This probably has been proven wrong but I used ACV in my does' water tubs, especially just prior to breeding season. We always had MANY more baby doelings born than buck kids and I attributed it to the vinegar in their water.
The theory was that the 'buck semen' is always first to hit the doe when breeding occurs. The ACV the doe drinks has helped wash out the area, killing off the early semen. This allows the pokey 'doe semen' to arrive in good health and ready to turn into a baby doeling. I can see a lot of reasons why that should be an old wives tale, but I do know it worked for me!
Besides it being overall beneficial, when they need to be hauled to strange places, the ACV helps mask any different tastes in the new water, making them more willing to drink it.
So far, my chickens don't really care for it, and since they free range during the day, they have access to more water sources than I provide so I'm not treating their water. Tho in the summer, I think it does help with the bug (especially fly) populations.
Last year I had 2 Longhorn bulls corralled fairly close to the house and to the feed room. They weren't especially friendly so I 'might not have been' as diligent in cleaning out their manure as I should have been. I did keep their water vinegared and it kept the flies down noticeably. That hay and manure has sat ever since last July so it's well rotted and is a wonderful addition to my raised beds. (All good things come to those who wait, even if it is only rotted cow manure <G>!)
One thing I always did with my pregnant does was to clip the hair on their tails just prior to kidding. Yucky - Butt syndrome once they kid, otherwise, and it seemed to last for weeks. Didn't hurt anything, but staring at them 2x per day while milking wasn't very pleasant. I also shaved their udders, especially the rear portion as they filled with milk just to keep the drainage from sticking to them. (If you hand milk and strain it, there are just some things you don't want in there to begin with.)
flylo