U.S. patent application number 11/753226 was filed with the patent office on 2007-09-20 for animal feed and methods for reducing ammonia and phosphorus levels in manure.
Invention is credited to Edward Carroll III Hale.
Application Number | 20070218168 11/753226 |
Document ID | / |
Family ID | 34229427 |
Filed Date | 2007-09-20 |
United States Patent
Application |
20070218168 |
Kind Code |
A1 |
Hale; Edward Carroll III |
September 20, 2007 |
ANIMAL FEED AND METHODS FOR REDUCING AMMONIA AND PHOSPHORUS LEVELS
IN MANURE
Abstract
An animal feed is provided that employs a substantially
indigestible cation exchanger capable of binding ammonium cations
and an acidogenic substance to acidify an animal's manure and
thereby create ammonium cations that can be bound by the cation
exchanger. The animal feed reduces ammonia emissions from manure
produced by animals fed the animal feed compared to the emissions
obtained from manure when an acidogenic substance is fed alone and
compared to the emissions obtained from manure when a cation
exchange capacity material is fed alone. According to another
aspect of the present invention, a method of lowering ammonia
emissions from manure is provided. The present invention also
provides a method for reducing soluble phosphorus levels in manure
and a method for reducing total phosphorus levels in manure. In a
further aspect of the present invention, a method is provided that
yields manure that may be used alone or in concert with other
materials to act as a fertilizer having advantageous ecological
properties. Another aspect of the present invention provides a
method for reducing insect populations associated with manure.
Inventors: |
Hale; Edward Carroll III;
(Franklin, IN) |
Correspondence
Address: |
WOODARD, EMHARDT, MORIARTY, MCNETT & HENRY LLP
111 MONUMENT CIRCLE, SUITE 3700
INDIANAPOLIS
IN
46204-5137
US
|
Family ID: |
34229427 |
Appl. No.: |
11/753226 |
Filed: |
May 24, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10868070 |
Jun 15, 2004 |
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11753226 |
May 24, 2007 |
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60499988 |
Sep 4, 2003 |
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60541500 |
Feb 3, 2004 |
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60541622 |
Feb 4, 2004 |
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Current U.S.
Class: |
426/61 ;
426/271 |
Current CPC
Class: |
A23K 50/75 20160501;
Y02A 40/20 20180101; Y10S 426/807 20130101; A23K 50/10 20160501;
Y10S 426/805 20130101; Y02P 20/145 20151101; A23K 20/142 20160501;
A23K 20/26 20160501; A23K 20/28 20160501; C05C 3/00 20130101; C05D
9/00 20130101; C05F 3/00 20130101; Y02A 40/205 20180101; C05C 3/00
20130101; C05D 3/00 20130101; C05F 3/00 20130101; C05D 9/00
20130101; C05F 3/00 20130101; C05F 11/00 20130101 |
Class at
Publication: |
426/061 ;
426/271 |
International
Class: |
C12H 1/04 20060101
C12H001/04 |
Claims
1. An animal feed comprising: an acidogenic composition and a
cation exchanger, wherein said acidogenic composition is a
fermentable fiber, said fermentable fiber promotes the formation of
ammonium cations in waste material produced by an animal provided
said feed, and said ammonium cations bind to said cation
exchanger.
2. The animal feed of claim 1, wherein said fermentable fiber is
selected from the group consisting of cellulose, soybean hulls,
distiller's dried grains with solubles, distiller's dried grains
without solubles, wet distiller's grains with solubles, wet
distiller's grains without solubles, sugar beet pulp, wheat
middlings, and a combination thereof.
3. The animal feed of claim 1, wherein said cation exchanger
includes diatomaceous earth.
4. The animal feed of claim 3, wherein said diatomaceous earth is
Celite.RTM. diatomaceous earth.
5. An animal feed comprising: an acidogenic composition; a cation
exchanger: and a source of crude protein, wherein said acidogenic
composition promotes the formation of ammonium cations in waste
material produced by an animal provided said feed, said ammonium
cations bind to said cation exchanger, and said source of crude
protein contains a limiting amount of at least one amino acid.
6. The animal feed of claim 5, further including an amino acid
supplement having at least one amino acid selected from the group
consisting of lysine, methionine, threonine, and tryptophan.
7. The animal feed of claim 6, wherein said fermentable fiber is a
source of said amino acid selected.
8. The animal feed of claim 6, wherein said fermentable fiber is
selected from the group consisting of soybean hulls, distiller's
dried grains with solubles, distiller's dried grains without
solubles, wet distiller's grains with solubles, wet distiller's
grains without solubles, sugar beet pulp, wheat middlings, and a
combination thereof.
9. The animal feed of claim 6, wherein said cation exchanger
includes diatomaceous earth.
10. The animal feed of claim 9, wherein said diatomaceous earth is
Celite.RTM. diatomaceous earth.
11. A method for reducing the level of ammonia aerosol from manure
having a pH and containing ammonia, the method comprising the steps
of: providing an animal feed including, a cation exchanger capable
of binding ammonium cations, and an acidogenic composition wherein
said acidogenic composition is a fermentable fiber, and feeding
said animal said feed, wherein said feeding reduces said pH of said
manure produced by said animal and causes at least a portion of
said ammonia to protonate producing said ammonium cations.
12. The method of claim 11, wherein said cation exchanger retains
said ammonium cation binding capability after passage through a
digestive tract of said animal.
13. The method of claim 12, wherein said feeding includes feeding
said feed to said animal selected from the group consisting of a
pig, a sheep, a cow, a chicken, a duck, a turkey and a goose.
14. The method of claim 11, wherein said providing includes
providing said animal feed including a fermentable fiber selected
from the group consisting of cellulose, soybean hulls, distiller's
dried grains with solubles, distiller's dried grains without
solubles, wet distiller's grains with solubles, wet distiller's
grains without solubles, sugar beet pulp, wheat middlings, and a
combination thereof.
15. The method of claim 11, wherein said providing said animal feed
including said cation exchanger includes providing diatomaceous
earth.
16. The method of claim 15, wherein said providing said animal feed
including said cation exchanger includes providing Celite.RTM.
diatomaceous earth.
17. The method of claim 11, wherein said providing said animal feed
further includes providing a source of crude protein having a
level, wherein said crude protein is limiting in at least one amino
acid.
18. The method of claim 17, wherein said providing said animal feed
further includes providing said feed containing an amino acid
supplement, having at least one amino acid selected from the group
consisting of lysine, methionine, threonine, and tryptophan.
19. The method of claim 18, wherein said amino acid selected is
contained in said fermentable fiber included in said animal feed
and said fermentable fiber is selected from the group consisting of
soybean hulls, distiller's dried grains with solubles, distiller's
dried grains without solubles, wet distiller's grains with
solubles, wet distiller's grains without solubles, sugar beet pulp,
wheat middlings, and a combination thereof.
20. The method of claim 19, wherein said providing said animal feed
including said cation exchanger includes providing diatomaceous
earth.
21. The method of claim 20, wherein said providing said animal feed
including said cation exchanger includes providing Celite.RTM.
diatomaceous earth.
Description
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/868,070 filed Jun. 15, 2004, which claims
the benefit of U.S. patent application Ser. No. 60/499,988 filed on
Sep. 4, 2003, U.S. patent application Ser. No. 60/541,500 filed on
Feb. 3, 2004, and U.S. patent application Ser. No. 60/541,622 filed
on Feb. 4, 2004, all of which are hereby incorporated by
reference.
FIELD OF THE INVENTION
[0002] The invention relates generally to animal feeds and methods
of feeding animals that produce more environmentally benign waste
products.
BACKGROUND
[0003] The number one complaint filed with both state and federal
environmental agencies against animal producers involves odors.
What is true for animal producers in general is also true for
poultry producers. Controlling odors associated with poultry manure
is a continuing problem for poultry and egg producers. Aerosol
ammonia is one of the primary causes of nuisance odors associated
with confined animal feeding operations. Since aerosol ammonia
comprises a large portion of the odor associated with poultry
litter, measures to control odor at poultry operations should
incorporate strategies to reduce ammonia volatilization. In
addition to ammonia's role as a component in nuisance odors, high
levels of gaseous ammonia adversely affects animal health and the
safety of people working in these environments.
[0004] Aerosol ammonia levels in hen houses with shallow pits and
monthly manure removal have been measured to be in the range of 46
parts per million (ppm). Similarly, the levels of aerosol ammonia
in hen houses with deep pits (manure-drying pits where manure is
removed annually) have been measured to be in the 46 ppm range.
Gaseous ammonia levels are especially high in winter, when hen
house ventilation is restricted to conserve heat. During cold
weather, gaseous ammonia levels in hen houses often exceed the 46
ppm range.
[0005] Poultry, for example, chickens and turkeys, continuously
exposed to 20 (ppm) ammonia vapors exhibit significant respiratory
tract damage after only six weeks. Chicks exposed to 20 ppm ammonia
for 72 hours are much more susceptible to Newcastle Disease than
chicks reared in ammonia-free environments. A high level of ammonia
in the environment of laying chicken hens is also known to reduce
egg production. For a more thorough discussion of the effect of
high levels of gaseous ammonia on animal health and production, the
reader is directed to the following articles that are incorporated
by reference herein in their entirety. See: Avian Dis. 8:369-379,
1964; Deaton et al. Poultry Sci., 63:384-385, 1984; McQuitty et al.
Canadian Agricultural Engineering 27:13-19; Strombaugh et al. J.
Anim. Sci. 28:844, 1969. Similarly, high ammonia levels correlate
with a reduction in the amount of animal feed converted to animal
body mass and reduced weight gain in hogs.
[0006] In addition to ammonia's adverse effects on animal health,
exposure to high levels of aerosol ammonia also adversely impacts
human health. For example, exposure to aerosol ammonia
concentrations in the range of 25 parts per million (ppm) produces
discomfort in workers, and even brief exposures (<5 minutes) to
ammonia can cause nasal irritation and dryness. In recognition of
the ill effects of aerosol ammonia on human health, both the
National Institute for Occupational Safety and Health (NIOSH) and
the Occupational Safety and Health Administration (OSHA) identify
ammonia as a health hazard. Currently NIOSH rules set the
permissible exposure level (PEL) for ammonia over an 8-hour period
at 25 ppm. OSHA rules set a PEL, over an 8-hour period, at 50 ppm.
OSHA also recognizes that an aerosol ammonia concentration of 300
ppm ammonia is immediately dangerous to life or health (IDLH). 29
C.F.R. 1910.120 (2003) defines IDLH as "[a]n atmospheric
concentration of any toxic, corrosive or asphyxiant substance that
poses an immediate threat to life or would cause irreversible or
delayed adverse health effects or would interfere with an
individual's ability to escape from a dangerous atmosphere."
[0007] In addition to the problems associated with aerosol ammonia
in animal manure, manure often times comprises high concentrations
of water-soluble forms of phosphorus. High concentrations of
phosphorus can cause environmental problems, especially if the
phosphorus finds its way into surface water sources or shallow
aquifers. Manures from monogastric animals such as hogs and poultry
are especially high in phosphorus due to the inability of
monogastric animals to digest phytic acid, a phosphorus-rich
compound commonly found in animal feeds. The presence of high
levels of soluble phosphates in manure is especially problematic
when manure is disposed of by spreading it over fields or when
feedlots are located near watersheds or above shallow aquifers.
Examples of environmental damage caused by manures high in soluble
phosphates include fish kills and bacterial or algal blooms
exacerbated by the introduction of phosphates from manure into
surface waters.
[0008] While plants require phosphorus in order to grow, excess
levels of phosphorus can stunt plant growth and in some cases cause
plant death. This is especially problematic, as one common means of
disposing of manure is to use it to fertilize plants. Accordingly,
phosphorus must be provided to plants in amounts conducive to and
not detrimental to plant growth and development. When phosphates
are provided to plants in amounts that exceed the plants' ability
to absorb these compounds, excess phosphates accumulate in the soil
or find their way into the watershed.
[0009] One widely used measure of fertilizer efficacy is the
fertilizer's Nitrogen to Phosphate ratio (N:P ratio). For most
plants, a N:P ratio in the 5.8:1 range is acceptable. When the N:P
ratio is substantially lower than 5.8:1, a compound may provide
more phosphate than plants can readily absorb while providing less
nitrogen than the plants require for optimal growth. Off-gassing of
ammonia lowers the nitrogen content in manure, thereby decreasing
the nitrogen/phosphorus ratio in the manure. Especially if manure
is already high in phosphorus, as ammonia is off-gassed the N:P
ratio may become so low that the manure must undergo costly
processing before it can be used as a fertilizer.
[0010] Clearly then, there is a need for methods to produce a
manure that exhibits low levels of gaseous ammonia and has a N:P
ratio in a range suitable for its ready use as a fertilizer.
SUMMARY OF THE INVENTION
[0011] One embodiment of the invention is an animal feed ration
that helps to reduce the level of volatile ammonia in manure
produced by an animal fed the ration. One embodiment comprises a
cation exchanger capable of binding ammonium cations and an
acidogenic compound, wherein the acidogenic compound lowers the pH
of the manure produced by an animal fed the animal feed such that
ammonia in the manure is protonated to produce ammonium cations. A
variation of this embodiment includes a level of crude protein
reduced relative to a conventional feed. In one variation of this
embodiment, the reduced crude protein feed is supplemented with at
least one at least partially purified amino acid.
[0012] Another embodiment is a method of reducing the level of
ammonia aerosol from manure, comprising the steps of providing an
animal feed including a cation exchanger capable of binding
ammonium cations and an acidogenic compound and feeding the animal
feed to an animal. The acidogenic compound is present in one
variation of this embodiment such that the initial pH of the
animals' excreta is reduced to a pH of .ltoreq.9.3. In another
variation of this embodiment, the pH is reduced to <7.
[0013] Still another embodiment is a method of producing manure
comprising the steps of providing a feed ration including a cation
exchanger capable of binding ammonium cations and an acidogenic
compound capable of reducing the pH of the manure and feeding the
feed ration to an animal. At least a portion of the ammonia in
manure produced by animals fed these rations is protonated to form
ammonium cations that bind to the cation exchanger.
[0014] Another embodiment is a fertilizer comprising manure
produced by an animal fed a ration including a cation exchanger
capable of binding ammonium cations and an acidogenic compound that
reduces the pH of the manure.
[0015] Another embodiment is a method for controlling the number of
insects associated with manure. The method comprises the steps of
providing a feed ration including a cation exchanger capable of
binding ammonium cations and an acidogenic compound capable of
reducing the initial pH of the manure produced by an animal fed the
feed ration and feeding the feed ration to an animal. At least a
portion of the ammonia in the manure is protonated to form ammonium
cations that bind to the cation exchanger.
[0016] Another embodiment comprises an animal feed including a
cation exchanger capable of binding ammonium cations and an
acidogenic compound, wherein the acidogenic compound lowers the pH
of the manure produced by an animal fed the animal feed such that
ammonia in the manure is protonated to produce ammonium cations. In
this embodiment, the manure has a substantially lower level of
aerosol ammonia than manure produced by an animal fed a
conventional industry standard diet.
[0017] A further embodiment of the present invention comprises a
method of reducing the level of ammonia aerosol from manure. The
method comprises the steps of providing an animal feed including a
cation exchanger capable of binding ammonium cations and an
acidogenic compound capable of reducing the pH of manure produced
by an animal fed the animal feed and feeding the animal feed to an
animal. At least a portion of the ammonia in the manure is
protonated to form ammonium cations that bind to the cation
exchanger. In this embodiment, the animal feed reduces the pH of
the manure produced by the animal fed the animal feed compared to a
pH expected from a manure produced by the animal when it is fed a
conventional industry standard animal feed. The animal feed in this
embodiment also increases the amount of ammonium cations protonated
from the ammonia in the manure produced by the animal fed the
animal feed compared to an amount of ammonium cations protonated
from ammonia in a manure produced by the animal when it is fed a
conventional industry standard diet.
[0018] Yet another embodiment is a method for reducing the level of
soluble phosphorus in manure comprising the steps of providing an
animal feed including a cation exchanger capable of binding
ammonium cations, an exchangeable phosphate reactive metal
associated with the cation exchanger, and an acidogenic compound
and feeding the animal feed to an animal. The animal manure
produced by this method has lower levels of soluble phosphorus than
manure produced by the animal fed the conventional
industry-standard animal feed. In still another embodiment, the
phosphate reducing feed further includes compounds that reduce the
amount of phosphate in the manure. Compounds such as phytase reduce
the amount of phosphate in the manure by making more phosphate
bioavailable for incorporation into animal tissue and products.
[0019] Another embodiment is a fertilizer comprising manure
produced by an animal fed a ration including a cation exchanger
capable of binding ammonium cations and an acidogenic compound. The
acidogenic compound is present in the ration such that at least a
portion of the ammonia in the manure is protonated to form ammonium
cations. Fertilizer made from manure produced by the animal fed the
inventive ration has a more favorable (higher) N:P ratio than
similarly produced fertilizer made using manure produced by animals
fed a conventional industry standard diet.
[0020] Still another embodiment is a method for controlling the
number of insects associated with manure comprising the steps of
providing a feed ration including a cation exchanger capable of
binding ammonium cations and an acidogenic compound and feeding the
feed ration to an animal. The acidogenic compound reduces the pH of
manure produced by an animal fed the animal feed the ration such
that at least a portion of the ammonia in the manure is protonated
to produce ammonium cations. The manure produced by the animal fed
the feed ration reduces the number of insects associated with the
manure from a number of insects associated with a manure produced
by the animal fed a conventional industry-standard feed ration.
[0021] In still another embodiment, an animal ration is amended to
produce a first manure produced by an animal fed said amended
animal ration, said first manure having a high N:P ratio relative
to a second manure produced by said animal fed a conventional
industry standard diet. The inventive amended animal ration
includes means for lowering a total amount of crude protein in the
amended animal ration relative to a total amount of crude protein
contained in the conventional industry standard diet; means for
lowering a volatile ammonia content of the first manure relative to
a volatile ammonia content of the second manure; means for
increasing an amount of bio-available phosphorus in the amended
animal ration relative to an amount of bio-available phosphorus
contained in the conventional industry standard diet; and means for
reducing a total amount of phosphorus in the amended animal ration
relative to a total amount of phosphorus contained in the
conventional industry standard diet.
BRIEF DESCRIPTION OF THE FIGURES
[0022] FIG. 1 is a graph of ammonia emissions measured from hen
manure samples. These data were collected over a 7-day period and
are reported in units of parts per million (ppm). Briefly, manure
samples were taken from chicken hens fed one of the following three
feed rations: a.) a control feed ration identical to an industry
standard feed, wherein the control ration included 18.8% crude
protein by weight and 4.2% calcium by weight; b.) a feed ration
similar to the control feed ration but supplemented with calcium
sulfate (gypsum) such that gypsum provided 45% of the calcium in
the feed; and c.) a feed ration similar to the control feed ration
supplemented with 2% by weight zeolite.
[0023] FIG. 2 is a graph of ammonia emissions from chicken hen
manure measured over a 7-day period. The ammonia emissions are
reported in units of parts per million (ppm) ammonia. Briefly,
manure samples were collected from hens fed one of the following
three feed rations: a.) a control ration including 18.8% crude
protein by weight and 4.2% calcium by weight; b.) a feed ration
similar to the control feed ration supplemented with about 2% by
weight zeolite and gypsum, the amount of gypsum added to the ration
was sufficient to provide about 45% of the calcium in the ration;
and c.) a feed ration similar to the control ration but having only
15.0% by weight crude protein. This ration was supplemented with
lysine such that lysine comprised 0.98% by weight of the feed, the
ration also included, 2% by weight zeolite, and gypsum. The amount
of gypsum added to trial c was sufficient to provide about 45% of
the calcium in the feed.
[0024] FIG. 3 is a graph of ammonia emissions in parts per million
(ppm), measured over a 7-day period, from chicken hens fed a) a
control diet of feed containing 18.8% crude protein by weight and
4.2% calcium by weight; b) the control diet supplemented with
gypsum, which was added in an amount sufficient that the gypsum was
the source of 45% of the dietary calcium; c) the control diet
supplemented with zeolite, when zeolite comprised 2% by weight of
the feed; d) the control diet supplemented with gypsum and zeolite
when gypsum was the source of 45% of the dietary calcium and
zeolite comprised about 2% by weight of the feed; and e) a reduced
(relative to the control diet) crude protein diet wherein the
calcium content remained at 4.2% by weight, and crude protein
comprised 15.0% by weight of the feed. Additional lysine was added
to the ration used in 5 e such that lysine comprised 0.98% by
weight of the feed. The feed used in FIG. 5 e also included gypsum
and zeolite. Gypsum was the source of about 45% of the dietary
calcium in the feed, and zeolite comprised about 2% by weight of
the feed.
[0025] FIG. 4 is a graph of ammonia emissions in parts per million
(ppm), measured over a 7-day period, from chicken hens fed a) a
control diet of feed when crude protein comprised 14.8% by weight
of the feed and calcium comprised 4.2% by weight of the feed; b) a
diet when crude protein comprised 15.3% by weight of the feed,
calcium comprised 4.2% by weight of the feed, gypsum was the source
of 25% of the dietary calcium, and zeolite comprised 1.25% by
weight of the feed; c) a diet comprising a reduced (relative to the
control diet) amount of crude protein when crude protein comprised
14.3% by weight of the feed, with additional lysine added so that
lysine comprised 0.84% by weight of the feed, calcium comprised
4.2% by weight of the feed, gypsum was the source of 35% of the
dietary calcium, and zeolite comprised 1.25% by weight of the
feed.
[0026] FIG. 5 is a graph of fly card data collected in hen houses
plotted as a function of weeks on which egg laying hens were fed
either standard or amended rations. These data illustrate a
significant reduction in the number of flies associated with hens
fed amended rations comprising zeolite and an acidogenic compound
versus hens fed the industry standard (control) rations. The
reduction in flies was first observed during week 4 of the study
and continued through the end of the study (week sixteen).
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] For the purposes of promoting an understanding of the
principles of the invention, reference will now be made to the
preferred embodiments thereof, and specific language will be used
to describe the same. It will nevertheless be understood that no
limitation of the scope of the invention is thereby intended, such
alterations, modifications, and further applications of the
principles of the invention being contemplated as would normally
occur to one skilled in the art to which the invention relates.
[0028] A number of explanations and experiments are provided by way
of explanation and not limitation. No theory of how the invention
operates is to be considered limiting whether proffered by virtue
of description, comparison, or example.
[0029] In most cases, the preponderance of nitrogen present in
excreta is in the form of urea. Urea present in the urine is a
source of the large amount of gaseous ammonia emitted shortly after
excretion. Urea in manure is converted to ammonia by urease, an
enzyme present in excreta that hydrolyzes urea into ammonia. A set
of chemical equations detailing the conversion of urea to ammonia
is as follows:
CO(NH.sub.2).sub.2+2H.sub.2O.fwdarw.+2NH.sub.4.sup.++CO.sub.3.sup.2-
(1) CO.sub.3.sup.2-+H.sub.2O.fwdarw.HCO.sub.3.sup.-+OH.sup.-
NH.sub.4.sup.++OH.sup.-.fwdarw.NH.sub.3.uparw.+H.sub.2O
[0030] As indicated previously, the enzyme urease catalyzes
reaction (1). Under acidic conditions, ammonia is readily
protonated to form ammonium cations, a less volatile positively
charged molecule. Ammonium has a pK.sub.a of about 9.34. Once the
pH of the manure becomes high enough, free ammonium will
deprotonate to form ammonia, which is more likely to off-gas than
is the ammonium cation. Low pH favors ammonium formation, so the
presence of acidogenic compounds in manure favors the conversion of
ammonia to ammonium. However, as illustrated by the above set of
chemical equations, the pH of manure tends to increase over time as
urea and other nitrogen containing compounds are converted into
ammonia and hydroxyl ions (OH-) are released. The release of
hydroxyl anions tends to increase the pH of the manure.
[0031] Those of skill in the art will recognize that nitrogen
present in undigested amino acids in the manure may provide a
source of additional aerosol ammonia emissions. Additional volatile
ammonia can form in manure as proteins, amino acids, and other
nitrogen-bearing molecules in manure are broken down by either
microbial or chemical action. In general, degradation of non-urea
nitrogen sources, such as amino acids found in proteins, does not
generate large amounts of ammonia at any given time; instead, such
degradation facilitates a slow, gradual release of nitrogen.
[0032] Reducing the pH of manure can reduce ammonia volatilization,
regardless of its immediate source from manure. Ammonium is a weak
acid with a pK.sub.a of about 9.34. It behaves more like an alkali
earth metal than does ammonia. The pH of manure can be reduced by
adding acidogenic compounds to an animal's feed rations. In one
embodiment of the invention, acidogenic compounds are compounds
that are converted into pH-reducing compounds in an animal's
digestive tract. When the pH of manure falls to below the pK.sub.a,
the equilibrium between uncharged volatile ammonia (NH.sub.3) and
the less volatile cationic form ammonium (NH.sub.4.sup.+) shifts in
favor of the production of ammonium cations.
[0033] Some acidogenic compounds not only lower the pH of manure
they react with ammonium cations to form stable compounds that are
not readily converted back to ammonia even as the pH of the milieu
increases. Acidogenic compounds that react with ammonium cations to
form stable compounds include, but are not limited to, aluminum
sulfate (alum), sulfuric acid, and sodium bisulfite. The formation
of compounds such as ammonium sulfate reduces the concentration of
free ammonium cations in the manure, thereby further shifting the
equilibrium between ammonium and ammonia toward the formation of
ammonium.
[0034] As used herein, the term manure refers to all forms of
animal excreta including feces, urine, and uric acid as well as
excreta mixed with binders, fillers, absorbents, and the like.
Examples of such absorbents include but are not limited to straw,
hay, processed paper products, fertilizer components, and the
like.
[0035] As used herein, the term urine refers to all forms of
nitrogen-rich waste processed by the kidneys of an animal. Manure
includes, for example, liquids produced by animals such as pig,
sheep, cows, etc.; and semi-solid forms as are commonly produced by
fowl, including, for example, chickens, ducks, geese, and the
like.
[0036] As used herein, an acidogenic compound is a compound that
can be added to an animal's feed to reduce at least transiently the
pH of the animal's manure. One group of acidogenic compounds
includes compounds that are digested by an animal to form products
that reduce the pH of manure produced by the animal. Still another
group of acidogenic compounds substantially survives digestion, and
they themselves can be found in the animal's manure acting to
reduce the pH of manure. Either type or a combination of both types
of acidogenic compounds can be used to practice the invention.
[0037] As used herein, the ratio of Nitrogen to Phosphorus may be
expressed as either N:P or N/P. Also, as used herein, the term
"conventional industry standard diet" and the term "industry
standard feed" have substantially similar meanings. These terms
refer to animal feeds that generally do not include appreciable
amounts of acidogenic compounds or cation exchange materials that
are excreted and find their way into manure produced by the
animals. Acidogenic compounds and cation exchangers may be added to
animal feed in order to reduce the level of ammonia emitted from
manure produced by animals fed such diets.
[0038] For example, one such conventional industry standard diet is
the one recommend by HY-LINE International for W-36 egg producing
hens. For a further discussion of this conventional industry
standard diet, the reader is directed to "Hy-Line Variety
Commercial Management Guide 2003-2004" published by Hy-Line
International, West Des Moines, Iowa, U. S. A. and available online
at www.hyline.com, which document is incorporated herein by
reference in its entirety. Those of ordinary skill in the art will
recognize that the conventional industry standard diet varies from
species to species, and even within a given species may vary
depending upon factors such as variety, age, health, and the
utility of the animal.
[0039] The reduction in manure pH achieved by supplementing an
animal's feed with an acidogenic compound is temporary, generally
lasting only between one and three days. Lysine, cellulose, benzoic
acid or salts of benzoic acid, or ammonium salts of carboxylic
acids are all examples of acidogenic substances. Additional
examples of acidogenic compounds that may be added, with varying
degrees of success, to animal feed to reduce the pH of manure
include salts of mineral acids, such as alkaline earth metal salts
of mineral acids. Examples of the latter group of acidogenic
substances include, for example, calcium chloride and calcium
sulfate (gypsum).
[0040] Additionally, certain materials, when added to manure, may
inhibit the activity of the enzyme uricase. Uricase acts in concert
with other enzymes to convert uric acid in poultry manure to urea.
Urea is then converted into ammonia by the enzyme urease. The
optimal pH for uricase activity is generally around 9.2 SU. Uricase
activity drops off below pH 7 SU and above 10 SU. Reducing the pH
of manure below 7 inhibits uricase activity and decreases the
amount of ammonia associated with the manure.
[0041] Compounds containing zinc, copper, manganese, and magnesium
are known to have an inhibitory effect on uricase activity. These
metals inhibit uricase activity irrespective of pH. These effect
inhibitory effects of low pH and specific metals may be combined by
feeding animals mineral acids made from metals that inhibit uricase
activity. However, directly feeding animals high levels of salts of
such metals may have a detrimental effect on animal health. For
this reason, these compounds are often fed as an electrolyte, or as
an acidogenic substance fed in concert with other less toxic
acidogenic substances.
[0042] It may be advantageous to add acidogenic compounds to animal
feeds that provide more than just a reduction in pH or the capacity
to form stable compounds with ammonia or ammonium cations. For
example, acidogenic compounds such as calcium sulfate and calcium
chloride provide the animal with a source of calcium and an anion
(either sulfate or chloride) and also provide anions that react
with ammonium cations to form stable nitrogen rich complexes. The
amino acid lysine is another example of a compound that can have an
advantageous impact on both animal health and ammonia reduction. If
an animal is fed lysine including a counter-anion, when the lysine
is metabolized the counter anion may survive the digestion process
and combine with ammonium cations in the manure.
[0043] As mentioned earlier, a portion of the ammonia found in
manure comes from the breakdown of amino acids in the manure. The
major source of amino acids in animal manure is undigested or only
partially digested proteins and peptides originally found in the
animal's feed. "Crude protein" is a general term used to describe
proteins comprising a wide range of amino acids added to or at
least found in animal feeds. In part because animals have the
capacity to biosynthesize some amino acids but not others, an
animal feed may be deficient in some amino acids but harbor an
excess of other amino acids.
[0044] Most animals require minimum amounts of specific amino acids
in their diets in order to thrive. Amino acids that must be
provided to an animal in its diet include amino acids that the
animal cannot biosynthesize. These amino acids are referred to as
essential amino acids. Similarly, some animals will grow more
efficiently if they are provided a diet rich in certain amino acids
than if they are fed a diet having sub-optimal amounts of these
amino acids. Limiting amino acids are amino acids present in an
animal feed at such low levels that they limit the productivity of
the animal fed that diet. In part because of the unequal
distribution of amino acids in various crude protein sources, a
crude protein source may have an excess of some amino acids while
being deficient in other amino acids.
[0045] The list of essential amino acids and amino acids that are
difficult to biosynthesize varies from species to species but often
includes, for example, lysine, methionine, threonine, and
tryptophan. These are also primary amino acids that often act as
limiting factors on the metabolism of a laying hen.
[0046] When excess amino acids are excreted, they break down and
contribute to the amount of volatile ammonia in the excrement.
Given that proteins in manure contribute to the amount of ammonia
produced by the manure, reducing the levels of crude protein fed to
an animal can help to reduce the amount of volatile ammonia in an
animal's manure.
[0047] It is one aspect of the invention to reduce the level of
volatile ammonia in manure by reducing the amount of crude protein
in an animal's feed rations. While this approach clearly helps to
reduce the amount of ammonia in an animal's manure, care must be
taken with this approach as imbalances in amino acid content are
magnified when crude protein levels are reduced. In order to
simultaneously reduce the level of excess amino acids in an
animal's feed while at the same time providing an optimal level of
all amino acids, animal feed can be supplemented with specific,
otherwise limiting, amino acids. By significantly reducing total
crude protein levels and adding back a required amount of one or
all of these limiting amino acids, it is possible to reduce the
total amount of amino acids excreted by hens without reducing the
hen's metabolism. Fewer excreted amino acids result in less
nitrogen (and less ammonia) in the manure.
[0048] In still another aspect of the invention, volatile ammonia
levels in manure are reduced by adding compounds to an animal's
feed ration that are converted to cationic compounds which react
with ammonium cations to form stable compounds. Compounds that can
react with ammonium cations to form stable compounds include but
are not limited to sulfate. Sulfate anions readily react with
ammonium cations to form ammonium sulfate. Ammonium sulfate is
stable at alkaline pH. Accordingly, nitrogen sequestered in the
form of ammonium sulfate is not free to form volatile ammonia even
as the pH of the manure drifts upwards.
[0049] One particularly good source of sulfate ions for the
practice of the invention is gypsum (calcium sulfate). Gypsum is
inexpensive, and in addition to providing a source of sulfate ions
for the control of ammonia levels in manure, it provides the animal
with a required element, calcium.
[0050] Simply feeding an animal a ration rich in gypsum may not be
enough to significantly reduce the amount of volatile ammonia in
the animal's manure. Referring now to Table 1 and FIGS. 1 and 3,
the amount of ammonia off-gassed from manure produced by an animal
fed rations supplemented with gypsum only increased 24 hours after
the manure was produced relative to the ammonia off-gassed from
manure produced by an animal fed a control ration. Over the period
of one week, the levels of ammonia emitted from manures produced by
hens fed rations supplemented with gypsum were only 15% lower than
the levels of ammonia emitted from manures produced by hens fed
control rations.
[0051] In another aspect of the invention, an animal is fed a
ration comprising compounds that effectively bind ammonium cations.
One particularly attractive method is to feed the animal a cation
exchanger that substantially retains its affinity for cations even
after it has passed through the animal's digestive tract. Materials
with a high cation affinity include compounds with a high cation
exchange capacity. One class of compounds with high cation exchange
capacities that are particularly useful for the practice of the
invention is the class of zeolites. Zeolites have a high capacity
to bind cations such as ammonium ions, and zeolites generally can
pass through the gut of most animals with their affinity for
cations substantially unchanged.
[0052] Referring still to Table 1 and FIGS. 1 and 3, merely feeding
an animal rations supplemented with zeolite alone does not
significantly reduce the level of ammonia off-gassed from manure
produced by the animal. One plausible explanation for these data,
presented by way of illustration and not limitation, is that the
manure produced by hens fed a diet supplemented with zeolite, but
not an acidogenic compound, is alkaline. Highly alkaline conditions
favor the formation of ammonia, and ammonia does not effectively
bind to zeolite.
[0053] It is one aspect of the invention to feed animals a ration
comprising both one or more cation exchangers such as zeolite and
one or more acidogenic compounds. Acidogenic compounds in the
animal's manure will reduce the pH of the manure, thereby promoting
the protonation of ammonia to form ammonium, which can then bind to
zeolite.
[0054] Referring again to Table 1 and FIGS. 2 and 3, hens fed
rations comprising both gypsum and zeolite produced manure that
off-gassed substantially less ammonia than manure produced by hens
fed rations formulated with neither zeolite or gypsum (or with only
one of these compounds). Again by way of explanation and not
limitation, it is likely that the sulfate in the manure (from
gypsum) reduced the pH of the manure and reacted with some of the
ammonia to form ammonium sulfate. At the same time, ammonium
cations that did not react with the sulfate anions bound to zeolite
in the manure. Ammonium cations bound to zeolite are not readily
deprotonated even at alkaline pH, and therefore the overall level
of ammonia off-gassed decreased over the 1-week period for which
data was collected.
[0055] In yet another aspect of the invention, the level of
volatile ammonia in animal manure is reduced by feeding an animal a
ration comprising reduced levels of crude protein and supplements
of zeolite and calcium sulfate (gypsum). Referring still to Table 1
and FIGS. 2 and 3, the amount of volatile ammonia from hen manure
was further reduced by reducing the amount of crude protein in the
animals' rations. Manures with the lowest level of ammonia were
those produced by hens fed reduced crude protein diets wherein the
feed was supplemented with both zeolite and gypsum.
[0056] Poultry excrement is rich in uric acid. Accordingly, poultry
manure is essentially a semi-solid. In other animals, for example,
hogs, the animal's excrement is comprised of a semi-solid (feces)
and a liquid (urine). If an animal's excrement contains urine in a
liquid form, then it can be physically separated from the animal's
feces.
[0057] Sequestering of liquid urine and semi-solid feces is most
readily accomplished when the animals are housed in a controlled
environment. Because a large percentage of the urea is found in
liquid urine, it is advantageous to collect the urine separate from
the remainder of the animal's excreta. When practical, separating
urine from feces helps to control the release of ammonia from the
manure. However, even when manure and feces are separated,
degradation of nitrogen rich compounds in the feces may still
result in the release of ammonia.
[0058] Yet another aspect of the present invention provides a
method for lowering the amount of ammonia off-gassed from animal
excrement separated into liquid and semi-solid components.
Physically separating feces and urine decreases the rate at which
ammonia is formed and off-gassed from the feces. Absent the
hydroxyl ions formed primarily by the urea-/urease-catalyzed
reaction in the urine, the pH of feces does not rise as quickly as
when urine is present. The tendency toward a lower pH helps to
reduce the rate of ammonia production. When compounds that reduce
the pH of the animal's feces are present, the rate of ammonia
production is further reduced. Ammonia off-gassing from feces
separated from liquid urine is reduced still further when zeolite
or some other ammonium binding cation is present in the manure.
[0059] When it is impractical to separate an animal's feces and
urine, as is the case with poultry, the pH of the mixed manure can
be reduced by the addition of acidogenic compounds to the animal's
diet. One or more acidogenic compounds in the animal's feed ration
is capable of lowering the overall pH of the animal's manure,
thereby increasing the concentration of ammonium relative to
ammonia in the manure. A feed comprising both an acidogenic
compound and a cation exchanger, such as zeolite, further reduces
the level of ammonia off-gassed as zeolite forms stable complexes
with ammonium cations. However, the pH of most manures rises over
time, thereby favoring the production of ammonia. Because the pH of
manure tends to increase over time, one aspect of the invention is
to add one or more acidogenic compounds and zeolite to the animal's
feed ration. Ammonium cations formed under low pH conditions are
then trapped by the zeolite before they can deprotonate to ammonia
as the pH increases.
[0060] Urease is most active in the pH range between 6.5 SU and 7.0
SU. Those of ordinary skill will recognize that ammonium ions form
when ammonia is protonated and that a low pH strongly favors this
reaction. Therefore, the presence of acidogenic compounds in an
animal's feed that helps to reduce the pH of the animal's manure
will reduce the amount of ammonia off-gassed from the animal's
manure.
[0061] If zeolite is present in manure at the same time ammonium
cations are formed, then the zeolite will bind the cations.
However, once the pH becomes alkaline, the equilibrium between
ammonium and ammonia will favor the formation of ammonia, which
does not bind to zeolite. The result of experiments summarized in
Table 1 and FIGS. 1 and 3 demonstrate that this is the case. There
is a marked increase in the rates of ammonia emitted from manures
formed by animals fed rations comprising zeolites but no acidogenic
compounds over the 24-48 hour period right after excretion.
[0062] One embodiment includes feeding fowl a feed comprising
calcium, protein, and phosphorus levels consistent with the
nutritional requirements of birds of that species, variety, and
age. In this embodiment, nutritionally available phosphorus levels
are supplemented by addition of phytase to the feed. Phytase
converts phytic acid, a source of phosphate that most birds cannot
metabolize, into a bio-available form of phosphate. By adding
phytase, the total amount of phosphate added to the feed can be
reduced.
[0063] If required, inorganic phosphate in the form of dicalcium
phosphate is added to the feed. For example, a feed ration may
contain about 0.1% available phosphorus. Additional phosphorus may
be present in the feed as phytic acid. The enzyme phytase can be
added to the feed to increase the amount of bioavailable phosphorus
by an additional 0.1%. The added dicalcium phosphate supplies the
balance of the phosphorus that the animals require without
significantly contributing to the amount of phosphate in the
animal's manure.
[0064] The total amount of crude protein in the feed can be reduced
compared to the level of crude protein found in industry standard
rations. For example, initial reductions in crude protein levels
preferably approached 4% in the amended diet compared to a standard
diet. Lowering total crude protein levels will result in lower
levels of protein in the manure and therefore microorganisms and
insects metabolize less ammonia into volatile ammonia released into
the atmosphere from protein in the manure. The actual amount of
purified amino acids that needs to be added back depends upon the
level of the limiting amino acids in the feed and the nutritional
requirements of the animals.
[0065] As the birds age, they require less protein and phosphorus.
Accordingly, the level of crude protein and phosphorus in the
bird's diets can be reduced as the animals age. Those of ordinary
skill in the art will recognize that this is a standard practice
for laying hens. Reduced crude protein levels in feed may follow
this trend as the bird ages as well, but dietary levels of limiting
amino acids must be met if bird health and performance are not to
suffer. In the event that proteins levels are reduced to the point
when an amino acid becomes limiting, purified forms of the limiting
amino acids are added back to crude protein-reduced feeds to insure
bird health and performance.
[0066] In one embodiment, gypsum is substituted for limestone as a
source of at least some of the calcium the animals require. Gypsum
contains a lower weight percentage of calcium than limestone, and
this factor is taken into account when supplementing feed with
gypsum to insure that the animals receive an adequate amount of
calcium. In one embodiment, the weight percentage of calcium
derived from gypsum is approximately 23%, and the weight percentage
of calcium derived from limestone is approximately 38%. In another
embodiment, gypsum accounts for 25% to 35% of the amount of
supplemental calcium added to the animal's feed.
[0067] In one embodiment, zeolite is added to the feed such that it
comprises between about 1.25% to about 2% by weight of the ration.
The zeolite used to supplement the feed can be a naturally
occurring clinoptilolite that contains significant levels of
exchangeable calcium and magnesium.
[0068] The ratios of gypsum substitution and zeolite addition may
be varied, as may the particle sizes of the gypsum and zeolite
materials chosen. It is well established that smaller particles
dissolve in the gut faster than larger particles. Laying hens
require a slow release of a sufficient level of dietary calcium in
order to make effective use of it during eggshell production. For
this reason, pulverized limestone (small particle size) is
considered a less effective dietary supplement than larger
limestone particles.
[0069] The gypsum and zeolite materials chosen for addition to the
rations may be varied from the more preferred materials taught
herein and still achieve the unexpected results of the invention.
By way of example, and not of limitation, gypsum comes in hydrous
and anhydrous forms and may be obtained in a variety of size
gradations.
[0070] It should also be noted that crude protein levels in the
instant feed ration may be varied. Feed so amended may require the
addition of various purified amino acids so that the ration will
include the minimum amount of any specific amino acids necessary
for animal health.
[0071] Zeolites come in many different types and size gradations,
and those chosen by the skilled practitioner for use in the present
invention may be naturally occurring or manmade and may be of any
usable size. Zeolites used in the invention may be pre-loaded with
certain usable cations or may have beneficial cations already
present. Use of any of a variety of acidogenic substances and types
of zeolite or other high cation exchange capacity materials may
also be of utility to the skilled artisan in achieving the
unexpected results of the present invention. One especially useful
form of zeolite is zeolite loaded with dissociateable phosphate
binding metal. Such phosphate binding metals include, but are not
limited to, magnesium and calcium.
[0072] Additionally, other animals besides hens may be fed suitable
rations according to the teachings of the present invention in
order to achieve the goals of the invention. Those of skill in the
art will recognize the dietary requirements of the other animal(s)
chosen, and modifying the preferred embodiments of the present
invention to suit such other animal(s) needs will not require undue
experimentation.
[0073] All animals require a bioavailable source of phosphorus;
therefore, all nutritionally complete animal feeds must include a
source of bioavailable phosphorus. However, if animals are fed a
diet too rich in phosphate, then they will excrete the excess
phosphorus or, more accurately, compounds comprising phosphorus
such as phosphates. Manure from animals fed excess phosphorus may
be a rich source of water-soluble phosphate. The disposal of animal
manure with a high soluble phosphate content can be problematic, as
soluble phosphates can contaminate both surface waters and
aquifers.
[0074] Given the potential for environmental damage presented by
manure high in soluble phosphate, reducing the phosphorus content
of manure may be of great environmental benefit. One way to reduce
soluble phosphates in manure is to add phosphorus-reactive metals
such as iron, calcium, magnesium, and aluminum, to the subject
animal's manure. One problem with this approach is that overfeeding
of some of these metals may be detrimental to animal health. For
example, ill effects of overfeeding iron, magnesium, and aluminum
are known.
[0075] One aspect of the invention provides a method of reducing
soluble phosphate levels in animal manure by feeding
phosphorus-reactive metals without compromising animal health.
Animals are fed a ration comprising zeolite that binds high levels
of phosphorus-reactive metals. The animal does not take up
phosphorus-reactive metals bound to zeolite until they are released
in exchange for another zeolite-binding cation. Feeding animals a
form of zeolite with a high natural level of phosphorus-reactive
metals (or is pre-loaded with such metals) has an unexpectedly
beneficial impact on the level of soluble phosphate in the animal's
manure. Zeolite binding phosphorus-reactive metals, that can
dissociate from the zeolite especially in exchange for other
cations, are an effective means of delivering phosphate reactive
metals to the manure. Other cations in the manure, for example,
ammonium cations, may displace the dissociatable phosphate reactive
metal, which then reacts with excess phosphorus to form an
insoluble complex.
[0076] Data summarized in Table 3 illustrate some of the beneficial
effects of feeding animals rations comprising zeolite-binding
phosphorus-reactive metals and gypsum. An animal fed a ration
comprising zeolite binding metals and gypsum produce manure with a
lower level of soluble phosphate than manures produced by an animal
fed industry standard (control) rations.
[0077] In one aspect, the invention provides animal rations capable
of reducing the total amount of phosphates in an animal's manure.
Many rations, especially rations rich in grains, contain phytic
acid. This compound is a major phosphorus storage source in plants.
Monogastric animals in particular have difficulty digesting phytic
acid. Adding phytase to a feed ration that includes phytic acid can
increase the amount of bioavailable phosphorus in the ration.
Phytase is an enzyme that catalyzes the hydrolysis of phytic acid
to inosital and phosphoric acid. As illustrated by the results
summarized in Table 3, feeding a monogastric animal a feed
comprising reduced levels of phosphate results in the production of
manure with lower levels of soluble phosphates.
[0078] Phosphoric acid is more readily absorbed by monogastric
animals than is phytic acid. Therefore, adding phytase to animal
feeds comprising phytic acid elevates the level of bioavailable
phosphorus in the feed. For a more complete discussion of phytase,
the reader is directed to U.S. Pat. No. 6,548,282, which patent is
incorporated by reference herein in its entirety.
Experiment
Experiment 1
[0079] In order to determine the efficacy of adding a high cation
exchange capacity material pre-loaded with phosphate-reactive
metals and acidogenic substances to animal feed rations, a test
flock of white leghorn hens (HyLine W-36) was prepared. The test
flock was subdivided into several units so that the effects of the
various feed strategies could be monitored and compared. One unit
acted as a control. This unit was fed a conventional industry
standard diet, which initially comprised 18.8% by weight of crude
protein, 4.2% by weight of calcium, and 0.5% by weight of
bioavailable phosphorus. The conventional industry standard diet
fed to the hens of this and the following examples as a control
ration was substantially similar to the diet rations described in
"Hy-Line Variety Commercial Management Guide 2003-2004" published
by Hy-Line International, West Des Moines, Iowa, U. S. A. and
available online at www.hyline.com.
[0080] A second unit was fed a ration of similar characteristics,
which differed from the control unit in that gypsum was partially
substituted for limestone such that 45% of the calcium supplement
for the diet was derived from gypsum. A third unit was fed a ration
substantially similar to the control ration, differing from the
control ration in that it comprised a naturally occurring
low-sodium clinoptilolite zeolite added such that it comprised 2%
by weight of the feed ration. The form of zeolite used in ration 3
comprised a significant level of exchangeable phosphate-reactive
calcium and magnesium. A fourth unit was fed a diet substantially
similar to the control diet, differing in that it comprised zeolite
in the amount of 2% by weight, and gypsum was partially substituted
for limestone such that 45% of the supplemental calcium was derived
from gypsum.
[0081] The fifth unit was fed a ration comprising 2% by weight of
zeolite and gypsum substituted for limestone such that 45% of the
supplemental calcium was derived from gypsum. However, this fifth
ration had a significantly reduced crude protein level, being
reduced from 18.8% by weight as in the control diet, to 15.0% by
weight. This diet also contained 0.5% bioavailable phosphorus. The
ration of the fifth unit was further amended with a purified form
of the amino acid lysine such that lysine comprised 0.98% by weight
of the feed to avoid detrimental effects from not providing enough
limiting amino acids to thrive. All rations in the study were
equivalent in terms of kilo-calories (kcals) per pound.
[0082] All rations comprising limestone added as a source of
calcium included granular limestone having particle sizes ranging
from just under 1/4 inch in diameter down to a coarse dust. It is
well settled that the speed of calcium uptake in hens is influenced
by granulation size of the source of calcium. For laying hens, a
slow, continual uptake is preferable; hence the calcium source is
moderately coarse. Smaller granules would digest too quickly, and
the excess calcium liberated would be excreted, rather than used by
the bird for vital functions.
[0083] During the experiment, the number and quality of eggs
produced by hens fed various rations were compared. Hens fed the
amended rations showed some initial improvement in production over
hens fed control rations. Eggs produced by hens fed the
gypsum-substituted rations (hens in the second unit) weighed
slightly less than eggs produced by hens fed the control
ration.
[0084] In the second phase of the experiment, the approximate upper
limit of gypsum replacement for the second, fourth, and fifth units
of hens was measured. The amount of gypsum in the ration was
increased and the amount of limestone in the ration was decreased
such that 66% of the supplemental calcium in the ration was derived
from gypsum. Hens fed this ratio produced slightly fewer eggs, and
the eggs they did produce had a slight (but still acceptable)
decrease in eggshell quality. In the next experiment, gypsum was
added to the ration such that gypsum contributed 75% of the
supplemental calcium in the ration. Hens fed this ration produced
fewer eggs than hens fed the control ration, and the eggs they did
produce had unacceptable shell quality.
[0085] In still another variation of the experiment, the amount of
calcium derived from gypsum was reduced to 45% of the total amount
of calcium fed to the animals. When gypsum was supplemented at this
level, both egg shell quality and egg production figures returned
to acceptable levels. Cumulative data collected over a 1 year
period, including data from the period of very high gypsum
supplementation, showed an approximate 4% increase in egg
production from hens fed the amended rations relative to hens fed
control feed rations. Eggs produced by hens fed the
gypsum/zeolite-amended rations were also, on average, heavier than
eggs produced by hens fed the control ration. Hen mortality was
similar in all groups.
[0086] The production increase and egg weight increase noted may be
due to better living conditions for the test hens compared to hens
in a normal production environment. The increases may also be
attributable to a feed formulation that enables the hens to make
more efficient use of the feed, or the increases may be caused by a
combination of factors including the aforementioned reasons.
[0087] One conclusion of the aforementioned study is that white
leghorn hens (HyLine W-36) should not be fed a diet in which
greater than about 66% of the calcium is derived from gypsum. Still
another conclusion is that such hens should be fed a diet that
derives 50% or less of its calcium from gypsum.
Experiment 2
[0088] Manure produced by hens fed a ration that included the
optimal amount of gypsum substituted for limestone was assayed less
than 1 hour post-excretion. This manure was immediately transported
to a laboratory, where the manure from each unit was homogenized
and a 25-gram aliquot placed in a flask. The flask was supplied
with air via an air pump. The air passed across the manure and
collected the ammonia emitted. The ammonia-laden air was then
bubbled through an acid solution to capture the ammonia. Every 24
hours, for a period of 7 days, the acid solution was changed out
for fresh solution, and the samples were assayed to determine their
levels of ammonia. Data resulting from the initial lab analyses are
illustrated in Table 1.
[0089] FIG. 1 illustrates the effect of supplementing chicken feed
with zeolite in the absence of added acidogenic substances.
Chickens fed rations supplemented with zeolite alone did not
produce manure that emitted less ammonia than manure from birds fed
the control ration. A comparison with ammonia emission levels
collected in Table 1 indicates a 13% increase in ammonia emission
levels from manure produced by chickens fed feed comprising zeolite
compared with the ammonia emission levels from manure produced by
chickens fed the control ration.
[0090] Also illustrated in FIG. 1 is the effect of substituting
gypsum for limestone on ammonia emissions. By week two of the
study, the amount of ammonia emitted from manure produced by hens
fed gypsum was lower than the amount of ammonia emitted from manure
produced by hens fed the control diet. However, the buffered nature
of the manure appears to take over in the 24-48 hour period, and
ammonia emission rates determined for manure collected even from
hens fed a gypsum-rich diet increased significantly. Still,
comparison calculations collected in Table 1 illustrate that over a
1-week period there was a 15% reduction in overall ammonia
emissions from manure from hens fed the experimental diet.
[0091] As FIG. 2 illustrates, when gypsum-substituted diets were
augmented with zeolite, there was a significant and unexpected
decrease in ammonia emissions from manure collected from hens fed
the amended feed compared to manure collected from hens fed the
control diet. Comparison calculations in Table 1 indicate that over
a 1-week period, relative to the manure from hens fed the control
ration, there was a 47% reduction in the amount of ammonia emitted
from manure produced by hens fed the gypsum plus zeolite diet, as
compared to a 15% reduction observed in manure collected from hens
fed the gypsum-supplemented diet.
[0092] Referring again to Table 1, comparing the control diet with
the gypsum/zeolite diet containing standard crude protein levels
shows an 85% reduction in ammonia emissions for the 0-24 hour
period. The data in Table 1 for the 24-48 hour period comparing the
same diets shows a 69% reduction in ammonia emissions.
[0093] Manure from hens fed the gypsum/zeolite-augmented ration
showed a 38% lower level of ammonia emissions in the first 24-hour
period and 59% lower ammonia emissions in the 24-48 hour period
than manure collected from hens fed a gypsum-augmented diet. The
tendency of poultry manure to increase in pH appears to contribute
to a general increase in ammonia emissions starting in the 24-48
hour period. However, this increase is substantially lower in
manure from hens fed a ration comprising gypsum and zeolite than in
manure from hens fed a ration comprising gypsum alone. Clearly,
feeds comprising zeolite and an acidogenic substance acting in
concert provide a significant advance in the art, as this
combination reduces manure ammonia emissions to an unexpected and
significant extent when compared to industry standard diets or
diets augmented with just a cation exchanger or just an acidogenic
compound.
[0094] Additionally, FIG. 2 illustrates the unexpected and
beneficial effects on manure ammonia emissions when crude protein
levels in feed are reduced in combination with the addition of
gypsum/zeolite. Comparison calculations in Table 1 indicate a 77%
reduction in ammonia emissions from manure produced by chickens fed
this reduced protein combination diet over the 1-week study period
as compared to emissions from manure produced by chickens fed the
control diet.
[0095] A comparison of Table 1 data for control diet emissions to
low crude protein levels/gypsum/zeolite augmented diet emissions
indicates a >99% reduction in ammonia emissions in the 0-24 hour
period and a 94% reduction in the 24-48 hour period. When those
same figures are compared to the standard crude protein
levels/gypsum/zeolite augmented diet, the low crude protein
level/gypsum/zeolite augmented diet has 98% lower ammonia emissions
in the first 24-hour period and 82% lower ammonia emissions in the
24-48 hour period.
[0096] As illustrated in FIG. 3, hens fed a ration comprising an
appropriate level of one or more acidogenic compounds and one or
more indigestible cation exchangers produced manure that off-gassed
less ammonia than manure produced by animals fed the control
rations. Hens fed rations comprising zeolite, an acidogenic
compound, and lower levels of unabsorbed crude protein produced
manure with the lowest level of ammonia emissions.
Experiment 3
[0097] Older manure is continually being covered over by fresh as a
manure pile accretes. Because ammonia emission occurs from the
surface of the manure, accretion may act to suppress ammonia
emissions. If this is true, then reducing the amount of ammonia
off-gassed from fresh manure even transiently may help to reduce
the level of ammonia in a whole hen house.
[0098] In order to test this hypothesis, an entire layer house was
fed a ration comprising 1.25% zeolite with 25% of the supplemental
calcium derived from gypsum. A second layer house used as a control
was fed a control ration with no zeolite and all of its
supplemental calcium derived from limestone. Crude protein levels
in the two rations were nearly identical: 15.3% and 14.8% of total
ration weight, respectively.
[0099] Because birds in the gypsum/zeolite-amended feed house could
likely not tolerate an immediate shift from the standard rations to
the amended rations, birds fed the amended ration were weaned from
their standard diets to the amended rations over a period of about
6 weeks. Testing for aerosol ammonia at the outlets for house air
circulation fans was begun as the diet approached the final levels.
Readings were taken at 10 exhaust fan outlets in each house, and
the average values of those readings were recorded. Outside
temperatures were also recorded to determine if ammonia emission
rates correlated with temperature. The experiment was carried out
during cold weather when house ventilation is kept at a minimum to
conserve heat. During the cold-weather phase of the experiment, pit
fans, which are fans placed in the manure collection pit to
circulate air to aid in drying manure, were not in operation. Under
these conditions, the level of ammonia measured at the exhaust fans
fairly represents the average ammonia level in the house.
[0100] The data from this phase of the test is summarized in Table
6. As the birds acclimatized to the amended diet, the level of
ammonia measured in the house decreased, with an average reduction
of 68% over the term of this phase of the study. Near the end of
the study, the level of ammonia in the atmosphere of the house
correlated well with the level of ammonia emissions measured from
manure samples collected from hens fed similar rations monitored
over a 1-week period. Compare, for example, the data in Table 6
with the data in Table 5 and FIG. 4.
[0101] As the weather warmed, the pit fans were activated, and
ventilation rates increased. Again, ammonia emission readings were
obtained at the same 10 fans used as data points previously.
Special attention was paid to insure that the same numbers of
ventilation fans were in operation in both houses during periods of
time when data was being collected. Airflow is a significant factor
with regard to ammonia emissions. To a point, increases in airflow
cause increases in ammonia emissions measured at the vent fans. As
illustrated by the data in Table 7, an increase in ammonia
emissions was noted in both houses as a result of the pit fans
being placed in operation. However, the levels of aerosol ammonia
in houses in which the hens were fed a gypsum/zeolite amended
ration were significantly lower than the levels measured in the
houses with hens fed the control diet. There was, on average, a 43%
reduction in the amount of aerosol ammonia in the houses fed the
amended diet over the houses fed the control diet over the term of
this phase of the study.
[0102] No negative effects on egg production, shell strength, or
bird health were noted in this whole-house study. In fact, quite
the opposite was noted. Egg production, shell strength, and bird
health were unexpectedly improved in birds fed the amended rations
over birds fed the industry standard ration.
Experiment 4
[0103] At least some of the ammonia associated with animal manure
is derived from the chemical and microbial degradation of amino
acids present in the manure. Reducing the level of crude protein in
an animal's rations may help to reduce the amount of ammonia
produced in the animal's manure by reducing the major source of
undigested amino acids in manure: undigested or only partially
digested proteins or other polypeptides.
[0104] Referring now to Table 5 and FIG. 4, an experiment was
carried out to determine if reducing crude protein levels and
increasing the level of gypsum substituted for limestone in the
amended feeds would decrease the level of ammonia emitted by birds
fed the amended ration. Accordingly, one group of hens was fed a
control ration. A second group of hens was fed a ration comprising
gypsum substituted for some of the supplemental calcium in the
ration and lower levels of crude protein than the control ration.
The levels of ammonia emitted by manure excreted by these birds
were compared. The control values were measured from manure
collected from hens fed the same feed ration as the hens in the
control group of the whole house study. The 25% gypsum curve shows
the effect of the amended diet fed in the whole house study. The
35% gypsum curve illustrates the effect of reducing crude protein
from 15.3% by weight of the ration to 14.3% by weight as well as
increasing the gypsum-based calcium replacement levels to 35%. All
amended feeds comprised 1.25% zeolite by weight. These data were
generated using the same analytical methods as previously
described.
[0105] Referring still to Table 5 and FIG. 4, whole-house ammonia
emissions in houses where hens were fed gypsum/zeolite amended
rations were approximately 80% less than in the control house.
Reducing crude protein by 1% from 15.3% by weight to 14.3% by
weight, and at the same time increasing gypsum-based calcium
supplementation rates to 35% instead of 25%, garners an
approximately 95% reduction in ammonia emissions (relative to the
control house). That level of reduction was unexpectedly high. To
confirm this, the test was repeated using fresh manure. The
reduction in the rate of ammonia production and in the total amount
of ammonia emitted was virtually identical between the two
experiments.
[0106] Moisture levels are known to be a factor affecting ammonia
emissions. Therefore, the percentage of solids in each manure
sample was also determined. Solids contents in manures generated
from consumption of amended and control rations were very similar,
ranging from about 20% to 24% for freshly excreted manure.
Experiment 5
[0107] High levels of total phosphorus and, especially, high levels
of soluble phosphates in manure pose significant threats to the
environment, particularly when the manure finds its way into the
watershed. The following survey was conducted to determine if
adding phosphorus-reactive metals bound to zeolite to an animal's
feed rations could reduce the amount of soluble phosphate in the
animal's manure.
[0108] Referring now to Tables 2, 3, and 4, manure produced by hens
fed rations comprising zeolite had less soluble phosphorus and less
total phosphate than manure generated by hens fed standard rations,
even when the total amounts of bioavailable phosphorus in each
ration were the same. The observed drop in the total amount of
phosphate in manure produced by hens fed rations comprising 2% by
weight of zeolite are illustrated in Table 2. The drop in total
phosphate levels observed was unexpected. This reduction in total
excreted phosphorus may be due to zeolites promoting more efficient
uptake and utilization of bioavailable phosphorus.
[0109] Since soluble phosphorus is environmentally problematic, the
ratio between soluble and total phosphorus in manure is of
interest. Referring now to data in Table 3, test rations were
supplemented with phytase, an enzyme that tends to elevate the
amount of bioavailable phosphorus in grain-rich animal feeds.
Additional manure samples were collected, and both total and
soluble phosphorus amounts were determined analytically. These data
support the conclusion that feeding zeolites comprising
exchangeable phosphate-reactive cations appears to reduce
significantly the solubility of phosphorus in manure as well as the
total amount of phosphorus excreted.
[0110] The zeolite used in this experiment contained exchangeable
calcium and magnesium cations. The reduction in the amount of
soluble phosphate may be due to the formation of insoluble metal
phosphate compounds.
[0111] In another aspect of the invention, synthetic zeolites can
be doped with calcium and magnesium before the zeolite is added to
animal feeds. Zeolite dosed with a metal such as calcium and/or
magnesium will help to reduce the amount of soluble phosphate in
manure produced by animals fed a diet comprising the zeolite.
[0112] Tests were conducted on full size layer houses to determine
if the amended rations of the present invention lowered the soluble
phosphate levels in manure produced under production conditions.
Hens in one house were fed a control ration while hens in a second
house with conditions identical to the first house were fed the
amended rations used for the large-scale study. Samples of manures
of similar age were removed from the manure collection areas of the
two layer houses. Samples were analyzed for total Kjeldahl
nitrogen, ammonia, and total/soluble phosphorus. All results were
reported on a dry weight basis, and these data are summarized in
Table 4. Manure from birds fed a gypsum/zeolite-amended diet
contained 5.58% nitrogen, 0.93% ammonia, 0.97% total phosphorus,
and 0.14% soluble phosphorus. Manure from birds fed the control
(industry standard) ration contained 4.88% nitrogen, 1.94% ammonia,
1.08% total phosphorus, and 0.30% soluble phosphorus.
Experiment 6
[0113] It is another aspect of the invention to produce manure that
is better suited for use as a component of fertilizer than is
manure produced by animals fed standard rations. Plants require
both nitrogen and phosphorus; however, too much of either element
can adversely affect plant health. The ratio of nitrogen to
phosphate (N:P ratio) of manure produced by hens fed standard
rations is oftentimes so low that this manure must be processed
before it can be used to produce fertilizer. This processing adds
to the expense of fertilizer made from such manure. Manure produced
by hens fed the amended feed of the present invention had an
unexpectedly more favorable N:P ratio.
[0114] In order to determine if the combination of feeding hens a
cation exchanger, an acidogenic compound, and one or more
phosphate-reactive metals would have an impact on the manure's N:P
ratio, hens were fed the various rations. The nitrogen/phosphorus
(N:P) ratio of manure from birds fed the amended ration is 5.8:1,
whereas manure from control birds exhibited an N:P ratio of 4.5:1.
The N:P ratio of manure produced using the rations of the present
invention is better suited for use in plant fertilizer than is
manure produced by animals fed the control ration. It is also worth
noting that the reduction in ammonia levels in manure from birds
fed amended feed is roughly consistent with the previously stated
reductions in aerosol ammonia levels observed in the large-scale
study reported in Experiment 4.
[0115] Manure from hens fed the amended ration has a lower level of
soluble phosphate than manure from hens fed the control ration.
Given that soluble phosphate in surface water can be a significant
environmental problem, manure produced by animals fed rations
comprising gypsum/zeolite amended feed makes for more
environmentally friendly manure. When the manure generated from
consumption of the amended feed gets applied to a field, there is
less phosphorus that can dissolve in rain and run off to the local
streams and ponds.
Experiment 7
[0116] Still another aspect of the invention is a method of
reducing the number of flies associated with manure produced by
animals fed the inventive rations. This unexpected benefit was
first observed in the whole-house trial. Referring now to Table 8
and FIG. 5, fly card data were collected over a 1-week period. Data
were collected from whole houses in which hens were fed either the
control (conventional industry standard diet) or one of the amended
diets. One amended diet included, a zeolite and 25% gypsum, and the
other amended diet included zeolite, 35% gypsum, and reduced crude
protein levels (crude protein levels were reduced by 1%). These
feeding experiments were carried out in duplicate.
[0117] As illustrated by the data in Table 8 and FIG. 5, there are
fewer flies in houses in which hens were fed the gypsum/zeolite
amended ration than in houses in which hens were fed the control
ration. A similar reduction was also observed at the manure storage
pit level and at the bird cage level. Additionally, noticeably
fewer maggots and flies were present in the house in which the
amended feeds were utilized. This effect may be based on
acidification of the manure, as many types of fly larvae are not
tolerant of a growth medium with a pH below 7 SU. TABLE-US-00001
TABLE 1 Ammonia Emission Control Feed Amendments Gypsum/ Gypsum/
Zeolite Zeolite Control Zeolite Gypsum Std CP Reduced CP Day 1 288
144 69.5 42.8 0.99 Day 2 235 398 178 73 13.1 Day 3 57.9 107 142
90.6 50 Day 4 13.8 22.4 76.3 62 50 Day 5 4.9 6 26.9 30.4 17 Day 6
2.12 3.95 13.2 15.4 6.68 Day 7 1.67 2.81 6.59 4.4 2.8 Totals 603.39
684.16 512.49 318.6 140.57 % Reduction 0.00 -13.39 15.06 47.20
76.70
[0118] TABLE-US-00002 TABLE 2 Effects of zeolite on total
phosphorus excreted, shown in units of lbs./ton of manure
Supplemented with % Reduction in zeolite Control Diet Phosphate
Sample 1 29.54 39.28 24.80 Sample 2 32.66 40.64 19.64 Sample 3 28.9
29.68 2.63 Sample 4 17.42 24.4 28.61 Sample 5 26.58 33.84 21.45
Sample 6 13 19.58 33.61 Sample 7 12.46 19.88 37.32 Sample 8 10.5
20.06 47.66
[0119] TABLE-US-00003 TABLE 3 Effects of Zeolite on Soluble/Total
Phosphorus Ratio. Zeolite Control % Reduction (ppm) (ppm) in
Soluble Phosphate Soluble Phosphorus 207 2760 92.50 Total
Phosphorus 1380 3900 64.62 % Soluble Phosphorus 15.00 70.77
[0120] TABLE-US-00004 TABLE 4 Manure Analysis, results reported on
a dry weight basis. Supplemented Unsupplemented feed feed (ppm)
(ppm) Total Kjeldahl Nitrogen 55700 48800 Ammonia 9290 19400 Total
Phosphorus 9670 10800 Soluble Phosphorus 1360 3000
[0121] TABLE-US-00005 TABLE 5 Results of dose response/optimization
study. 35% Gypsum 35% Gypsum 25% CP reduced by CP reduced by
Control Gypsum 1% Trial 1. 1% Trial 2. Day 1 112 32.2 1.69 4.96 Day
2 185 31.6 1.47 0.79 Day 3 64.1 6.6 10.8 1.89 Day 4 7.96 1.55 2.06
2.36 Day 5 2.2 0.76 1.15 1.79 Day 6 1.56 1.15 1.14 1.87 Day 7 1.32
1.12 1.29 1.80 Total 374.14 74.98 19.6 15.46 % Reduction 0.00 79.96
94.76 95.87
[0122] TABLE-US-00006 TABLE 6 Averaged Ammonia Emissions at Exhaust
Fan Inlets Measured When the Pit Fan Ventilation Fans Were
Inactivated. Outside Date Amended Feed Control % Reduction
Temperature Day 1 18.0 41.6 56.7 38 Day 2 17.2 45.5 62.2 23 Day 3
15.7 40.0 60.8 28 Day 4 15.0 43.1 65.2 36 Day 5 14.8 35.0 57.7 20
Day 6 14.5 36.4 60.2 16 Day 7 18.0 39.6 54.5 12 Day 8 16.9 37.0
54.3 2 Day 9 11.5 42.7 73.1 24 Day 10 12.8 45.4 71.8 34 Day 11 12.0
48.8 75.4 34 Day 12 12.0 53.0 77.4 37 Day 13 8.6 48.8 82.4 46 Day
14 8.3 43.3 80.8 38 Day 15 5.9 41.1 85.6 48
[0123] TABLE-US-00007 TABLE 7 Averaged Ammonia Emissions at Exhaust
Fan Inlets Measured When the Pit Fan Ventilation Fans Were
Activated. Outside Date Amended Feed Control % Reduction
Temperature Day 1 37.7 56.1 32.8 48 Day 2 34.8 57.3 39.3 48 Day 3
27.6 50 44.8 49 Day 4 12.1 30.7 60.6 56 Day 5 30.6 42 27.1 62 Day 6
23.1 36.1 36.0 50 Day 7 22.5 40.9 45.0 54 Day 8 21.4 45.9 53.4 47
Day 9 16.2 27.9 41.9 57 Day 10 21.1 38.9 45.8 42
[0124] TABLE-US-00008 TABLE 8 Fly Count Data: Gypsum/Zeolite
Amended Feed vs. Conventional Industry Standard Diet. Amended Feed
Control Week 1 1.2 1.2 Week 2 1.8 1.6 Week 3 1.8 1.4 Week 4 1.8 2.2
Week 5 1.8 1.8 Week 6 1.8 2.2 Week 7 1.8 2.6 Week 8 1.8 2 Week 9
1.6 2 Week 10 1.8 2.2 Week 11 1.2 2.8 Week 12 1.4 2.4 Week 13 1.2
2.8 Week 14 1.6 2.8 Week 15 1.4 3 Week 16 1.8 3.2
[0125] While the invention has been illustrated and described in
detail in the figures and foregoing description, the same is to be
considered as illustrative and not restrictive in character, it
being understood that only the preferred embodiments have been
shown and described and that all changes and modifications that
come within the spirit of the invention are desired to be
protected. As well, while the invention was illustrated using
specific examples, theoretical arguments, accounts, and
illustrations, these illustrations and the accompanying discussion
should by no means be interpreted as limiting the invention. All
patents, patent applications, and references to texts, scientific
treatises, publications, and the like referenced in this
application are incorporated herein by reference in their
entirety.
* * * * *
References