Can babies be born with animal allergies?

DP, his father & grandfather are all allergic to horses. DP almost died as a kid when he first touched one. I also have a mild allergy to them.

So we're really worried that DS is/will be also allergic the same as DP is. The reason this is such a worry is that my family all own/ride horses and are around them everyday. Their house has horse hair in it as they bring it in from outside etc. As a precaution we will not be visiting them at their home, just in case.

But can babies be born with such a severe allergy to animals? Or do they develop over time?

We would like to eventually get him tested to be absolute certain, but I've no idea what age they can do that.

I'll be asking my GP about all this when I go for my 6 week check up, but I thought maybe someone here knows anything/has any info. I've tried good ol google but couldnt find anything.

TIA