Horse Behaviour Linked to Poor Nutrition

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Natural nutrition must be our first priority for keeping a horse healthy both physically and mentally. Many health issues can be attributed to poor nutrition and that includes behavioural problems.
Back in the days when I was instructing full time I used to think training could solve almost all issues.
Then I realised you couldnt train a horse effectively if it was feeling pain in its feet from poor saddle fit or from the bit or any other kind of physical pain for that matter.  And then I discovered another problem that caused negative behaviour chronic mineral imbalance.
I have come to realise that even more issues are the result of the grass we allow our horses to eat combined with imbalances or lack of certain minerals. Or the massive imbalance that rapidly growing grass can cause in Autumn and Spring it has been widely reconised in cattle as grass tetany but until recently it has not been recognised or proven in horses.
So many people struggle with horses that are overexcitable nervous jumpy suffer separation anxiety have a sour attitude cant move forward and are generally uncontrollable and think that better training will fix the horse.
Sure some horses can be trained into submission with various techniques but that just causes the horse to shut down eventually it doesnt solve the cause of the problem.
Are these behavioural issues? What has changed in the horses life?
First its best to check that pain isnt causing a problem then look at any changes made to their diet
1 Have they moved to a new paddock
2 Is the grass short and under stress?
3 Been fed something different such as ryegrass or clover hay?
4 Their living situation have they been removed from the herd or lost a herd member?
5 Has a particular grass such as Rye Grass Clover Paspalum Couch Grass Phalaris Blue Canary grass Cats ear flat weed looks like dandelion Tall Fescue in reasonable amounts in the paddock?
6 Has a weed increased such as Cape weed Patersons cures St Johns Wart Fire weed Poison buttercup or Deadly night shade?
7 Have you changed or cut out the vitamin and mineral supplement you feed in the past 23 months?
8 Or have you made changes to the equipment you use new saddle bridle pad girth etc?.
Any or all of these can affect a horses behaviour.
So if youve changed your horses diet then