This article is from the WSSF 2008 AFRMA Rat & Mouse Tales news-magazine.
By Veronica Simmons, 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 1 of 3 of the N.F.R.S. Breeding and Showing Seminar series that took place July 22, 2001. See Part 2 “Breeding for Show & Exhibition” in the WSSF 2008 issue of AFRMA Rat & Mouse Tales and Part 3 “Questions on Basic Genetics: Basic genetics most relevant to rat breeders”.
Anyone seriously interested in fancy rats would have gained from going to the NFRS’s Breeding and Showing Seminar in Baldock on 22 July because it covered nutrition and the biology of breeding, as well as show preparation, the merits and drawbacks of the different varieties, and elementary genetics. The seminar was held as part of the society’s 25th birthday celebrations and was free to all members of the NFRS.
Nutrition was the first topic to be explored by Lisa Grove and Ann Storey. They explained that specially formulated rat foods had been around for only a few years and most established breeders had their own feeding methods which were usually based on rabbit mix [rabbit mixes in England consist of several types of grains, rolled peas, beans, etc., Ed.] and additives. Too much protein is bad for adult rats because it can cause kidney disease, especially in older bucks, and rabbit food is fairly low in protein content (about 12 to 14%). Conversely, rat kittens and nursing mothers need a lot of protein. Lisa said she knew a breeder who fed his rats on bread, fruit, and vegetables and they were fit and long lived. High-fat diets are not advisable because they have been linked to mammary tumours. However, rats kept in sheds need more fat than house rats.
Ann said that rats had a high requirement for copper and that this was found in seafood, meat, and leafy green vegetables. Copper deficiency shows as light circles round the eyes. She thought that poisoning from excess copper was very rare. Two mineral and vitamin additives which she recommended were SA37 and Dr. Squiggles’ Daily Essentials. Seaweed powder was good for the pigmentation of dark varieties, she said.
It is better to keep most rats thin, she advised. However, show rats need to be heavier because they lose weight traveling. Lisa said that her rats were given pasta and Chappie [dog food, Ed.] the night before going to a show. They agreed that feeding was more important than show preparation; condition goes in through the mouth.
Ann then described the biology of breeding rats whether they were intended as pets or for showing. She thought it could be fun and educational to breed one litter of rats provided you knew where the extra babies were going. You should always choose fit parents to breed from and the baby does should be separated from bucks at 5 weeks to avoid early pregnancies. She said that some people mistook rats’ testicles for tumours. Sometimes they did not descend, but any buck chosen for breeding should have ‘two good ones.’ Old bucks are more likely to carry genetic mutations so be wary of using bucks over 2 years old, she warned.
When choosing does to breed from, Ann said that they should be at least 4 months old and have a complete coat. Does in moult were often not 100% fit. They should have their first litter before they were 7 months old. As they got older, does tended to put on weight, come into season less frequently, and be less fertile. She explained that rats were reflex ovulators and needed to be mated several times before the eggs were released (unless you really did not want the doe to get pregnant in which case one swift encounter could lead to a litter). If does were slow coming on heat, Ann suggested putting some shavings from the buck’s cage in theirs. Gestation lasts about 22½ days and during this time, you should give the doe a normal nutritious diet without overfeeding her. Ann warned people not to palpate the doe to see if she were pregnant as it could do damage.
The pregnant doe should be kept on her own to have her litter. If she went beyond 22½ days, there was no need to worry if she seemed all right and there was no discharge, Ann reassured. Pregnancies can last up to 28 days if the eggs are implanted late. It is best to clean the doe’s cage before she gives birth and then give her lots of bedding (not cotton wool or newspaper) to make a nest. Ann advised not to clean again until 10 to 12 days after the birth as it is unwise to disturb the nest. Very occasionally things go wrong and the doe fails to gave birth because of uterine inertia. Ann was dubious whether a caesarean was needed in most cases because many does passed the dead babies a few days later. She warned against disturbing does when they were in labour as it could stop their contractions.
When the doe comes out of the nest, is the time to check up. See that she looks all right then put her in a safe place (away from bucks) and have a quick look at the litter. If there is a pale patch showing in the kittens’ stomachs, they have been fed. Any dead ones can be removed. It is normal for there to be some blood on the bedding.
Wild rats have an average of seven or eight kittens in their litters, but domesticated rats have far more—on average 12 but it can be as many as 18. This is not good for a doe, especially if she is to have more than one litter. Babies take everything from their mothers including calcium from her bones. Ann said that laboratory rats were weaned at 3 weeks old but she thought that too early and that 4 to 5 weeks was better. It was very unusual for does to kill their litters and would be caused by a hormonal problem. Some does were frightened of their litters. These kind of does should not be bred from.
Under 5 days old it is very difficult to hand rear kittens, Ann said, and the best chance of saving them is to find another doe with a similarly aged litter and to mix them with hers.
Lian Vince demonstrated the finer points of show preparation—nail trimming, ear and tail cleaning and bathing—on an adorably long-suffering buck. She admitted that it wasn’t always so easy. She warned against skinning tails and recommended using a soft toothbrush with soap or shampoo. One should check for bites and lumps and so on when preparing them. Ann added a warning against using hair dryers on rats in case it crisped their ears!
In the afternoon, Lisa gave advice on breeding show rats and described the different qualities of the well known varieties so that people could select the ones which were best for them. The text of this paper appears on page 49. The final paper was intended to elucidate the basic knowledge of genetics needed by rat breeders and will be in a future issue.