Breeds & Genetics

Farmers are sold breeds the way people are sold medicine, as if the animal alone will fix the farm. It will not. Genetics sets the ceiling of what an animal can achieve. Feed, water, housing and health decide how close it gets to that ceiling. An exotic pig in a bad house on a poor ration will perform worse, and die more often, than a hardy local pig in the same conditions. Understanding this before you spend money on stock will save you a great deal.

Heritability: why some traits improve quickly and others do not

Heritability describes how much of the variation you see between animals is passed to the offspring rather than caused by their environment. It runs from zero to one, and it is the single most useful genetic concept for a practical farmer.

• Moderately to highly heritable traits include growth rate, backfat thickness, feed efficiency and carcass leanness, generally in the region of 0.3 to 0.5. These respond well and fairly quickly to selecting good parents. Buy better genetics and you will see better growth.
• Lowly heritable traits include litter size, piglet survival and other reproductive traits, generally around 0.1 to 0.15. These barely respond to selection within a herd. They respond instead to crossbreeding, to sow nutrition, to farrowing supervision and to housing.

The practical consequence is blunt. If your problem is that pigs grow slowly, better genetics may genuinely help. If your problem is that piglets die in the first week, no breed on earth will save you. That is a management problem and it stays a management problem.

Genotype by environment interaction

Improved commercial genetics has been selected under conditions of unlimited clean water, a balanced ration available at all times, temperature control and tight disease control. Take that animal and put it in a hot, dusty pen on maize bran and kitchen waste, and it will not simply perform a little worse. It will perform far below its potential, may be more susceptible to heat stress because of its greater lean growth and lower fat cover, and can be more sensitive to disease pressure. Meanwhile the local pig, selected over generations for surviving exactly those conditions, keeps going.

This is why the standard advice is upgrade your management first, then upgrade your genetics. In practice, do them in step. When your pigs are reliably reaching market weight on the feed you can afford, that is the moment to bring in better genetics, because now the animal can express what you paid for.

What upgrading realistically buys you

Moving from unimproved local stock to a good improved cross, with management held constant and adequate, typically buys you faster growth, a leaner carcass that butchers pay more for, and a larger mature size. Crossbreeding also buys you hybrid vigour in reproduction, which is one of the few reliable ways to lift the low heritability reproductive traits. What it does not buy you is hardiness, disease resistance, or forgiveness of mistakes. You are trading robustness for performance, and the price of that trade is paid in feed and management.

The rule to carry forward

Match the animal to the system you can actually run, not the system you wish you had. Be honest about the feed you can buy every week for the next five months. If you can guarantee a balanced commercial or well formulated home ration, go for improved genetics. If your feeding is going to be variable and partly based on whatever is available, a hardy cross with some local blood will make you more money than a high performance animal you cannot feed properly.

Only a handful of breeds and their crosses are genuinely available across East and Southern Africa. Knowing what each contributes lets you buy on purpose rather than on the seller's description.

Large White (Yorkshire)

White, erect ears, long body. The most widely distributed improved breed in the region and the backbone of most commercial herds. Strong maternal traits, good litter size, good milking ability, good growth and a lean carcass. It is a genuine dual purpose breed: good enough as a mother and good enough as a terminal sire. If you can only access one improved breed, this is usually the one to build on.

Landrace

White, long body, large forward drooping ears. Selected hard for maternal performance. Typically excellent mothering, good milk production, long body which is associated with more teats and more rib pairs. Slightly less robust than the Large White in tough conditions in many farmers' experience. The Large White by Landrace cross sow is the standard commercial mother worldwide, and for good reason.

Duroc

Red or brown, drooping ears, thicker set. Excellent growth rate and feed efficiency, more intramuscular fat which gives better eating quality, and a reputation for hardiness and robust legs. Duroc boars are widely used as terminal sires over Large White by Landrace sows. As a pure maternal line the Duroc usually gives smaller litters than the white breeds, so use it on the male side.

Hampshire

Black with a distinctive white belt over the shoulders and front legs. Very lean, muscular carcass, good growth. Used as a terminal sire where available. Less common in smallholder circles in the region than Large White, Landrace and Duroc, but present.

Indigenous and local pigs

Local breeds and landraces, including the Mukota type in Zimbabwe and Mozambique, the Windsnyer type in southern Africa, the Ashanti type in West Africa and various unimproved local populations elsewhere, are usually small, often black or dark, slow growing and fat by commercial standards. Do not dismiss them. They tolerate heat, walk further, cope with fibrous and variable diets, are generally better at surviving on low input systems, and local sows are often excellent, attentive mothers. Their weakness is commercial: slow growth, low mature weight, fatter carcass, and a live weight that butchers paying by the kilogram will not reward.

The productive use of local genetics is usually as the female base, crossed with an improved boar, which lifts growth and carcass while keeping some of the hardiness and mothering.

What improved really means when someone sells you a pig

Very few smallholder sales in the region involve genuine pedigree stock with recorded ancestry. Most animals sold as Large White or as improved are crosses of unknown composition. That is not necessarily bad, but you must price accordingly and buy on the evidence in front of you, not on the label. Ask these questions:

1. Can I see the mother, and how many piglets did she wean in her last litter?
2. Can I see the father, or do you know what he was?
3. What was this litter's birth date, and how many were born and weaned?
4. What has this animal been fed?
5. Is there any record on paper?

A seller who can answer three of those five is worth buying from. A seller who can answer none is selling you an unknown animal at a known price, and the price should reflect that.

Crossbreeding is the cheapest genetic improvement available to a smallholder, because it works immediately and it works on exactly the traits that selection struggles with.

Hybrid vigour

When you cross two unrelated breeds or lines, the offspring often outperform the average of the two parents. This is hybrid vigour, or heterosis. Crucially, heterosis is largest in the traits with the lowest heritability, which means reproduction and survival, the same traits that resist ordinary selection. A crossbred sow will typically wean more piglets in her lifetime than either purebred parent line, through some combination of better conception, more piglets weaned per litter, better milk and better longevity. Crossbred piglets also tend to be more vigorous and survive better than purebreds.

Note where the benefit sits. Crossbred piglets give you a modest lift in growth and survival. A crossbred sow gives you a much larger lift, because her advantage applies to every litter she produces for years. That is why commercial systems everywhere use a crossbred mother.

The standard three breed plan

The plan used by nearly every commercial pig industry in the world, and entirely workable at small scale, is this:

1. Cross two maternal breeds, typically Large White and Landrace, to produce your sows. These sows have hybrid vigour in reproduction.
2. Mate those crossbred sows to a terminal sire of a third breed, typically a Duroc or Hampshire, chosen for growth and carcass.
3. Sell every animal from that final cross. Keep none of them for breeding.

The result is maximum hybrid vigour in both the mother and the slaughter generation, and clear roles for each breed. It also keeps your thinking simple: sows come from one place, the boar comes from another, and everything the boar sires goes to market.

The trap: continuous uncontrolled crossing

The mistake smallholders make is keeping a daughter from every cross and putting whatever boar is nearby onto her. After three or four generations, nobody knows what any animal is. Hybrid vigour dilutes, breed composition becomes random, performance becomes unpredictable, and it is very likely that relatives are being mated because everything descends from the same one or two local boars. The herd drifts and no one can explain why the litters got smaller.

The rotational option for very small herds

If buying replacement gilts is not possible for you, a two breed rotation is a workable compromise. Use a Large White boar for one generation, keep the best daughters, use a Landrace boar on them, keep the best of those daughters, then back to a Large White boar, alternating each generation. This retains a useful part of the hybrid vigour indefinitely and, most importantly, it forces you to bring in a new unrelated boar or new semen every generation, which is your inbreeding protection.

Two disciplines make a rotation work. First, record which breed of boar sired each female, so you always know which boar she is due to be mated to next. A coloured ear tag or a notch system is enough. Second, never keep a boar that was born on your farm from your own females.

What to do this season

If you have local sows and want to improve, the highest return single decision is to introduce a good improved boar or improved semen, and keep the resulting crossbred daughters as your future sow herd while selling the males. That one move typically buys you better growth and better carcass in a single generation without losing your existing females.

The gilts you choose today are your herd for the next three to five years. A mistake here repeats itself in every litter she produces. Spend real time on this decision, and never buy a breeding female on impulse at a market.

Count and check the teats first

This is the first thing to do and it decides many purchases on its own. Count functional, evenly spaced teats. You want at least 12, and 14 is better. Regional litters commonly run 10 to 14 born, and a piglet without a teat does not eat, because piglets establish a fixed teat order in the first days of life. Reject blind teats, inverted teats that do not protrude properly, and teats bunched together or set too far back where a piglet lying down cannot reach them. Count on both sides. Teat number and quality cannot be fixed later.

Legs and feet

Watch her walk on a hard surface before you look at anything else on the body. Lameness is one of the leading reasons sows are culled early, which means a gilt with weak legs will never repay the cost of buying her. Look for a strong, even stride, feet with two even toes taking the weight, pasterns that are springy but not flat to the floor, and legs set square under the body rather than close together at the hocks. Reject anything that is stiff, buckles at the knee, or stands on the back of its pasterns.

Body and underline

She should have length and depth of body, a good width across the chest and over the hams, and a straight or slightly arched back. Avoid extremes. A very fat gilt often has trouble conceiving and may have fat deposited in the udder; a very thin gilt has not had the nutrition to develop properly. Check the vulva: it should be well developed and of normal size and shape. A very small or upward tilted vulva is associated with later breeding problems.

The evidence that matters most: her mother

Physical inspection tells you about the individual. Her mother's record tells you about the genetics you are actually buying. Ask to see the sow card. How many litters has the dam had? How many born alive per litter? How many weaned? Did she rear them herself without excessive losses? Has she ever been treated for repeated returns to heat? A gilt out of a sow that has weaned 10 or more piglets across several litters is a far better bet than a better looking gilt out of an unrecorded sow.

Health and source

Buy from as few sources as possible, ideally one. Every additional source is an additional chance of importing disease. Look at the whole herd she comes from, not just her: coughing, scouring, thin animals, sores, or a dirty pen environment all tell you what you would be buying. Ask what the herd's health programme is and what she has been treated for.

Isolate every incoming animal for at least three to four weeks, in a separate pen, fed and attended to last, before she meets your herd. This is the single most important thing you will do with a purchased pig, and it is covered in detail in the biosecurity module.

Getting her to first service

Gilts commonly reach puberty around five to eight months of age, but do not serve her at her first heat. The usual recommendation is to serve at the second or third observed heat, at roughly eight months of age and around 110 to 130 kg live weight, with adequate fat cover. Serving too young and too light gives small first litters and a short productive life. Expose her to a mature boar daily from around five to six months of age to stimulate and bring on cycling, and record every heat you observe so you know her 21 day rhythm.

The boar contributes half the genetics of every piglet born on your farm, so he matters far more per animal than any single sow. He is also, for a small herd, often the worst value animal on the place. Decide deliberately.

The economics of keeping a boar

A mature boar eats roughly as much as a dry sow every day of the year, needs his own strong pen, and produces no saleable output. In natural mating, one mature boar can serve in the region of 15 to 25 sows, and a young boar considerably fewer. So a farmer with four sows is feeding a full time animal for four services a year each. On that arithmetic the boar is a significant cost per litter.

Against that, a boar is always available, requires no technician, no heat detection precision beyond the basics, and no cold chain. In many rural areas he is simply the only option that works.

If you keep a boar

• Buy him unrelated to your females and record where he came from. He is your inbreeding risk.
• Do not work him too young. Start light use from around seven to eight months, and build up. A young boar overworked early can be damaged for life.
• Limit services. A mature boar can typically manage in the region of one service per day with rest days, and less in hot weather. A young boar should do markedly less.
• Keep him cool. Heat damages sperm production, and the effect is delayed: a boar heat stressed today may show poor fertility for around six weeks afterwards, because sperm take that long to develop. Shade, ventilation and wallowing or wetting facilities in hot weather are fertility measures, not comfort measures.
• Feet and legs. A boar with sore feet will not serve. Keep his floor non slip and not abrasive.
• Safety. A mature boar is dangerous. Never enter his pen without an escape route and a board to shield yourself. Serve in a dedicated mating pen with good footing, not in a slippery corridor.
• Replace him before he breeds his daughters. Plan to change the boar or the semen line every 18 to 24 months.

Artificial insemination

AI gives you access to genetics you could never afford to own, removes the cost and danger of keeping a boar, and greatly reduces disease risk since no animal enters your farm. Where a supplier exists within a few hours' travel, it is often the better option even for a small herd.

What it demands from you is precision. Fresh boar semen is normally stored at around 16 to 18 degrees Celsius, not in a household fridge and never in a freezer, and typically stays usable for only a few days. It must be protected from sunlight and from sudden temperature change, and handled gently. You must be able to detect standing heat accurately, because you are inseminating on a schedule rather than letting a boar decide.

Heat detection, whichever method you use

Signs of heat in a sow or gilt include a swollen, reddened vulva, restlessness, mounting other pigs, reduced appetite and a discharge. The decisive test is the standing reflex: with a boar present or with boar contact, press firmly down on her back and sit or lean over her loin. If she stands rigid with ears pricked and will not move, she is in standing heat. Standing heat commonly lasts around two to three days in sows and is often shorter in gilts. The practical rule is to serve or inseminate once standing heat is confirmed and again about 12 to 24 hours later. Check for heat twice a day, morning and evening, not once.

Remember the wean-to-service interval: a sow in good body condition normally returns to heat about 4 to 7 days after weaning. Thin sows return later or not at all, which is a feeding problem, not a breeding problem.

A herd improves through two doors: the one animals come in through and the one they leave through. Most smallholders manage the entry door and neglect the exit door, then wonder why performance stalls. Unproductive sows are the most expensive animals on any pig farm, because they eat every day and return nothing.

When to cull a sow

Decide the rules before you are standing in front of the animal, because in the moment sentiment always wins. Cull for:

• Reproductive failure. Repeated returns to heat after service, or failure to come into heat within a reasonable period after weaning despite good body condition. A common working rule is to cull after two or three failed services.
• Consistently small litters. Not one bad litter, which happens to any sow, but a pattern across litters that is well below your herd average.
• Poor mothering. A sow that repeatedly savages piglets, crushes an unusually high proportion of her litter, or produces too little milk. Some of this is management, so check your farrowing pen before you blame the sow. If she does it in a good pen twice, she goes.
• Lameness and structural failure. Feet and legs are a leading cause of sow culling worldwide. A sow that cannot walk comfortably cannot be productive.
• Not enough functional teats for her litter size.
• Chronic disease or persistent poor condition despite adequate feed.
• Age. Sow output typically climbs through the first several parities, peaks in the middle of her life and declines afterwards. Most commercial systems cull sows somewhere in the region of the sixth to eighth parity, though a genuinely productive older sow with sound legs is worth keeping.

Replacement rate

A herd needs a steady flow of gilts entering. Annual sow replacement rates in commercial herds commonly run around 30 to 50 percent, which means roughly one third to one half of your sows are replaced each year, whether through planned culling or unplanned losses. For a smallholder with four sows, that means planning to bring in or select one or two gilts a year, every year. If you do not plan this, you will end up with a herd of old sows all failing at once and no replacements ready, which forces you to buy in a hurry, at a bad price, from whoever has stock, with all the disease risk that implies.

Select replacement gilts early, at around four to five months, mark them clearly, and feed and manage them as future breeding stock rather than as finishers. A gilt raised on a finishing ration and pushed to grow fat is not well prepared for breeding.

Keeping inbreeding out

Inbreeding is quiet and cumulative. It shows up as smaller litters, weaker piglets, higher piglet mortality, slower growth and more deformities, and by the time it is obvious it has been happening for years. In small herds fed by one or two local boars, it is very common.

Four rules will protect you:

1. Never breed a boar to his own daughters, his mother or his full sisters. This is the highest risk pairing and the easiest to avoid.
2. Replace the boar or change the semen line every 18 to 24 months, before his daughters reach breeding age.
3. Never keep a home bred boar out of your own females. Buy him in, or use AI.
4. Record parentage. Ear tag or ear notch every animal you keep for breeding, and write the sire on the sow card. You cannot avoid mating relatives if you do not know who is related.

If you and your neighbours all use the same boar, your herds are effectively one herd genetically. Coordinate: agree that you buy boars from different sources and rotate, or share the cost of AI. This is a conversation worth having before it is a problem.