Spring grass or something else?

[Sossigpoker]

We have started to turn out again. I've been hand grazing my cob and started access to grass slowly and he's had about 3-4 hours out on grass before this spring without ill effects.
Yesterday he had about 3-4 hours in our fat paddock (small paddock with little grass as it tends to get grazed the most in the spring).
When I brought him in , when leading he went to nip me which is very unusual for him a he's a very kind and well mannered boy normally. Then in his stable he did a lot of yawning and some lip curling , I actually thought he had something stuck in his mouth but couldn't see anything. He started eating his hay so I thought unlikely to have anything stuck .

My instructor tacked him and schooled him after I left and apparently he was pretty much insane. Spooking at everything (he's not normally spooky ) , acting cold backed, felt like wanted to bolt at every opportunity. Just completely out of character!
He's a sensitive boy but not stupid, usually if you have a horse being silly out hacking and not going past a gremlin my boy will give them a lead as he doesn't worry about a lot. So his behaviour was just offthe scale unusual for him.

Would it be possible for the grass to have caused this ? And maybe he had a belly ache hence the face pulling? The grass in that paddock is very short so presumably would be all green, sugary shoots coming up.
Would it be better for him to go out in a paddock with longer grass but maybe not for long (he's a cob so will get fat !).
My instructor is riding him again today to see if he's any different and he won't go on grass before hand.
I know the spring grass can make them fresh but he was just off the scale off his rocker !

 

[Flamenco]

Yes its possible its the grass. I'd try keeping him off it or try a magnesium supplement. Google magnesium deficiency and see if it sounds familiar.

It could be something else but as magnesium imbalance is behind most spring silliness I'd try this first.

 

[Sossigpoker]

Forgot to say that he's already on magnesium (Vetrocalm). He has been on brewers yeast but about a week ago I stopped it to Lincoln brewers yeast with prebiotic. I can't imagine that being the cause though.
Has anyone else experienced a horse being terrified, off his rocker and panicky (that's how I'd describe it not just fresh ) due to spring grass ?

 

[Flamenco]

Yes - mine was!

You may need more magnesium than in a supplement. Mine was much as you describe, since feeding barefoot diet with about 50g magnesium per day he's been his usual calm and sensible self all year round. He doesn't need this much all year just spring and autumn.

Previously tried NAF Magic (3.6g mag per scoop) and the Equine America one (10g mag per scoop) with a slight improvement. There may not be as much magnesium as you expect in the supplement.

I find spookiness returns when changing diet - e.g swapping brand of brewers yeast. The gold label brewer yeast didn't do anything for mine (bought when run out of usual one) but found one on ebay which works well.

If you have a look at the Calm Healthy Horses website they have a before and after diet changes checklist. We went from 45 (!) issues to occasionally having a couple. I didn't buy their products but the checklist is great at helping you to identify whether supplements work.

Spent nearly a year solving this so you're welcome to PM me if I can help.

 

[Sossigpoker]

Thank you so much I will up his magnesium for now and have stopped the Lincoln yeasacc/brewers yeast just in case. He seems more his normal self today , no face pulling and no biting so hopefully he's a bit less insane to ride.
I will check out that website too.
Thank you again.