)

Chemical Action

HCl in stomach Bile in sm. intestine

Why is it good to have simulation techniques for rumen digestibility

High cost of digestion trials, allow simulation of rumen fermentation

Where is water absorbed in the digestive tract

In ruminants there is a net absorption in rumen and omasum. All species have net absorption in ileum, jejunum, cecum, and large gut

Describe the nylon bag technique in ruminants. What is its value? When is it most useful

In the nylon bag technique, a small sample of feedstuff is placed in a bag that is then inserted into the rumen with a fistula. After the desired amount of time, the bag is removed and loss of feedstuff material due to fermentation is analyzed. This procedure demonstrates the relative differences between different feedstuff products and is useful for analyzing the affects of rumen digestion on grains or other concentrates

What is the point of a "weigh-suckle-weigh"

In this trial, suckling young are weighed before and after suckling to determine the effects that a diet has on the mother's milk production

Baby horses can absorb immune antibodies for 36 hours after birth.

It is especially important that the horse receive colostrum as soon as possible after it is born because there is no transmission of antibodies across the placenta in the uterus

What are the problems with using internal indicators to calculate digestibility

Lignin: incomplete recovery and difficulty in analysis Silica: recovery is a problem due to contamination with soil

Why don't hibernating animals need to drink water

Metabolic and preformed water is enough to sustain normal functions in hibernating individuals

What is metabolic water? What chemical component yields the most metabolic water upon hydrolysis? Which one supplies the most net metabolic water

Metabolic water is the water produced in oxidation. More metabolic water is produced per gram of fat (1.07), however carbohydrates produce the greatest net metabolic water

What are some common lab animals used in nutrition studies

Mice, rats, guinea pigs, birds like Japanese quail, reptiles and fish

Milk is mostly water. Why do nursing animals need even more water

Milk has high protein values, so more urine is needed for excretion. This means nursing animals need more water

What is the associative effect in digestibility data

Mixture of feedstuffs do not always give results that would be predicted from digestibility values of the induvial components; example, addition of one component stimulates the digestion of the basal diet, which may lead to an over 100% digestibility (though not possible of course)

What are the two stomach types in livestock? What is the subcategory listed under one of the types

Monogastric: one or simple stomach, can be broken down into monogastric and monogastric with cecal fermentation. Ruminants have more than one stomach compartment

How does protein intake affect water intake

More protein increases water intake because of greater urinary excretion or excess protein as urea

How does feed intake above maintenance affect digestibility in ruminants

More rapid passage through GI tract, there is less time for microbial or enzymatic activity on the digesta

How does urea consumption affect urine volume

More urea means that more urine is required for excretion

Define growth in both a narrow and a broad sense

Narrow: constructive or assimilatory synthesis of one substance at the expense of another (nutrient) that undergoes dissimilation Broad: growth of an animal consists of an increase in body weight resulting from assimilation by body tissues of ingested nutrients

Water and cell turgidity and shape

Osmotic pressure. Water is necessary to the life and shape of every cell. The movement of solids depends on their size (molecular weight) and the permeability of the membrane. Water can move freely across 'the cell membrane in response to osmotic pressure

Is there a valid reason for not allowing an animal unlimited access to water

Over ingestion of water can be deadly. For example, calves can die if they consume too much water before their kidneys adapt to water vs milk

ruminant relies on saliva for its buffering action

Saliva contains bicarbonates (Na+ and K +) that buffer rumen acids, especially the volatile fatty acids. The VFAs would soon damage the rumen wall if they weren't buffered.

Why must we feed horses their amino acids and we don't have to feed the cow any

Since horses are not ruminants, they are incapable of absorbing most microbial protein, so amino acids must be supplemented into their diet

What are the advantages of using laboratory animals as models for farm animals in nutrition studies

Some studies require large numbers of animals and housing facilities for them (it would be too expensive and inefficient to use farm animals); also shorter lifecycles allow data to be obtained covering several generations per year

Starch-feedlot, grain diet

Starch (bacterial amylase) > glucose (fermentation) > VFAs

How does stomach capacity affect digestibility

Stomach capacity affects eating rate, amount eaten, and passage rate through GI tract

What does bile do

Stored in gall bladder, helps solubilize and emulsify fats, forms complex with fatty acids, aids in absorption and digestion, helps increase pH of chyme

Define deglutition

Swallowing, reflex passing of food or liquid (anything) from mouth to stomach

What is the advantage to doing a balance trial rather than just a digestion trial

The added data provide more complete information on animal nutrient requirements or nutrient utilization from feedstuffs, determines nutrient absorption and utilization to determine total intake and excretion which helps determine net retention or loss

What is prehension

The mechanical process of getting food to the mouth, accomplished in many ways. Includes capture of the food itself

Compare the water needs of a desert rat to that of producing livestock

The rat does not require drinking water. Whereas the livestock require copious amounts of water

Why do different animals use very different kinds of feeds

The type of digestive system an animal has determines the types of feed it can digest. The more complicated the feed, the more the complicated the digestive tract

The small intestine is lined with a mucosa layer

There are folds within this layer, especially in the jejunum, called "valvulae conniventes" that increase the surface area considerably

What is the relationship between dry matter consumption and water consumption as long as the animal is not in heat stress

There is a positive linear relationship between dry matter consumption and water consumption. However, under stress feed decreases and water increases

What is the point of digestion trials

These are used to determine the proportion of the nutrients in a feed or diet that are absorbed from the GI tract.

What are the advantages of growth trials

They allow the accumulation of relatively large amounts of data at reasonable cots, animals usually can be maintained under conditions similar to normal environment, measurements are easily obtained, results are a reflection of a fundamental biological response, yet can be applied directly to commercial production systems

Why feed Megalac

Used to increase the fat in a ration. Remain unaltered by rumen fermentation and have no effect on fiber fermentation. Increase fat content in diet by 7-8%.

Energy sources for ruminants

VFA 50-70% Bacterial Cells 5-10% Feed digested enzymatically 20-30%

Is the water in feed an important contributor to livestock water needs? If so, how important

Water content in feedstuffs is variable. 5-7% in mature plants, 90% or more in lush young vegetation. So, it can be important. For example, sheep eating hay drank 88% of their water, but sheep seldom drank water when their forage moisture content was 65-70% or higher water

How is water's thermal conductivity useful in dissipating body heat

Water's thermal conductivity enables animals to transfer heat from deep regions of the body and dissipate heat through evaporation: 21% via sweating, 16% via conduction and convection from skin, 5% respiratory

What is the function of the large intestine

Water, electrolytes, vitamins, minerals, and volatile fatty acids are absorbed with emphasis on water and electrolytes. Bacteria grow here

Bird Small Intestine

Well-developed duodenum Small jujenum and ileum -do not have lactose

Bolus

a small rounded mass of a substance, especially of chewed food at the moment of swallowing. Ruminants later regurgitate and chew thoroughly, this process is essential to rumination.

Glandular stomach name in cow

abomasum

Water Absorption

absorbed from most sections of the GIT in most species. The amounts absorbed vary from species to species and from diet to diet. There are a few disorders that reduce water absorption

VFAs formed include

acetic acid (C2), propionic acid (C3), butyric acid (C4), and valeric acid (Cs), lactic acid is also produced

Water serves two basic functions in the body

aiding body metabolism and temperature regulation

The main function of the complex stomach of the ruminant

allow the animal to use roughages (cellulose) as a source of energy. Microorganisms present in the first three stomachs ferment material and provide nutrients otherwise unavailable to the animal.

Compounds that ionize in water due to polarity

amino acids, glucose, and minerals

Fats are

amphoteric to water

feces can contain about 50%

bacteria by weight

cecal fermenters

cecal digestion occurs

Since the large intestine can only absorb free amino acids, not whole proteins, the microbial protein remains unused. Some species have adapted a mechanism to make use of this protein. The adaptive mechanism is called

cecotrophy

Physical or mechanical action

chewing - mastication, grinding in G.I. Tract (bird), omassum - ruminant, digestive turbulence

large intestinal vitamin K is very important in

chickens

Horses must chew thoroughly before swallowing because

food goes directly into the glandular stomach for digestion to begin. They don't regurgitate.

The horse small intestine is the same as a pig except it has no

gall bladder, direct secretion of bile into the duodenum that has been measured to be approximately 300 ml/hr

Ruminants

have more than one stomach compartment where both fermentation and other digestion occurs

Monogastric herbivores have the large intestine of greatest relative volume, while carnivores

have the smallest

The metabolic water produced per gram is _____ for fat than for carbohydrates (.56) or proteins (.40); however, carbohydrates supply more net metabolic water

higher (1.07)

Another important function of the rumen is to store food

how the ruminant evolved. As noted earlier, they would eat rapidly, run and hide in the woods, and then chew. This helped them avoid predators

If proteins or carbs are in urine

indication of kidney damage or a metabolic disorder.

Water exists in two general compartments in the body

intracellular and extracellular

mucin

lubricant for saliva

fats go into the

lymphatic system, to the thoracic duct, and empty into the vena cava.

Solvent properties are important because most protoplasm (where much biochemistry takes place) is a

mixture of colloids and crystalloids in water

The small intestine is the chief site of food digestion and nutrient absorption for

monogastrics

Digestive process is over when

nutrients from the feed are in an absorbable form

Monogastric

one stomach, simple-stomach -can be pure or cecal fermentors

rumen wall is covered with small finger like projections called ______. which increase the absorptive surface of rumen.

papillae

three salivary glands

parotid, submandibular (submaxillary), sublingual

VFA absorption is by ____ diffusion and occurs directly through the ruminal wall as well as later in the gut

passive

emulsification

physical process of breaking up large fat globules into smaller globules, thereby increasing the surface area that enzymes can use to digest the fat, fat suspended in liquid

digestion

preparation of food for absorption

Ammonia (NH3)

produced as a fermentation product from deamination of dietary amino acids or NPN sources. The bacteria do this. It can be reincorporated into bacterial protein ( they need it to manufacture protein) or absorbed into the bloodstream. Some is lost as urea

Glandular stomach name in chicken

proventriculus

Rumination is the combined processes of

regurgitating, remasticating, and reswallowing, may take place up to eight hours per day

The large intestine ( colon and cecum) is roughly equal in size to the ______ and thus has a large fermentation capacity, digesting cellulose and producing B-complex vitamins

rumen

complex stomach is comprised of four compartments

rumen (paunch), reticulum (honeycomb, hardware stomach), omasum (manyplies, stockman's bible), and abomasum (true stomach).

Salivation

secretion and mixing of saliva with food

Prehension

seizing and conveying of food to the mouth, mechanical process

Cells are intolerant to body temp. changes, the heat capactity of water therefore plays a vital role in

temperature regulation

rumen, reticulum, and omasum are collectively known as

the forestomachs -lining of these organs is comprised of stratified squamous epithelium. This is a nonglandular epithelium that does not produce mucous

Oxidation

water is a product of the reaction. This is called metabolic water or water of oxidation

Hydrolysis

water is a substrate in the reaction and is broken down to H+ and OH- and added to something else. The H+ to one, the OH-to another

What portion of the body mass is water? Molecules

½ - 2/3 body mass of adults, 90% of newborns. 99% of molecules

What are the four important overall functions of water in body metabolism? Briefly describe them.

- All of the body's biochemical reactions require water. - Water is the "universal solvent", compounds ionize due to polarity, protoplasm, is mixture of colloids and crystalloids in water, fats do not dissolve in water but when they form micelles they can - Water transports solids in GI tract, blood, tissues, cells, urine, and sweat. Carries nutrients and waste - Water Hydrolysis and oxidation, in chemical reactions

Extracellular water accounts for the second largest water compartment

-Accounts for 1/3 of body water-20% of body weight. -Interstitial space (between cells). -Blood plasma (accounts for 6% of extracellular water). -Lymph fluid. -Synovial fluid (lubricates joints) -Cerebrospinal fluids. -The rest of the body water (25-30%) is found in the gut and urinary tract.

Protein fermentation

-Bacteria are approximately 50%protein and 3% lysine -Microbial action can improve quality of low-quality protein or reduce quality of high-quality protein, because nitrogen is required for bacterial growth

Animals use water from several sources

-Drinking water-most frequent -Water in feed-silage and young grass -Metabolic water -Water (other than metabolic water) from body reactions. -Water in tissue catabolized for energy. protein is catabolized for energy in the first stages of energy deprivation. There is a good deal of water in protein tissues

Rate of passage of feedstuffs through the rumen

-High concentrate rations pass through much faster than poor-quality roughage rations. -Finely ground forage also passes much more rapidly than whole (long) hay. Grinding forage can actually reduce its digestibility because it leaves the rumen too quickly for the microorganisms to digest it

Water and lubrication

-Joints. Synovial fluid. -Muscles. Water helps them glide past each other. -Spinal column. Cushion between vertebrae. -Eyes. Itis a lubricant for the eye and is involved in sight. -Lungs. It also aids in gas exchange in respiration by keeping the alveoli of the lungs moist

Lipid fermentation

-Most individual and mixed feeds are low in lipids (2-5%). Ruminal microbes saturate the otherwise unsaturated fatty acids in plant feedstuffs. This is the reason why ruminant body fat is saturated. -Excessive fat intake causes decreased fiber digestion. A maximum of 5% fat should be fed unless it is in bypass form. -Protected fat such as Megalac, and Energy Booster can be used to increase the fat in a ration, although these are expensive. remain unaltered by rumen fermentation and thus have no effect on fiber fermentation.

Glandular stomach

-Physical breakdown of food occurs because of the churning action created by the contractions of the strong stomach muscles. -Food is also mixed with the chemicals and enzymes that need to work on it. - HCl denatures proteins, activates pepsin, provides optimum pH for enzymes -Rennin hydrolyzes milk protein casein -Pepsin acts on proteins -Lipase on fats - food storage that allows animal to eat more, metered into lower gut

General fermentative reactions that occur in the rumen are of several types. MCO=Microbial

-Protein > Amino acids > NH4+ > MCO protein > Abomasum -NH4+ > MCO protein -Starch > Soluble sugars > VFAs > Absorbed or pass to abomasum -Crude fiber > Soluble sugars > VFAs > Absorbed or passed to abomasum -Unsaturated fat > Saturated fat

VFA concentrations

-Rumen fluid from cattle on grain diets will have concentrations of 100-120 mmol VF As and a pH of 5.5 -6.0. -On forage diets the VFA concentrations are lower; 60-80 mmol VF As and a pH of 6,5-7.0

Dietary protein

-Ruminal degradable proteins. soybean meal-72% RDP cottonseed meal-60% RDP casein-JOO¾ RDP -Ruminal undegradable proteins (bypass or escape). blood meal-18% RDP meat meal -24% RDP fish meal-20% RDP brewer's grains-4 7% RDP

Heat is also a major product of fermentation

-The heat of fermentation is a part of the total heat increment of the animal. -It is useful in winter to keep the body warm but detrimental in summer because it can contribute to overheating and thus reduce production

Saliva also has an excretory function

-Toxic metals like mercury (Hg) and lead (Pb) are secreted -precipitate with sulfides is formed as a result of bacterial fermentation in the mouth. The precipitate migrates to the comers of the mouth and can be seen as a blue line on the gum

Rate of passage of food through the digestive tract

-Varies with species. It is faster in carnivorous birds. -Varies with age and health. Faster rate in young. -Consistency of feed. The drier the food the longer the rate of passage. -Hardness of feed. The harder the food the longer the passage. -Moisture in feed. The greater the water content the faster the rate of passage. -Most of the food passes through the digestive system in 24 hours. Half is passed within four to six hours.

omnivore large intestine is less capable than the herbivore's but more capable than that of the carnivore

-Vitamin synthesis, water, and electrolyte absorption are similar to the carnivore. -Cellulose digestion is a function of retention time. The longer it is in the lower gut the more likely some digestion will take place. Studies indicate that up to 18-20% crude fiber digestion in high fiber diets fed to swine is possible.

succus entericus

-alkaline secretion by glands in the small intestine itself in large amounts -function is to lubricate, dilute, and increase pH of the contents of the small intestine.

Defecation

-discharge of excrement. Internal and external anal sphincters control the exit of material from the body

Ionophores

-feed additives that alter ruminal metabolism by favoring propionic acid-producing species. There are nearly 80 known ionophores (Ensminger, p. 261 ). Rumensin (monensin sodium) fed at 5-30 g/ton complete feed and Bovatec (lasalocid) fed at 10-30 g/ton feed are approved as feed additives for cattle. -originally approved as coccidiostats in poultry. -work by altering the type and concentration of microbial species in the rumen.

Duodenum

-first part of sm. intestine, in most species it forms a loop -Bile and pancreatic secretions enter the small intestine here. -main site of food breakdown in the small intestine.

bacteria also contain energy, vitamin K, and B-vitamins that the animal is able to digest, absorb, and use

-formation of these vitamins by the rumen bacteria frees the ruminant from dietary B-vitamin requirements under normal circumstances. -Niacin in dairy cattle, thiamin in feeder cattle, and animals under stress are examples. There are thiaminases in some feeds that can destroy thiamin. Vitamin B12 can be a problem if cobalt is lacking. -microorganisms do not synthesize vitamins A, D, and E. -bacteria also produce enough essential fatty acids for the animal

Bile

-formed in the liver -concentrated (up to 20x for some species) and stored in the gall bladder -Some species like the rat and horse don't have a gall bladder. As continual rather than meal eaters, they secrete bile continuously

Omasum

-function is unclear, probably involved in water and VFA absorption -Animals that have the omasum surgically removed suffer no ill effects

Reticulum

-functions as a site of microbial action -acts as pacemaker of rumen contractions

esophageal groove (reticular groove)

-groove that can contract and form a tube that acts as a bypass of the rumen and empties into the omasum -function of this groove is to keep milk out of the young ruminant's undeveloped rumen -If a calf drinks milk too fast or if the groove does not close, milk can get into the rumen of the calf -milk can't be adequately digested in the immature rumen and will literally "rot." -calf will develop a severe case of diarrhea or scours due to proliferation of bacteria and production of toxins in the rumen

Brunner's glands

-in the small intestine secrete another small intestinal secretion called duodenal juice. -secreted in small amounts -responsible for activating trypsin through its constituent enterokinase that is the main activator of trypsin

The jejunum of many species is covered with microscopic villi

-increase absorptive surface area -villi have a core (stoma) that contains smooth muscles, blood capillaries, and lymph capillaries. The villi are covered by intestinal epithelium -Microvilli cover the villi and increase the surface area of an individual villus by 600 times -Nutrients are absorbed across the villi and pass either into the lymphatic system or the circulatory system

Saliva functions

-moistening, lubricating -solvent action -washing action -disinfectant -buffering action (particularly for ruminants) -provides nutrients to rumen microogranisms -antifrothing -excretory function

Bird Mouth

-no soft palate. -Absence of teeth. -Salivary glands are present, but in small numbers and are poorly developed. -There is salivary amylase in the saliva though it is of little value. -There is very little or no digestion here.

Key features of large intestine

-no villi (absorption is restricted) -mucous glands line it for lubrication -no digestive enzymes secreted by animal, any found are left over from earlier or provided by microorganisms

Several things influence warer need

-regulating body temperatures. -Directly correlated to OM intake (3-6 units H20 per unit of dry matter). -Lactation increases H20 requirement by 1kg H20/kg milk. -Pregnancy -Protein increases H20 requirements because of urea that is toxic and must be diluted to prevent it from damaging the kidney. -High ambient temperature that increases losses due to insensible perspiration. -Age, body weight, type of production and level, weather, and type of ration all affect requirements. -NaCl consumption increases water consumption. -Design, accessibility, and cleanliness of water containers affect water consumption.

Jejunum

-second and longest part of sm, intestine -digestion continues but its major job is absorption

Horse stomach

-smaller stomach than other species. It provides only 8% of the capacity of the tract. fed small portions of ration several times daily. bare minimum, two times daily feeding. -does not have extensive muscular activity compared to other species. The feed tends to arrange itself in layers -prone to more stomach disorders than other species. Colic and ruptured stomachs both occur. Colic is very common. -limited bacterial fermentation in the stomach with lactic acid being the major product. -Gastric ulcers are a problem, but the relationship to feeding practices has not been firmly established.

gizzard (ventriculus)

-specialized grinding organ. -Varies in muscularity depending on type of food. -Large and well developed in many wild animals. -Smaller and less developed in commercially raised -normally contains grit to aid in the grinding of feed to smaller particles; with modern processed rations grit is unnecessary. -There are no enzymes secreted here; those from the proventriculus work here

Rumen contractions

-start with the reticulum and spread to the rumen. -very strong and are caused by contraction of the powerful rumen muscles. -function to mix the rumen contents and are essential for optimum microbial digestion. -move the contents through the digestive tract. -heavier particles settle in the reticulum and are passed on through the omasum to the abomasum. -lighter particles float on the top of the rumen-these are subjected to rumination.

Defecation reflex

-stimulated by the pressure of feces in the rectum. -assisted by parasympathetic nervous signals that intensify the peristaltic waves of the large intestines. -Valsalva maneuver. They breathe deeply, close the glottis, and then flex the abdominal muscles. This puts pressure on the fecal contents and helps expel them

Ileum

-third part of sm. intestine -connects to large intestine and some absorption occurs

Mouth of Pigs

-used primarily for grinding feed by the teeth and mixing with saliva. -Saliva (pH of 7.4) moistens feed -Saliva is produced by three pairs of glands: parotid, mandibular and sublingual. -only farm mammal in which any amount of the enzyme ptyalin (amylase) is secreted in the saliva. about 100 times more powerful. -Ptyalin begins to break down the starch in the feed. pH is too low (acid) in the stomach for ptyalin to act on the starches.

eructation (belching)

-very important mechanism for ruminants. -large quantities of gas produced by the rumen microorganisms must be removed (600 liters/day may be produced). -Contractions of the upper sacs of the rumen force the gas forward and down. The esophagus then dilates and allows the gas to escape. Much of the gas goes into the trachea and lungs. This provides a muffling effect

Give nine reasons we might conduct feeding trials other than to measure growth or digestion

1) Lactation feeding trials can be used to determine the effects of feedstuff on the quantity or quality of milk. 2) Feeding trials can be used on birds to determine the effects that feedstuff have on eggs. 3) Trials can be conducted on animals such as horses or greyhounds to determine how diets affect speed and endurance. 4) Feeding trials can be used to visualize how an animal utilizes nutrients or the nutrients required to maintain day-to-day normal functions. 5) These studies can also be used to determine how a toxin in an animal affects the animal's usage of a particular nutrient in its diet. 6) Feeding trials can be used to determine how the lack of a certain nutrients, such as iodine, affects individuals. 7) One can learn the ideal amounts and nutrients required for a male animal to produce healthy sperm by undergoing a feeding trial where specific nutrients are removed or added. 8) Feedstuff quality can be compared using a feeding trial to determine the cheapest brand/type of feed that can be given while the animals remain healthy. 9) Feeding trials can show the likelihood of certain diseases or conditions developing based on the quality of the feedstuff given.

Approximate time of passage of an adult ruminant (cow) on an average ration is

1. First material in tract goes through in 12 hr with 0 hrs in rumen 2. Mean time spent in tract 3-4 days with 2 days in rumen 3. last material through tract 10 days, 7-8 days in rumen

Digestive Process Mechanisms

1. Physical/mechanical 2. Chemical action 3. Enzymes

The body can lose almost all its fat and over 1/2 its protein and survive. However, a ____ loss of water will result in death for most species

10%

In a growth trial, how can we deal with the fact that growth is a variable biological parameter

12 to 15 or more animals per treatment to detect statistical differences, remove some of the biological variation by using full or half siblings, animals with a similar genetic background, generations of inbreeding and selection programs, genetically identical twins either naturally or by gene-cloning

Generally speaking, how much water do animals need per quantity of dry feed consumed

2-5 kg of water per kg of dry feed when not under heat stress

Total number of microbes in rumen

2.5 x 10^15 microorganisms or 2,500,000,000,000,000.

The horse is only about ____ as good at fiber digestion as the ruminant

2/3

What are VFAs of importance in the rumen and what does the animal do with them

Acetic acid (C2), propionic acid (C3), butyric acid (C4), and valeric acid (Cs), lactic acid is also produced. They are absorbed through the rumen wall and supply 50% of the energy requirement for the ruminant

How does one account for the fact that apparent digestibility of a protein in a feed is influenced by the level of protein in a feed

Amount of endogenous protein tends to be constant, so at higher protein intakes the endogenous fraction is smaller percentage of total N excretion. True digestibility remains the same despite low and high diets

What are the factors that affect nutrient utilization from a given feedstuff

Animal's species, age, physiological state, type of GI tract, level of consumption (plane of nutrition), physical form of nutrient (pelleted, ground, processed), diseases and parasites, and the balance of nutrients within feedstuff and associated diet constituents

What types of diets are usually fed to animals in a growth trial

Animals are fed test diets in congruence with similar animals fed a standard diet that is known to allow normal growth

What do bacteria do in the gut of a monogastric herbivore

Bacteria can help digest cellulose and produce B-complex vitamins, they also produce bacterial protein via fermentation, but monogastric herbivores cannot easily digest this

Describe eructation and the consequences if a ruminant is unable to eructate

Belching gas, contracting upper sacs of rumen force gas through dilated esophagus, much of it enters the lungs and trachea making a muffling effect. Bloat can occur if gas cannot escape. Creates distention of rumen that can be seen on the left side. Froth or foam produced

Fiber-grass, silage diets

Cellulose (bacterial cellulase) > glucose (fermentation) > VFAs

What happens to water consumption in relation to water need on lush pastures

Consumption of more water than needed

Why do you think that dairy cows drink so much more water than beef cows

Dairy cows produce milk, which is mostly water, therefore they need more water

Describe one·(or more) situations where a perfectly normal animal might not need to drink water

Desert animals, animals eating high water foliage, freshwater fish

What types of factors determine the relative importance of these to a specific animal

Diet, habitat, and ability to conserve body water

Why is feed efficiency a useful estimate of nutrient adequacy of a test diet

Diets that promote a high rate of gain will usually result in a greater efficiency than diets that do not allow rapid growth

Why have purified diets not solved completely the dietary essentiality of all trace minerals

Difficult to determine if amount needed is extremely small and even highly purified inorganic element sources may contain trace amounts of contaminating elements

Explain why ruminants, cecal fermenters, and monogastrics have such different abilities for digesting forages

Digestion is completed through physical, chemical, and enzymatic reactions. However, ruminants, cecal fermenters, and monogastrics have different digestive systems, meaning that digestion occurs differently in each category and therefor different nutrients are required for each species. Ruminants for example, have multiple stomach compartments which enable them to use microorganism fermentation before the chyme enters the small intestine. This means that the products produced by the microorganisms can be broken down and absorbed and therefore, ruminants can digest and benefit from forages with large amounts of plant materials. Monogastrics, like carnivores, however, have a singular stomach and do not gain the benefit of a mutualistic relationship with fermenting bacteria before absorption occurs. This combined with other factors makes digesting and benefiting from plant-based diets difficult, if not impossible in the case of obligate carnivores such as cats. Between these two extremes, there are cecal fermenters. These species are monogastric, but they are capable of fermentation in the cecum of the large intestine. This enables them to break down and absorb volatile fatty acids in their large intestine (which is longer compared to other monograstics). While they cannot absorb the bacterial protein produced, like ruminants, some can practice cecotrophy to redigest the material and take advantage of the microbial by-products. This allows cecal fermenters to eat high plant diets, though arguably not as efficiently as ruminants

Define digestion. What are the three major methods (mechanisms) of digestion? Describe them

Digestion is the process by which food is prepared for absorption. Physical/mechanical (chewing and muscular action in digestive tract), chemical action (HCl in stomach, bile in small instestine for fats), enzymes to break chemical bonds by adding water (produced by GI tract and accessory organs, produced by microorganisms, biological catalysts, needed to speed digestion of carbs, lipids and proteins).

How can you treat/prevent bloat

Don't use feedstuffs with high legume contents, feeding hay before letting grazing occur, no grazing in rain or dew saturated fields. Treat with poloxalene, feed 2-3 ounces of laundry detergent per day, use trocar and cannula to puncture rumen

Name the nutrients produced as a result of rumen fermentation

Energy, vitamin K, and B-vitamins, some essential fatty acids

salivary amylase

Enzyme in saliva that breaks down starch to maltose, not significant in digestion -found in man, apes, pigs, guinea pigs, rats, squirrels and some birds -not in cattle, dogs, cats, or horses

Why is weight gain not always a precise estimate of diet utilization

Equal increases in body weight between animals does not indicate equal growth of body tissues; for example, one animal may add muscle while another adds fat, but both are gaining weight

Describe the methods of water loss from the body in detail, but no greater detail than the course guide

Expired H20 from lungs which is 90% saturated, vaporized from skin via diffusion (blood brings water to skin) and sweating, feces, and urine (urea requires a large quantity of water, uric acid does not require water (birds))

Why do similar animals digest a given diet to different events

Factors such as mastication, variation in absorptive capacity, specificity of digestive transport systems

What are ionophores? What do they do and what is the outcome of feeding them

Feed additives that alter ruminal metabolism by favoring propionic acid-producing species. 80 known. Antibiotics that work by altering type and concentration of microbial species in rumen. Increased propionate and decrease acetate, methane and lactate. Improve feed efficiency and increase daily gain

What is the usual way of determining true digestibility of nitrogen in ruminants

Feed graded levels of protein, determine excretion, and construct regression line back to zero protein intake and calculate the fecal excretion

What is feed efficiency

Feed required per unit of weight gain or weight gain per unit of feed

What are the methods used to estimate endogenous excretion of nitrogen

Feeding nitrogen free diet and determining nitrogen in feces, feeding several levels of nutrient nitrogen and calculating fecal level by regression analysis back to zero, feeding a completely digestible protein

How does digestion occur in the avian? What are the differences between a chicken and a pig

Food enters crop where it is moistened (some species have fermentation), then it moves to proventriculus where gastric juices (HCl and pepsin) are present, it then enters the gizzard where food is ground, from there it enters the sm. Intestine, where digestion and absorption works, next it enters the ceca and experiences some water reabsorption, from there it enters the lg. intestine where most water is reabsorbed and vitamin K synthesis occurs

What measurements do growth experiments usually include

Growth experiments usually include measurement of absolute gain in body weight during a period of feeding a test diet. Rate of gain is then expressed as average daily or weekly gain (absolute) or in terms of final weight as a percentage of initial weight (relative gain)

Order of saliva produced largest to smallest

Herbivore > Omnivore (1500 ml/day) > Carnivore (200 ml/day)

What are the properties of water that allow it to have a marked effect on temperature regulation

High specific heat, high thermal conductivity, and high latent heat of vaporization

What is the purpose of saliva in the horse

Horse saliva has no enzymes, so it serves the function of moistening, lubrication, and the like

Describe the significance to the horse of being a cecal fermenter

Horses are capable of eating roughage because they have an active cecal bacterial population that digests fiber

What does pancreatic juice do? Include a description of the function of each enzyme

Hydrolysis, splits compounds by placing H on one side and OH on other side. Trypsin, chymotrypsin, carboxypeptidase and aminopeptidase digest proteins. Intestinal lipase breaks down fats into fatty acids and glycerol. Amylase is specific for starch, other enzymes for dipeptides, disaccharides

How can an animal increase heat loss through the lungs? Can you think of an environmental situation in which evaporative cooling would not be a very efficient and one where it would be highly efficient

Increased blood flow to the lungs will increase heat loss via the lungs. Evaporative cooling is highly efficient in dry, hot environments because the water quickly leaves the skin (dehydration is a concern), in humid climates water is less likely to evaporate

What is the effect of salt consumption on water consumption and excretion

Increased salt consumption increases excretion of water both through fecal and urine excretion. So, more water is needed

How does fat consumption affect water intake

Increases intake in fats means increases water intake

What are the functions of saliva? Reduce the functions to one-word answers. You should find eight of these

Lubrication, solvent, washing, disinfectant, buffering, nutrients (microorganisms), antifrothing, excretory

How does milk production affect water consumption in cattle

Milk production requires more water

Why is it difficult to delineate the water requirements of an animal

Numerous dietary and environmental factors affect water absorption and excretion. Water is important in regulating body temp, ability to conserve water, differences in activity, and physiological state between individuals and species. Directly correlated to OM intake, lactation, pregnancy, protein, high ambient temp, age, weight, production and level, weather, type of ration, NaCl consumption, design, accessibility, and cleanliness of water

Why do nutrient requirements for growing animals change throughout the growing period

Nutrient requirements change throughout growing period in direct response to changing needs of individual organs and organ systems making up the whole animal

What are the major anatomical differences in the avian and the pig? Describe each along with its function

Pig: mouth for grinding and saliva with ptyalin (amylase), simple stomach without rennin, digestion of protein and fat in sm. Intestine, 24 hours to empty stomach. Pancreas (trypsin, chymotrypsin, carboxypeptidase, pancreatic lipase and amylase, maltase, sucrase, lecithinase), lg. intestine absorbs water and moves waste. Avian: lack teeth, have gizzard and crop. Mouth has no soft palate, small salivation with little amylase, crop is food storage and moistening fermentation occurs, proventriculus (stomach with HCl and pepsin), gizzard (contains grit for grinding, no enzymes), sm. Intestine duodenum, no separated jejunum or ileum, no lactose, digestion and absorption), two ceca, water reabsorption, fiber digestion, water-soluble vitamin synthesis, lg. intestine (main water reabsorption, vitamin K synthesis in chickens), cloaca

Compare and contrast the end products of protein and carbohydrate digestion between the pig and the cow. (This is an exercise to determine if you understand the predominantly enzymatic digestion of the pig compared to the microbial digestion of the ruminant that is then followed by enzymatic digestion.)

Pigs are monogastric omnivores. In the stomach, HCl and the enzyme pepsin work together to denature proteins. Once the chyme enters the small intestine, bile and pancreatic enzymes work together in the duodenum to further digest the material. They break down proteins into amino acids and peptides and carbohydrates into molecules such as maltose and glucose that can be absorbed into the blood stream. Any bacterial work done within a pig's digestive system is accomplished in the large intestine, this means that unlike cows, pigs are unable to digest bacterial proteins or take proper advantage of the volatile fatty acids produced by fermentation. Cows on the other hand, are ruminants. Within the rumen, carbohydrates are digested by bacteria to produce volatile fatty acids, half of which are absorbed through the rumen itself. The microbes in the rumen also produce bacterial protein, even converting nonprotein nitrogen, into protein that can later be digested by the animal. Some of the bacteria travel with the food through the reticulum where more volatile fatty acids are produced and absorbed. In the abomasum and small intestine, the remaining protein and carbohydrates are broken down much like in the pig, enabling the cow to absorb amino acids from the food, bacterial amino acids, small sugars like glucose that were not converted to fatty acids during fermentation, and previously unabsorbed fatty acids

Describe the importance of water to life

Required in largest amount by living creatures, most abundant chemical substance on earth, 10% loss of water will result in death for most species, 20% for others. No life is known to exist where liquid water does not exist

What are the common names of the four ruminant stomachs

Rumen (paunch), reticulum (honeycomb/hardware stomach), omasum (stockman's bible), abomasum (true stomach)

What is the relative volume of each compartment in the ruminant "stomach"

Rumen 80%, reticulum 5%, omasum 7-8%, abomasum (8-9%)

What is bypass protein and what are the implications to production of feeding it? Why is forage utilization enhanced by feeding adequate nitrogen to the ruminant

Ruminal undergradable proteins are bypass proteins. They still contain ruminal degradable proteins, though to a lesser extent. Forage utilization is enhanced by N through positive associative effect. One feed increases the utilization of second feed

Why is the horse prone to stomach disorders

Since the stomach is small and lacks the muscular activity compared to other species, feed arranges itself in layers

How does the body prevent itself from having large changes in temperature

Since water makes up such as large portion on the body and it has such a great capacity to store heat, sudden and large changes in body temperature are avoided

Why do we use the term "apparent digestibility" instead of simply "digestibility"

This term takes into account the unabsorbed feed residues and the components, such as nitrogen, carbon, fats, and carbs that come from sloughed off cells in the GI tract (endogenous origin).

Why use digestibility by difference

To determine the digestibility of feedstuff when fed in a mixture with one or more other feeds

What is the advantage of a paired feeding experiment

To rule out factors such as physical characteristics, nutrient content, or palatability which may affect total voluntary intake

True or False: Nutrient metabolism and the metabolic pathways for different animals are essentially the same

True

True or False: The digestive system determines what the animal can successfully use. The more complicated the feed the more complicated the digestion tract must be.

True

In order to determine changes in body composition during growth in beef cattle without grinding a whole carcass, what can we do

Use the 9-10-11 rib cut which has been shown to give relatively accurate estimates of total carcass fat, protein, water and ash. You can obtain it from one side of the carcass with or without the bone

Why use the indicator method instead of a conventional digestion trial

Used when it is impossible or inconvenient to measure total feed intake or to collect total feces

Explain the problem of getting an accurate weight on animals in a growth trial. Why is it a problem, in which animals is this the biggest problem, and how do we correct for it?

When an animal is alive and weighed, that number contains the values for the tissue mass, water, and any substances in the animal's GI tract. Therefore, the weight is not an accurate measurement of growth. This error tends to be greater for animals that are ruminants, because they have larger GI tracts that can hold more material. The easiest way to correct this problem is to find the average of two to three weights obtained on consecutive days.

Swallowing (deglutition)

a complex action involving over 22 muscles in the mouth, pharynx, and esophagus -under neural control -peristalic waves -cardiac valve at the end of esophagus prevents feed in stomach from coming back up

lysozyme

an enzyme found in saliva and sweat and tears that destroys the cell walls of certain bacteria

Providing H20 ad libitum is the best way to provide H20. An exception to this occurs when

animals have been water deprived or over heated. Such animals may over consume if allowed water ad libitum. In this case it is better to restrict intake over a period of several hours and allow the animals limited water at intervals until they have rehydrated

Describe in detail what happens in the large intestine and cecum of the horse

bacterial breakdown of cellulose and carbs to produce VFAs which are absorbed by the cecum. Bacterial synthesis of water-soluble vitamins and bacterial synthesis of protein (though horses do not practice coprophagy unless they are on a poor diet). Cecum is primary area of water reabsorption

Enzymes

biological catalysts that speed the rate at which a particular reaction will reach equilibrium

"The _______ systems of mammalian species display a greater degree of structural and functional diversity than any other organ system of the body"

digestive

Rumen

main function is to act as a site of anaerobic bacterial fermentation. Undeveloped at birth, it begins developing in response to the calf eating solid food and can be functional (partially) by six to eight weeks. most food (85-95%) is fermented to some degree

Bird Esophagus

portion of the digestive tract connecting the mouth and the stomach or proventriculus. The first section connects the mouth to the crop

Carbohydrates, amino acids, fatty acids, water-soluble vitamins, and most minerals absorbed from the small intestines are transported by

the portal vein to the liver

True or False: The digestive tube is actually outside the body so digestion has to be extracellular

true

Abomasum

true glandular stomach in monogastrics and has the same functions