Melanoma test? Anyone herd of it? Colour genetics?

[Liz5152]

Hi, Has anyone ever herd of a blood test for Melanoma? I have just bought a 15.3hh 8 year old Dun mare. She is very green, and done nothing other than hacking out and walking/trotting before I bought her. I have tried schooling her, but she is resisting going forward into canter, or once she has she won't maintain it more than a few strides. My main thoughts are that it is just a combination of her not knowing what I am asking of her and maybe I need some more schooling myself to give her the clear aids she needs. My plan was to send her away to a local school for a couple of weeks so she can have some intense training to get over the hurdle. However, the lady has asked I get her tested for Melanoma (blood test was suggested) as she said she had seen this before a long time ago and the horse had melanoma on its spine making it uncomfortable to go forward. The logic behind the Melanoma theory is because my mare has a Cremello father - but he is double diluted, so from my understanding he does not carry the grey gene? Is this correct? Also has anyone herd of a Blood test for Melanoma as my vet has not. Both myself and the lady from the school think it is a long shot, but would like to check it out if possible.. anyone have any thoughts?

 

[TarrSteps]

I'm confused, why would she be any more likely than any other non-grey horse to get melanoma. It's POSSIBLE but why go there first when there is such a long list of other possible reasons for loss of performance?

I know there is no dependable blood test for melanoma in people so would be surprised to hear about one in horses. There is one in development for people that has something to do with raised proteins but my understanding is that is still experimental.

 

[flintfootfilly]

I don't know about a melanoma test, so can't comment on that.

But if you genuinely feel your horse is abnormal in the way she is restisting canter, then personally I'd opt to have a comprehensive blood test done (to include muscle enzymes, especially CK but also AST and LDH). Have that done at least 2 days after she's done any work, and at home and without any other stresses like travelling etc, so you get a true baseline result.

If that shows anything other than absolutely within reference range, I'd check how much selenium she is receiving in her diet. To be honest, I'd check that anyway because a lot of the UK is deficient, and lack of selenium is associated with muscle problems in a wide variety of species. Even if you choose not to check grass/hay, then do make sure she is on a balancer which gives around 1mg per day (per 500kg horse) of selenium in the form of selenium yeast (aka selplex or organic selenium). My favourite at the moment is Blue Chip Original. Total dietary intake of 1mg selenium per day is the minimum recommended amount according to NRC.

I say all this because I've had 6 ponies showing varying degrees of work intolerance, and varying degrees of grinding to a halt. In the most normal of them, I started to notice it when they were unable to sustain more than a few strides of canter when I started introducing canter in our ridden work. The worst affected pony could only manage a very slow unadjustable walk and a few strides of trot before grinding to a halt. It could be this, or it might be something different, but there's no harm in checking the diet and blood in any case.

I found muscle enzymes started to improve around 4 months after starting the balancer with organic selenium, so if it is, then expect a bit of a wait before improvements show.

My gang showed signs very similar to EPSM (which is another disease which tends to affect a lot of muscles in the horse's body), but tested negative on a hair sample for that disease, and 2 of them showed no signs of type 2 EPSM on a muscle sample.

Hope you get to the bottom of it. I don't think I'd be pursuing the melanoma route, unless there were extensive visible melanomas to make you think there might be more going on internally.

Sarah