an overview of my current breeding strategy and objectives
(last updated 27/08/19)
I established the Zephyr line of rats over the course of a number of years, starting in 2004 with rats from several other lines, and I then incorporated additional outcrosses in 2009. After initially planning to breed for powder blue, I became very attached to american mink and cinnamon after it popped up in my early litters, and since then I have focused on conserving and developing varieties which are based on this gene, while maintaining the now distinctive 'Zephyr temperament' - confident friendly affectionate people centred rats with an intelligent curiosity and playful cheeky streak. Since the outcrosses in 2009, I have seen a general improvement in the common health issues of benign mammary tumours in the girls and hind limb degeneration in the boys, which both tended to occur at around 2 years, and lifespan has increased slightly, now often being closer to 2 1/2 than to 2. This improvement is possibly also reflected in a slower rate of development as kittens, so eyes open a few days later, and the moult happens a couple of weeks later, therefore I now home close to 8 weeks old rather than my original 6. These improvements are most likely also helped by an improved diet and more challenging housing resulting in leaner fitter rats.
As with most things in life, the course of rat breeding does not always run smoothly, and having suffered problems among rats born in 2017 (most likely due to an unknown virus), some of my progress reversed, but I'm working to get my lines back on track, and planning an outcross in the next year which will be related to the one in 2009.
In the past I generally mated does at around 6 months, but there is a possibility that late fertility is connected with longer lifespan, so selecting the offspring of does that can be relied upon to breed older is one way to try to extend expected lifespan. It also enables breeding decisions to be made at an older age so that more health information is available. I began working towards breeding at an older age by testing (when appropriate) whether the does could manage a second litter at 9 - 12 months. Health is generally good in my lines, but I keep a constant eye out for any trends that indicate cause for concern, and rely on owners of Zephyrs to keep me up to date regarding their rats. Occasionally a particular litter will do badly when compared with other litters, and in these cases I don't breed on from them.
Breeding at around 8 - 10 months for a first litter has generally been successful so I am beginning to switch to an 8 month generation gap in most cases. There may be additional litters where necessary for test matings or if it is going to be advantageous for a doe to have a second litter, and there are always times when plans don't necessarily work out and a doe may be mated earlier or later.
I shall be 'tidying' up my lines as much as possible, separating them in terms of the genes they are expressing so that each litter has more of the varieties that I am needing for that line, and this should give me greater choice of which kittens to keep. My standard plan is to breed two or three litters in each generation for each line, with generations spaced every 8 - 12 months, plus additional test or development litters when needed.
In order to protect my lines, I will aim to keep two strands within each line as separate from each other as possible. This means that if a problem crops up in one strand I can either drop that strand completely if it is serious enough, or use the stronger strand to bolster the weaker one.
I maintain a core line of rats expressing or carrying the american mink gene so that these rats can be crossed into any of my side lines. This line will have an offshoot for american cinnamon essex.
I formed my first side line when platinum (red eyed, pale icy coloured coat) and quicksilver (a ruby eyed variety with a bluer coat) surfaced in a litter in 2010. My platinums require american mink and pale british blue (caused by the same gene as the show standard british blue but probably with modifiers), as do quicksilvers, but platinum has an additional dominant modifier.
My second side line for havana and havana agouti emerged when an 'orange' gene turned up unexpectedly in Spring 2013, later confirmed to be red eye dilute, aka RED (denoted 'r' and responsible for buff and topaz). The show standard for havana was written many years ago and it's not known what the genetics of the rat it was based on were, however my chocolate american minks who are carrying 'r' match the standard well. Havana agouti is also a very attractive variety and I hope that both these varieties will become more widely bred.
I have a third side line for silvermanes begun in 2016 following an import from Canada. I have decided to concentrate on agouti based varieties as the silvermane can often look a bit patchy on self rats. I will have one strand which is based on dominant chocolate agouti, and the other strand will be agouti and american cinnamon. A full history of this project is documented on this page.
With regards to my main american line, I had been working to consolidate good dumbo, but I'm not happy with their ears, so while I may get dumbos pop up occasionally, I am no longer going to be planning my litters around them, which will mean fewer american line litters and the chance to expand other lines instead. In future I will focus on maintaining a basic line of black, agouti, american mink and american cinnamon, and will test mate when convenient to remove chocolate and buff from them so that they can be used to cross into the platinum line when required. I'm also planning to introduce essex markings into an american cinnamon strand in late 2019, and will attempt to create some double minks (american mink combined with UK mink) in 2020 for assessment. I will continue to work on improving type while also maintaining temperament.
My carefully laid plans for the platinum line ran into various problems during 2018, and I was at risk of losing the platinum gene. I think they have now been pulled back from the brink using rats from my other lines. Unfortunately, an undesireable coat mutation (probably recessive) has cropped up following an inbreed, and I will be endeavouring to remove the gene through carefully chosen matings, but may not have platinums who are completely free of it for some time. Ideally I would like to establish a solid line of clean quicksilvers (i.e. not carrying chocolate or RED), and a secondary strand for platinum and platinum agouti as well. I had decided to keep some british blue based carriers in this line, but this decision coincided with a drop in health, and in case the two were connected, I am switching back to mostly using american mink based carriers instead.
I am aiming to make my havana line completely chocolate based, and will sometimes have chocolates as well as chocolate americans and havanas. Most litters will be self based so that I can increase my selection options for havana and hopefully reduce the degree of silvering, but I will keep havana agouti going as a secondary variety in one of the strands. I'll continue to promote the variety within the fancy in the hope that other breeders might choose to pick it up so that it can progress from having just a Provisional Standard to a Guide Standard and thence to a variety class in its own right.
Within the silvermane line, I shall be selecting for stronger examples of the silvermane effect over the next few generations having focussed first on their temperament which now seems suitable for pet homes. My preferred base colours will be agouti (for the mask), chocolate agouti (for the contrast between golden coat and black eyes and whiskers), and american cinnamon (just because!). Rats from this line will be kept out of my other lines, since it's not yet clear what else the outcross has brought in, although I may consider a havana agouti hybrid line.