While some cows don't care at all what calf is sucking on their udders, many other cows are reluctant to allow any other calf to nurse but their own. What is very irritating is if you bought a dairy or dairy cross cow to be a nurse cow and she refuses to allow the other calves to nurse on her. Her udder may be swollen and hard with several gallons of milk, but she stubbornly refuses to give in, sometimes savagely kicking and head-butting the calves away.
You may be tempted to call it quits, milk her out, and then bottle-feed the calves. Of course, that is one option, but if you decide to do this, you will be tied to twice a day milking and bottle feeding for several months. Teaching her to accept calves that are not her own may take a significant amount of time on the front end, but it will save you hours of work in the weeks to come.
1. Restrain her and put the calves on her.
Put the cow in some sort of restraint to get her used to the calves. If you have a milking stanchion, that will be perfect, but a squeeze chute will do in a pinch. You may need to put a pan of feed in the cow's face to teach her to associate nursing those calves with pleasant things.
She may still kick at the calves, but you can tie her back leg to the side of the stanchion to prevent this. If the calves have never nursed on a cow before, it may take some guidance to teach them where the milk comes from. This usually takes at least two people. Most of the time, a hungry calf will quickly figure out where the milk bar is located.
Be very careful if you have a kicking cow. Getting in there to help the calf find the milk can be dangerous!
The ultimate goal of having a nurse cow is that the cow allows the calves to nurse whenever they like. Once the calves figure out where the milk comes from, they will definitely be interested in suckling on her teats. However, some cows get angry that the calf wants to nurse and butts them away. You can get a pair of hobbles for the cow that will keep her from kicking the calves when they nurse. She will still be able to walk, but won't be able to kick. Keep her penned in a small, level area while she figures things out to keep her safe. After a few days or even a couple weeks, she will likely become resigned to her fate as a nurse cow. When she's wearing hobbles, be able to check on her frequently for safety.
3. Trick her.
If the cow is already nursing her own calf, you may be able to simply pen the bottle calves in the same pen with the mother cow. Usually the bottle calves figure out how to sneak in from the rear of the udder when the mother is nursing her own calf. Also, we've had success by putting calves in with a mother cow at night. She can't see well enough to realize that the calf sucking on her is not her own.
4. Coats of skin.
If your mama cow lost her own baby and is reluctant to adopt a new baby, you can skin the dead calf and tie it to the new baby. The mother will smell her old baby on the new one and be more likely to accept it. After two or three days, you can remove the calf-skin and the mother will probably accept the orphan just fine.
Nurse cows are a wonderful addition to your ranch and a good one can raise several calves each year. However, teaching one to accept calves can be challenging. Be patient and stubborn and you will probably be able to convince the nurse cow to accept other calves.