One of the big advantages of farming pigs is their ability to reproduce.
Sows can produce over two litters per year with in excess of 20 piglets weaned. This is a very high reproductive rate compared to cattle and sheep for example. This article covers the basic information you need to adequately manage breeding pigs.
When to breed
As many as 85-95% of sows return to oestrus (i.e. will stand for the boar) within four to seven days after weaning, so plan weaning around the availability of a boar and have him present before you wean.
How to detect pigs in heat
At weaning, place the sow in a pen next to the boar so that she is aware of his presence. On day three after weaning the sow should be checked twice daily for signs of heat. The initial signs are reddening and swelling of the vulva but the sow is only ready to accept the boar when she stands still to pressure applied to the back by pressing firmly on the rump and lower back. If the sow stands still without attempting to get away she is ready for the boar.
How to manage the boar
If you only have a small number of sows it is not necessary to prevent overuse of the boar so the sow can be run with the boar and nature be allowed to take its course.
For supervised matings, allow two matings 24 hours apart if you are confident at heat detection. If not then three matings 12 hours apart is recommended.
Put the sow with the boar and wait while they mate. A successful mating is usually completed in three to five minutes. The boar will spend some initial time nudging the sow before mounting and if the sow attempts to avoid contact with the boar at this stage she is not ready.
After mounting make sure that he has entered the sow. It is recommended to gently direct the pizzle by holding the sheath if the boar is having difficulty. Boars quickly get used to this manipulation. A gelatinous clump is often discharged onto the ground after a mating, this is normal and does not mean that the mating was unsuccessful – in fact it is a good sign.
After a successful mating, separate the pigs and repeat the process in 12 to 24 hours. Boars are capable of servicing 2-3 sows per week (each service comprising 2-3 matings) for an indefinite period if the matings are supervised. His fertility is likely to be lowered if he is overworked or if not used at least once a week, so keep him occupied.
Reproductive values you need to know
|1st heat after weaning||4-7days|
|Time between heats||21 days (± 3days)|
|Gestation (pregnancy) length||114 days (3 months, 3 weeks, 3 days)|
|Puberty||180-190 days of age|
Factors affecting sow performance
Management has a major influence on sow performance. By following some basic principles, sow performance can be maintained at a consistently high level.
|Piglets as mummies||<0.5%|
*Farrowing rate is the number of sows/gilts farrowing as a percentage of the number mated
MMA: Mastitis Metritis and Agalactia
This has a devastating effect on some litters. The affected sow fails to let down her milk and by the time she recovers two to three days later the entire litter may be lost. Treatment often gives disappointing results because it is started too late, so early detection and intervention is important.
A more effective option is to have a prevention strategy in place. The disease is not fully understood but E. coli and other bacteria that are commonly found in faeces are the most likely cause, so hygiene is important along with these other strategies.
This is just an overview of a complex area. Problem-solving requires discussion at an individual level, so we encourage you to contact us with any enquiries you may have.