2 Answers

Advice here :http://www.ehow.com/how_2053684_feed-orphaned-calf.html

Similac does not suggest that their formula is good for a calf. I would consult a veterinarian. Where is the calf's mother? Why is he not taking her milk? You should get some raw cows milk and feed it to him. 

Things You'll Need
Bottle
Nipple
Colostrum
Powder milk replacer

Instructions
Colostrum for first three days

1
Prepare the bottle for the calf to nurse. Wash well the bottle and nipple with dishsoap and rinse thoroughly. For the first feeding, fill the bottle half full with warm colostrum. Colostrum is the first milk from a cow. The best source for colostrum is from the cow. You can get colostrum from a dairy or buy a powdered from a local livestock supply store. The bottles are plastic and hold about half a gallon. The oversized nipples will come with the bottle. The colostrum can be warmed in the microwave and should be warm, but not hot. The best way to test the temperature is to put a few drops on your wrist as you would for a human baby.

2
Feed the calf as soon as it can stand comfortably. This is usually within a few hours of birth. Ideally, the calf should be standing to feed. If it is not strong enough, a calf can be fed while it is still lying down. Gently insert the nipple of the bottle into the calf's mouth. The bottle should be held in front and above the calf's head so that the neck arches gently. Consider how a calf would have to reach under and up to reach its mother's udder. This position allows for milk to easily flow into the calf's stomach rather than its lungs.

3
Encourage the calf to suckle by pulling the nipple up and down slightly while it is in the calf's mouth. The calf's instincts should kick in. Normally, a calf will suck weakly with a little encouragement. Do not be discouraged if the calf does not take the entire half bottle of colostrum.

4
Feed the calf milk replacer two times per day for the first three months. During the second feeding, encourage the calf to drink an entire half gallon of colostrum. The colostrum is full of special nutrients that will help the calf become stronger and more immune to early viruses.

5
Prepare subsequent bottles using part milk replacer and part colostrum. Slowly increase the milk replacer while decreasing the colostrum over the first three days until the calf is on full milk replacer. Feed the calf with warm milk.

Read more: How to Feed a New Born Calf | eHow.com http://www.ehow.com/how_5640536_feed-new-born-calf.html#ixzz2R8f2WSCS