Ref Code: PIG18

Category

Teaching - 2
Research - 4

Objective

To determine the pregnancy status of a sow.

Alternatives to animal use for teaching

Video presentation

Details of procedure

Methods of pregnancy diagnosis

1. Non-return to oestrus - sows are closely observed when they reach 17-22 days after joining. The non-pregnant sow displays the signs of oestrus especially if a boar is used for detection (see SOP PIG15).
2. Ultrasound - usually used in the 3rd to 5th week after mating (after 21 days).
   1. Real-time ultrasound - this is the most common and accurate system in use in commercial piggeries. Portable machines can be attached to the wrist.
      Quiet sows can be tested in groups. Otherwise move sows to stalls, if not already individually housed. Test sows after 21 days since mating. Place the ultrasound probe on the sow's belly, just above the udder line. Ensure there is enough ultrasound gel on the probe to have good contact with the skin.
      A pregnant sow will have dark circles (the sacs the piglets float in) visible on the ultrasound screen. If unsure, re-check the sow in a week’s time.
   2. Depth-amplitude ultrasound - this detects the fluid-filled uterus. It is inaccurate if pigs are close to oestrus (due to fluid accumulation) or for sows that are later than 60 days' gestation (less fluid).
   3. Doppler ultrasound - this detects the pulsation in the uterine arteries of the sow and foetus. The pulsing throbbing noise is detected using ear phones. It can be difficult to use these machines in noisy environments, so choose a quiet time of day such as when the sows are resting.
      Put the ear phones on, put the oil on the end piece and hold the probe to the sow's belly, just in front of the hind leg. Listen for the distinctive pulse noise of the uterine artery.
3. Visual inspection of sows' bellies, udders and conformation - pregnant sows will usually 'bag up' late in gestation. Their bellies will bulge and there will be a defined line between the udder and belly. It is most useful if there are accurate records of mating.

Work safely - do not place your arms between bars while pregnancy testing sows or this can result in the arm being broken or crushed if the sow suddenly moves.

Drugs, chemicals, or biological agents

Ultrasound gel if using real-time ultrasound; vegetable oil or gel for Doppler ultrasound.

Impact of procedure on the wellbeing of animal(s)

Nil

Reuse and repeated use

No limit on the number of repetitions.

Care of animals(s) during/after procedure

Take care to move the sows quietly in groups.

Pain relief measures

Nil

Qualifications, experience or training necessary to perform this procedure

Demonstrators

Should be familiar with the correct techniques and the anatomy of the pig before attempting this procedure.

Procedures should be demonstrated before being attempted by students.

Students

Should be aware of the reproductive physiology and anatomy of the sow.