Because it causes heel pain, so horse will try and place foot down toe first to relieve pressure in the painful area. Horses prone to navicular issues often have poor foot balance and long toe /low heel conformation so there is more stress on the structures in the heel region and incorrect breakover of the foot which also may cause tripping. . This is why remedial shoeing for navicular involves restoring the foot balance (usually by shortening the toe) and also providing more heel support. Hope this helps
babybells yes, tripping is a symptom of navicular. However it can also just be a lack of balance (horse or rider), lack of fitness, pure laziness, bad shoeing, arthritic problems, sore back, poor eyesight, badly fitting tack... all sorts can cause tripping. It's worth investigating it if it happens frequently though.
I'd first of all ask your farrier or if possible a farrier you dont normally use who can see if her feet are to long, and if this is ruled out then consult a vet.
my big lad, had mild navicular, but was sound, I took him in a show last xmas, and he tripped on a corner in the in hand class, suddenly went hopping lame, and turns out he has fractured his pedal bone when he tripped. we only realised he had navicular when he got scanned for the fracture.....
Cue exceptionally guilty mummy, and a horse that got pts! was not a nice xmas and new year!!!
I never actually connected the two, however, now you have kind of put it bluntly, it makes total sense!