Summer scours

[countryguy]

Please tell me what the heck causes summer calf scours.I try to do everything right and yet every year I get a calf with a nasty case of the shits.Found the one this year a little too late-even cowman's miracle scour remedy didn't work this time.Is this just nature at work or am I doing something wrong?

[grassfarmer]

We had a couple of cases this year too - in calves born once the cows were out on fresh grass getting moved every day so build up of disease wasn't a factor. What I did notice was that of the last 5 cows we calved three young cows with far too much milk (ie enough each for 4 calves) didn't have any trouble. The two that scoured belonged to older cows that had adequate milk supply but not nearly as much milk as the younger three. I concluded their problems stemmed from poorer colostrum and antibody levels. These are lower production cows and in normal times would have been culled for being later calving and turning in poorer calves. The three younger cows maybe should be culled too - young cows calving later because they milk too much which affects their wintering ability? Both calves pulled through, one with the aid of a "cowman dose" the other we couldn't catch easily.
It certainly can be problematic scouring in hot weather, although it's not as tough weather as in the the cold winter season the dehydration can be a lot worse.