This article is from the WSSF 2008 AFRMA Rat & Mouse Tales news-magazine.

By Lisa Grove, N.F.R.S., England

From Pro-Rat-a, No. 125, Sept./Oct. 2001, the N.F.R.S. journal. Permission given to reprint article.

This is part 2 of 3 of the N.F.R.S. Breeding and Showing Seminar series that took place July 22, 2001. See Part 1 “N.F.R.S. Breeding & Showing Seminar” and Part 3 “Questions on Basic Genetics: Basic genetics most relevant to rat breeders”.

When breeding rats specifically for show and exhibition purposes, there are five main objectives that you need to select for, these are:

1. Type and size
2. Temperament
3. Health
4. Colour and markings
5. Fertility

Increasing size in progressive litters of kittens is really not that difficult. You mainly need to outcross the line/rat to a typier strain/animal, decrease the litter size to four to six kittens, select the largest boned kittens (and not the best colours and/or markings), and feed well.

Even doing this only once can dramatically change the size and type of the subsequent generation. If the desired result is not attained, or the size of the resulting kittens has only increased slightly, then repeat the process, being careful not to outcross to lines that will alter the colour or markings too much.

When line breeding, select only the largest, heaviest brother and sister to mate together. Be careful not to produce kittens that end up at the other end of the scale—kittens that are overweight and short bodied with chopped rumps and cobby heads.

The NFRS type standard mainly asks for the does to be fit and racy and the bucks to be large and typy. It can be difficult to produce both types in one line. Huge, typy bucks tend to produce huge, typy does that will need continuous dieting to keep them ‘racy’ enough for the show bench, and naturally fit active does may not produce the biggest, stockiest bucks.

With this in mind, it may be better to think about which sex shows better for each variety. With the varieties below there will be exceptions to the rule, but the majority of these varieties win more at shows in the following gender:

Selfs – Does show better, simply because of their shorter coats. Bucks also tend to silver more in the darker colours.

Marked – Markings are not gender specific, but again does will show better due to the shorter coat and in the darker colours will keep their colour longer.

Rex – Bucks show better as their coats have more curl.

Silvered – Bucks silver much better than does.

Silver Fawn – Does keep a whiter belly and have a shorter coat.

Topaz* – Does tend to be less ‘sooty’ than bucks and have a shorter coat.

Himalayan – Does will shade up less and have a paler body colour, keep cleaner, and have a shorter coat.

Siamese – Bucks will shade more and have a deeper body colour, so show better in this variety.

Agouti and Cinnamon – Does have a shorter coat and tend to have a brighter colour than bucks.

Cinnamon Pearl – Both bucks and does seem to colour similarly, but does have a shorter coat.

Pearl – Bucks seem to win more than does as they have a better colour and tend to be less sooty.

Blue Agouti – Does again win more simply due to the shorter coat which shows better condition.

Chinchilla – Bucks show better in this variety as they have less brown in the coat and more silvering.

So now you can decide whether to select more for huge, typy bucks or for fit, racy does.

Once you have this fixed you can then start worrying about the ‘fine tuning’ on your line of rats, selecting also for a bold eye, worrying about the shape of their heads, length of the body and tail, and the placement of the ears!

Selecting for temperament shouldn’t be difficult, and it isn’t when breeding rats specifically as good pets. For this you select your most friendly, laid-back, and tractable animals to breed from.

For exhibition purposes a rat with this kind of personality is not always good. A fat-looking flat rat that dozes in its show tank all day and goes all ‘baggy’ and stupid when you pick it up is not going to show itself off to its advantage nor attract attention from a passing judge.

A doe that shows well must be fit looking, active, and interested in her surroundings. A doe that dances around in her show tank and looks bright and alert attracts the judge’s eye. But a doe like this can often be flighty and difficult to handle, especially when on heat.

A buck that has been bred to be typy, large, and attractive to the opposite sex is often overly receptive to the pheromones given off by other bucks in its class and will react in a normal buck-like manner to this threat to his manhood by becoming very territorial within his tank, scent marking the sides by rubbing his (now greasier than when you bathed him last night) shoulders against them. He may also be reluctant to be handled, maybe even aggressively so to any intruders in his closely guarded territory. This type of buck can also become very imprinted on his ‘home territory’ where he feels safe and secure within his close knit hierarchy and will object to being put in a show tank full stop, let alone being brought to a show.*

It is difficult to decide whether to breed from a rat that repeatedly takes offence at being handled by a judge, when at home it is fine. After all, this animal has more often than not been bred to be butch, large, and typy and is just being itself.

Breeders must try to attain a happy medium between a dozy and a hyperactive rat. I have found that intelligence can be the key. Clever, well-stimulated rats are more likely to take an interest in their surroundings and be more receptive to new environments. Less intelligent and under-stimulated rats are more likely to find new situations less interesting or even frightening.

It sounds like basic common sense only to breed from rats that are in peak condition but with some varieties being neglected and becoming scarce, you sometimes have to breed with a rat that you know may have a propensity for certain health problems such as respiratory illness, malocclusion, or barbering.

In this case it is always recommended to outcross the line in the first instance to a type/line of rats that are as ‘problem-free’ as possible.

I personally believe that a ‘problem-free’ line is impossible to produce. As all fancy rats have a leaning towards respiratory illness and tumours, it is impossible to guarantee that an animal is unlikely to have any problems with its health. It is just that with in-breeding or line-breeding, these tendencies can be exaggerated and before you know it, a line is throwing does that all get mammary tumours before they are 6 months old. So problem-free or as problem-free as possible rats are difficult to find. Agouti rats tend to be the most robust and are a good choice as when Agouti is bred to Agouti continuously, these suffer the least problems.

Some fanciers can live with inherent genetic problems such as barbering. Selectively breeding from non-barberers and frequently outcrossing the line lessens the chance of barbering kittens being born in a litter.

Other fanciers will throw their hands up in horror when one of their rats barbers its legs and discontinue breeding from that branch of their line. Most of us would see that as a more responsible action but if that rat/line is an important one or the only source of that variety, then the decision may not be so lightly taken.

Health problems that are probably genetic and should be kept in mind include respiratory illness, a propensity towards skin mites, blood clotting problems, tumours, kinked tails, and a tendency towards obesity.

To be honest, none of us is usually very scientific or sensible when it comes to deciding which variety of rat to breed. Most of us choose a variety first because it is our favourite or we find it most attractive, others take on a variety by accident or to maintain a variety that is under threat.

Perhaps it would be better if we gave more serious thought to which varieties suited us before we took them on. Some suit those of us who are more competitive than others by being easier to breed and hence will give a greater chance of giving winners and of winning more often. Other varieties may suit those who relish a challenge by being more difficult to breed. Some of us may enjoy the show preparation side of getting the rats ready for show. A paler variety would suit this person better than a breeder who climbs out of bed 10 minutes before they are due to leave for the show and quickly puts the rats in their show tanks as they are getting dressed!

I breed and show varieties in which does show better because I have not much room and I try to keep to a minimum number of cages. Does can be housed in quite large groups, and I keep the number of bucks I own to a bare minimum.

Another consideration is the maintenance of each variety:

Pink-eyed White – These rats need to be cleaned out frequently to ensure ‘whiteness’ of coat. It is often difficult to sell pink-eyed kittens.

Black-eyed White – These are usually genetically marked. There are not many BEW kittens in each litter produced. These rats need to be cleaned out frequently to ensure ‘whiteness’ of coat. They are often deaf.

Champagne – These rats need to be cleaned out frequently to ensure cleanliness of coat. It is often difficult to sell pink-eyed kittens.

Blue – The does in this variety should be bred from before they are 6 to 8 months old to lessen the risk of haemorhaging whilst giving birth. It is also recommended that they have no more than two litters. Colour depth can be difficult to attain. This variety can rust or go patchy and can silver quite heavily.

Black/Chocolate/Mink – Colour depth can be difficult to attain. These varieties can rust or go patchy and can silver quite heavily.

Buff* – Colour depth can be difficult to attain. These rats need to be cleaned out frequently to ensure cleanliness of coat.

Marked – Lots of kittens have to be produced to breed good marked rats and culling litters may be needed. It is difficult to produce good show-quality rats and with new genes flooding the country from the continent, the content of marked litters is now even more difficult to predict.

Rex – It is difficult to breed show-quality rats. It is important that kittens are rehomed to responsible pet owners only and that these pet owners and new breeders are educated in the pitfalls of breeding double rexes.

Silvered – Most bucks will lose their silvering around 9 months to 1 year old. Most silvered varieties also go patchy and rusty. There are inherent problems with type. Colour depth can be difficult to attain.

Himalayan – These rats need to be cleaned out frequently to ensure cleanliness of coat. It is difficult to ensure darkness of points with whiteness of body.

Siamese – These have a propensity towards long coats and are best kept in sheds. Problems with short tails.

Silver Fawn – These rats need to be cleaned out constantly to ensure cleanliness of coat. It is often difficult to sell pink-eyed kittens.

Topaz* – Some Topaz rats can suffer from a clotting deficiency. These rats have a propensity towards getting fat. There is some barbering in Topaz lines and problems with short tails.

Agouti – These rats have a propensity towards getting fat. If repeatedly bred together it can be difficult to keep the colour ‘bright.’

Cinnamon – These rats have a propensity towards getting fat. If repeatedly bred together it can be difficult to keep the colour ‘bright.’

Blue Agouti – These rats often have small eyes and problems with short tails.

Pearl – These rats need to be cleaned out constantly to ensure cleanliness of coat. Pearls have a history of throwing maloccluded kittens.

Cinnamon Pearl – These rats have a propensity towards getting fat. This variety has a history of throwing maloccluded kittens.

Chinchilla –A small number of actual ‘chinchillas’ appear in a litter. Stomach bloat in kittens (which have to be euthanized) can occur.

Please don’t let this put you off taking on any of our old established varieties but it is better to be aware of potential problems when undertaking any new project. Many current breeders of these varieties have found ways to minimise problems.

Continual line-breeding can promote sterility, especially if rats that have a low fertility are used in successive generations; for example, to continue a particularly good marked line.

Another problem that can occur is low fecundity, which means that the doe will only have a small number of kittens in each litter. This sounds ideal, but it often means that the kittens will be very large which can cause birthing difficulties.

Again, outcrossing to an unrelated line usually cures this problem.

* Notes:
Topaz = U.S. Fawn
Buff = U.S. Beige
Aggressive behavior is severely penalized in AFRMA shows.
Some faults listed in the U.K. varieties may not be a problem with U.S. lines.

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