If you are a Cal Poly student enrolled in AVS 303, then these notescover
every subject that will be (possibly) be covered on the final examination.
Do not memorize (you won't be able to), try to understand overall concepts
and relationships as much as possible.  Make sure you are familarwith the
calculations we have covered in class, particularly those covered most
recently.  These notes are a little cryptic (since I wrote themto lecture
from, not publish), but you should be able to use them to fill in anygaps
in your own class notes (assuming you took any).  :-)

If you are NOT enrolled in AVS 303, and are just cruising the websitefor
some obscure reason, you're welcome to do so as well. :-)

Good luck!
 
 

Feedstuffs

High energy feeds:

Of the six classes of nutrients (carbos, fats, protein, vitamins, minerals,
water), energy is going to be provided from carbos, fats or protein.
Different feeds provide differing amounts of nutrients.  In ahigh energy
feed, the majority of the energy is going to be readily available from
soluble carbohydrates (those that don't have to be fermented) or fromfats.
High energy sources generally have low to moderate levels of protein. If
they had high protein levels (over 20%), they would be classified asa
protein source, not as a high energy source.

Cereal grains - most commonly used in livestock rations include corn,oats,
barley, milo, wheat, rye, triticale (cross between wheat and rye) and
millet.  Most grains have a protein level between 8 -14% (wheatmay go up as
high as 22%), and most grains are deficient in lysine, tryptophan,
methionine and threonine (milo and rice).  Corn especially isvery deficient
in lysine, but also most commonly fed grain because highest in
energy—therefore, corn based rations must be balanced with anotherprotein
source, such as SBM to provide sufficient amino acids.

Fat content in grains is between 1 -6%, most are between 2-4%. About half
are available for energy, the rest are fat soluble vitamins, pigments,etc.

The carbohydrate in grains is primarily in the form of starch, which
accounts for between 41 - 72 of the grain kernel.

 Corn is highest in starch, followed by milo, wheat, barley, ryrand oats
are lowest. Starch is related to energy, so corn is highest in energy,oats
are lowest.

 Starch differs in chemical composition in different grains. Amylose is a
linear, straight-chain polymer of glucose, amylopectin is a branched-chain
of varying length.  Both types of starch are found in the endospermof the
grain kernel.

The carbohydrate found in the cell walls and hulls (in oats and barley)is
primarily cellulose. Provides some energy, must be digested through
fermentation, not a significant portion of the energy content.

All cereal grains are low in calcium, moderate to high in P.  Ina lot of
grains, the P is in phytate, so unavailable.  Grains are generallya poor
source of trace minerals and except for yellow corn, are very low in
carotene.

Yellow corn is preferred as a poultry feed because of xanthophyll content,
contributes to yellow color of skin and yolk.  Corn most commonlyfed grain
because highest in digestible energy and lowest in fiber.  Represents80% of
all the grain fed to livestock in U.S.  Corn is prone to moldsand fungus,
especially on processed grains, which may contain mycotoxins. In ruminants,
lowers feeding quality and reduces performance.  In horses, causes
leukoencephalomalacia, or aflatoxicosis.  Also caused blind staggers,but
not se-related.

Milo is second most commonly fed livestock feed, tolerates drought andheat
better than any of the other cereal grains.  However, milo yieldsless grain
per acre than corn in good growing conditions, so milo is only grownin
places where corn won't grow well.  Milo has only slightly lessfeeding
value than corn, and some data indicates an equal feeding value whenfed to
swine and poultry.

Barley represents about 4% of all grain fed to livestock.  Hashigher
protein content (11-16% Dry matter basis) than corn, but because oflower
starch content and higher fiber content, has less feeding value thancorn or
milo.  Categoried as Pacific coast or not Pacific coast—PC islower in
protein.  Barley is more likely to cause bloat in feedlot cattlewhen fed as
a major component of ration, and because of fiber content, does notallow
for maximum feed efficiency in swine rations.  Not a large componentof
poultry rations, again due to high fiber.

Oats - Has lower feeding value than the previous grains because of lower
starch content and higher fiber content.  On a volume basis, provideshalf
the energy that corn does.

In 1950's oat production was around 40 million acres, now around 10,decline
due to primarily to poor yields.  Genetic improvements in othercereal
grains 35-100%, in oats only 9-13%.  Protein content is relativelyhigh
compared to other grains (11-14%, can go as high as 24%) and has thebest
amino acid profile of any of the cereal grains (though still relatively
deficient).

  Because of high fiber content, not commonly fed to poultry. Oats are
between 28-45% hull, and hull is about 31% fiber.  In situationswhere
maximum production is wanted, oats are generally of too low a feedingvalue
as compared to the other grains, but is used sometimes to provide bulk(ie
finishing swine).

Oats contain an alcohol-soluble protective factor which protects youngpigs
from gastric ulcers.
Most common grain fed to horses because of fiber content - high starchcan
produce cecal acidosis, changes to plasma glucose, so oats are better.

Wheat - majority is grown for human consumption, which produces wheat
by-products that can be used as livestock feed; or can be grown entirelyas
a livestock feed crop.

Divided into hard and soft varieties, within hard/soft are winter and
spring.  Hard wheats are higher in protein (13-16%) and gluten,so
preferable for bread making.  Soft wheats are between 8-11% .

AA distribution better than for corn, but still deficient.  Verypalatable
to most species, very high in energy value (3rd highest behind cornand
milo), but is grain mostly likely to cause acidosis in the rumen orcecum.

Wheat produces several by-products:
Wheat bran - outer covering of the wheat kernel.  19% of the totalprotein
and the majority of the vitamins are contained in the bran
Wheat middlings (mids), mill run, shorts and red dog are essentiallyall the
same thing except with decreasing fiber content - contains bran, germ,
flour, tailings, etc.
Wheat germ - 28% protein, classified as a protein supplement
Wheat mid, mill run etc are most commonly fed to swine, poultry anddairy
cattle.

 Wheat bran is commonly fed to horses because believed to havelaxative
qualities, but does not.  Bran was fed as 50% of total ration,did not
increase fecal water content.  Also extremely high in P (1.27%).
Horseowners don't see it as a grain because its fluffy, but has higher
energy content than whole oats.

Triticale - hybrid cross between wheat and rye, nuttitive quality somewhere
between the two, feed value somewhat below wheat.  Not commonlygrown as a
livestock feed.

Rye - somewhat less palatable to livestock than other grains and contains
two antinutritive factors; an appetite-depressing factor in the bran,and a
growth-depressing factor in the entire grain.  Can be fed up to40% of the
grain ration in adult animals, but should not be fed as a major componentof
the ration in growing animals.

Rice - rice itself is generally too expensive a feed as a whole grainto
livestock, but when it is, about 8% CP.  The only portion whichis fed to
livestock (horses) is rice bran, which is outer layer of the rice grain.
Rice bran, depending on extent of processing, contains 13-24% etherextract,
most of which is available to the animal.  Marketed as designerfeeds for
horses as an energy feed, and highly processed rice bran does havefeeding
value second only to corn grain or pure fat.

However, extremely expensive due to processing required to stabilizefat
content;

other drawbacks, highest source of P (1.57%), which is mostly in highly
available form, so one or two pounds can upset a Ca:P ratio.

Relationship between fiber and energy:

CF   <4  6  10  12  19  24
 

DE(Mcals/kg) 3.5-3.7  3.3-3.5  2.9-3.1  2.6-2.9 2.4  2.2

   28  30  34-38

   2.0  1.5-1.75 1.4-1.5

Example: You're given a feed tag that tells you the crude fiber contentis
19% and contains 10% fat.  What is it's energy content per kg?

Calculate energy derived from the fat.  Fat = 8.98 Mcal DE/kg,so multiply
fat content by 8.98:
(.10)(8.98) = .89 Mcal/kg)

If your feed is 10% fat, then it's 90% everything else (the 19% crudefiber
part).  19% crude fiber equates to 2.4 Mcal/kg.  So multiply(2.4
Mcal/kg)(.90) = 2.16 Mcals/kg.

Add together the energy from the fat to the energy from everything else=>
.89 + 2.16 = 3.05 Mcals/kg.

Back to high energy feeds from cereal grains - we talked about midsand mill
run from wheat, and you can get these from other grains as well.

High energy liquid feeds - Includes molasses, condensed soybean solubles,
liquifued corn product, and whey.

Molasses is primarily a by-product of sugar production, but not always.
Most comes from sugar cane, but also sugar beets, citrus, starch andwood.
Molasses from cane and beets are a by-product of sugar production. Citrus
molasses is the partially dehydrated juice from citrus pulp. Starch
molasses is a by-product from the manufacture of glucose from cornstarch.
Wood starch (also lignin sulfonate or hemicellulose extract) is a byproduct
from the manufacture of pressed woods and wood pulp.

All molasses are categorized according to Brix, correlation to density.
Most molasses products are between 67- 78% dry matter (22-33% moisture),
dehydrated 94-95% dry matter (much more expensive.)

With exception of beet molasses, all are high in calcium, not becauseof
molasses source (cane, corn, whatever), but because of substances thatare
used in the processing methods.

2-6% crude protein, low in vitamins A,D,B1 and B2, but are a good sourceof
pantothenic acid and niacin.  Energy content 3.4-3.5 Mcal/kg,similar to
oats, but while energy in grains in primarily in the form of starch,in
molasses energy is in the form of monosaccharides/simple sugars, primarily
sucrose, fructose and glucose.

Molasses are also high in reducing agents which have an effect on lysine,
research reported destruction of 0.5% lysine content per day. So if
molasses is in grain mix, 1/3 of lysine content would be destroyedwithin 3
months and ½ destroyed within 5 months.  Doesn't mean tonot use molasses in
grain mix, just means to either feed grain quickly, supply additional
lysine, or don't feed grain mixes with a lot of molasses to young,growing
animals.

Molasses is added to livestock rations for four reasons:
1) increases palatability
2) reduces dustiness of feed in processing (remember risk of explosionsin
grain mills)
3) binder in pelleting or to keep loose particles of feed (ie vit/min
premix) from sifting out
4) sometimes used as a carrier for a mineral or protein source (suchas
urea) provided as a lick to range cattle.

Molasses is usually added to grain as 5% of the total mixture. More than 5%
in loose grain mix in hot, humid weather may lead to mold, and morethan 10%
makes it too sticky and hard to handle.  When used as a binderin pelleting,
molasses usually added between 7-10%.  All molasses products havea laxative
effect and rations more than 15-25% cause diarrhea and digestive upset.

Palatability differs among different types of molasses. Cane molasseshas
the most pleasing odor and is the most palatable, this is the one usedfor
human consumption (blackstrap molasses).  Beet molasses has afishy odor,
but doesn't affect palatability for livestock.  Cattle like woodmolasses
the least, and pigs like citrus molasses the least.

Other high energy liquid feeds are condensed soybean solubles, by-productof
washing soy flour.  Low in protein, about 33% sucrose, comparablein energy
to corn, can be fed up to 10% of ration.
Liquified corn product - result of enzymatic and heat treatment ofentire
corn grain.  Not used to a large extent in livestock rations,but has same
energy content as whole grain.

Whey is by-product from cheese making industry.  After you removebutterfat
and casein from milk, what's left over is whey.  Is usually dehydratedto
one extent or another, which increases cost but decreases transportcosts.

Whey is 10-13% crude protein on a dry matter basis, and 55-70% lactose
sugars.  Pigs can be fed up to 20% of their total dry matter aswhey, cattle
up to 30%.

By-product feeds
Beet pulp - what's left over after sucrose is removed from shreddedsugar
beets in sugar production..  Pulp can be ensiled or fed fresh(if livestock
are very close to mill), usually dried as fed either loose in shreddedform
or pelleted.  If pelleted, beet molasses is usually added backin as a
binder.

Beet pulp is right on the edge of being categorized either an energyfeed or
a roughage, as crude fiber is 18%.   For years, energy contentwas listed as
being less than any of the cereal grains, but in feeding trials withsheep,
cattle and recently horses, actual feeding value is close to that ofcorn.
Difference is that while other high energy feeds supply energy as either
starch, sugars or fats (all of which must be fed in limited quantitiesand
can produce digestive upset), energy in beet pulp is derived from soluble
fibers.  End product of digestion is VFAs.  (What does thattell you about
what species this can be fed to?)

Beet pulp can be fed as up to 70% of total ration for cattle and sheepand
has been safely fed as 45-50% of the total ration for horses. Contains
about 10% crude protein, 0.7% calcium.  At face value, this isgood source
of calcium, but beet pulp is also high in oxalates, which bind calciumand
make unavailable, so probably should not be considered a source ofcalcium.
Because of oxalate content, should not feed large amount to lactating
broodmares or growing horses.

Fruit or Citrus pulp - what's left over after juice has been removed. Most
common sources are apple, oranges and grapefruit, grape in some regions..
Calcium hydroxide or calcium carbonate is used in processing, so pulpis
high in calcium. Can be fed fresh, ensiled or dehydrated (then becomes
pomace) If they screen it to get finer particles, then citrus meal. 7-9%
CP, energy content similar to good grain hays (about 2.3 Mcal/kg). Can
replace part of the roughage portion of the ration, up to 15% of total
ration in horses (more than that unpalatable), up to 50-60% of thetotal
ration for ruminants.  However, feeding more than 2 kg/day todairy cattle
produces off flavor in milk.

Dried bakery waste - leftover stale cakes, breads, candies, nuts, etc9-12%
CP, 10-15% fat, , very low in fiber.  Energy varies accordingto content,
but very high in energy (3.9 Mcals/kg) because refined and high insimple
sugars and fats.  When available, energy feed of choice for starterpigs and
dairy cattle.

Myths about feeding beet pulp:
1) You shouldn't feed beet pulp because it's too high in sugars. Nope.  All
the sugar has been removed in processing.  The carbohydrates inbeet pulp
are soluble fibers, such as pectin.
2) It causes choke if it's fed dry.  Beet pulp has been fed dryas 45% of
the total ration during research feeding trials with no problems ofchoking.
Horses that choke on beet pulp pellets are usually horses that bolttheir
food, so choke is function of the speed of eating, not what they'reeating.
3) Dry beet pulp will swell up in the stomach and cause gastric rupture.
Rate of gastric emptying is a function of the amount of strain on stretch
receptors in the stomach walls, so beet pulp swelling in the stomachwill
move out of the stomach and into the gut long before rupture wouldoccur,
except in animals with an impaction or other pathology which physically
blocks peristalsis.
4) Dry beet pulp will suck all the water out of a horses system andcause
dehydration.  Horses will consume 3 kgs of water for each 1 kgof dry matter
consumed, so little or no fluid is absorbed from the gut.  Therehas never
been a reported case of impaction or digestive problem caused by feedingdry
beet pulp.

What soaking beet pulp does do:
1) increases palatability
2) Provides ideal medium for adding other supplements, fats, grain,
medicine, etc
3) Ideal for geriatrics because easy to eat without teeth, easy todigest,
good partial replacement for hay
4) Ideal for horses prone to founder because maintains weight withoutrisk
of endotoxicosis

What's endotoxicosis/enterotoxemia?
Let's say you have microbial population in the cecum.  Bug A isa
Lactobacillus spp of some sort that tolerates pH between 4.5 - 7.5. Bug B
is Clostridium spp that tolerates pH ranges between 6 -7.5.

You feed a horse a large amount of starch at a single meal.  Usuallystarch
is digested and absorbed in the SI, but too much overflows and undigested
starch bypasses the SI and goes into the cecum.

Different types of bugs prefer different types of substrate—some reallylike
only cellulose, others like cellulose but really, really like starch,ie
Lactobacillus spp.  All this starch drops into the cecum, theLactobacillus
spp go nuts and with all this food, start multiplying like crazy. As they
digest the starch, they secrete VFAs, including primarily lactic acid(hence
Lactobacillus).  As they multiply, more and more lactic acid issecreted and
pH in cecum begins to drop significantly, and other species of bugsbegin to
die off, secrete endotoxins.  Endotoxins are absorbed throughthe intestinal
wall and cause laminitis in horses, overeating disease in lambs.