What is Line Breeding?

To answer this question in one word, it is inbreeding. However the word inbreeding has unpleasant connotations, particularly to the layman, so line breeding is a phrase used by breeders who practice this. Basically any cat that is mated to a relative is being line bred. A lot of people – especially novice breeders– shy away from this idea. This may be because, in human terms, any mating between close family members is frowned upon and indeed seems slightly horrific. Some of this distaste may rub off onto our views about cat breeding. However it can be a useful tool when used intelligently. Moreover, cats have no such compunction and mums are happy to mate with sons, grandfathers with granddaughters and so on. Obviously what cats are happy to do and what is in the breed’s interest does not always coincide. In the following article I will use the term “inbreeding” rather than line breeding as I feel it is more honest.  I'm not into inbreeding my cats in a big way myself and use frequent outcrosses, but sometimes having a really good ancestor on both sides of the pedigree can produce wonderful kittens, so long as health is always top of the list of priorities.

Quink as a 'teenager'

Let us look at Quink's pedigree as an example.  His pedigree name is Quil Gyldenloeve.  Because he has a very short pedigree he is on the 'reference register' for GCCF.  You only have to go back three generations to find a 'novice' - ie a cat from the forest (Champion Putte), of unknown ancestry.

Quink's pedigree

So we don't know if Putte is inbred or not.  We can but hope!  The rest of the pedigree looks as though there are no other cats appearing more than once - so he seems to have no inbreeding at all.  However if you go back... and back... and back to the ends of all the lines in his pedigree, you can see that a few cats do appear more than once after all.   It's very slight though.  

So what happens if you avoid inbreeding?

Well, for a start, in the world of Norwegian Forest Cats it is very difficult to avoid some measure of inbreeding as some cats (particularly well-used stud cats) appear in pedigrees time and time again, albeit possibly so far back in the pedigree that the breeder may not realise without special research. This is in spite of NFCs having one of the widest gene pools of all breeds. In my opinion, some of the early breeders of Forest Cats in Norway did repeated matings of very closely related cats, to an extreme extent, and that is not something I would like to see happen again. A certain amount of diluted inbreeding is seen in many breeds and so long as the common ancestor(s) do not have health or temperament problems then it is harmless. However if one tries to have little or no inbreeding in a pedigree then what happens is that the results of a mating are very unpredictable. That is why there are huge variations within the NFCs in this country and indeed worldwide. There are also enormous variations within individual litters. Experienced breeders are often pleased when they have some sort of uniformity within a litter and within litters of repeat matings. Sometimes they are fooled when the kittens are all one colour and pattern however! Otherwise breeding NFCs amounts to little more than a lottery. I have seen (both in my own cattery and in others) cases of large parents producing small offspring; small parents producing good-sized offspring; two cats with dipped profiles producing kittens with straight profiles; and vice versa, and so on. It always amazes me how variable NFCs are, after I bred Abyssinians for some years with very predictable and consistent results. The latter is probably due to a much smaller gene pool in the breed as a whole – something that has its advantages and disadvantages.

Vieuxtemps Indigo

We once had an 'oops' mating that resulted in father-daughter progeny!  This was when Magnus had been neutered but was still fertile.  He was mistakenly allowed to reach his daughter and, sod's law, they mated.  The result was two lovely and very similar blue tabby kittens, Indigo and Indiana.  

Champion Magnus More og Romsdal, father of Indigo

A father-daughter mating certainly wasn't what I had had in mind, but the kittens were robust and beautiful so no harm was done on that occasion.  

What happens if you avoid inbreeding to a large extent, is inconsistency and unpredictable type. Resulting litters are likely to be healthy and large but may have hidden recessive defects.

We are fortunate to have a large gene-pool for the NFC breed, worldwide and also within the UK. This means that we have a wide choice from which to pick and choose the best of the cats available to breed on from. Of course this doesn’t always happen as some breeders use cats for breeding merely for reasons of convenience or sentimentality. However we are in a better position than many breeds when it comes to diversity of breeding stock. So should we make a point of capitalising on this fact and doing as many outcrosses as possible in our breeding? To answer this question we need to know the answer to another:

What happens if you do practice inbreeding (and probably call it line breeding)? 

There are some good things to be said for inbreeding. The obvious one is that litters become more consistent. If a cat is “doubled up” in a pedigree then that cat’s characteristics will have a doubly strong influence. When a cat is considered a particularly brilliant example of a breed then sometimes it appears in a cat’s pedigree many times. I counted the repetition of one such “super cat” in a UK pedigree and it appeared 13 times in just a few generations! Before you drawback in horror let me also say that the cat whose pedigree I mention is actually a reasonable size (as far as I can tell from looking as I haven’t handled him), healthy and very successful for a number of years both on the show-bench and as a stud. Hence in this instance the inbreeding cannot really be faulted even if most of us would avoid such extreme practice.

Another benefit of inbreeding is that, if there is a recessive genetic fault in a cat, then it will very likely be revealed in the inbred offspring. I remarked above that a cat who is doubled up in a pedigree will have double influence on the genes (depending on how far back the doubling up occurs, of course). Let us take as an example the father-daughter mating I had many years ago, by mistake. The father had no known genetic defects and was a healthy, good-looking cat. However he may have had a recessive fault. If that had been the case then that fault would only “show up” if his mate carried the same fault. With unrelated mates this would be unlikely. Some genetic defects can be secretly carried for generations just because the cat with the recessive (hidden) defect has never been mated with a cat also carrying the same recessive defect. If you have a doubt whether or not a cat is carrying a recessive defect then you can check it out by repeating the suspected carrier in a pedigree. If no kittens in the resulting litter have that defect it is very likely that the suspected cat is free from the defect.  That is fortunately what happened with my “oops” mating mentioned above.

So, with inbreeding, the faults but also the good points are doubled up in the progeny. Hence if a cat with a very strong chin, for instance, is repeated within a pedigree twice or more times, then that strong chin is more and more likely to appear in the kittens. Something happens that we call “fixing” a characteristic; and if intelligent line-breeding has taken place over a number of generations with the breeding stock carefully selected from each generation, then the “look” of that line is firmly entrenched and is likely to be passed on even to the offspring of an outcross mating.

This Vieuxtemps  litter brother and sister, from completely
unrelated parents, are inconsistent in type

To sum up, the benefits of inbreeding are discovery and hence elimination of any hidden genetic defects, together with a consistent and distinctive “look”.

 If inbreeding has been carried out then it is wise to use outcrosses frequently also. An outcross is a mate with very few or no shared ancestors. Repeated inbreeding can cause “inbreeding depression” meaning not that the cats go moping around miserably, but that individual kittens and also numbers in litters decrease in size. If you mate two very closely related parents, even if those parents are huge cats, offspring are likely to be smaller.  Conversely, an outcross can immediately restore the size of the individual and the size of the litter (assuming that the individuals concerned are large and fertile of course). This phenomenon is known as “hybrid vigour”.

If you look at the pedigrees of famous and successful breeders here and abroad (for example, the Pan’s cats of Norway and Jette Madsen’s world-winning Felis Jubatus lines from Denmark) you will see that they have carried out inbreeding but also included plenty of healthy outcrosses. If a cat has been extensively used and repeated in pedigrees – Pan’s Polaris is perhaps the most famous example – then it is fairly certain that that cat has no genetic health problems if these have not shown up in multiple progeny.

My previous stud cat, Dansbjergs Pelle Halelos as a youngster.Pelle had been purposely line bred to 'fix' some excellent characteristics
and as a result his litters were very predictable and beautiful.

Vieuxtemps Vantage Vroom, Pelle's son, was from a complete outcross mating yet looks very like his father due to Pelle's specially bred 'fixed' look.Vroom has done very well on the showbench.

So what should breeders do? My own experience of this is that I have done both inbreeding and complete outcrosses. With the inbreeding I have immediately seen a particular “look” which more or less replicates the look of the cat that was repeated in the pedigree. Naturally I have used cats that I really like as “repeats” so the resulting look is therefore one that pleases me. When I imported my stud Pelle (above, now retired) I chose him because he comes from completely different lines from my existing cats. It was time for a thorough outcross. However he came from a breeder who has, over many years, performed careful and intelligent inbreeding so that her cats have a distinct “look” incorporating the features she considers important in the Norwegian Forest Cat. This has been done so effectively that I find that kittens from that stud, resulting from unrelated females of mine and other people’s, tend to carry on his distinctive and predictable “look”. This is because the stud has fixed characteristics due to the way his pedigree was planned. Of course, his bad as well as his good points are likely to be fixed – fortunately he appears to have no genetic defects. I feel my own way forward would be to continue to combine inbreeding with outcrosses in an attempt to maintain the “look” whilst at the same time achieving hybrid vigour. Of course breeding high quality cats is easier said than done, which is all part of the fun.  I am writing this article to clarify what the good and bad sides of inbreeding are, and to dispel the myth that all inbreeding is a bad thing. It can be a good thing too – in moderation.

Keeping a Norwegian Forest Stud Cat

In an island such as ours, stud cats are particularly important to their breed.  Although it is much easier now than when I started, bringing in new breeding cats still isn't easy or cheap.  A few good quality NFC studs – by which I mean of excellent type, health and temperament – can have a far-reaching effect over many years as their beneficial genes gradually spread throughout the Forest Cat population which is still relatively small here (though rapidly growing). Likewise, a stud cat with poor type, temperament or health can have a disproportionately adverse effect on the breed as a whole within the UK. Hence it is very important indeed that stud owners are careful to use only the highest-quality males for breeding. Obviously the same applies to females, but to a much lesser extent. If a healthy queen is bred every year for six years and averages five in a litter, then she will introduce thirty kittens to the world during her active life. A stud cat on the other hand may father that many kittens, or more, every single year!

Kyrrekatt Kistrand as a baby - he was the first NFC stud cat we had, and an absolute darling.
He also managed to kill the 'indestructible' aspidistra plant that he's sitting on in the picture.

My personal view is always that the health and happiness of the individual cats is even more important than the welfare of the breed, and very much more vital than the satisfaction of the relevant humans (though these things are often linked). So if there is a really super stud cat who isn’t happy and thriving in his lifestyle, he should be neutered in order to lead life as a happy pet rather than kept entire for the convenience of his owners. What one person considers a satisfactory life for a cat may be considered cruelty by others, of course. In fact I sometimes think that there are as many ways of keeping cats as there are breeders. In some countries studs are kept in isolation in small indoor cages, which would be considered unacceptable by most animal-lovers and certainly by the cats themselves. At the other extreme, some kind owners have sacrificed their own comfort in order to give their cats the best possible life; I have been to homes where the males are allowed to live as part of the family, indoors, but with access to a safe outside enclosure when they want. These homes usually smell overwhelmingly of stud cat to the point where a visitor would reel back at the fumes; for very few studs do not spray and even if they never deviate from the litter tray, the reek of their urine is incredibly strong. If someone could invent a pleasant perfume with as much staying-power as tomcat spray, their fortune would be made! Some novice stud owners have been heard to say “my boy doesn’t spray” but very often this is when the stud is very young – spraying sometimes begins as late as 18months of age. Of course, there do exist a few entire males who are compatible with a home life but then the owner has to be extremely careful that there are no mis-matings; keeping a female and male cat together will almost certainly result in unintentional kittens, for the male will know that the female is on heat before any human could guess, and if there is a stud right there, the queen doesn’t even need to waste energy in calling aloud if she doesn’t want to. 

This is International Champion David Austin av Boxerhaven, a wonderful Norwegian boy who was imported to Denmark.  Carli of Gyldenloeve cattery allowed us to borrow him for a few months during which time he fathered some kittens in the UK, including our own Valentine.  This was a great opportunity for improving the blood lines in Britain.

In the UK I have seen many stud cats because I started breeding a quarter of a century ago (eek!) and for many of my litters, used outside studs. (I only got my own boys once I had the time, space and number of mates they deserved. It isn’t kind to buy a male if you have only one or two females – they will inevitably become frustrated if they do not have a large enough harem.) So I have seen good and bad conditions for numerous boys, and have tried to work out a life that I feel is kind to my own studs. Often people do not intend to be cruel, but are simply unaware of their cats’ needs. Apart from the basics of food and shelter, Forest Cats need space and company. I think if a cat is kept in a “run” it should literally be able to run; a few paces in either direction is simply not enough, and they should have trees or wooden shelves to climb and scratch as well as human and feline company on a frequent basis. Even from a selfish point of view, it makes sense to ensure the contentment of your stud; a frustrated male cat can become irritable (and dangerous); noisy; lose weight; and even refuse to “perform”. 

International Champion Tilia Nova's Ingjalf, another magnificent stud we were kindly lent by Carli of Gyldenloeve.  Ingjalf has his own post in the September 2011 section of this blog.  He was one of my favourite cats, ever.

I remember once having a conversation with an exhibitor at a cat show who was describing how impressed she was at the premises of the breeder of her show neuter (not an NFC as it happens). Apparently the breeder kept all her cats in spotless white plastic pens in the garden, and it was all so very hygienic. But during our conversation it became apparent that there was not a blade of grass or natural log in existence – just a couple of metres of white plastic for each cat, kept separate from the others for “health reasons”. What a lonely life those poor cats must have had.

Father, Quink, likes to help bring up his kittens and teach them how to be Forest Cats 

In the countryside, a free-range male cat will roam over a huge distance looking for mates, and studies have shown that a typical patrol area will measure 7 miles in diameter. By means of territorial marking the cat will attempt to keep out other entire males, and if he comes across a male intruder a fight will almost certainly ensue. Sometimes these sound worse than they are; a few chunks of fur will fly, the inferior combatant will retreat and no real harm will be done. At other times there will be genuine injuries, and even a small bite will usually lead to an abscess, which of course can become quite serious in the case of feral toms without access to antibiotics. If two mature entire males come face to face inside a restricted space, such as a breeder’s home or cat-garden, the fight is likely to be bloodier as there is little opportunity for the weaker male to escape. So when I say that stud cats should not live alone, it is not generally a good idea to keep two studs within sight, sound or smell, let alone reach, of each other. Many novice breeders will purchase two good-natured young males and think that they can share a living space, but it is almost inevitable that at some point there will be a nasty fight. I have met one Danish breeder who has several studs sharing the same area in her large home, but this is extremely unusual. It is in the nature of even the most laid-back Forest Cat stud to become aggressive towards other males, and usually one will be the bully whilst the other is dominated and miserable.  However I have had some success with having two studs enjoy each other’s company – and they are both from the lines of the Danish breeder I mentioned, Carli of Gyldenloeve.  Quink is now neutered but this photo was taken while he was still entire.  Valentine is still a stud cat here at Vieuxtemps.

Valentine and Quink chilling out in each other's company

I have heard of some Scandinavian breeders who allow their stud cats to roam free out of doors; I believe that the famous Pan’s Truls was one of these and one day he simply didn’t return home. However in Britain this is hardly practical nor indeed ethical, as your stud will be actively increasing the population of unwanted moggy kittens, and probably picking up nasty diseases into the bargain, not to speak of possible injuries. However this is one instance where your stud cat, if he had his way, would disagree with me in his choice of lifestyle!

Another thing I feel is important for the quality of life of a stud cat is to ensure that he isn’t active for too long. He deserves an early retirement especially if he has been confined away from the household and kept outdoors, so he can mellow into becoming a beloved pet or show neuter, with time spent on the sofa with the rest of the family, without the stress of being stopped from spraying or mating when he shouldn’t. It isn’t fair to keep a cat for many years in the inevitably constricted lifestyle that is the lot of a pedigree stud. Comparatively early neutering also helps to ensure that a stud isn’t over-used within the breed as a whole within the UK. The wider the gene pool, the better it is for the health of the breed.

Champion Magnus More og Romsdal, one of our previous NFC studs caring for one of his kittens.  Magnus was a big gentle blue ticked tabby boy we imported from the Netherlands.

My impetus for writing this article is that there are quite a lot of new breeders of Forest Cats lately – it is great to see the breed growing in strength within our country. I’m sure some people will disagree with my points of view, and they are welcome to put their own thoughts forward. But new breeders sometimes simply don’t realise the needs of a stud cat. It really isn’t a good idea to get a stud until you have had a few years’ experience as a breeder using outside stud cats, and have had a chance to build up the required number of queens for his use. If you are intending to allow outside females to use your stud, you need to be sufficiently experienced to be able to predict what kittens can be produced by a particular mating, and to be able to take responsibility for someone else’s cat staying with you for a few days or even weeks. Cat mating is quite a complex ritual and requires sensitivity and experience on the part of the humans. Of course is it convenient to have two studs– many people like to do this, or indeed have even more, so as to have alternative mates for their own queens and for queens they have sold to other breeders. Inviting sold female kittens back for a mating can be quite a money-spinner in fact! If visiting queens are accepted, you need to have separate quarters so the two cats can get to know each other through wire mesh before being allowed to mix freely. It is also necessary for the stud cat to have an escape shelf on which to spring should the female attack him after mating – which can happen sometimes due to discomfort from the male’s barbed penis. 

Breeders, please ask yourselves – will your studs really have enough mates, company, interesting activities and human attention? If the answer is “no” to any of these, then think twice before embarking on getting a stud. It can be more problematic than it seems.

Dansbjerg's Pelle Halelos, whom we imported from Denmark for his lovely type, size, health and temperament.  Here he is snuggling up with his friend Champion Ragna More og Romsdal.