that's moved the conversation on a bit from losses at calving to calf losses to weaning, I wouldn't be happy with 5% here but that's with a lot of observation and some intervention, the trouble is you never know 100% which births are going to give trouble so I would think you may have to except something like 5% if you are going to more or less leave them to it but I wouldn't know, be interesting what people do achieve on such a systemObviously you can't guarantee to wean 100% every year.
But I think calf mortality loss of 5%? would be acceptable.