Muddy Lungs

not sure how else to describe them.

I was doing up about 20 rabbits for a fellow tonight and giving them a good look over as I did them and about 18 of them had this muddy look to the lungs. I called him to ask if he had sick rabbits or just what was going on with them, he was stunned. He said I have nothing going on...no sneezing, weepy eye or anything like that. I said, mind if I ask on a board or two that I'm on...he said go ahead.

So... let me see if I can describe what I saw. Did NOT take pictures as I merely needed to get the job done.

of the 18, 14 of them were identical. break the membrane to the lung and I saw these grey lungs. I would pull them out and they were this muddy looking grey/browny colour with the faintest pink tinge around the outside. They felt spongy odd, not spongy normal.

2 of the 18 were 1/2 muddy and 1/2 red speckled pale pink lung.

2 of the 18 when I pulled the lungs out turned into mush in my hands and looked like pus kinda... like ...oh...like the gick that came out of abscess of cow when I was young. It was gross.

the rest of THOSE two rabbits I examined carefully. intestinal track looked fine. They had coccidiosis... one or two specks in the liver. So nothing very bad there. Couldn't see anything wrong with the carcass and the animals themselves seemed very bright and normal bunnies. I would never had guessed they'd have these odd lungs.

Time between death and removal of lungs was no greater than 2 minutes...IF even that. Cut of head, remove legs, hide, open 'em up, and done. really not that long of a time span...so it wasn't degradation due to excess time being taken.

Any thoughts?

We are both quite eager to understand what this might be. He says his herd is bright, productive, and doesn't appear ill. He's treated for coccidia and the livers of his rabbits were significantly better than 2 months ago.

Thank you.

How old were the rabbits and how much did they weigh? Also what breed/mix? This sounds like an air quality problem maybe.

3-3.5 months old, weight between 3.8 and 6 lbs. a mix of jap and mag harles

I am thinking some sort of lungworm...http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/120700.htm

The pathogenic effect of the other lungworms has a similar basis, but frequently such severe clinical signs are not produced, perhaps due to a more restricted localization in the lungs and less severe infections. The patent phase and the associated lesions last >4 mo for some lungworms ( M apri and A abstrusus ) but can be >2 yr ( M capillaris ). The lesions in pigs with M apri are a combination of localized bronchitis and bronchiolitis with overinflation of related alveoli, usually at the edges of the caudal lobes. In pigs, hypertrophy and hyperplasia of bronchiolar and alveolar duct smooth muscle with marked mucous cell hyperplasia are striking features. Near the end of the patent period (as adult worms are killed), gray-green lymphoid nodules (2-4 mm) are formed; fragments of dead worms may be found microscopically in these nodules composed of lymphocytes and plasma cells surrounding a central zone of eosinophils.
In M capillaris and P rufescens infections, chronic, eosinophilic, granulomatous pneumonia seems to predominate; the reaction is in the bronchioles and alveoli that contain the parasites, their eggs, or larvae. They are surrounded by macrophages, giant cells, eosinophils, and other immunoinflammatory cells, which produce gray or beige plaques (1-2 cm) subpleurally in the dorsal border of the caudal lung lobes. Small (1-2 mm), greenish, nodular lesions may also develop. The effect of these lesions in sheep is minor, perhaps because of the predominantly subpleural location. This infection represents the lower end of the pathogenic spectrum for lungworm

Sorry there is a lot of technical reading but the words "gray plaques" did jump out at me. Now this is for livestock not specifically rabbit but horses and donkeys are mentioned as well and all share the same sort of biology.This would more likely happen out on the ground I would think than in a closed rabbitry, so it would depend on the husbandry of the rabbitry.