I got two goat kids from an auction at 1.5 weeks old. They both had diarrhea and were skinny. I put them on 1/3 buttermilk and 2/3 whole milk from the store. I was worried they had some sort of bacterial infection so I added some s.boulardii I have - it's called "Yeast Against Yeast" in Europe and is strong against many bacterial infections including c.difficile, without harming any of the good yeast/bacteria that is supposed to be there - which makes it far superior to antibiotics! I also added in some TriEnza from Houston Nutraceuticals, a digestive enzyme that breaks down the proteins in food in the stomach (or in the bottle). It made the milk clabber so I had to enlarge the openings in the nipples. One problem with babies that are having trouble digesting the milk is that it fails to form a curd and passes through, so I thought that may help.
You can buy s. boulardii
online (I think I got mine on Amazon) and it's pretty cheap, especially compared to products like ProBios that sells for $65 at my feed store. Mine came in capsules that were easy to open and pour into the milk. It's a yeast, tastes like yeast, animals like the flavor so no troubles getting them to eat it.
Now one baby is completely recovered and the other is well on the way. They stayed bouncy and active throughout.
I started making my own buttermilk because it's less than half the price of the bought kind and doesn't have thickeners, etc. You *can* make it by just mixing 1 cup buttermilk from the store with 3 cups of cold milk, letting it sit out overnight. I worried about the risk of bacterial contamination since the babies were already compromised so I heated the milk to scalding to kill any organisms in it then let it cool to room temperature and added the culture. I noticed it lacked the bitter flavor that the batch where I didn't use heated milk had. One more thing about making your own buttermilk - they get more of the butterfat that way. A lot of the nutrition in the milk is in the butterfat and I don't think giving skim milk is good for them. Everyone insists they must be given whole cow's milk, not skim or lowfat.
The difference between yogurt and buttermilk is that the cultures from buttermilk can be acquired from raw milk - which means it's supposed to be in the milk already and would be if it hadn't been heat-treated. Let to ferment for 24 hours it totally digests the lactose in the milk (really they both do) and it's really nice that buttermilk can be made at room temperature while yogurt needs to be kept warm. The lactococcus bacteria in the buttermilk culture make a chemical called Nisin, which is a pretty decent natural antibiotic.
When I heat the milk, I just heat the milk by itself (very fast if you use a larger pot) then add in the buttermilk. That way I avoid the risk of killing the probiotics by heating the milk too hot.
I've read some folks add in an egg yolk for extra nutrition and it's supposed to be a scours remedy. I'd only use fresh eggs from my own hens for that. I'm pretty sure they won't be contaminated with bacteria.
Around here the goat dairies won't
sell you kids if you're going to give them the powdered milk replacer - they say it kills them.