Proper Burial Techniques for Small Farm Animals and Poultry Mortalities Under 25 kg.

Agdex#:	725/400
Publication Date:	June 2003
Order#:	03-049
Last Reviewed:	June 2003
History:	Replaces OMAFRA Factsheet Proper Burial Techniques for Small Farm Animals and Poultry Mortalities Under 25 kg, Order No. 96-079
Written by:	Hugh W. Fraser - Horticultural Crop Structures & Equipment & Nutrient Management Issues Specialist/OMAF

Table of Contents

1. Introduction
2. Ground Water Contamination Concerns
3. Surface Water Contamination Concerns
4. How Suitable Is Your Land For Burial Of Mortalities?
5. Other Concerns
6. Expected Mortality Losses
7. Burial Guidelines
8. Digging A Proper Hole
9. Record Keeping

Introduction

All livestock or poultry farms have dead animals (mortalities) resulting from disease, accidents or competition. Under Ontario's Dead Animal Disposal Act (DADA), farmers with dairy or beef cattle, swine, sheep, horses or goats are required to dispose of mortalities within 48 hr after knowledge of their death in 1 of 3 ways, by:

• Licensed Dead Animal Collectors (LDAC),
• composting, or
• burial under 0.6 m (2 ft.) of soil

This factsheet deals with burial as an option for disposal for small livestock or poultry mortalities under 25 kg in liveweight size on the farm where they were produced. Poultry are currently not included in the DADA, but they still must be disposed of in an environmentally sensitive manner, since the Environmental Protection Act " prohibits the discharge of contaminants that are likely to have an adverse effect on the natural environment". Pick up by a LDAC is the preferred method of disposal since it promotes resource, reuse and recycling. However, animals under 25 kg have a much lower commercial value than larger ones, and a free LDAC pick up is difficult to justify.

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Ground Water Contamination Concerns

Burial of mortalities in areas susceptible to ground water contamination could result in adverse affects in nearby wells. The potential for ground water contamination and subsequent well water contamination is a function of the soil type, bedrock depth, and ground water depth.

Soil Type

Coarse soils may increase ground water contamination risks because they allow rapid movement of liquids away from the burial site with minimal filtration or treatment.

Bedrock Depth

Open fractures in bedrock permit rapid movement of contaminated water with minimal filtration or treatment. Shallow bedrock is therefore a concern.

Ground Water Depth

The zone above the ground water table up to the soil surface is effective in destroying some biological contaminants. However, this zone is minimal in areas where the water table is high. Depending on the combination of these three features, the ground water contamination potential could change. Ontario's Environmental Farm Plan (EFP), prepared by the Ontario Farm Environmental Coalition (with technical expertise from the Ontario Ministry of Agriculture and Food, among others) specifies a method of determining the potential for ground water contamination on the farmstead. It indicates how to determine if the ground water contamination potential is:

There are no ideal burial conditions to reduce the potential for ground water contamination because areas with clay soils often have a high ground water level. Avoid areas of thin soil cover over a bedrock layer. For the purposes of this factsheet, use Table 1 to determine which ground water contamination category the burial site falls into. For more information on attending an EFP workshop, call the OMAFRA Agricultural Information Contact Centre at 1-877-424-1300.

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1 - High; 2 - Moderate; 3 - Low; 4 - Very Low

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Surface Water Contamination Concerns

Improper burial of mortalities can also result in surface water contamination affecting the water quality draining into watercourses, open-top catch basins and ponds. Some land has a higher potential for surface water contamination because of the topography and soil type.

Topography

Hilly land is of more concern than flat land, since it promotes more rapid surface water runoff during spring runoff or heavy rainfall.

Soil Type

Since they promote more rapid runoff, heavier soils such as clay are of more concern than lighter soils such as sand. Unfortunately, the best soil condition to reduce ground water contamination (a fine-grained, heavy soil like clay) also helps promote rapid runoff that can contribute to surface water contamination. This paradox complicates the choosing of an ideal burial site. However, in most cases, the optimum burial site is one that is relatively level, while following the guidelines to reduce the potential for ground water contamination. Refer to Table 1.

How Suitable is Your Land for Burial of Mortalities?

To check the suitability of a farm for burying mortalities, consult soil and topographic maps, and dig test holes in the area to see how close the ground water is to the soil surface. Dig your test holes in early spring when the ground water is normally highest. 50 mm (2 in.) soil auger probes are available in extendable lengths that allow simple depth investigations up to 3 m (10 ft.). Do not bury mortalities on hilly land, because the soil covering the mortalities could wash out during rainstorms, and surface water could become contaminated. Keep burial sites on relatively flat land that is less than 0.5% slope (0.5 m drop per 100 m).

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Other Concerns

If mortalities are not buried properly, wild animals, dogs, or birds could exhume them and help spread diseases. Partially decayed mortalities are unsightly, attract rodents, smell and are a breeding spot for flies.

Expected Mortality Losses

Different types of animals have different death losses, but death rates are usually highest when the animals are young. Table 2 lists some of the estimated masses of mortalities.

1. Since poultry are not included in the DADA, they can be held in freezers during winter for future burial in warm weather, or periodic pickup by a LDAC.
   
   
2. Many LDAC will not pick up sheep mortalities because of Bovine Spongiform Encephalopathy (BSE) fears, so adults up to 75 kg in size are shown as well, requiring a large burial hole.

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Burial Guidelines

It is impossible to bury mortalities during cold weather when the ground is frozen. Burial in most parts of Ontario should only be done during the eight "warm months" between April and November. During the winter, have swine or goat mortalities picked up by an LDAC as specified in the DADA or composted. Sheep are also covered by the DADA, but because of fears of Bovine Spongiform Encephalopathy (BSE), many LDAC will not pick them up. If an LDAC will not pick up your sheep mortalities in winter, dispose of them through proper composting. Poultry are not included in the DADA, so they can also be stored temporarily in a freezer for future burial, or for periodic pick up by an LDAC. In fact, freezers could be used in the summer to temporarily store poultry mortalities for a few days until there are enough to make digging a hole more practical. Use common sense when burying mortalities. Some of the following guidelines were originally developed by the Missouri Department of Natural Resources, but have been adapted for Ontario conditions. The guidelines are based on a safe maximum mortality weight per area of land.

Burial Rates

The suggested burial rate varies according to the EFP method of determining the ground water contamination potential. (See Tables 1 and 3). Note that burial of mortalities is not recommended on soils that have a high ground water contamination potential.

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For example, suppose a swine farmer has 8 farrowings/week (Table 2) with 1,700 kg (3,740 lb) of mortalities produced over the eight "warm" burial months. At a local Ontario Environmental Farm Plan workshop, the farmer established that the ground water contamination potential was moderate. From Table 3, about 1,000 kg (2,200 lb) of mortalities can be buried on each hectare, so 1.7 ha (4.2 acres) of burial land is required every year. In another case, a farmer produces 200,000 broilers each year. From Table 2, about 5,600 kg (12,320 lb) of mortalities are produced in the eight "warm" burial months. The farmer has established the ground water contamination potential to be very low, so from Table 3, slightly more than 1 ha (2.5 acres) of burial land is needed each year.

Returning to the Same Burial Sight in Future

Do not use more than about 10% of your land for burial in any one year. In other words, only use a burial site once every 10 years.

Burial Depth and Cover

Dig the burial hole about 1.0-1.2 m deep (3-4 ft.) below the original ground level. Deeper holes are more difficult to dig, particularly if the inside slopes are quite steep; shallower holes would not permit at least 0.6 m (2 ft.) of soil cover; and wider and longer holes could take an unacceptably long time to fill before moving on to another site. A hole this size should accommodate the relatively small size of mortalities up to 25 kg in weight. Immediately cover animal or poultry mortalities with a minimum of 0.6 m (2 ft.) of soil, including soil crowned up over the hole about 0.3 m (1 ft.) deep. This mounding helps prevent scavenging animals from exhuming the mortalities, allows for settling and helps shed surface water.

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Maximum Mortality Weight and Spacing of Burial Sites

Several small burial sites that are spread out with less mortalities in each one are better than fewer, larger sites with many mortalities in each. With this in mind, it is recommended that each burial site have no more than about 500 kg (1,100 lb) of mortalities in them, and not be closer than about 15 m
(50 ft.) apart.

Distances from Burial Sites to Water Sources

To protect the water in wells, use the separation distances found in Table 4, based on the EFP method for determining the ground water contamination potential.

1. Minimum to be consistent with water well regulations made under the Ontario Water Resources Act R.R.O. 1990, Regulation 903 "Wells"

Providing the burial sites are on relatively flat land under about 0.5% slope, the separation distances from burial sites to open-top catchbasins, ponds used for watering livestock or poultry, or natural watercourses should be at least 50 m (165 ft.) if possible. Even though it may be difficult on systematically tiled land, try to keep burial sites at least 15 m (50 ft.) from drainage tiles, if possible. Neighbours may be concerned about the burial of animal or poultry mortalities on the farm, because of odours, aesthetics, flies, dogs, vermin, or contamination of their drinking water. As a guideline, don't bury mortalities any closer than about 15 m (50 ft.) from all property lines, and 100 m (330 ft.) from neighbouring homes. Keep mortalities and burial sites out of view, if possible.

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Digging a Proper Hole

There are 2 methods of digging a hole:

• back-hoe for big holes, or a
• tractor-mounted post-hole auger for small holes.

Occasionally holes are dug using a shovel, but this is too time consuming and difficult on a regular basis.

Big Holes Using a Back-Hoe

You can hire a contractor to dig a deep, narrow hole (usually one hoe-width wide), to gradually fill over time. (See Figure 1). Unfortunately, there are two problems with filling a hole over an extended period. First, the mortalities may only be partially covered with soil between burial intervals, allowing exhumation by wild animals or dogs. Second, an open hole could be hazardous to wildlife, domestic animals, farm equipment, hunters, all terrain vehicles, and children.

Figure 1. Big hole dug by a back-hoe for up to 500 kg of mortalities.

To prevent problems, cover mortalities with 0.15 m (6 in.) of soil between burial intervals, then cap the hole with a 13 mm (1/2 in.) thick 1.2 x 2.4 m (4 ft. x 8 ft.) piece of plywood, or equivalent, that is secured on the top edges with soil. Install a bright flag warning of the hole location. Do not leave a hole such as this 'unfilled' for more than a few days. To keep mortality weight in the hole under 500 kg (1,100 lb), dig big holes no more than 1.2 m (4 ft.) deep, 2.0 m (6.5 ft.) long at the top and 0.5 m (1.5 ft.) wide at the top and bottom (since the entire hole is usually one backhoe width wide). The excavated volume of a hole this size is only about 0.8 m³ (1.0 yd³), which could be dug by an experienced back-hoe operator in minutes. Other problems include rainwater accumulating in the hole between burials, and safety concerns with slumping inside slopes since they are usually steep. Do not allow any one to jump into a deep hole such as this, since unstable side slopes could collapse.

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Small Holes Using a Tractor-Mounted Post-Hole Auger

Tractor-mounted post-hole augers are available in a number of diameters. The smallest diameter of hole that is practical to consider for burial of mortality purposes is about 0.3 m (1 ft.), since anything smaller would not fit a 25 kg mortality without some difficulty. For farmers with many mortalities to bury, owning a tractor-mounted auger in diameters up to 0.6 m (2 ft.) might be justified. Again, cover mortalities between burial intervals with at least 0.15 m (6") of soil, use a secured plywood cap and flag the hole to provide warning. See Figure 2. Try not to leave a hole unfilled for more than a few days. A hole 1.2 m
(4 ft.) deep and 0.3 m (1 ft.) in diameter can handle about 50 kg (110 lb) of mortalities. A few holes could be augered at one time, then used as they are needed, provided they were suitably covered, secured, and marked with warning flags.

Figure 2. Auger hole for up to 50 kg of mortalities.

Record Keeping

Keep records of the burial sites to avoid digging again too soon in the same location. Important information to record for each site is its:

• exact location in relation to some fixed point
• date of burial
• type and size of animal mortalities
• reason for death
• approximate total weight of mortalities.

Consider drawing burial locations on an aerial photo of the farm to help with your record keeping

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