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From: TSS ()
Subject: Composting Cattle Carcasses for bedding and mad cow diseases
Date: August 29, 2005 at 2:25 pm PST


Composting Cattle Carcasses
David B. Fischer and Ted L. Funk
07/21/2005
TAKE HOME MESSAGES
Illinois dairy producers are allowed to compost dead animals under the new rule.
Compost site must be located at least ¼ mile from nearest residence that is not a part of the facility.
Decomposition of a mature dairy cow will take approximately 6 to 8 months.
Illinois composting rules can be reviewed at: http://www.agr.state.il.us/Laws/Regs/DeadAnimalDisposalReg.pdf
Illinois cattle, sheep, and goat producers can compost dead animal carcasses under Illinois Department of Agriculture rules that recently took effect in October 2004. Swine, poultry and fish producers had been permitted to compost for some time. Currently, cattle carcass disposal is most commonly accomplished through rendering services. However, after the concern of Bovine Spongiform Encephalopathy (Mad Cow Disease) and the prohibiting of feeding bovine animal-derived protein to cattle, rendering costs have risen which prompts producers to look for other options. Other carcass disposal options are either burial or incineration. With incineration being costly and highly regulated, burial was the only other viable option until now. If managed properly, composting cattle carcasses can be an environmentally safe and economically feasible method to dispose of on-farm mortalities. However, if not properly managed composting can be a problem leading to regulatory implications. Let’s review some of the questions producers may have about the composting process.

WHO REGULATES CARCASS COMPOSTING IN ILLINOIS?

The Illinois Department of Agriculture Bureau of Animal Welfare is the regulatory authority for composting carcasses, and for the Dead Animal Disposal Act in general. Illinois EPA and Illinois Department of Public Health may become involved in investigating complaints about composters.

DO I HAVE TO REGISTER MY COMPOSTING SITE WITH THE DEPARTMENT?

Composter site registration is not required at this time.

WHERE CAN I SET UP MY COMPOSTING SITE?

The site must be located at least ¼ mile from your nearest neighbor’s residence and it must be placed on a suitable location with adequate diversions to prevent surface water from draining to the compost pile. Avoiding water from entering the pile is important in order to give the producer the control over the moisture content of the compost pile. Also, it is essential to keep composter contents from leaching to groundwater or running off to surface water.

WHAT TYPE OF A COMPOST FACILITY CAN I CONSTRUCT? MUST IT BE A ROOFED CLOSED-IN FACILITY?

A concrete slab with treated lumber bin walls and a roof is preferable. Roofing provides the producer with more control to regulate the amount of moisture during both wet and dry weather, which is important for proper composting. Also the solid flooring and surrounding area allows for easy access to turn the pile or for adding materials to the pile during wet, muddy conditions. The facility could also be as simple as setting large round hay bales end to end on a solid limestone or geotextile base making three-sided rectangular bins. The bale compost setup is not recommended as a permanent installation.

You need at least two composting bins, one primary and one secondary. The best way to get the carcass compost to reheat and finish composting is to move the pile over into another bin.

HOW BIG SHOULD MY COMPOSTER BE?

The size depends entirely on the amount of mortality you expect per year. The minimum bin size for a single cow carcass is about 10 feet square and walls five feet high (double it because you need two bins).

WHAT TYPE OF ORGANIC MATTER CAN I USE TO SUPPLY THE CARBON SOURCE NEEDED?

Sawmill sawdust is best because of the fine particles that can fill-in around the carcass. Mixture of finely chipped wood, chopped corn cobs, straw, and/or chopped corn stalks will work. The material must be absorbent, maintain its structure to allow the pile to “breathe”, and be a good carbon source for the composting organisms. Wheat straw by itself is not good, as it packs down too tightly. Whole corncobs have too little surface area and need to be chopped or ground. Up to 50 percent of the finished compost can be recycled back to the primary bin. Experience with composting other animal species shows that you will need a ratio of about 3.7 cubic yards of sawdust per 1000 pounds of carcass composted. You should keep a good supply of carbon source on hand, and you may need to keep it covered so you can control the moisture content.

WHAT OTHER ITEMS DO I NEED?

A compost thermometer with a 36 inch stem is vital for monitoring temperatures and is required by the regulation. You will need a method to get water to the composter to maintain the right moisture. A bucket loader for turning the compost after the first “heat” cycle and for loading out the finished compost is also essential for managing the operation.

WHAT IS THE COMPOSTING PROCEDURE FOR PROPER DECOMPOSITION OF ANIMAL CARCASSES?

Two composting cycles are needed to complete the decomposition. The carcass may need to be prepared or “processed” to allow for maximum exposure to air, moisture, nutrients and carbon. Animals weighing more than 300 pounds compost faster with some processing including slicing the large muscle areas and opening the thoracic and abdominal cavity. Lancing the rumen will reduce tendency of the carcass to bloat, may reduce odor problems, and it will make it easier to keep the carcass covered with carbon source. The carcass provides the nitrogen source and some moisture, while you will add the carbon source. The moisture content of the compost is important and should be maintained at 40 to 60 percent. Prepare the pile with at least 12 inches of sawdust or other carbon source on the base followed by placing the animal on the sawdust. Large animals should be laid with the backbone down. The animal carcass must be covered totally with at least 12 inches of sawdust or other adequate carbon source (more is better). You will need to add carbon source material to the pile periodically as the carcass breaks down (check the composter as part of your daily routine).

Monitor the temperature of the pile using the 36” thermometer, and record the temperatures and date. Composting temperature in the center of the pile should reach 130-150 degrees F. for an extended period. Three or four months after the initial loading, use a bucket loader to move the pile into the secondary bin. Add water if necessary. Check the temperature in the secondary bin to make sure it re-heats. Following the second heat cycle (another 2 to 4 months) the compost is ready to spread on a field. You may have some large bones remaining, but they can be put back into the primary bin for further breakdown.

WHAT PROBLEMS CAN I ANTICIPATE WITH COMPOSTING?

Odors: As long as you add sufficient carbon source to the pile and keep the carcass covered, odors should not be a problem. You may have odors emitted briefly when you turn the primary bin and move its contents to the secondary bin.

Scavengers: You may have to fence the poster, but usually keeping the carcass well covered with carbon source is sufficient to keep odors down so that digging scavengers are not attracted.

Leaching and runoff: Grade around the composter to keep clean storm water away from the bins. Don’t overwater the compost. Use proper type and sufficient amounts of carbon source materials.

Insufficient composting rate or low temperatures: Adjust moisture as needed. In winter it is difficult to “jump-start” decomposition of a cold carcass.

HOW DO I DISPOSE OF THE FINISHED COMPOST PRODUCT?

Applying it to the field with a box type manure spreader is recommended because animal carcass compost is a very good source of fertilizer for the crops. It should not be given or sold as compost for off-farm use. The compost N, P, and K should be considered part of the nutrient management plan for the field.

WHERE CAN I GET MORE INFORMATION ON COMPOSTING?

NRCS Ag Waste Management Field Handbook (see http://www.wcc.nrcs.usda.gov/awm/awmfh.html).

Illinois Department of Agriculture, Illinois Dead Animal Disposal Act and Code. (see http://www.legis.state.il.us/commission/jcar/admincode/008/008000900001100R.html). There are also several web sites at state land grant universities.

WHERE CAN I BUY A COMPOST THERMOMETER?

You can expect to spend about $90-100. Look for 36 inch long, 5/16 inch diameter stem. Two choices (about the same price) are listed:
1). Reotemp heavy duty (5/16” by 36”) windrow composting type.
www.reotemp.com, phone 1-858-784-0710.
2). Omega heavy duty (5/16” by 36”) windrow composting type. www.omega.com/temperature, phone 1-888-TC-OMEGA.

http://www.google.com/url?sa=t&ct=res&cd=3&url=http%3A//www.traill.uiuc.edu/dairynet/paperDisplay.cfm%3FContentID%3D7651&ei=HhwTQ6CAIMjy4QGo7-G8Cg

Whole Animal Composting of Dairy Cattle

Michael Looper, Ph.D., NMSU Extension Dairy Specialist


Even the most well managed dairy operations experience animal loss due to weather, natural causes, and/or illness each year. Rendering services currently pick up most on-farm mortalities. However, with the concern of Bovine Spongiform Encephalopathy (BSE; commonly know as Mad Cow Disease), the feeding of animal-derived protein to cattle is prohibited. This has decreased the need for animal rendering and increased the cost of removing mortalities from the farm. The abundance of stockpiled manure and old feedstuffs on dairy operations make whole animal composting a feasible alternative to carcass disposal. Objectives of this publication are to outline factors that affect proper composting procedures and discuss how to compost cow mortalities on the farm.
Proper Composting Procedures
Composting is the natural decomposition of organic materials by microorganisms that require oxygen (aerobic). Although many aspects of composting are not exact, there are several factors that affect the success of the composting process which are:

carbon and nitrogen ratios (C:N ratio)
moisture content
particle size
oxygen concentrations
temperature.
The proper mix of composting materials requires both carbon and nitrogen at a 25:1 to 30:1 ratio. With the proper C:N ratio, odor will be kept to a minimum, and an environment conducive to the growth of microorganisms will be obtained. It is usually necessary to add plant materials such as old feedstuffs or straw to have the proper carbon levels in the manure compost mix. Sawdust is the preferred carbon source due to its high absorbent characteristics and ability to make contact with the carcass. Moisture content of the compost mixture should be 50 to 60%. Moisture concentrations of greater than 60% will generate odors and increase the chance of leachate (runoff) from the compost pile. A general rule of thumb is if the mixture feels moist but no water drips from a handful when squeezed, the moisture is adequate. To ensure aeration of the compost pile, particle size of composting materials should range between 1/8 to 1/2 inches in diameter. Particle sizing increases the porosity (air space) of the pile allowing air to enter, maintaining oxygen concentrations to optimize microbial growth. Aeration by turning also introduces air into the compost pile. Optimal composting temperatures range from 110 to 150°F. Compost piles need a layer of inactive material (~1 foot thick) to insulate the pile and maintain high temperatures. Temperatures above 131°F for 72 hours are necessary to destroy human pathogens and most plant pathogens. Furthermore, weed seeds usually are destroyed at 145°F. Extremely high temperatures are detrimental to the composting procedure with microbial activity declining at temperatures greater than 160°F.

How To Compost Whole Cow Carcasses
Contrary to popular belief and practice, simply covering mortalities in manure is not considered composting. An animal carcass is generally a mass with a low C:N ratio (high nitrogen levels with relatively low carbon), a high moisture content, and relatively no air. Consequently, compost materials must include high C:N ratios, moderate moisture, and satisfactory porosity for aeration. Proper composting consists of layering the carcasses with composting materials in a static pile until the soft carcass tissue has fully decomposed.
Site selection is important to the overall success of the composting procedure. Location of the composting pile should allow easy access, minimal travel, convenient handling of manure and straw/old feedstuffs, and a proper distance from live cattle. Sites near neighbors and water sources or streams should be avoided. Make certain that surface runoff and other pollution controls can be implemented at the site. Good drainage of the compost pile also is necessary to prevent pooling of water. Ideal slope should be 1 to 3% for proper drainage. The composting pad should be firm but does not need to be paved. Sand or gravel at a depth of 6 inches is desirable when current soils conditions are not acceptable.
Construction of the compost pile should begin by placing a plastic liner (6-mil) 10 to 12 feet wide and the length of the pile or windrow. Next, place a base of compost materials (manure and straw/old feedstuffs) on top of the plastic liner approximately 1.0 to 1.5 feet deep. A general recommendation is a 50:50 ratio of manure and the carbon source. This ratio will vary with the chemical and biological characteristics of the manure and carbon source. Laboratory analyses of raw composting materials are necessary to get the optimal compost mixture. The carcass should then be placed on the top of the base. To decrease composting time and to allow the carcass to be laid flat, the body cavity of the animal should be opened. Water can be added at this time. Finally, completely cover the carcass with 8 to 12 inches of the compost mixture. Repeat layers as necessary until the pile or windrow is approximately 6 feet high. A thermometer should be placed 2.5 to 3 feet into the pile to monitor internal temperatures. When temperatures fall below 145°F, the pile can be turned using a front-end loader or windrow turner. Make certain carcasses remain fully covered after turning. Large square hay bales can be placed around the perimeter of the pile to protect from pests. Furthermore, if there is runoff from the compost pile, the hay will act as an absorbent.
In a properly managed compost pile, the core temperature of the pile should reach 145°F in 3 to 4 days. After approximately 2 weeks, volume of the pile will reduce to 1/2 its original size; the pile then should be turned. Decomposition of a mature dairy cow carcass generally takes 6 to 8 months with a few small bones remaining. The remaining bones will be soft and shatter easily when passed through a manure spreader during land application.

Bovine Composting Experiment in New Mexico
Recently, twelve cow mortalities were used to initiate whole animal composting on a large (~3000 lactating cows) southern New Mexico dairy operation. Compost pile construction was established by spreading a sand/manure mixture on a level site to a depth of approximately 10 to 12 inches. A single mortality was then placed on the mixture and covered with the compost mixture to a depth of 1.5 to 2 feet. A similar technique was used to cover each mortality. Dimensions of the final pile were 14 to 15 feet wide and 6 feet in height. A temperature data logger was placed 2 feet into the pile to record internal temperatures. Rainfall totaled 2 inches at the dairy during the experiment, and no additional moisture was added. Carcasses were uncovered at 8 weeks and 4 months to determine time needed to decompose cows. Compost pile temperatures reached a high of 143°F approximately 1 week after pile establishment. At 8 weeks, carcasses were 60 to 65% decomposed. The bones were clean, and the flesh was 90% decomposed. After 4 months, carcasses were somewhat difficult to find with several small bones (7 to 10 bones/carcass) remaining. It should be noted that the pile was not aerated nor were other carbon sources added. The goal was to mimic what would actually be completed on a dairy operation. It is obvious from this study that the addition of moisture, aeration, and other carbon sources would have decreased composting time but would have increased the dairy’s labor and cost.

Summary
By following a few general composting recommendations, whole animal composting can be a successful, environmentally safe, and economically feasible method to dispose of on-farm mortalities. Remember, composting procedures are not absolute and are somewhat forgiving. Trial and error accompanied with close monitoring of pile characteristics will usually produce successful results. It is advised that prior to implementing whole animal composting on your dairy, check local and state requirements regulating animal mortality disposal. The biological process of composting animal mortalities is similar to the processes of composting other organic materials. Mortality compost is an excellent source of fertilizer for crops utilized by the dairy farm. However, the compost generated from the decomposition of animal carcasses should not be given or sold as compost for use off-farm.


References:
Bagley, C. V., J. H. Kirk, and K. Farrell-Poe. 1999. Cow Mortality Disposal. Utah State University Extension Publication AG-507.

Field Guide to On-Farm Composting. 1999. NRAES-114.

Ohio’s Livestock and Poultry Mortality Composting Manual. 1999. Ohio State University Extension Publication.

On-Farm Composting Handbook. 1992. NRAES-54.

Trinca, L. A., B. Miller, and F. R. Beard. 1999. Bovine Mortality Composting in Northern Utah. Presented at the ASAE/CSAE-SCGR Annual International Meeting, Toronto, Ontario.


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Department for Environment, Food and Rural Affairs
Nobel House, 17 Smith Square, London, SW1P 3JR
Out of hours: 020 7270 8960

Up to index

212/04
4 June 2004

LIVESTOCK FARMERS URGED TO TAKE STEPS TO REDUCE THE RISK OF BOTULISM IN THEIR HERDS STEMMING FROM USE OF POULTRY LITTER

Livestock farmers are being urged to dispose of poultry litter and carcases properly following a marked increase in cases of suspected cattle botulism in England and Wales. From 1997 to 2002, the Veterinary Laboratories Agency investigated an average of four botulism incidents each year but 20 potential botulism outbreaks were investigated last year.

The VLA said there was evidence that litter from deep-litter broiler houses was the cause of disease in many of the recent outbreaks.

Investigations have revealed that affected cattle had direct or indirect contact with poultry litter when it was used as bedding for housed animals, as a fertiliser on grazing land and when it was stored in or adjacent to fields where cattle were grazing. Cases have also occurred when cattle were fed silage from fields fertilised with poultry litter.

Losses have varied from a death of a single animal to the loss of up to 80 per cent of the herd. Botulism in cattle causes a progressive paralysis, beginning with stock becoming unsteady on their feet and ending several hours later in death.

When botulism is suspected in food animals, the Food Standards Agency require that meat and milk are withheld from entering the food chain for two weeks after diagnosis of the last clinical case within the herd.

Alick Simmons, head of Defra's veterinary epidemiology and zoonosis division, said that while there were benefits from recycling of poultry litter as fertiliser on farmland, farmers had to ensure that they were complying with the law.

Spreading poultry litter on land which contained carcases or parts of carcases was illegal and put at risk the health of their cattle and possibly that of their neighbours, he added.

Defra/VLA recommend that the following actions are taken to reduce the risk of disease and economic loss.

Poultry carcases and carcase material must be collected and disposed of in accordance with the Animal By-Products Regulations 2003, ie by rendering or incineration.
Poultry litter should not be used as fertiliser on the surface of grazing land or land used for conserving hay or silage.
Poultry litter that is recycled into agricultural land must not contain poultry carcases or carcase material.
Poultry litter should not be used as bedding material for livestock.
Poultry litter should be disposed of by incineration, deep ploughing or burial.
Facilities or equipment used for poultry litter transport and diposal should not be used for storing, mixing or distributing feeding stuffs.
Access of scavenging domestic and wild animals, birds or livestock to stored litter should be prevented.
Good personal hygiene precautions should be observed when handling litter because poultry litter may contain a range of human pathogens.


--------------------------------------------------------------------------------

Notes for editors

1 Botulism is caused by either ingestion or preformed toxins produced by the bacterium "Clostridium botulinum" in decaying crops, vegetation or carcase material. Poultry litter may be a source of "Clostridium botulinum" organisms, spores or toxins. Botulism is not a notifiable disease.

2 The Animal By-Products Regulations 2003 (SI 1484) provides for the administration and enforcement of Regulation (EC) No 1774/2002 which prohibits the composting of poultry which die on farm and the application to land of manure or poultry litter containing carcase material. Local authorities are responsible for enforcement.

3 A letter from the VLA is today published in the Veterinary Record, providing advice to vets on the issue.


--------------------------------------------------------------------------------

END

Public Enquiries: 08459 335577
Press Notices available via Defra website
www.defra.gov.uk
Defra's aim is sustainable development

http://www.defra.gov.uk/news/2004/040604a.htm

Defra Helpline: 08459 33 5577

Helpline@defra.gsi.gov.uk

Name

Address

Address

Address

Address

To: All livestock farmers

17 April 2003

NEW RULES ON DISPOSAL OF FALLEN STOCK FROM 1 MAY 2003

I am writing to inform you about new EU legislation, the Animal By-products

Regulation, which will ban the routine on-farm burial and burning of animal

carcases when it applies in Member States from 1 May 2003. From that date

the only legal methods of disposal will be rendering or incineration. The only

exceptions from the ban in the UK are for remote areas of the Highlands and

Islands of Scotland.

On-farm incinerators will be allowed provided that they conform to certain

standards and are approved. Guidance on incinerators is enclosed with this

letter.

Alternatively, you can, as now, contact your local knackerman and arrange for

the carcase to be collected. If you do not know who provides this service in

your area you can ring the help line on 0845 8507070 which will be in place

by 1 May. The costs will depend on those prevailing in your area and must be

agreed by you with your local collector.

We are aware that the ban on burial will cause difficulties for some farmers

who will be faced with increased costs of disposing of fallen stock. To help

keep these costs down the Government is willing to assist with the setting up

of a low cost voluntary scheme to which farmers can subscribe. Details of

this scheme and how it would work are attached. You will see that

compared to typical charges under existing collection arrangements

there are substantial savings to be made.

The Scheme can only be viable if sufficient people are willing to join and it is

recognised that the full benefits of economies of scale can only be made

when it is fully operational. The charges being proposed do not represent the

full costs of the scheme. This is being heavily subsidised by government

initially to enable it to become established although in the future the

government would expect industry to take increasing responsibility for funding

and operating the Scheme. In the event that take up is not adequate to make

the scheme viable then farmers will need to make their own arrangements for

collection and disposal of fallen stock and the government’s role will be limited

to enforcement of the ban on on-farm burial and burning of carcases.

If you are interested in joining such a scheme please register your interest by

completing the attached tear off slip below by 6 May and returning it in the

enclosed SAE. If interest is sufficient to warrant it we will contact you again

with joining instructions.

TSE Directorate

Defra

-------------------------------------------------------------------------------------------------------

Please tick boxes which apply below.

I wish to register an interest in joining a scheme for the collection and

disposal of fallen stock. Yes No

If you do not wish to join such a scheme is this because:

No longer have the cost have alternative arrangements

any livestock please specify…………………

Name BARCODE

Address

Address Signed …………………………………

Address

FALLEN STOCK SUBSCRIPTION SCHEME

How it will work

The Scheme will be open to all agricultural holdings and all species of

livestock on such holdings. Members will be given a membership number on

payment of the subscription fee. It is proposed that there will be a central body

set up jointly by Government and industry, but run by the industry, responsible

for administering membership of the Scheme, collecting subscriptions and

paying contractors.

Members of the Scheme will then be entitled to have their fallen stock picked

up free at the point of collection once their membership details have been

verified. Collection will be undertaken by approved contractors who are able

to meet the strict biosecurity standards required. In most cases this will be

the local knackerman who is familiar with the farm.

What it will cost

The proposed fee is £100 per year for the average holding. There will be

discounted rate of £50 for small holdings* and a higher rate of £200 for large

holdings**. If there is a high uptake of the Scheme these rates should be

sufficient to keep the Scheme self-financing with the aid of an initial

government subsidy, but they will need to be kept under review in the light of

experience and as government subsidy is reduced in the future.

* Small holdings are defined as those with less than 20 cattle or 20 horses or 100 sheep or

100 goats or 100 deer or 100 pigs or 1000 poultry or for mixed holdings the equivalent of 20

cattle where 1 bovine = 1 horse = 5 sheep/goats/deer/ pigs or 50 poultry.

** Large holdings are defined as those with more than 200 cattle or 200 horses or 1000 sheep

or 1000 goats or 1000 deer or 1000 pigs or 10,000 poultry or for mixed holdings the

equivalent of 200 cattle where 1 bovine = 1 horse = 5 sheep goats/deer/ pigs or 50 poultry.

NB All other livestock including exotic livestock will be considered = 1 bovine for this purpose

How you can save money – some examples

Medium holding with 50 cows, 50 -60 sheep and 60-70 pigs

Based on estimates of mortality rates and typical costs for collection and

disposal of fallen stock, a holding of this size could expect to have 2 cows

(one of which is assumed to be under 24 months, and the other over 24

months which will be collected free as now under BSE testing arrangements),

3 sheep and 4 pigs requiring collection over a year. Typical costs of collection

and disposal are: £90 per cow, £15 per sheep and £12.50 per pig.

Total cost: £185 compared with subscription fee cost £100.

Small holding with 40-50 pigs and 500 poultry

Expected number of fallen stock are 3 pigs and 50 poultry. Costs are £12.50

per pig and £0.65 per bird.

Total cost: £70 compared with subscription fee cost £50

Large holding with 100 cows, 600 sheep

Expected number of fallen stock are 4 cows (assume one under 24 months as

above), 30 sheep. Costs are : £90 per cow and £15 per sheep.

Total cost: £540 compared to subscription fee cost £200.

Q & A ON COLLECTION AND DISPOSAL OF FALLEN STOCK

Q1 Why is ban on on-farm burial or burning to be introduced?

Many farmers have buried stock on their farms for years and doubt whether

there is any justification for this ban. The Commission’s view has been

influenced by a number of scientific opinions which take into account factors

such as the potential for polluting water courses and the lack of scientific

information available on how persistent the prions that cause diseases such

as BSE and scrapie are in soil.

Q2 Why hasn’t government acted sooner? When will the Scheme

start?

The Government has been in discussion with the livestock and disposal

industries since April 2002. A scheme was proposed as a means of

encouraging compliance and reducing costs to individual farmers. However it

is not needed as a means of establishing an infrastructure to dispose of fallen

stock. DEFRA has received assurances from the knacker and rendering

industries that this is already in place. The delay in progressing matters

rapidly was because no agreement could be reached on how such a scheme

would be funded.

Q3 Will there be a transitional period to allow on- farm burial until a

national scheme is in place?

No. A national scheme is being proposed in order to reduce the cost of

collecting and disposal of fallen stock and to encourage compliance.

However, an infra-structure of knackers‘ yards and renderers throughout the

country which farmers can use to comply with the new rules now.

Q4 Who is responsible for the disposal of fallen stock?

We take the view that all industries are responsible for disposing of their own

waste and farming is no exception. If the industry signs up to this government

subsidised voluntary scheme it will help maintain public confidence in its

ability to dispose of its waste in a safe and sustainable manner.

Q5 Is there sufficient capacity within the existing collection and

disposal industry?

The collection and disposal industries are confident that there is sufficient

capacity within the existing infrastructure to deal with the estimated additional

quantities of fallen stock.

Q6 What will be the permitted routes for disposal of fallen stock? Are

composting and bio-digestion permitted disposal routes?

From 1 May under the new Animal By-products Regulation fallen stock must

be disposed of to approved rendering or incineration facilities or hunt kennels

(where they exist) (see below). The composting or bio-digestion of fallen

stock is currently illegal. The new EU rules will not change this position,

however if the EU Scientific Steering Committee are convinced by a report

they have received from UK industry on biodigestion, this system of disposal

may be permitted in the future.

Q7 Will hunt kennels be permitted to collect fallen stock under the

Animal By-Products Regulation?

Yes. The Regulation will permit hunt kennels to continue collecting fallen

stock. However, they will be required to upgrade to knackers' yard standards if

they wish to do so for the purposes of feeding to hounds. DEFRA will issue

hunt kennels with advice about how to go about this.

Q8 Would State Aid Rules permit 100% Government funding of a

National Fallen Stock Collection and Disposal Scheme?

New Community guidelines for State aid allow Member States to fund aid

100% of collection and disposal costs only where the aid is fully recovered

from the meat sector e.g. by a levy.

Otherwise, Member States may grant State aid of up to 100% of costs of

collection, and 75 % of the costs of destruction of fallen stock.

Q9 Do other Member States fund National Fallen Stock Collection and

Disposal Schemes?

The situation regarding Government funding in other Member States is

complicated. Based on data provided by each Member State, the European

Commission issued a paper on 20 November 2001. It showed that the level

of Government support varies across the Community, with farmers in some

countries paying the full cost of disposal while in others the Government or

local authority provides varying levels of support. Furthermore, in some cases

Government recoups the costs, for example, in France this is done through a

tax levied on the retail sales of meat.

Q10 Does the Government have a statutory obligation to pay for the

collection and disposal of fallen stock for the purpose of TSE

Testing?

No. Although the testing of all fallen cattle aged over 24 months for BSE is

required by the EU TSE Regulation, the Regulation does not require Member

States to pay for the collection or disposal of these carcases. The decision

was taken by Defra to provide Exchequer funding to ensure that all required

carcases would be tested to assist DEFRA in meeting their EU obligations.

This would continue to be the case if a subscription scheme were to be set up

although this position may change if the requirements for testing change.

Cattle farmers may still wish to join the subscription scheme in order to benefit

from having cattle under 24 months and calves picked up free at the point of

collection.

Q11 Who will enforce the new legislation on the disposal of animal by-

products, including fallen stock?

Local authorities, usually Trading Standards, who currently enforce the Animal

By-Products Order 1999, will be the enforcement authority for the EU

Animal By-Products Regulation.

Q12 How can the new EU rules be enforced?

It is important that carcase movements are fully traceable. Both the Animal

By-Products Order 1999 and the EU Animal By-Products Regulation require

the keeping of records of any carcases that are sent off-farm for disposal

elsewhere. Enforcement authorities will check that such records exist and the

number of carcases disposed of. Inspections will also be made of on farm

incinerators to check that they comply with the standards required in the

Regulation.

Q13 What about Fly-tipping?

Wherever possible, where a carcase is dumped on private land, the owner of

the animal will be identified and held responsible. However, if ownership

cannot be proven, responsibility for disposal rests with the landowner. The

local authority, usually Trading Standards, has powers under the statutory

nuisance provisions of the Environmental Protection Act 1990 to deal with

"accumulations or deposits which are prejudicial to health or a nuisance".

Appropriate action can subsequently be taken against the owner of the

carcase.

GUIDANCE ON ON- FARM INCINERATORS

As an alternative to joining the National Fallen Stock Collection Scheme you

may wish to consider incinerating carcases on your farm. This is allowed, but

you will need to comply with the legislative controls that apply to on-farm

incinerators.

WHAT ARE THE CONTROLS ?

Approval

Your incinerator will need to be approved. If you only use your incinerator for

animal carcases it needs to be approved by the State Veterinary Service.

If you burn other materials as well it will need to be approved by either the

Local Authority or the Environment Agency, depending on its size.

Incinerators which operate at more than 1 tonne/hour are authorised by the

Environment Agency (or SEPA in Scotland). Incinerators which operate at

between 50kg/hour and 1 tonne/hour are authorised by the Local Authority in

England and Wales, but by SEPA in Scotland.

Planning permission may be required, particularly for incinerators which

operate at more than 50kg/hour.

Standards for incinerators

Low capacity incinerators (less than 50kg/hour)

• Must be designed, equipped and built so that the gas in the secondary

chamber achieves 850ºC for 2 seconds. The temperature will need to be

monitored by a temperature sensor that measures the temperature of the

gas leaving the chamber.

High capacity incinerators (over 50 kg/hour)

• Must also be designed so that the gas in the secondary chamber reaches

850ºC for 2 seconds, but in addition-

• Each line must be equipped with at least one auxiliary (ancillary) burner.

This must come on automatically at start up until the temperature is

reached and at any point during combustion if the temperature falls below

850ºC.

Requirements for approval

In addition to meeting the equipment standards outlined above, you will need

to meet some additional requirements to obtain approval.

• There must be total physical separation between the incinerator and the

livestock and their feed and bedding with fencing where necessary.

• Farmers must incinerate only their own fallen stock unless the incinerator

is approved as a shared incinerator (see below for further information).

• Ruminant carcases must be incinerated whole. Large ruminant carcases

(e.g. large bovines) must be sent off site for disposal if they are too big to

fit the incinerator without cutting up.

• Pigs and poultry can be cut up e.g for post- mortem. But they must be cut

up in a suitable area, the fluid must be collected and incinerated and the

by-products incinerated immediately.

• Any equipment (e.g. the shovel) must be dedicated to the operation of the

incinerator and not used elsewhere on the farm.

Remember also that no incinerator can operate effectively if it is overloaded.

Mobile incinerators

Mobile incinerators can be valuable for disposing of material that it is

preferable not to have to move off site e.g anthrax cases. However they also

have the potential to spread disease from farm to farm. If they are to be used

they will need to comply with strict biosecurity measures and be operated by a

dedicated operator. They must also be designed and managed in such a way

as to prevent unauthorised or accidental release of any polluting substances

into soil, surface water and ground water.

Shared incinerators

If farmers want to share a stationary incinerator it will need to be sited on

premises on which no livestock are kept. If the premises was originally part of

a livestock holding it must be completely separated with a dedicated entrance

and equipment. You should also be aware that although a Waste

Management Licence is not needed at present the requirements are expected

to change in 2004. At that time shared incinerators which operate at below

50kg/hour will additionally require a Waste Management Licence issued by

the Environment Agency or SEPA. This does not apply to low capacity

incinerators that are used only to dispose of stock that die on the farm on

which the incinerator is located.

TIMING

Low capacity incinerators

• New incinerators will need to comply with all the requirements from 1 May

2003.

• For incinerators that were in place on 1 November 2002 there is a

transition period to allow inspection of the premises to take place and

operators to modify or replace their incinerators as necessary. This ends

on 30 December 2004.

• If a low capacity incinerator, (<50kg/hour), is to be used to incinerate SRM

or ruminant carcases from which the SRM has not been removed, all of

the provisions of the new Regulation must be complied with from 1 May

2003. Farmers are advised to contact their local Defra Animal Health

Office for advice.

High capacity incinerators

• New incinerators must comply now. The relevant legislation took effect on

28 December 2002.

• Incinerators installed before 28 December need to meet the full

requirements by 28 December 2005.

http://www.defra.gov.uk/animalh/by-prods/fallen/NewRules.pdf


SPONGIFORM ENCEPHALOPATHY ADVISORY COMMITTEE

Minutes of the open session of the 87th meeting held on 21st April 2005

At

The Conference Centre

Holiday Inn Bloomsbury

Coram Street

London

WC1N 1HT

snip...


- - 16

ITEM 3 – USE OF CATEGORY 3 ANIMAL BY-PRODUCTS IN

FERTILISER (SEAC 87/4)

- - 17

54. Mr Steve Wyllie (Defra) provided the background to the issue. In

1996 the use of MMBM in fertiliser for agricultural land was banned

to cut off potential routes of TSE exposure to livestock. In 2002,

EU legislation was introduced that classified animal by-products

(ABP) into Category 1 (high risk material from animals with

suspected or confirmed TSE), Category 2 (condemned meat from

diseased animals) and Category 3 material (fit for human

consumption). Category 2 and 3 material was permitted to be

used as fertiliser, but in the case of all Category 2 material, and

Category 3 material of mammalian origin, only if reduced to a

particle size <50 mm and pressure cooked (>133ºC and 3 bar for

20 minutes). In addition, category 3 material could be used in

compost if reduced to <12 mm and heated to 70ºC for at least one

hour. Appropriately-treated Category 2 and 3 ABP could be

applied to non-pasture land. Non-pasture land included a period

when farmed animals cannot graze. A three week non-grazing

period is currently being proposed by the Commission, based on

an EFSA opinion.

55. Mr Wyllie explained that, in contrast to the EU regulations, no

rendered MMBM is allowed in fertiliser spread on any agricultural

land under current UK regulations. An anomaly also exists within

UK legislation as category 3 ABP can be treated in a biogas or

composting plant and applied to land. However, if it is treated in a

rendering plant it is designated as MMBM and cannot be applied to

agricultural land even though it is treated under more severe

conditions than it would in a composting/biogas plant. Defra is

considering amending the UK legislation to address the anomalies

and align UK with EU regulations. As an initial step, Defra

commissioned VLA to conduct a release assessment (RA) to

estimate the TSE-related risks associated with the use of rendered

Category 3 ABP as fertiliser on non-pastureland.

56. Dr Amie Adkin (VLA) presented the methods, inputs and

assumptions made in the RA together with the results. The RA

considered scenarios of scrapie in sheep, theoretical BSE in

sheep, and BSE in cattle, under current conditions, and assessed

the impact of removal of the OTM Rule. The RA consisted of four

successive modules:

Farm Module

57. The farm module estimated the numbers of cattle and sheep within

the last 12 months of incubation of scrapie or BSE, that are

slaughtered for human consumption per year. It was assumed that

BSE is present in the national sheep flock and the prevalence of

- - 18

BSE or scrapie is not stratified by age, a lamb having the same

probability of being infected in the national flock as an adult sheep.

Slaughter Module

58. Using data from the farm module, the slaughter module estimated

the quantity of infectious material (expressed as oral ID50), passed

as fit for human consumption, leaving slaughterhouses per year.

For BSE in cattle it was assumed there was no risk associated with

liver, kidney, lung, stomach, blood and trimmings. It was also

assumed that animals are fully infected and that carcass

contamination of the food chain could occur via four routes:

insufficient removal of spinal cord, spinal cord contamination from

splitting the carcass, brain tissue from the captive bolt used in

slaughter, and the presence of DRG.

59. For the scrapie and BSE in sheep models it was assumed that

positive animals were fully infected, the infectivity for BSE in sheep

is the same as scrapie, and that carcass contamination of the food

chain could occur via two routes: insufficient removal of spinal cord

and via infectious tissues not designated as SRM.

Rendering module

60. Using the information from the slaughter module, the rendering

module estimated the concentration of infectivity in fertiliser (oral

ID50 per kg). It was assumed that all TSE infectivity remaining on

the carcass after SRM controls subsequently enters category 3

waste. This was a pessimistic assumption as other routes such as

landfill, composting or ingestion which would reduce infectivity

levels were not included. It was assumed that 50-75% of Category

3 MMBM would be used in fertiliser production.

Land module

61. The land module estimated the infectivity of TSE on non-pasture

land three weeks post application (oral ID50 per m3) on the basis of

the estimates from the rendering module. It was assumed there

was no decay of TSE in soil, no leaching of TSE beyond 1 cm of

topsoil, and that the yearly input of fertiliser to land is applied in

one dose.

62. Dr Adkin explained that the final results of the study related to

infectivity in soil available per year, not the probability that a cow

becomes infected. The exposure of cattle to that infectivity was

outside the scope of the RA. Information on the frequency of cattle

- - 19

on non-pasture land, the length of stay and consumption of soil

and vegetation would be required for an exposure assessment.

The final results from the land module were (with 5th and 95

percentiles):

• The average TSE infectivity on non-pasture land per year

from cattle with BSE would be 2.0 x 10-11 bovine oral ID50

per m3 (1.7 x 10-12, 6.1 x 10-11)

• The average TSE infectivity on non-pasture land per year

from sheep with BSE would be 5.0 x 10-9 ovine oral ID50

per m3 (1.3 x 10-10, 1.8 x 10-8)

• The average TSE infectivity on non-pasture land per year

from sheep with scrapie would be 2.4 x 10-6 ovine oral

ID50 per m3 (3.9 x 10-7, 5.8 x 10-6), 500-fold greater than

for BSE in sheep.

63. Dr Adkin indicated that the model was sensitive to the amount of

MMBM fertiliser applied annually, the effect of rendering on TSE

infectivity, the titre of TSE infectivity in tissues and, in the scrapie

model, the proportion of natural scrapie that is BSE. Removal of

the Over Thirty Month Scheme (OTMS) would increase BSE

infectivity 60-fold but infectivity levels would still be extremely low.

A worst case scenario had been modelled assuming a fully

infected entire BSE carcass including SRM was rendered into one

batch of fertiliser (a one in a million million occurrence). In this

case, the BSE infectivity on non-pasture land would increase by 6

orders of magnitude from a mean estimate of 2.0 x 10-11 bovine

oral ID50 per m3 to a mean of 5.0 x 10-5 bovine oral ID50 per m3.

64. In opening the discussion, the Chair indicated that the RA had

been sent to an independent epidemiologist Professor Dirk Pfeiffer

(Royal Veterinary College, London) for review. Professor Pfeiffer

concluded the RA was logically structured and the data and

assumptions clearly described. The results had been presented

with due consideration of the assumptions. He noted that the

processes used in developing the model, obtaining the data and

scrutinising the model were not documented. It was unclear

whether the quality of unpublished and published data was

scrutinised or taken at face value. In summary, the model

structure was appropriate and the conclusions plausible. Improved

documentation would enhance the credibility and transparency of

the model outputs.

65. A member had also reviewed the RA in detail and concurred that

the RA was thoroughly carried out. It was noted that, with the

OTMS, the RA had assumed an infectivity level leaving the

slaughterhouse of 140 bovine oral ID50 per year whereas other risk

- - 20

assessments had used lower values. Dr Adkin commented that

the difference was due to inclusion of a fully infected carcase,

rather than considering carcases at different points in the

incubation period. In addition, the model contained different routes

of contamination of the carcase post SRM controls that are not

included in other assessments. It was suggested that the

assumption of all infectivity remaining on a carcass entering

category 3 waste and being spread as fertiliser was perhaps overly

pessimistic.

66. Dr Adkin was asked why no uncertainty estimate had been

included regarding the OTMS removal scenario. Dr Adkin

indicated that the estimates for the number of infected cattle to

slaughter were based on a peer-reviewed back-calculation model

from Arnold and Wilesmith (2003)2. The model had not been set

up to provide the 5th and 95th percentiles in the case of OTMS

removal. This had now been explored and the overall results had

not changed significantly as a result of including the uncertainty

estimate. Dr Matthews added that a previous qualitative risk

assessment indicated the risk was very low, and he felt the correct

approach for a quantitative RA was to use pessimistic

assumptions. There were many uncertainties in terms of the

process once material left the abattoir, regarding rendering plant

used, volumes of waste and how this material would be used

subsequently, therefore estimates had been based on consultation

with industry representatives, and if estimated infectivity levels

remained low even with pessimistic assumptions this could be

considered reassuring.

67. A member noted that the assumptions in the RA were dependent

on effective enforcement. It was suggested that a 3 week nongrazing

period could be difficult to enforce. In addition, it had been

assumed that no imported MMBM was used in fertiliser.

Enforcement should be considered in developing policy.

68. It was noted that even distribution of infectivity in fertiliser, and its

even distribution across land had been assumed. In reality, TSE

infectivity spread would be heterogeneous. Dr Adkin explained

that this scenario had been addressed to some extent by the worst

case scenario in which a fully infected entire BSE carcass was

rendered into one batch of fertiliser.

69. Dr Adkin added that it had been assumed that there was no

degradation of prion protein during the assumed 3 week non-

2 Arnold M. and Wilesmith J.W. (2003) Modelling studies on BSE occurrence to assist in the

review of the over thirty months rule in Great Britain. Proc Roy Soc Lond B 270, 2141-2145

- - 21

grazing period. Members considered that should TSE agents

persist in soil, infectivity could accumulate over time. Dr Adkin

indicated that the accumulation of infectivity over time was not

addressed, as an exposure assessment had not been carried out.

In order for such accumulation to occur TSE infectivity would have

to be applied on multiple occasions to the same location, which

may be unlikely. One study indicated there would be 98% decay of

the agent over 3 years3. Dr Matthews observed that accumulation

would be against a backdrop of decreasing TSE prevalence. Mr

Wyllie added that Defra- and EU-funded research is being

conducted to investigate the behaviour and degradation of TSE

agents in soil.

70. A member considered that, since the TSE agent is a protein, it was

likely to decay quickly due to the pH of, and bacteria present in,

soil. However, a member pointed out good evidence suggesting

that the Chronic Wasting Disease agent persisted in the

environment. Dr Matthews informed members that a VLA project

on infectivity in sheep exposed to the farm environment indicated

that material on pasture is infectious for at least 2 months.

Members agreed that in view of the resistance of PrPsc to

degradation, evidence from CWD and the VLA studies, it was safer

to assume survival of the agent in soil for a significant amount of

time.

71. In response to members’ questions about the field spreading of

fertiliser, Alan Brewer (Defra) informed the committee that some

dust can arise from the activity, both from the fertiliser distribution

process (that depends on the type of spreading mechanism) and

from tractor wheels kicking up soil in arable situations. But it was

not possible to indicate whether there was any likelihood of dust

particles containing fertiliser drifting onto adjoining fields. He

added that it was recognised as good practice for farmers not to

spread fertiliser into hedges and watercourses.

72. Members asked whether cross-contamination between category 2

and category 3 material could occur on processing. Mr Wyllie

indicated that Category 2 and Category 3 materials had to be

rendered in separate buildings, although these could be on the

same site.

73. Members asked if the final result of the RA could be an

overestimate of scrapie infectivity due to the assumption that all

sheep were adults. Dr Adkin indicated this may be a pessimistic

3 Brown P. and Gajdusek D.C. (1991) Survival of scrapie virus after 3 years’ interment.

Lancet 337, 269-270

assumption as adult sheep have larger tissue sizes. Dr Matthews

commented that genotyping studies from the abattoir survey

indicated there is a high prevalence of arginine-carrying sheep at

codon 171 and that therefore infectivity was more likely to be

restricted to the central nervous system rather than other tissues

and the RA had assumed the worst case.

74. Members noted that infectivity in fertiliser has the potential for

intraspecies recycling and poses a different risk from dead-end

infections. It was recommended that surveillance was essential to

detect infected animals and identify such a cycle.

75. It was noted that multiple risk assessments tended to consider

single routes but often routes were cross-linked. It was suggested

that consideration should be given to risk assessments that

consider such links rather than specific routes in isolation.

Members asked whether risk assessments could be produced in a

consistent way and asked if there was a forum to discuss inputs to

risk assessments. Dr Matthews indicated that a "Neuroprion Risk

Assessment" group was looking to peer review data and generate

a consensus for risk assessments. Dr Adkin indicated within the

EU, risk analysts are reviewing parameters to enable comparison

of models.

76. In summary, the committee concluded:

• it was content with the approach used and assumptions

made in the risk assessment.

• the assessment predicted that TSE infectivity levels on land

as a result of the application of fertiliser would be extremely

low. However, because of the likely heterogeneous nature

of infectivity in fertiliser and the uneven spread of fertiliser,

TSE infectivity levels might be higher in some geographical

locations than predicted.

• controls to ensure that category 3 material is processed

separately from Category 1 and Category 2 material be

audited.

• a watching brief be kept on CWD and BARB cases to

assess the possible persistence of the agent in the

environment.

snip...

http://www.seac.gov.uk/minutes/final87.pdf

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