Duke's itchy belly opening (Be sure and skip this one unless you have a horse!)

I'm posting these photos for an online vet to check out to see if he can tell me something about that hole in Duke's abdomen.

It was a bit difficult to take a picture AND open that hole but my arm will go in there almost up to my elbow WITH a towel wrapped around it!

Just to see how far back that opening is in the "big picture"

Very difficult to see but the opening is just in front of that piece of wood shaving.

The opening isn't very "open" until you reach into it - but open enough that shavings and bugs DO sometimes get in there.

The opening is right there in that shadowed space DIRECTLY in front of his penis.

Okay!  Here's the answer I just got from "Dr Mike," a horse vet at  JustAnswer.com:

From Dr Mike Monday, January 02, 2012 10:41 AM EST

The photos show the dorsal preputial orifice. There is a wide individual variation in the depth of the invagination and the diameter of the opening, on a horse Duke's size, it can range from just 4 or so inches wide at the opening, and only go up 8 inches or so, to about twice those dimensions. This opening is the source of the "crouping" sound geldings make as they trot, as air is moved in and out.

Duke may have an unusually expansive and relaxed opening, but I'm not sure I'd call it a genetic anomaly beyond normal individual variation.

The smegma buildup that makes him "itchy" is a normal skin discharge in that area, and you need to walk a fine line between keeping it clean enough to be comfortable, but not so clean that the normal bacterial population is disturbed. The only true infections in this area I've seen were a direct result of too frequent/thorough cleaning.

Dr Mike

 

Then I asked:   

Thanks so much! If it's twice the "normal" size that would definitely explain it.  Can you tell me what you suggest I use to clean it so that I won't make it TOO clean, but I can still stop him from kicking himself in the tummy and laying down trying to scratch it against the ground?

 

And he responded:

I try to use just water. If the buildup is really greasy, I'll use a bit of Ivory dishwashing soap, rinsing well afterwards. Some of the commercial sheath cleaners can be pretty irritating, and a more potent antibacterial product can kill the good bacterial populations.

Excellent!  Apparently I've been doing the right thing by accident.  I generally just wet a towel with warm water and wipe him out with that.  Every six months or so when he gets really antsy, and I'm bathing him with that EZall spray I shoot some of that in there and then rinse it out good.  Guess that's been as good a way to deal with it as any.  Terrific!  Good to know there's nothing actually "wrong" with Duke.  Wish Anne would have explained that to me so I wouldn't have had to worry about it all this time.  Oh well.  I'm just very relieved to know what it is now. 

 

And I have to say, I definitely recommend that JustAnswer.com web site!  Thanks, Dr. Mike!

 

But of course I couldn't just forget about it at that point.  I did another online search once I got the correct term from "Dr. Mike" and found this info on the Google Books site.    This figure and the following explanation make it even easier to understand exactly what that hole actually is:

 

 

I think I'll leave this on here after all instead of deleting it in case someone else is trying to find out what's up with this on their horse.