I think from what you describe, that was the ‘helpless newborn herd member’ reaction.
Not all critters have it, but it will be highly developed in, say, old broodmares who have had tons of foals, and nurse cows. Occasionally, it will occur in a gelding- those are the tolerant fellows that get put out with the babies right at weaning. (Granted, weaning ain’t newborn, but there is some sort of protective instinct in those geldings toward young 'uns.)
If I’ve just assisted a cow birth, and am wet with fluids, and I go feed either my TB gelding or my Jersey cow, I’m going to get licked to death.
My Jersey cow somehow knows when a calf is newborn and helpless and its mama isn’t around; she’ll take a calf like that for her own in a few days. But a ten day old calf that has an attentive mother is a two or three week fostering process if we need to get rid of the mama for some reason.
My QH gelding, my two maiden mares, or my had-one-foal mare…could not care less about birth fluids or newborn calves.
Last spring, we moved cows to their forest pasture after gathering them from a lower pasture- in all, it was about a 6 mile move. One day- or two day-old calf made the first part of the move, but hid in the sagebrush. We looked for that little bugger for several days, and would have let mama backtrack to find it, but she wouldn’t leave the water trough in the forest. We found that baby three days later, still alive and kicking. We roped her and tied her up standing so she wasn’t struggling, and waited for Mr. Fillabeana to come back with the 4-wheeler so he could whisk her up to the forest. While we waited, we stroked, scratched and loved on baby. My TB gelding participated, nuzzling and giving love with us.
If we separate calves from cows, say to vaccinate or haul them, and my TB gelding is anywhere nearby, the calves will end up either right at his feet, or if he isn’t inside the corral, right across the fence where he’s tied up. (It is common to leave one mama cow in the pen with the babies, to keep them calm. We just let them go hang out with my horse.)
You do have to be careful in such a situation that your horse is REALLY okay with baby calves running underneath and bumping on horse legs, because most horses will kick a calf, or threaten with a kick to tell them not to get too near. But some horses are baby calf magnets…
And by the way, this same TB gelding will bite 500 pound calves that he’s trying to move (well, WE are trying to move, and he’s helping me!). He will help keep an upset mama cow from running over Mr. Fillabeana while he tags a newborn calf. He sometimes lives in the horse pasture with a few bulls (1000 pounds and up), and he has a GREAT time bossing the bulls around…makes for bulls that respect a horse, instead of charging your horse.
Anyway, I think your gelding might have that protective instinct, but he’s never seen a newborn calf before so there was a bit of fear. I wouldn’t have trusted him, either, not to kick or strike at the time. With more exposure to calves, he might be trust-able in the future, but I agree with your careful assessment.