What is a pregnosticator and how does it work?

I am not familiar with the "pregnosticator" (maybe prognosticator), however, there are several methods of detecting pregnancy in sows. One device that has been around a long time uses ultrasound transmitted from a probe. Ultrasound waves pass into the sow’s body and are reflected back from the tissues/fluid in the sow’s uterus, giving a positive sound tone. Once the sow is 65-70 days in pig, testing accuracy decreases as uterine liquids decrease. Be aware that this type of tester will give a positive signal from any fluid in the sow’s abdomen, including urine.

Another type of tester is based on the doppler principle. In this case, a probe attached to a pair of earphones emits high frequency sound waves. These sound waves pass into the sow’s abdomen. A pulsating sound relayed via the earphones indicates pregnancy.

Pregnancy scanners are the ultimate in terms of technological application and cost. A probe picks up an image of the uterus, which is then displayed in black and white either on a small screen or a head-up display incorporated into a headset. Normally sows are scanned at 23-24 days and again this allows barren sows to be picked up at the second return date. A skilled operator can also identify cysts, cystic ovaries and the like.