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!
 
 

Supplemental Protein Sources

Protein is the most expensive nutrient to supply, and also the nutrientmost
likely to be deficient in production livestock rations.  In equinerations,
expense is not considered a factor and most rations are excessive inprotein
and deficient in energy.

Protein requirements are different for different species.  Forexample,
monogastric species and young ruminants require sufficient essentialamino
acids.  Mature ruminants can manufacture their own essential aminoacids,
but require a sufficient supply of digestible amino acids or nitrogen,such
as ammonia or urea.

Other food sources (roughage, energy, etc) supply some protein, but
generally not enough to meet animal's requirements for anything otherthan
mature maintenance, therefore additional supplementation must be suppliedin
ration.

Mature horses generally do NOT require protein supplementation—eventhough
protein requirements increase slightly during reproduction, lactationor
work, needs are met through increase in feed consumption, not throughan
increase in nutrient density in diet.  The only class of productionin which
protein supplements are sometimes required is during the first 18-24months
of growth, after that should be fed at mature protein levels (8-10%).

When selecting a protein sources, considerations are going to be
availability, cost, digestibility, amino acid content, content of other
nutrients (ie, P) and presence of undesirable compounds (toxins or
anti-nutritive factors).

Protein supplements can be derived from four major categories:
1) plant sources, such as soybean or cottonseed meal
2) animal sources, ie meat meal, milk by-products and fish meal
3) miscellaneous sources, ie algae, yeasts, and poultry waste
4) nonprotein nitrogen, urea, ammonia and amines

Of plant-derived proteins, soybean meal represents 64% of world tonnage
production; followed by canola meal, cottonseed meal, sunflower, peanutand
copra.  All of these are collectively known as oilseed meals. Can either be
fed whole, more commonly fed as a by-product after oils have been removed.

Oilseed meals have crude protein contents between 40-50%, are highly
digestible, with moderate to good biological value (not as high a BVas
animal source proteins).  As a general rule, low in Ca, high inP.  Most
oilseed meals are low in cysteine and methionine and usually low inlysine
1.4-1.7%).  Exception is soybean meal, which is higher in lysine(3.4%) than
most animal sources except for fish meal (6.2%).

Other plant protein sources include legumes (peas and beans), some milling
by-products including germ meal or corn gluten meal, distillery/brewery
by-products.  These sources are lower in crude protein (between20-30% CP),
energy, digestibility and biological value; and higher in crude fiberthan
the oilseed meals. (But also lower in cost).

Soybeans are considered to be best plant protein source because highin
palatability, digestibility, high TDN (81%) and high in lysine. Cooked
soybeans have much higher feeding value than raw soybeans because of
presence of several anti-nutritive factors:
appetite-depressing factor
growth-depressing factor
four different antitrypsin factors (reduces protein digestibility)
goitrogenic factor
saponins - plant glycoside which form a soap-like stable foam in water

All of which are neutralized through heat treatment.

Canola meal - by-product of oil production.  Original plant wasrapeseed,
which contains high levels of goitrogenic compounds and glucosinolates.
Through genetic selection, levels of these compounds has been reducedso
that plant is categorized as a different species from rapeseed (nowtermed
canola).

Cottonseed meal - by-product of cotton fiber and cotton seed oil production.
CSM is palatable for ruminants (who will eat anything), less palatablefor
swine and poultry.  Contains gossypol, relatively toxic to monogastric
species, less toxic to ruminants unless at high levels.  Gossypolis present
either in free or bound form, free form is most toxic, but most iseasily
removable in processing.

Animal source protein supplements

Includes meat meal, meat and bone meal, tankage, blood meal, other assorted
packing house leftovers, dried poultry waste, milk products, fish meals,and
shrimp and crab meals.

Meat meals are usually standardized to contain between 45-55% CP, whichis
approximately 85% digestible.  The difference between meat mealsand tankage
is that tankage contains added dried blood.  Most meat meals are28-36% ash,
which makes them a significant source of minerals, primarily Ca, P,K, Mg
and Na

Packing house by-products such as liver meal, glandular meal, hydrolyzed
hair, feathers or leather meal are categorized as "miscellaneous mammalian
products", may contain 70-80% crude protein which, after being heatand
pressure treated, is well utilized by ruminants.  Dried poultrywaste
contains 28% crude protein, but because about two-thirds of the CPis in the
form of non-protein nitrogen (which cannot be utilized by non-ruminants),
poultry waste can only be fed to ruminant species.

Dried whole milk is a high quality protein, but is usually too expensivefor
use as animal feed, usually only used as a milk replacer; or in swine
starter rations or in pet food.

Fish meals contain 70-80% crude protein, have high TDN (75-80%), andhas
higher lysine content than any other protein source (animal or plant).
Meals generally have most of the fat content removed, especially forswine
and poultry rations, because flavor of oil is objectionable to animal
(reduces palatability) and also because the fats flavor meat.

Single cell protein sources include algae and yeast products. Cultivated
algae produces about 10 times the protein per acre as soybeans, sois an
important potential source of protein for both humans and animals. Contains
about 50% CP, but is low biological value, has a bitter taste whichlimits
its use and is difficult to harvest and process.

Yeasts are generally a by-product of breweries.  Can be eitherdead yeasts,
which are only a source of protein, or live yeasts, which may haveprobiotic
properties (help re-seed microbial populations in the rumen or cecum). Most
yeasts are 40% CP, with high BV, but high costs limit use.

Non-Protein Nitrogen - only available to ruminants with a functioningrumen
as a protein source.  Primary sources are urea or ammonium phosphateor
biuret.  Urea cannot be fed to ruminants being fed primarily onlow quality
forage, because does not provide sufficient carbohydrates.  Without
sufficient carbos in ration, the pH in the rumen rises, microorganisms
cannot process ammonia fast enough, excessive ammonia is absorbed through
the rumen wall and urea/ammonia toxicity results.

When sufficient carbohydrates are provided, 1/3 of the total N can be
provided in the form of NPN.

 Biuret is a condensation product of urea, provides alternativeNPN source
to urea.  More costly than urea but is less likely to cause toxicity.
Cannot be fed to lactating dairy cows because biuret shows up in milk.