Mini pig hair loss

[Juniper]

Two of our three mini pigs have experienced hair loss this spring in patches on their backs and flanks. The skin doesn’t look particularly irritated, no sores or abnormal redness that I can see, and there are smaller hairs regrowing in the missing patches although it is growing slowly. The skin is a bit flakey and noticeably lighter on the patches on the black pig. The pigs are 9 years old, no change in husbandry other than the Trucare z/m that we used to feed are no longer being sold so they aren’t getting that anymore. They eat mazuri mini pig, hay pellets and hay for fibre, fruits, veg and whatever they can forage (albeit they’ve cleared their half acre paddock pretty well). The patches appeared shortly after a routine late winter worming with ivermectin, although the timing may be coincidental. Pigs seem otherwise normal. Any thoughts?

 

[Mini Horses]

Lice would be my thought -- that ivermectin would kill. Put some Vaseline on those spots, every few days. You may not have seen until winter hair shed.

 

[Finnie]

I do not have any experience with pigs, so my thoughts may be of no help. But I wonder if stopping the minerals contributed? I know with goats (which I also do not own) that lack of some minerals can cause issues with the coat. Even if pigs do not have those kind of susceptibilities, is it possible that at their advanced age, they simply need more minerals than they can metabolize from their feed? I do not know if mineral supplements are required for pigs or optional.

My other thought was like @Mini Horses said. Mites or lice. But you said you put ivermectin on. Maybe the Ivermectin killed the lice and that’s why the hair is starting to grow back now?

I see that this is your first post! Maybe you’ve been lurking till now? Welcome to the forum!