The vacuum pressure should be about 10 inch Hg. and should be set between 10 to 12 inch Hg. Same for cow or goat milkers. Try not to get more than 15 inch hg, too much suction will bruise the teats. bellow 9 will slow the milking process. This pressure suggestion is base on pulsator based milkers. I see some cheap milkers that does not come with a pulsator, nor a vacuum gauge, nor regulator where you can adjust the pressure. The pulsation create a motion of the inserts/inflations in the cups, that is equivalent a massaging therapy to the odder, and mitigate the suction applied to the teats and stimulate the blood circulation, and reduce the bruising.
Never buy those milker that put a consistent suction to the teats and pulling out the milk. The best and reasonable milkers are at
https://milkersupply.com. The cow milkers, or goat milkers, all come with the components I mentioned.
Jack
