- Preparing the farrowing room is key
- Evaluate the environment daily
Raising health piglets depends on good farrowing management.
To appreciate the details of the farrowing process, it is necessary to understand the structure of the pelvis and the reproductive tract at farrowing.
In the televised training which was broadcast across Vision Group TV platforms – Bukedde TV and Urban TV – Dr Micheal Buwembo explained that as farrowing approaches, the vulva becomes enlarged, together with the vagina that leads to the cervix or opening into the womb.
A small lubricated hand and arm can be inserted into the vagina to just beyond the cervix without damage. The neck of the cervix opens into the two long horns of the womb that contain the piglets. The umbilical cord of the piglet terminates at the placenta which is attached to the surface of the womb. Nutrients pass from the blood of the sow across the placenta and into the developing piglet. The placenta also extends around the piglet as a sac that contains fluids and waste materials, produced by the piglet during its growth. The placenta and the sac are referred to as after birth.
How does farrowing start
This is an intriguing mechanism activated by the piglet once it reaches its final stage of maturity, at approximately 115 days after mating. The sequence of events is depicted in the photos below.
The piglet activates its pituitary and adrenal glands to produce corticosteroids. These hormones are then carried via its bloodstream to the placenta.
The placenta then produces prostaglandins which are circulated to the sow’s ovary. As you will have seen earlier, the corpora lutea in the ovaries are responsible for the maintenance of pregnancy.
Prostaglandins cause them to regress, thus terminating the pregnancy and allowing the hormones that initiate farrowing to commence.
The farrowing process
This can be considered in three stages, the pre-farrowing period, the farrowing process, and the immediate post-farrowing period when the afterbirth is expelled.
The pre-farrowing period
The preparation for farrowing starts some 10 to 14 days before the actual date, with the development of the mammary glands and the swelling of the vulva. At the same time, teat enlargement occurs and the veins supplying the udder stand out prominently.
The impending signs of farrowing include a reduced appetite and restlessness, the sow standing up and lying down, and if bedding is available chewing and moving this around in her mouth. If she is loose-housed on straw she will make a bed. Within 12 hours of actual delivery of piglets, milk is secreted into the mammary glands and with a gentle hand and finger massage, it can be expressed from the teats. This is one of the most reliable signs of impending parturition.
A slight mucous discharge may be seen on the lips of the vulva. If a small round pellet of faeces is seen in the mucus and the sow is distressed, farrowing has started and the first piglet is likely presented backward. This small pellet is the meconium or first faeces coming from the rectum of the piglet inside. An internal examination is immediately required. The final part of stage 1 is the opening of the cervix to allow the pigs to be pushed out of the uterus, through the vagina, and into the world.
The farrowing process
This can range from 3-8 hours and piglets are usually delivered every 10 to 20 minutes but there is a wide variation.
Consult the sow and litter card to see if there have been any previous problems at farrowing. For example, if a sow has had high stillbirth rates, monitor her more closely and take any necessary actions. There is often a gap between the first and second piglet of up to three-quarters of an hour. The majority of pigs are born head first but there are more pigs presented backward towards the end of the farrowing period.
Immediately before the presentation of a pig, the sow lays on her side, often shivering and lifting the upper back leg. This is an important point to take note of because it may indicate the presence of a stillborn pig. The twitching of the tail is seen just as a pig is about to be born.
Delivery of the placenta
This usually takes place over one to four hours and is an indication that the sow has finished farrowing although some afterbirth will sometimes be passed during the process of farrowing. Once the sow has completed the farrowing process certain signs should be observed.
- She appears at peace, grunts, and calls to the piglets.
- The shivering and movement of the top hind leg cease. If this is still occurring, likely, a pig is still presented.
After the placenta has been delivered, there will be a slight but sometimes heavy discharge for the next 3-5 days. Provided the udder is normal, the sow is normal, and eating well ignores it, it is a natural post-farrowing process.
Occasionally, a pathogenic organism enters the uterus causing inflammation. This may cause illness, requiring treatment.
More in the video below;