Dwarfism in Miniature Horses

a very short article by Sharon Packer

 The time of year is on us. It is so exciting when these little baby horses come into the world and most of us look forward to each unique new born life that appears almost as if by magic during the night.

 For some people it is a little different .. foaling is problematic, stressful and often results in non-viable foals or even dwarfs... why is this?

 I became concerned when I learned that many breeders have in fact had dwarf foals. Cute I thought? - not so.. First it happened with my friend who bred American miniatures.. she had not one dwarf but several and each time she sold the mares quickly.. then I heard that Falabella breeders had this as well and again the mares were sold and nothing was said..

 What really brought it home to me was when I retired a mini show pony of mine. A beautiful mare who was such a character. I decided to retire her early as she wasn't Falabella in any way, and she put so much into making her foals that I did fear that one year she would lose her life. This mare retired with her daughter to a lovely wildlife park nearby, but they wanted one last foal from her.

 The day she left me was the last time I saw her alive. I found out later that she had produced a foal but it was round in shape, like a huge deformed ball and it killed her. She just couldn't give birth to it and she must have ruptured inside...Just thinking of it tares me apart.. and I had no idea why or what had happened until I started to look into dwarfism out of curiosity.

I found out that some American Miniature breeders lose as much as a third of their foals through dwarfism – that's right, and because dwarfs rarely live long, if they do it's through a great deal of medical intervention and a huge amount of TLC, we aren't really aware of them. Many die in the womb and are aborted and many are just born very deformed. My mares foal had a classic deformity and usually these round deformed foals are aborted when the foetus is very small.

 I also found out that some traits of dwarfism actually are very similar to the look that many breeders are deliberately trying to achieve with extreme dished heads, over exaggerated Arab type heads, small size and stature... so in a way they are masking the time bomb! - Who is to know if some of these horses aren't in fact dwarfs themselves, but simply not displaying the symptoms of the dwarfs that die?

 It is in fact very likely that some of these horses who display what we may think is the ideal, are in fact carrying the recessive dwarf gene. It has been shown that the gene is recessive which means that both parents must carry it for a dwarf to be produced – so why sell the mares only? - Why not stop breeding from both the mares and the stallions that produce these deformities? I in no way advocate this at all... There are many beautiful animals around who would be very useful to the breed even if it does look like they might carry the gene – but they should be used responsibly.

 The Falabella breed has been relatively free of this gene for some time – some say that dwarfism was deliberately introduced into the American miniature breed? - some say that all the miniature breeds will have dwarfs... but should we not be breeding responsibly and at least trying to keep our stock as free from recessive traits as possible, and if so how can we achieve this?

 

 

 

I am no genius or professor of genetics, so I looked to another breed with this very problem and I found a big horse breed that has suffered dwarfism for many years. This breed also suffered more of the more normal results of inbreeding as well such as the depression of the horses ability to resist disease, reduced fertility, reduced vigor, an increase in abortion and still birth. Does any of this ring a bell or two? With a thorough program of reducing inbreeding these breeders seem to have stopped the ever increasing numbers of dwarfs and recessive traits.

 The breed is the Friesian horse. They didn't go on a witch hunt and cull every horse or line that had thrown a dwarf. Why to do that they would have lost some of the most beautiful horses! - They introduced a program of testing inbreeding before they bred. They will now not register horses with an inbreeding coefficient of more than 5% over 5 generations - what's that you ask? - ok so it's another complicated calculation.. but we have a database that will do this for you.

I used to breed cats who too had a problem with a recessive trait so always checked the inbreeding before I paired my cats, and it worked! - I contacted the person who held my cats on their database many years ago and they were still there and were willing to take my current 'ancestry' database which I started 2 years ago, and transfer it to this new database which everyone can use. The database is here

 This simple check could save you not only the life of a foal but thousands of euros as well, and over time will make for a healthier breed.

Just to bring this problem home, here are some pictues of  of one such little dwarf in the USA called Romie

Romie2_dwarf 

 Romie_dwarf

 

 

 

 

 

 

 

 

 



This is what his owner says about him...

He gets his hoofies done every 4 weeks and has been wearing a set of Janell's Magic Shoes since he was about 3 mos old.. Working o.k. for him.. But hard going in the snow.. Romie is not living a perfect life. He is crippled and is only 21" tall. cannot raise his head, his back is roached and he has to have a very sprecial diet. And he has to wear special shoes 24/7 

 Romie3_dwarf

I would NOT wish that one any foal. But if it happens, I will love and care for any of my babies that happen to be dwarfs, for as long as I have them.   I lost the half sis, Pop Tart,  to Romie at only 4 & 1/2 mos old.. It still breaks my heart.. But now I know she dances at the Bridge and is free to be healty and happy there..  She would have grown more crooked like her brother.  She was an accidental breeding, as I had planed on never breeding her mom again.  But she found a way to find our other stallion.. He is Falabella..  So I know that it happens in all different lines..

 

    To use the online facility and to check if your future stallion and mare pairings are responsible, click on 'Inbreeding DB' . If you put in the name of your horse it might even be in the database already. You should also ensure that the 'generations' is set to 5 as that is the optimum for calculating the coefficient.Using this database you can also carry out test matings. Trying different stallions, you should be able to keep the inbreeding below 5% which will give you more chance of avoiding recessive defects in the next generation.

We also have another database called the 'Ancestry ' database – it is slightly different in that it gives all the relations of horses held in it and you can also print pedigrees online. If you want your horses added to this database please email me via the Contact Us page here either of the address above and we will add your horse to both! - copies of any original registrations and pictures are required for this one.

 Thanks to Jeanie from Pinataminis 
 Sharon Packer - Merrylegs Falabellas