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Discussion Starter · #1 ·
Just curious how common this is. I've never had to cull any kits due to failing to thrive and am asking how often this is to be expected and whether it varies depending on different lines or other similar factors.
 

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there's loads of causes which also means different action needs to be taken.If for instance, they are respi at a really young age then you might as well cull them.If they've had a rearing setback though they will probably catch up with a bit of nurturing during weaning.Any that have tails with zero flesh on are no hopers. Likewise laddered bellies or sunken sides.
 

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the fur is rough,the belly flat and has the appearance of bars across.Not unusual in old mice but in the young it's bad.
 

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SarahC, I think you may be referring to Rotavirus.

Cheshire Gleam, breeders cull primarily for the following reasons (chronological order):
- Deformities/Health-related (missing body parts, sick, etc)
- Peanuts (very small pinkies that will not survive to adulthood)
- Runts (small pinkies that are not viable for breeding. However, they can be used for pets but they consume milk resources)
- Gender (culling bucks)
- Coats (specific coloring or variation)
- Weight, Size of body and skull (Larger and boxy skulls become wedge-shaped), width between the ears (Ears wider apart often predict better ear-sets)

Infant mortality and survival rates are often directly determined by the genes in the specific mice, including how healthy are the pups, amount of deleterious recessives, and mother nurturing instincts.

The mice that you received from me should not have any issues of cannibalism or high infant mortality. At worst, you will get 1 or 2 runts in a litters. They also make great nannies and prefer communal nursing setups. They were bred that way for over 13 generations by removing mice that cannibalized or had low litter-survival rates.

Best of luck!
 

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Lake Mousery said:
SarahC, I think you may be referring to Rota

.

The mice that you received from me should not have any issues of cannibalism or high infant mortality. At worst, you will get 1 or 2 runts in a litters. They also make great nannies and prefer communal nursing setups. They were bred that way for over 13 generations by removing mice that cannibalized or had low litter-survival rates.

Best of luck!
rotavirus babies are distinct in having the appearance of greasy/sweaty coats.They often grow on perfectly well after a couple of unpleasant messy weeks rather than fail to thrive.
 

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Discussion Starter · #8 ·
Thanks both and I'm aware of the reasons many breeders cull as I practice most of the reasons you listed, excluding health related instances. I was referring specifically to failure to thrive because I've thankfully never encountered any mice that haven't been adequate or healthy enough to thrive and wanted to hear experiences/causes from others. I've now had twelve litters with the mice you gave me as I've put the merle buck to many of my does and later his offspring for which I appreciate. The does produced from your line also cope very well with rearing litters, alone and in groups as you said. Best wishes to each of you and thanks again!
 

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I unfortunately had it quite a lot when I first started with my blue line. I suspect the guy I bought them from wasn't as vigilant with his selection for healthy mice as he said. They would do absolutely fine until they opened their eyes, and then within days they would be tiny walking skeletons. I tried so many things, supplementing with more vitamins, better food, probiotics, etc but eventually just had to start ruthlessly culling the sick one's as they died within a week of opening their eyes anyway.
Until recently they had become very rare for me but I introduced some new stock in hopes of improving overall size and type, and suddenly I have loads of ftv babies again :( a mistake I much regret.
 

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I assume they are struck down when they stop getting the support of antibodies in mothers milk.Rabbits are the same and we are all used to the idea that puppies and kittens are at risk during weaning without inoculation.
 

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Sorry to hear about that SilverWings. The cause of infant death is likely deleterious recessive alleles that you will have to breed out again. I read that many genes within an organism, such as a mouse, do not become 'activated' until after or during lactation period. So initially the pinkies may appear healthy, but as their complete genomes manifest, deleterious recessives begin to occur. I learned in the past, that unfortunately medicine and supplements are of only temporary solution. The best long-term solution is like what you did, cull and avoid breeding unhealthy mice.

I am also experiencing a period of decreased infant survival rates due to negative genetics and poor mothers. This has occurred after I introduced some out-crosses from out of state show breeders. The mice have wonderful phenotypes but horrible health and behavioral characteristics.
 

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Discussion Starter · #13 ·
SilverWings, that sounds horrible, I couldn't imagine! Sorry that you and Lake Mousery are in a rough spot right now. The worst for me lately has been one of my Siamese does produced a litter of three babies and I'm guessing they were cannibalized being they weren't there the next day and a similar occurrence with another Siamese litter though only one baby went "missing", so to speak. I'm honestly surprised I haven't had more failures with this line being the main lot of them originated from Petco. Hope things start looking up for both of you soon!
 

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Discussion Starter · #15 ·
Oh wow, I see what you mean. Thanks for the examples, that's really helpful. Are there any common factors that make mice have laddered bellies?
 

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old age and parasites would be the most obvious but it is a visual symptom of poor condition so the causes are varied.In my experience laddered mice rarely come back to full health with the exception of those that have parasites and are treated.
 

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I am also experiencing a period of decreased infant survival rates due to negative genetics and poor mothers. This has occurred after I introduced some out-crosses from out of state show breeders. The mice have wonderful phenotypes but horrible health and behavioral characteristics.
hello dear
Teatv
 

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Yeah, I had the exact same experience with FMBA mice, and derived English pure lines. You also may get hit with a HUGE HORRIFIC decrease in immunity (mine was respiratory symptoms and often death a few weeks later) for your mice that were outcrossed to show mice. Also have fun with the tumors, often the English mice are culled early so that mammary tumors are an absolute hell in later age... (longevity = generally, low priority for show breeding)

I resolved it by completely scrapping the outbreds and just stuck with my lines. However, inbreeding depression will eventually set in- so either increase breeding populations to 100+ mice, get lucky with an outcross from a Pet store or non-English breeder (but then you may get unpreferred phenotype or temperament). If you can, try establish connections with local mice breeders and share stock with each other.

Best of luck
 

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Oh yeah I forgot, during my later years of breeding. I successfully overcame this issue, by outcrossing to wild house mice (males), since the agouti was very easy to breed out since dominant. Provided great immune systems and agility, but temperament was hit or miss (handle pups EARLY, preferably before eyes open). But did often take 2 generations to acquire previous phenotype (big ears, type, etc)
 
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