Livestock manure is a resource that must be managed: a chicken produces about 0.1 kg a day, a goat 1-2 kg and a cow 25-35 kg. Compost it downhill and downwind of buildings, at least 30 m from any water source, and never enter a manure pit, channel or closed store, because manure gas can kill in seconds.
Part of Barn & Livestock Housing Design
Manure management is the collection, storage and composting of animal waste so that it fertilizes crops instead of fouling water, attracting flies or poisoning workers.
Manure Is Fertilizer And A Gas Hazard In The Same Heap
Manure is a resource, not a waste product, but it has to be managed. It piles up daily, it carries disease organisms, it fouls water and it generates gas. The first three are ordinary farm hygiene. The fourth kills people every year, because the danger sits in the one place nobody expects to be dangerous: the pit or pack that has been quiet for weeks.
Daily production, approximately:
| Animal | Manure per animal per day |
|---|---|
| Chicken | 0.1 kg |
| Goat | 1-2 kg |
| Cow | 25-35 kg |
Collecting and composting is covered in Collection & Composting, and bedding in Bedding Systems. For using the finished compost, see Manure Use and Manure Cycling.
What You Need
- A composting area downhill and downwind of buildings, at least 30 m from any water source, and reachable by cart or wheelbarrow from the barn
- Carbon-rich material — straw bedding, leaves or wood shavings
- A fork, wheelbarrow and gloves
- A plan for keeping children and animals away from any pit or channel
Method: Handle Manure Daily
Step 1: Collect it daily or bed over it. Either scrape manure each day, or use a deep litter pack that is managed as in Bedding Systems.
Step 2: Move it to the composting area. Keep the route separate from the feed and milking routes.
Step 3: Build the pile with carbon. Mix manure with straw, leaves or shavings in the ratio given in Collection & Composting.
Step 4: Keep it away from water. Keep the pile 30 m or more from any water source. Runoff from a manure heap carries bacteria and nutrients into streams and wells.
Step 5: Wash hands and change boots after handling it. Manure carries organisms that cause illness in people, including bacteria, parasites and tetanus spores.
Worked Example
A holding of 2 cows, 6 goats and 20 chickens. Cows: 2 × 25 = 50 kg up to 2 × 35 = 70 kg a day. Goats: 6 × 1 = 6 kg up to 6 × 2 = 12 kg. Chickens: 20 × 0.1 = 2 kg. Total = 50 + 6 + 2 = 58 kg up to 70 + 12 + 2 = 84 kg a day. Over a week: 58 × 7 = 406 kg up to 84 × 7 = 588 kg.
Common Mistakes
- Putting the pile upslope of a well — runoff carries the leachate downhill.
- Treating the pit as an ordinary hole — see the danger block.
- Spreading raw manure on food crops right before harvest — the organisms in it survive on leaves and roots.
Safety
Manure gas kills quickly and without warning
A manure pit, deep wet litter pack, slurry store or under-floor channel produces hydrogen sulphide, together with ammonia, methane and carbon dioxide. Hydrogen sulphide is heavier than air (about 1.2 times as dense, a recalled figure) and pools at floor level and in pits. At dangerous concentrations it deadens the sense of smell, so “I can no longer smell it” means it is getting worse, not better. Stirring, agitating or emptying a store releases a slug of gas; people have died climbing in to rescue a collapsed worker.
Never enter a manure pit, channel or closed store. Never stir or empty a store with people in the building. Ventilate fully and keep everyone out of low spots until it has cleared. If a person collapses in or near a pit, do not go in after them: raise the alarm and rescue from above on a line. Do not use a flame to test the air; a flame ignites methane and tells you little about oxygen.
What’s Next
- Learn next: Collection & Composting — turning manure into compost
- Combine with: Zoonotic Diseases — what manure can carry