Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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ANTIMICROBIAL ADDITIVE FOR LARGE ANIMAL OR POULTRY
BEDDINGS
FIELD OF THE INVENTION
The present invention pertains to the field of bedding materials for use in
large animal
stalls and poultry barns.
BACKGROUND
The respiratory systems of horses, cattle, hogs and poultry can be harmed by
the presence
of ammonia in their barns, stalls, pens and other enclosures. At high enough
levels,, the damage
can adversely affect weight gain and feed conversion [Carr and Nicolson, 1980:
`Broiler
Response to three Ventilation rates, Am Soc.Arg.Eng 2: 414 - 418]. It is
therefore desirable to
reduce the quantity of ammonia to which these animals are exposed.
Ammonia is formed by enzymatic hydrolysis of urea, which is present in animal
waste.
The hydrolysis is catalyzed by the enzyme urease, which is produced by certain
microorganisms
that are commonly found in animal waste. Inhibition of microbial growth
through the addition of
an antimicrobial agent to animal waste should therefore reduce ammonia
production.
Inhibiting microbial growth is also desirable because certain microbes can
directly harm
animals. For example, Staphylococcus, Streptococcus and Escherichia coli
bacteria cause
mastitis, a disease of the mammary tissue of dairy cows. Other bacteria have
been known to
increase the mortality rates of poultry and reduce weight gain in other
animals.
The concept of using a particulate absorbent material comprising an
antimicrobial agent
such as BronopolTM is taught in the art (see Baldry et. al US 5,109,805). The
product disclosed
in Baldry et al. is a small animal litter for household pets, particularly
cats.
As a household pet litter, clay based absorbent materials are typically used
in un-admixed
form and in sufficient quantity to effectively absorb the entire volume of the
pet urine into the
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particulate material to maintain dry conditions in the litter box. For this
purpose, clay-based
materials, which have good absorbency characteristics, are commonly used. In
such applications,
all or substantially all of the absorbed urine is brought into intimate
contact with the antibacterial
agent carried in or on the particulate absorbent material thereby establishing
conditions
favourable to significant reductions in bacterial growth in litter
applications disclosed in Baldry
et al.
However, large animal stall and poultry barn bedding applications are subject
to vastly
different conditions than those of domestic pet litter applications. In order
to cope with the very
large volumes of urine produced by large animals such as horses and cows, or
large numbers of
animals, such as poultry or hogs, absorbent stall bedding materials must be
applied to the stall
floor in large quantities and changed frequently. In view of cost
considerations, a clay-based
absorbent material such as the domestic litter disclosed in Baldry et al. is
excluded as a suitable
large animal stall bedding material. Instead, the bedding materials of choice
for large animal
stalls and poultry barns are wood shavings and/or saw dust and/or straw, which
are commonly
available at a relatively low price.
While Baldry et al. discloses that antibacterial agents can be incorporated
into or surface
treated onto a variety of other absorbent particulate materials, the cost of
treating wood shavings
or straw with a bactericidal agent in the manner disclosed in Baldry et al.
would be prohibitive
and effectively excludes such an application of the teachings of Baldry et al.
to large animal stall
applications.
As noted in Baldry et al. at column 2, line 64 to column 3, line 7, the
presence and nature
of the absorbent material exercises a considerable effect on bactericidal
action, and a given
bactericidal agent may be more or less effective against bacteria in urine
alone or depending on
the particular absorbent material of which the litter is composed. Thus, the
effectiveness of anti-
bacterial agents in small animal litter applications such as those disclosed
in Baldry et al. is not a
reliable indicator of their effectiveness in the radically different large
animal stall applications. or
in instances such as poultry barns where larger areas require treatments.
Therefore a need remains for a cost-effective method of employing the
antimicrobial
properties of known bactericidal materials to large animal stall applications.
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SUMMARY OF THE INVENTION
In accordance with one aspect of the invention there is provided a method of.
reducing
ammonia levels in a large animal stall or poultry barn comprising the step of
applying an additive
comprising a clay-based particulate, wherein said particulate contains an
antimicrobial agent,
over the floor of an animal stall or barn in an amount of between 0.22 kg/m2
and 0.43 kg/m2.
BRIEF DESCRIPTION OF THE FIGURES
Figure 1 is a graph showing the mean ammonia levels (ppm) measured 30 cm above
the
manure over the test period using a clay-based particulate material with an
antimicrobial agent
(`Barn Fresh Plus") and without any treated material, (control) shavings
alone.
Figure 2 is a graph showing the percent difference in ammonia levels between
untreated
sections and sections treated with a clay based particulate material with an
antimicrobial agent
(`Barn Fresh Plus").
Figure 3 is a graph showing mean (t SE) of pooled (0-14 days) ammonia levels
(ppm)
under pine wood shavings in horse stalls treated with a clay-based particulate
material with an
antimicrobial agent ("NewSD"), a clay-based particulate material without an
antimicrobial agent
("OldSD") and untreated controls before rotation of treatments.
Figure 4 is a graph showing mean (t SE) of pooled (0-7 and 14 days) ammonia
levels
(ppm) on urine soaked wooden floors in horse stalls treated with a clay-based
particulate material
with an antimicrobial agent ("NewSD"), a clay-based particulate material
without an
antimicrobial agent ("O1dSD") and untreated controls after rotation of
treatments.
Figure 5 is a graph of mean ( SE) of ammonia levels (ppm) on urine soaked
wooden
floors in horse stalls two days after treatment with a clay-based particulate
material with an
antimicrobial agent ("NewSD"), a clay-based particulate material without an
antimicrobial agent
("OldSD") and untreated controls after rotation of treatments.
Figure 6 is a graph of mean ( SE) of ammonia levels (ppm) on urine soaked
wooden
floors in horse stalls 14 days after treatment with a clay-based particulate
material with an
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antimicrobial agent ("NewSD"), a clay-based particulate material without an
antimicrobial agent
("O1dSD") and untreated controls after rotation of treatments.
DETAILED DESCRIPTION OF THE INVENTION
The method of the present invention reduces ammonia levels in a large animal
stall or
poultry barn and comprises the steps of the applying a minor amount of a clay-
based particulate
material comprising a antimicrobial agent and d-a major amount of an absorbent
bedding material
over the floor of an animal stall or barn. It has surprisingly been found that
a clay-based
particulate which contains an antimicrobial agent can be used in relatively
small amounts in
combination with inexpensive bedding materials such as wood shavings, saw dust
or straw,
which are commonly used in large animal stalls or poultry barns, to reduce
microbial growth and
thus decrease ammonia production caused by micro organisms associated with
animal waste.
The clay-based particulate can comprise any of a number of suitable clay
minerals
including smectite, attapulgite, sepiolite, bentonite, kaolinite, gypsum, and
zeolite.
Preferably, the clay mineral is montmorrillonite. Optionally, the average
particle size of the
clay-based particulate is approximately -24 mesh.
Most preferably, the clay material is a naturally occurring mixture of
montmorrillonite
clay and diatomaceous earth such as is available from Western Industrial Clay
Products under
the trade names Barn FreshTM and Stall DryTM. Not only does the montmomllonite
clay have
exceptional absorbency characteristics which makes it suitable for absorbing
urine that has
passed through the straw,. saw dust or wood shaving bedding materials, the
diatomaceous earth
component is effective as an insecticidal agent to reduce the number insects
or insect larvae in
the stall or barn.
Preferably, the antimicrobial agent is 1,3-Propanediol, 2-bromo, 2-nitro,
which is sold in
powder form 'under the trade name BronopolTM and in liquid form under the
trade name
MyacideTM and is present in the clay-based particulate in a concentration of
from 50 to 250 ppm.
The antimicrobial agent can be combined into the clay-based particulate in the
manner described
in Baldry et al. In particular, the antimicrobial agent may be admixed with
the clay material
during the particle forming process. In the alternative, particles of the clay
based-particulate are
treated with the antimicrobial. agent, by means of the clay travelling through
- a gravity fed 6"
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diameter pipe at a flow rate of approximately 3.5 tonnes per hour. The clay
material passes
through a misting spray of antimicrobial agent at a pre-determined, pre-mixed
concentration. In
an alternative method of application, a known amount of clay travelling on a
moving conveyor
belt is sprayed with MyacideTM at an application rate pre-determined to
achieve 250ppm, or other
desired concentrations.
In addition to the use of BronopolTM or MyacideTM as the antimicrobial agent,
an
ammonia reducing agent such as phosphoric acid, citric acid, acetic acid or
aluminium sulphate
and a urease inhibitor such as cyclohexylphosphoric triamide, phenyl
phosporodiamidate, or n-
(n-butyl) thiophosporic triamide can also be incorporated into or surface
treated onto the clay-
based particulate to further reduce the level of ammonia production.
In accordance with one aspect of the present invention, the clay-based
particulate
comprising the antimicrobial agent is first applied over the stall or barn
floor, preferably in an
amount of between 0.22 kg/m2 and 0.43 kg/m2. Thereafter, a layer of straw
and/or wood
shavings and/or sawdust in an amount and manner as is conventionally used ' in
stall or barn
applications is applied over the clay-based particulate. When used in this
manner, the
inexpensive straw and/or wood shavings and/or- saw dust bedding material is
used as the primary
absorbent material, thereby permitting a relatively small quantity of the more
expensive clay-
based particulate to be used. By applying the clay-based particulate first, is
remains in direct
contact with the floor of the barn or stall where pools of urine tend to
collect.
In accordance with another aspect of the invention, the clay-based particulate
comprising
the antimicrobial agent can be applied to the stall or barn floor, preferably
in an amount of
between 0.22 kg/m2 and 0.43 kg/m2, after a primary absorbent bedding material
such as wood
shavings, saw dust or straw has been applied. An advantage of this embodiment
is that the
additive can be applied without first clearing the floor of bedding material.
It helps to dry the
bedding material, thereby increasing its usage time and reducing bedding
costs.
In accordance with yet another aspect of the invention, a minor amount of the
clay based
particulate comprising the antimicrobial agent can be admixed with a major
amount of the
absorbent bedding material such as wood shaving, saw dust or straw, preferably
in a weight ratio
of from 25:1000 to 75:1000, prior to application to the stall or barn floor.
An advantage to this
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specific embodiment is that the application of clay particulate and absorbent
bedding material
can be accomplished in a single step. Furthermore, mixing in this manner tends
to avoid the need
of multiple applications of materials, particularly in poultry barns where 2
applications (one for
bedding and one for clay particulate) would increase the operational costs.
5. EXAMPLES
EXAMPLE 1: Ammonia Emissions from Poultry Manure
The study was undertaken in a standard high rise caged layer-facility that
housed
approximately 36,000 birds that were 19 weeks old and had been housed in the
barn for 7 days at
the beginning of the study. Manure was about 1 cm deep over a pine wood
shavings base. The
manure area was comprised of four pits (rows) each measuring 1.2 in x 90.9 in.
The rectangular-
shaped barn was oriented in a north-south direction with air circulating fans
on the east side and
pit fans on the west side of the pit area.
A naturally occurring binary mineral particulate of about 50% diatomaceous
earth and
about 50% montmorrillonite clay into which had been incorporated commercially
available
BronopolTM to yield a concentration of about 50 ppm was applied at a rate of
0.27 kg/m2 over an
area covering approximately 44% of the manure on all four pits for a distance
of 40 in from the
south wall of the barn. This comprised the treated section of the manure. The
untreated section
of the manure covered a distance of 40 in from the north wall of the barn. A
buffer section of
approximately 10 in was maintained between the treated and untreated sections.
Ammonia was measured at sixteen different locations in the treated and.
untreated
sections immediately after application of the additive and once daily for the
11 day duration of
the study. The measuring locations were located on the first and third rows
from the east wall of
the barn.
A PassportTM Five Star Person Alarm (Mine -Safety Appliances Company,
Pittsburgh,
Pennsylvania U.S.A.) was used to measure ammonia levels. The device was held
approximately
20 cm above the centre of the manure pit during measurements.
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Statistical comparisons between the treated and untreated sections were
analysed using
the Student's t-test method. The t test employs the statistic (t), with n-1
degrees of freedom, to
test a given statistical hypothesis about a population parameter. The method
is suitable for use
with small sample sizes (<30) and when population standard deviation is
unknown.
RESULTS
Mean ammonia levels measured over the untreated section were significantly (a
< 0.001)
higher than levels measured over the treated section for each day of the study
(see Figure, 1).
Expressed as a percentage, the untreated sections had ammonia levels of
between 111 per cent
and 522 per cent higher than the treated areas over the course of the study
(see Figure 2).
The permissible ammonia exposure limit (PEL) as published by the AIHA
(American
Industrial Hygiene Association) is 25 ppm. As can be seen in Figure 1, the
untreated sections
had reached this threshold by day 11, whereas the treated sections remained
well below the limit
at the conclusion of the study. Thus, the present invention can be employed to
both reduce
ammonia levels and increase times between manure cleanings in poultry
facilities.
These results are surprising given that the additive was not used as the
primary absorbent,
but only a minor quantity was used in admixture with a major quantity of
conventional sawdust
bedding. This is important because during the first 10-14 days after a new
flock of chickens is
placed in a barn, mortality rates of chicks' increases with higher ammonia
levels.
EXAMPLE 2: Ammonia Emissions from Horse Manure
Six stalls in a cutting-horse operation were numbered and assigned to one of
the
following treatments:
1. A 'naturally occurring particulate comprising a mixture of about 50%
diatomaceous earth
and about 50% montmorrillonite clay (without antimicrobial agent) sold under
the trade
name Stall Dry7m ("OriginalSD").
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2. A naturally occurring binary mineral particulate of about 50% diatomaceous
earth and
about 50% montmorrillonite clay into which had been. incorporated commercially
available BronopolTM to yield a concentration of about 50 ppm ("AntibacSD").
3. No treatment ("Control").
5. The wood floors of the stalls were stripped of all shavings and treatments
were applied in
a quantity of 0.32. kg/m2. The floor of each stall was then covered with 0.85
m3 of clean pine
wood shavings. Ammonia levels were measured using a Passport Tm Five Star
Personal Alarm at
between 3 and 5 locations in each stall, above and below the shavings, each
day for the 14-day
duration of the study.
At the mid-point of the study (7 days), the stalls were cleaned of shavings.
Ammonia
measurements were taken with the ammonia meter placed directly on the floors
of the stalls.
One kilogram of test materials was sprinkled directly onto urine spots on the
floors of the stalls
and a fresh layer of shavings was placed over the stall floors.
After the initial 14 days of the study, the stalls were again stripped of
shavings and the
treatments. were rotated by one stall in an anti-clockwise manner. Ammonia
measurements were
continued daily for 7 days and then on a weekly basis for 4 weeks.
The assignment of treatments was as follows. Before rotation, treatment 1
without
antimicrobial agent (Original SD) was assigned to stall numbers 3 & 4,
treatment 2 with
BronopolTM (AntibacSD) to stall numbers 5 & 6 and treatment 3 (Control) to
stall numbers 7 &
S. After rotation, treatment 1 was assigned to stall numbers 3 & 8, treatment
2 to stalls 4 & 5 and
treatment 3 to stalls 6 & 7.
All ammonia measurements were statistically analyzed by ANOVA (Analysis of
'Variance) and Student's t-test methods.
RESULTS
The mean ammonia levels recorded under the wood shaving bedding materials
before and
after rotation are set out in Figures 3 to 6. Table 1 below summarizes results
of ammonia
measurements at different time intervals.
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Table 1. Mean ( SE) Ammonia Levels (PPM) Under Wood Shavings Before Treatment
Rotation for Treatments 1, 2 and 3.
Day # Treatment Mean ( SE) ANOVA Output
Ammonia Level
1-14 2 (Antibac) 11.4 1.52 DF 116
1 (Original SD) 19.7 3.02 F Ratio 5.886
3 (Control) 25.4 3.91 Prob>F 0.0037
The additive reduced ammonia levels measured below the shavings by* an average
of
approximately 53.1 per cent over the 14 days of the study.
Table 2 below summarizes the results of ammonia measurements before rotation
of
treatment.
Table 2. Mean ( SE) Ammonia Levels (PPM) Measured Under Wood Shavings During
the First
Two Weeks in the Initial Stall before Treatment Rotation for Treatments 1, 2
and 3.
Day # Treatment Mean ( SE) ANOVA Output
Ammonia Level
Period 2 (Antibac SD) 16.4 2.66 DF 120
1-14 1 (Original SD) 22.7 2.28 F Ratio 4.737
3 (Control) 28.4 3.25 Prob>F 0.0105
Day 2 2 (Antibac SD) 27.3 8.61 DF 17
1(Original SD) 28.7 6.84 F Ratio 1.295
3 (Control) 44.2 .9.04 Prob>F 0.3027
Day 14 2 (Antibac SD) 17.3 6:49 DF 17
1(Original SD) 25.3 4.59 F Ratio 1.272
3 (Control) 28.3 3.62 Prob>F 0.3089
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For pooled data of ammonia measurements taken from under the treatment areas
over the
entire duration of the trial, significantly lower levels of ammonia were
recorded in stalls treated
with AntibacSD compared to stalls treated with shavings alone. An average
reduction of 42 per
cent in ammonia levels was achieved. Further results are listed in Figures 3-6
below
The results of the study show that the use of the clay-based particulate
comprising
BronopolTM bactericide reduced the hydrolysis of ammonia on wood floors of
horse stables.
Ammonia reduction in stalls treated with the additive was as much as 66 per
cent lower than
levels in untreated stalls. Since the use of the same clay-based particulate
without microbial
agent produced only slight reductions in ammonia relative to untreated stalls,
the ammonia
reduction observed in stalls treated with the additive was due to the
inhibition of microorganisms
responsible for urease production.
As in Example 1, these results are surprising given that the additive was not
used as the
principal absorbent, but was used in minor quantities in combination with a
conventional wood
shavings absorbent bedding material.
Ammonia control action can be improved by either increasing the concentration
of the
antibacterial compound or by adding other materials having ammonia control
activity including
phosphoric acid, citric acid, acetic acid, aluminum sulphate and urease
inhibitors including
cyclohexylphosphoric triamide, phenylphosphorodiamidate and n-(n-butyl)
thiophosphorictriamide.
