Scours is the name we use instead of diarrhea. It indicates a loose watery stool. In young calves, it's usually due to an inability to digest all of the food it's taking in.
This can be due to too much milk being fed, the wrong type of milk replacer being used, the calf getting insufficient colostrum, a bacterial infection, having a new food introduced which it can't handle, and the list goes on.
The calf needs microbes in it's digestive system to digest it's food. If there are too few microbes, or the wrong type of microbes, the food doesn't get digested and passes through, still in bulk. It comes out loose and watery. The same thing happens if you overfeed. Too few microbes to handle it. The same thing happens if you introduce a new food too quickly. Not enough of the right type of microbes.
You don't know what, if anything, the calf ate before you got it. Consider that you're introducing a new food. Go slowly.
It's common to overfeed. It's also common to feed the calf a milk replacer that is unlike the milk it was formerly getting.
Milk replacers made from milk, rather than plant proteins, are more readily tolerated, but are more expensive.
Adding a probiotic to the milk replacer can help. So can active culture yogurt. That adds microbes to aid in digestion. Reduce the amount you're feeding. substitute some plain water.
With the best of care, many auction calves fail to make it. Do the best you can and be prepared to accept what happens.
If the calf didn't get the right amount of colostrum before you got it, whatever you do won't be enough to save it.
Here's a guide to milk replacers:
http://nahms.aphis.usda.gov/dairy/ba...k_replacer.pdf
Genebo
Paradise Farm
