Health, Disease and Biosecurity in Depth

Biosecurity is not a fence or a footbath. It is the set of rules that decide what is allowed to touch your pigs. For diseases with no vaccine and no treatment, and African Swine Fever is the headline example, biosecurity is not one control among several. It is the only control.

How disease gets in

Almost every introduction onto a smallholder pig unit arrives by one of these routes:

• New pigs bought in, especially from markets or unknown sellers, including a boar borrowed for service.
• People - traders, neighbours, other pig farmers, and you returning from a market or another farm.
• Vehicles and equipment - the trader's pickup, borrowed buckets, shared wheelbarrows, needles and knives.
• Feed - especially uncooked swill or kitchen waste containing pork, and feed stored where rodents and stray animals reach it.
• Other animals - dogs, rodents, free ranging pigs from neighbours, wild suids, and in parts of Africa soft ticks in old pig housing.
• Pig products - a piece of pork or a cured sausage brought onto the farm and dropped where pigs can reach it.

Zone the farm

Draw your farm on paper and mark two zones.

The dirty zone is everything outside the pig area: the road, the gate, the parking spot, the house, the market. The clean zone is the pig houses and the paths between them.

Then mark the line between them. That line should have exactly one crossing point. At that crossing point you need three things: a place to change or dip footwear, a place to wash hands, and a barrier that a casual visitor will not simply walk through.

The practical barriers

1. A perimeter that stops loose animals. It does not need to be expensive fencing. It needs to keep neighbouring pigs, dogs and pigs of unknown status out, and your pigs in.
2. Farm-only boots. A pair of boots or shoes that never leave the clean zone is worth more than any footbath. If you use a footbath, the disinfectant must be changed regularly and boots must be scrubbed clean of mud first, or the bath does nothing.
3. A visitor rule. No one who has handled other pigs in the last few days enters your pig houses. Traders and butchers wait at the gate or at a loading point. Pigs are brought to them; they do not walk down the pen line.
4. A loading area at the boundary. Buying and selling vehicles should never enter the clean zone. Build a simple loading race at the fence line.
5. Never share needles, knives or castration equipment between farms, and never between sick and healthy pigs.
6. Feed and store control. Feed stored rodent proof, off the floor, and never swill containing pork.

Cleaning between batches

All in, all out is the strongest routine available to a small farm. Empty the pen, remove all manure and bedding, wash with water and detergent to remove organic matter, then disinfect, then leave the pen dry and empty for a few days before restocking. Disinfectant applied on top of dirt is wasted money; the scrubbing does most of the work.

Write the rules and show them

Biosecurity fails when it lives only in your head. Write six or eight rules on a board at the gate in the language your visitors speak. It converts an awkward personal refusal into a farm policy, which is far easier to enforce with a relative or a persistent trader.

Most catastrophic outbreaks on small farms start the day a new pig arrives. A pig can be carrying and shedding disease while looking perfectly healthy. Quarantine is the single highest value routine in this whole module, and it costs almost nothing.

Before you buy

• Buy from a known farm, not from a market where pigs from many sources have mixed.
• Ask to see the herd of origin. Look at the whole herd, not the pig you are being sold. Are there thin pigs, coughing pigs, scouring pens, or recent deaths?
• Ask directly whether there has been any recent unexplained death, and whether there is African Swine Fever in that district.
• Ask what the pig has been fed, dewormed with and vaccinated for, and get it in writing if you can.
• Buy the fewest number of separate sources you can. One source is safer than three.

The quarantine pen

It must be:

1. Physically separate - as far from the main herd as your land allows, ideally downwind, with no shared drainage running from the quarantine pen towards the main pens.
2. No nose to nose contact - a solid barrier or a real gap, not just a shared wire wall.
3. Separately equipped - its own buckets, shovel, brush and feed scoop, marked in a different colour so nothing wanders.
4. Visited last - you feed and clean the main herd first, then the quarantine pen, then you leave. Never the other way round.
5. Separately booted - a dedicated pair of boots and overall for the quarantine pen, or wash and change on the way out.

The sequence

Plan for a quarantine period of at least 30 days. Shorter periods are common and are a compromise; 30 days gives most incubating diseases time to show.

1. Day 0. Unload at the boundary. Weigh or tape and record. Record where the pig came from, the seller's name and contact, and the date. Look over the whole animal: skin, ears, feet, breathing, eyes, dung.
2. Days 1 to 30. Check twice daily. Record temperature if you have a thermometer, and record appetite, dung consistency, coughing and any lameness. Any fever, off feed, red or blotchy skin, or bloody dung is a stop signal - do not move the pig closer to the herd, and call your vet or extension officer.
3. During quarantine. Deworm and treat for mange according to the product label, following your vet's advice, and give any vaccinations your area requires. Quarantine is the ideal window for this because you are handling the pig anyway and it is away from the herd.
4. End of quarantine. If the pig has been completely normal for the whole period, move it in. Even then, introduce it into a pen alongside a few of your own pigs first rather than straight into a large group.

The borrowed boar problem

A boar that walks between farms to serve sows is a disease delivery service. If you must use an outside boar, treat him exactly like a bought in pig: he is quarantined, or the service happens at the boar's home farm, or you use artificial insemination where it is available. Do not let a visiting boar walk through your pen line.

The pig that leaves and comes back

A pig taken to a market or a show and not sold has mixed with unknown pigs. It is a new pig now. Quarantine it on return with the same rules. Farmers find this hardest to accept and it is exactly how outbreaks arrive.

African Swine Fever is the defining risk for pig farmers in this region. There is no cure and no vaccine you can rely on to protect a commercial herd. Virulent strains can kill nearly a whole herd within days. Control is biosecurity, early recognition and rapid reporting. Nothing else.

What it looks like

ASF is not one picture. In acute form the signs commonly reported include:

• High fever, followed by pigs going completely off feed while still drinking.
• Pigs lying down, reluctant to move, huddling, weak in the hindquarters.
• Reddening or blotchy purple discolouration of the skin, most visible on the ears, belly, snout and inner legs, and most obvious on white skinned pigs.
• Difficult breathing, discharge from eyes or nose, vomiting, and diarrhoea that may be bloody.
• Abortion in pregnant sows.
• Death in a very short time, sometimes before you notice the pig was ill, and deaths that spread from pen to pen over days.

The single most important warning sign is not any one symptom. It is multiple pigs dying in a short period without an obvious explanation. Do not wait to be certain. ASF cannot be confirmed by looking at a pig; confirmation needs laboratory testing.

How it spreads

1. Direct contact between infected and healthy pigs, including nose to nose over a fence.
2. Feeding uncooked or undercooked swill containing pork. The virus survives for long periods in raw, frozen and cured pork products.
3. Contaminated boots, clothing, vehicles, equipment, needles and knives.
4. Contact with wild suids and, in parts of Africa, soft ticks that live in old pig housing.
5. Movement of infected pigs by traders, which is why a trader offering suspiciously cheap pigs during an outbreak is a serious danger.

The suspicion protocol

The moment you suspect ASF, act as if it is confirmed. Every hour matters.

1. Stop all movement. No pig leaves your farm. No pig, feed or equipment comes in. Do not sell, do not slaughter for sale, do not give a pig away.
2. Report immediately to your government veterinary officer, animal health technician or extension officer. In most countries in this region ASF is a notifiable disease and reporting is a legal duty. Reporting also protects your neighbours and may open access to official response support.
3. Isolate. Separate affected pens. Handle affected pens last. Do not move pigs between pens to make space.
4. Do not let dead pigs move or be eaten. Do not sell, butcher or share a pig that has died or that you suspect. Keep dogs and scavengers away from carcasses. Follow your veterinary officer's instructions on carcass disposal, which is normally deep burial or burning on the property.
5. Lock the gate. No visitors at all. Turn away traders and neighbouring farmers, politely and firmly.
6. Record everything. Dates, pen, pig identity, signs seen, times of death. This record is what allows the vet to work out how it entered and when.
7. Wait for official guidance before restocking. Clean and disinfect thoroughly, remove all manure and bedding, and leave the premises empty for the period your veterinary authority advises.

Why farmers lose more than they need to

The two behaviours that turn a bad outbreak into a regional disaster are panic selling of pigs at the first sign of trouble, and salvage butchering of sick or dead animals. Both move the virus off your farm and into other people's herds, and both are how the disease returns to you next season. If you sell into an outbreak, you are buying next year's outbreak.

Prevention is the whole strategy

Reread that sentence. Since there is nothing to treat with, everything you do about ASF happens before it arrives: no swill with pork, no unquarantined pigs, no visitors in the pens, no shared equipment, no borrowed boar, no vehicles inside the clean zone.

Parasites rarely kill pigs outright. They do something more expensive: they take a share of every kilogram of feed you buy, slow growth, and keep pigs on the farm for extra months. On many smallholder farms parasite control is the cheapest available improvement in feed conversion.

Internal worms

Pigs on soil, on deep litter or in pens that are not properly cleaned pick up worm eggs from contaminated ground and from their own dung. The signs are quiet:

• Poor growth and uneven pigs in a pen despite adequate feed.
• Rough, dull coat and a pot bellied look in young pigs.
• Occasional coughing, because some worm larvae migrate through the lungs.
• Visible worms in dung, which means the burden is already heavy.
• At slaughter, white spots on the liver, which is a common finding that tells you your control has been failing.

Ask your butcher or abattoir to tell you about liver condemnations from your pigs. It is free feedback on your worm control.

Mange

Mange is caused by a mite living in the skin. It is intensely itchy and it is contagious between pigs and through contact with contaminated housing and equipment. Look for:

• Constant rubbing and scratching against walls and posts.
• Thickened, crusty skin, especially inside and around the ears.
• Red spots and scratch damage on the flanks and shoulders.
• Poor growth, because an itching pig does not rest or eat properly.

Mange is often carried by the older breeding stock, particularly boars, and passed to every litter. If you treat only the growers, it comes straight back. Treat the breeding herd as part of any mange programme.

Treatment principles

Do not guess products or doses. Work with your vet or animal health technician on which product to use, and follow these rules whichever product you use:

1. Dose by weight. Underdosing wastes the drug and encourages resistance. Tape the pig and dose to the real weight, not to a guess.
2. Treat the group, not the individual. Treating one pig in a shared pen achieves very little.
3. Repeat correctly. Many treatments need a second dose after a defined interval to catch the stages that survived. Follow the label.
4. Observe withdrawal periods. Every product has a period before slaughter during which the pig must not be sold for meat. Record the treatment date and the earliest safe slaughter date on the pen card.
5. Record every treatment - date, pen, product, dose, who gave it.

Management beats medicine

You can deworm every month and still lose the battle if pigs are re-infected the same week. Break the cycle:

• Remove dung daily; worm eggs build up in accumulated manure.
• Clean and dry the pen between batches. Many worm eggs are tough, and thorough physical cleaning is the main tool.
• Treat and clean sows before farrowing so they do not pass a burden to the litter.
• Do not rotate pigs through the same small patch of bare soil year after year.
• Control rodents, which are involved in some parasite cycles and contaminate feed.

Judge it by results

After a proper parasite programme in a herd that had a problem, you should see it in the numbers: more even pigs in a pen, better daily gain, lower FCR. If nothing changes, parasites were not your limiting factor and you should look at feed quality, water and heat instead.

Early detection is worth more than any drug cupboard. A pig treated on day one usually recovers and keeps growing. The same pig treated on day four may survive but never catch up, and it has been shedding infection to its penmates the whole time.

The daily check

Do it at feeding, when pigs are naturally active. Feed, then stand back and watch for two minutes per pen.

1. Does every pig get up and come to feed? The pig that stays lying down is your first patient.
2. Breathing. Watch the flanks at rest. Fast, laboured or thumping breathing, and coughing when the pen is disturbed, are warning signs.
3. Dung. Walk the pen floor and look. Watery, bloody or unusually coloured dung tells you before the pig looks ill.
4. Movement. Any limp, stiffness, swollen joint or reluctance to bear weight.
5. Skin and ears. Scratching, crusting, red or blotchy discolouration, wounds, tail or ear bites.
6. Body condition. Any pig visibly smaller or thinner than its penmates.
7. The environment. Water flowing, feed present, bed dry, no draught, no smell of ammonia.

If something is wrong, mark that pig immediately with a livestock crayon and write it in the day book. Memory fails; marks and books do not.

Scours (diarrhoea)

Most common in piglets and newly weaned pigs. Causes range from infection to a sudden feed change, dirty water, and chilling. Actions: check and correct water quality and feed changes first, keep the pig warm and dry, provide clean water because dehydration is what kills, isolate badly affected animals, and involve your vet if it spreads through the pen or if piglets are dying. Never buy antibiotics on guesswork; get advice, use the correct product and dose, and observe withdrawal periods.

Respiratory disease

Coughing that spreads through a pen usually reflects both infection and environment. Dust, ammonia from wet floors, draughts, overcrowding and sudden temperature swings all make it worse. Improve ventilation without creating a draught on the sleeping area, remove wet bedding, reduce stocking density, and take veterinary advice on treatment. Coughing that is ignored becomes permanent poor growth in that batch.

Lameness

Look for the cause before treating. Rough or broken concrete, slippery floors, sharp objects, foot injuries, joint infection from a dirty environment, and fighting after mixing are all common. A lame pig eats less and loses condition fast. Isolate it where it can reach feed and water without competition.

The temperature habit

A cheap thermometer is one of the best purchases a pig farmer makes. Knowing that a pig is running a fever, rather than guessing, changes your urgency and gives your vet real information over the phone. Learn what your own healthy pigs read at the same time of day, and treat a clear rise above that as a signal.

Isolation pen

Keep one small pen empty for sick pigs. Move the sick pig out rather than moving the pen around it. Attend to it last. Clean it fully before the next occupant.

When to call

Call your vet or animal health technician when more than one pig in a pen shows the same signs, when a pig dies unexpectedly, when treatment has not worked within the expected time, or when you see anything that could be ASF. Calling early is cheaper than calling late.

In an outbreak nobody thinks clearly. The farms that come through are the ones where the decisions were made in advance, written down, and known to everyone who works with the pigs.

The one page plan

Write it on one sheet, laminate or cover it, and pin it in the feed store. It has six parts.

1. Contacts. Vet or animal health technician, government veterinary officer, extension officer, and a second farmer you trust. Names and numbers, written large.
2. Trigger list. The specific things that mean act now: any unexplained death, two or more pigs off feed in one pen, bloody diarrhoea, blotchy purple skin, abortion in a sow, or any pig down and unable to rise.
3. Immediate actions. Stop all pig movement on and off the farm. Close the gate to visitors. Handle the affected pen last. Isolate what can be isolated. Record what you see, with times.
4. Who does what. Name the person who makes the call, the person who feeds the affected pen, and the person who keeps the record. On a one person farm, name your stand in.
5. Not to do list. Do not sell pigs. Do not slaughter for sale. Do not move pigs between pens. Do not accept new pigs. Do not let dogs or neighbours near carcasses.
6. Restocking rule. No new pigs until the veterinary authority advises it, and not before full cleaning, disinfection and a written down empty period.

Investigating a sudden death

Sudden death is not a diagnosis, it is a question. Many events described as sudden death turn out to be African Swine Fever or poisoning, and both need investigating rather than assuming.

Work through this list before you conclude anything:

• How many? One pig or several? Several deaths close together in time is the ASF pattern and demands an immediate report.
• Was it really sudden? Ask whoever fed yesterday whether that pig ate normally. Often the pig was off feed and nobody recorded it.
• Poisoning. What changed in the last few days? A new feed batch, mouldy feed, a new ingredient, spilled pesticide, treated seed, rodent bait, a leaking chemical container, a plant in a new grazing area, or salt poisoning where water ran out and pigs then drank heavily. Check the feed store and the ground the pigs can reach.
• Physical causes. Overheating on a very hot day, crushing of piglets, fighting after mixing, electrocution, a fallen structure.
• Medicine. Was anything given recently, at what dose, by whom?

Then call your vet. Where it is available and safe, a post mortem examination is the fastest way to a real answer, and it should be done by, or under the guidance of, a qualified person. Do not open a carcass you suspect of ASF - report it instead, because opening it spreads virus. Keep the carcass secure, away from dogs and scavengers, until you have advice.

The mortality log

Keep it as a permanent record with these columns: date, pig or pen identity, age or weight, sex, signs seen before death, suspected cause, action taken, who was told. Add a column for what you changed as a result.

One death tells you little. Twelve rows in a log tell you a great deal: that most losses are piglets in the first week, or that deaths cluster after every feed change, or that one pen loses pigs and the others do not. That pattern is where the money is.

Review it

Read the mortality log at the end of every quarter alongside your feed and weight records. Write one sentence on what you will change. A plan that is never reviewed is decoration.