Breeding out allergies?

[MrLang]

I know there are some pretty experienced rat breeders here so I figured I'd ask before hitting the web...


As I have come to understand it, pretty much every rat carries Mycoplasma bacteria in the respiratory tract from birth due to a transfer in the birth canal. I'm not sure if this is directly related or not, but it also seems that almost every rat sneezes to some degree. I think it must be some combination of allergies, sensitivity to dust, and Mycoplasma bacteria that causes them to sneeze a lot more than other animals. Some go into respiratory distress more easily than others and some live healthy lives. The ones in the middle suffer from long term lung scarring that eventually shortens their life.

I've been observing my rats since I got them. There are a couple that sneeze pretty regularly but are not escalating or getting 'better' and there are a couple that don't sneeze at all, despite having 24/7 exposure to the animals that do sneeze. I had one go into distress and die when I first started the colony, but the other animals that were housed with it have stayed the same or even improved since the death.

Question 1: Can you selectively breed for improved respiratory health? What would you actually be controlling there... are specific allergies genetic, like to aspen? Strength of resistance to Mycoplasma bacteria in the respiratory tract? Sensitivity to dust IE overall respiratory heartiness?

Question 2: Short of keeping them on expensive substrate or trying to litter box train them and keep them on fleece, is there anything I can do to reduce the sneezes... it's quite distressing sometimes as I have grown fond of a couple of the little ratties. My sister gave me Baytril and Doxycycline but I am hesitant to medicate when the sneezing is the only symptom that any of them have shown.

I do keep the room as humid as I can (50-65%) to reduce the respiratory stress.

Thanks

[snakesRkewl]

Rats sneeze for the same reasons you do, breathing dust in.
If they are kept on clean bedding they sneeze less and get sick less often.
I've noticed more sneezing on pine over aspen but not really anymore advanced cases of myco due to using it.
Their respiratory system is fine as long as they aren't subjected to living on nasty bedding for days and days.

[sorraia]

Question 1: Can you selectively breed for improved respiratory health? What would you actually be controlling there... are specific allergies genetic, like to aspen? Strength of resistance to Mycoplasma bacteria in the respiratory tract? Sensitivity to dust IE overall respiratory heartiness?

It is possible to select for improved respiratory health, but it can take quite some effort, time (depending on the volume you are breeding for), and lots of records. What you are selecting for depends on what cause of the sneezing. It can be allergies - I once had a rat who sneezed on every bedding I ever tried except, believe it or not, alfalfa pellets. That rat also tended to have skin issues when fed certain foods. Other rats will sneeze due to irritants (i.e. dust). Other times it has to do with their over all health and immune system - a rat with a weaker immune system will more likely develop an infection, especially when exposed to irritants, and is more likely to succumb to that infection. It can also be environment - conditions that are too warm, too cold, too dry, or too humid.

In my experience: While I bred rats, I was selecting for respiratory health. Since I was breeding strictly for pets and not feeding them off at a young age, I was able to keep track of ALL individuals I bred and keep records on them, even after placing them in pet homes I would keep in touch with the new owners and keep updated on their health. If a particular lineage seemed especially prone to respiratory infection or sneezing, I stopped breeding from that line. If a particular rat seemed to have sensitivities before I bred it, I would remove it from the program and not breed it. If an animal developed sensitivities after I bred it, I would wait a little longer before breeding its offspring. I was also having rats necropsied to determine what condition their lungs were in at death, which helped determine how healthy their respiratory system was, but also helped determine if they had developed "silent pneumonia" (which had happened a couple times). Over the generations I saw less and less incidence of respiratory infection or irritation. Within just a few short generations I got to the point where my rats would only sneeze under stressful conditions: moving homes, "spring cleaning" when a lot of dust got stirred up, or major weather changes (such as from 100 degree summer heat to a sudden drop of 20+ degrees, rarely happens here, but sometimes does). By the time I stopped breeding rats, my animals were almost never sneezing. This program was a combination of selection against allergies, for stronger immune system, and for animals who handled stress better. During this time I also noticed an interesting trend: those animals with longer, narrower heads tended to be more prone to sneezing and sinus irritation (which would trigger sneezing) than those animals with shorter, broader heads.

Question 2: Short of keeping them on expensive substrate or trying to litter box train them and keep them on fleece, is there anything I can do to reduce the sneezes... it's quite distressing sometimes as I have grown fond of a couple of the little ratties. My sister gave me Baytril and Doxycycline but I am hesitant to medicate when the sneezing is the only symptom that any of them have shown.

I would avoid medicating unless absolutely necessary. Over the years I've seen an awful lot of people have to use stronger and stronger drugs to treat their rats with respiratory infections. I suspect part of this is because these "lower level" drugs have been thrown around and used so much. In my own personal experiences, Baytril doesn't even treat respiratory infection (I've even stopped taking my rats to those vets who prescribe Baytril). That experience is different from other people, so take it with a grain of salt.

That being said, a basic air purifier can help, because it will help reduce the amount of airborne dust in the air. Do not use an ionizer, but a basic hepa filter is helpful. Also look for bedding with the least amount of dust. I had good experience with using aspen (which is less expensive than a lot of other options), but had to stop using it because *I* developed allergies to it. I never used pine or cedar (the phenols in these can actually irritate the sensitive respiratory tissues in rats and contribute to sneezing and respiratory infection), though I have heard of people successfully using kiln-dried pine (not sure if they performed necropsies to see what the insides of the animals looked like after death, though). I don't know what the cost is, but I have seen horse bedding that's basically just shredded paper. I was given a bag of this once and it worked great, none of my rats had trouble with it (except the one super sensitive rat mentioned above). I've also used alfalfa pellets fairly successfully, but I suspect these will be going up in cost in the next year (if they haven't already).

[MrLang]

Extremely helpful post. Exactly what I was looking for.

Thanks!

The 2/6 rats I am thinking of that haven't been sneezing AT ALL are also the 2 widest cheeked rats. The one that died of distress had a very pointed face and the other male that's in with the sneeze-free guy has a pointier head as well. Very interesting.

And yeah, she is a vet but doesn't work with small animals much. She gave me what the course of meds would be from any other vet I think, and cautioned me to research before using them. What I found was what you said, that they might work for a little while but would not 'cure' the rats and would just give the other bacteria a jump start on resistance.

I'll keep them around to compound if my snakes ever get sick

[sorraia]

The 2/6 rats I am thinking of that haven't been sneezing AT ALL are also the 2 widest cheeked rats. The one that died of distress had a very pointed face and the other male that's in with the sneeze-free guy has a pointier head as well. Very interesting.

If you continue to see this trend, please let me know? Even if I'm not breeding rats now, I'm still interested to keep up on the latest and see these kinds of trends.

And yeah, she is a vet but doesn't work with small animals much. She gave me what the course of meds would be from any other vet I think, and cautioned me to research before using them. What I found was what you said, that they might work for a little while but would not 'cure' the rats and would just give the other bacteria a jump start on resistance.

I had one vet who prescribed Clavamox for a couple of rats I had who developed severe pneumonia. I kid you not, that stuff was like magic! I wouldn't recommend it for just little sniffles, but for a severe respiratory infection it seemed to really do the trick. These animals when from death's door to full health again within the couple weeks they were on that medication. Very very few vets seem to be willing to prescribe this though.

[aldebono]

I do believe that you can breed to improve the immune system.
My rats are kept outside and even though I cover them and monitor temperatures, some still get fairly sick in the winter from the temp swings bringing their immune system down. Just like people. I have a 1.4 that is over 2 years old that has never been sick and the females are still going strong and producing. I want to breed that line into all my color rats to improve them.

[FoxReptiles]

Very interesting thread. I recently started breeding rats and my 1st male was a definite sneezer. The litter I just posted about is actually his and I'm really hoping that all of his babies aren't prone to being irritated. I will definitely be interested in selectively breeding his offspring to hopefully improve the over-all disposition of my breeding stock.

I also had a very bad experience this weekend with a new female that I picked up. She was making some odd noises that I just mistook for her being a "more vocal" rat. I believe she actually had some respiratory issues going on and died a couple of days after I got her. I'll post a separate topic about my experience to try and get some feedback.

I was happy to read this question. It's been helpful as I try to read up on the issue.