Mare's milk can be tested to determine how close she is to foaling. This article will tell you how to obtain that sample safely and comfortably.
How to Milk a Mare
Familiarize your mare with having her udder handled early on in her pregnancy before it gets full and tender. Have someone hold her head. Always stand on her left side, in front of her stifle, facing her hind end. Grab her tail with your right hand and pull it towards you. Reach towards her udder with your left hand and touch it gently. If she accepts the touch give her a pat. If she is resistant, have the holder correct her with a tug on the lead. Do this every few days until she accepts the touch willingly.
Have someone hold her head. Using a wash cloth or sponge, clean her udder with warm water and mild soap. Follow with a warm water rinse to remove any soap residue. If she tolerates this without hesitiation, repeat every few weeks throughout her pregnancy. If she is resistant you must do this more often to get her used to the handling.
Towards the end of her pregnancy, your mare will start to develop a bag. That means that her udder is filling up with prefoaling fluid. This should not happen before day 300, if it does it could indicate a problem. Contact the vet immediately. Wash your hands with betadine scrub or use hand sanitizer. Get a small container to put the "milk" into.
By now your mare should be tolerant of having her udder handled, but make sure you have someone holding her head for you. Form an O with your thumb and forefinger. Snug the O up against the bag and close it base of the nipple. Knead your way down the nipple like you were squeezing toothpaste out of a tube. Only move your O partway down the nipple before moving it back up to the base to take another knead. The fluid should start to come out after a few repetitions. For the milk testing you only need a 2cc sample.
Once your mare has foaled, but before the foal has gotten to his feet you can milk some colostrum from you mare and feed it to him in bottle. Use a clean, plastic one cup measure for this. The technique is the same as for the milk testing, you knead downward gently on the nipple until the milk is flowing. Feed 4 ounces every 20 minutes until your foal is up and nursing on his own.