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Pork production: Managing the breeding herd

Good management is crucial for any pork producer who wants to farm profitably.

The ultimate goal of a breeding herd is to produce as many weaned pigs per breeding female as possible – per year and over her lifetime on the farm. Dr Peter Evans, a veterinarian, says this should be a major focus in a breeding herd management programme.


Both gilts (young females not yet mated or farrowed) and sows (a breeding female after her first litter) require specialised management. Evans suggests the best time to bring a gilt into the herd is at 24 to 25 weeks.

Young animals introduced into the herd are critical for good performance and litter size. It’s not advisable to have an ageing herd.”

  • The gilt shouldn’t be too fat or too thin. If she’s too thin, she’ll struggle to carry the pregnancy.
  • The feeding programme has to be adjusted to help the gilt continue growing.
  • A female only reaches her full body size and weight during her second pregnancy.
  • But she shouldn’t put on too much fat, because this could lead to birthing and milk production problems.
  • Most gilts reach their third oestrus cycle at 31 weeks of age, at which point their body weight should, ideally be 135 kg to 145 kg.
  • Fat thickness has to be measured to determine if their body is in top condition.

Farmers can measure fat thickness by doing a “visual condition score”, but Evans suggests that they use a P2 meter for greater accuracy, because this form of measurement is less subjective.


  • When female pigs reach the stage where they are classified as sows, they are close to achieving their full body mass.
  • Feeding has to be designed to ensure that sows will gain some fat, but not too much, during gestation.
  • Generally, 18 mm of back fat is suitable while farrowing, but after lactating back fat should reduce by 3 mm to 4 mm (a weaning P2 measurement of 14 mm to 15 mm).

Managing the servicing time is also important. Servicing can be done naturally, using a boar, or through artificial insemination (AI).

“Remember though that AI is a technical procedure that requires skilled management.” Insemination should occur when the sow is midway through the cycle. “At this time, farmers will get the best farrowing rate and litter size,” he explains.

If farmers are using natural mating, they should ensure that over-mating doesn’t occur as this could lead to injuries in the boar and sow, and it could cause uterine infections. Using old, heavy boars isn’t recommended. The area where mating takes place should be dry, to avoid slipping. Farmers should do oestrus tests on females three weeks after service to identify those that did not conceive.


  • Non-productive days occur when females are neither pregnant, nor suckling piglets.
  • It also occurs when pigs are served and miscarry or don’t become pregnant.
  • Such animals should be kept to a minimum in the herd.
  • The number of non-productive days is related to litters per sow per year.

Calculate litters/sow/year by taking the total number of litters born in a 12-month period and dividing this figure by the average number of females in the herd. Evans says that 2.4 litters/sow/year is a good average.

“It is crucial that farmers manage this ratio to produce as many weaned piglets as possible. You need a policy whereby you regularly replace older females with younger gilts.”

If an animal doesn’t milk well, has problems moving, miscarry her pregnancy more than once or is in poor condition because of chronic illness, she should be culled.

“Part of good management is keeping the percentage of animals having the top producing parities (or pregnancies) at their highest. Middle-aged sows are the highest producers on the farm.”

Keep meticulous records of your pigs’ performance so that you can measure performance against parity. Evans adds that farmers will run into trouble if the herd has an unbalanced age distribution.

If there are no young animals and many middle-aged animals, production will eventually collapse because there won’t be enough high-producing animals in the breeding herd.

“Don’t try to save money by not buying young gilts. You’ll save in the short term, but in the long term your business will suffer loss of profits.”


Farmers should have an appropriate vaccination programme to control potential reproductive diseases. A veterinary consultant can help farmers draw up a plan suited to the herd’s specific needs.

“Make sure you see the animals every day. The sooner treatment is administered, the less the chances are of animal’s becoming non-productive.”

  • This article was written by Wilma den Hartigh and first appeared in Farming SA.

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