I've only lost one tamed Lox, to mosquitoes. But note that, for some reason, you can't use a Lox in combat.

Wild Lox: Easily 3-hits you and takes a dozen hits to kill. Has no trouble killing anything that annoys it.
Tame Lox: If you mount it, and charge into a Fuling, it instantly loses 1/3rd of its life, even before getting hit. Dies easily to mosquitoes. When an enemy approaches, it goes berserk and breaks its enclosure, then gets trivially killed by the enemies from which it was perfectly safe until it broke its enclosure.

Summary:
Taming Loxes is completely useless. If you want meat, just wander around the plains and kill wild ones; it's much faster and easier.

Note that you can feed tame Loxes Cloudberries, which sometimes restores their health to full. And sometimes it doesn't, just giving them +1.6 HP per interval, which is useless.

@kolorotur I went and built 2-3 high on the wall with plenty of berries in there. I also went and lowered the pit a bit more too, so I'll see what happens from here on out - thank you for the guidance!

@KOTL Gaming I noticed that since I came back that they only regen with food now and ty for the tip (for others too that may not know).

deathsquitos I'm betting. Bane of my Lox herd.

ya, even with a large herd....I get one taken from me every now and again. I find the hides and meat, sometimes the saddles I put on them. I keep 4 saddled in a few locations surrounding my Plains compound to allow for a good chunk of Riding XP...when one critter's Stamina gets depleted, I jump on another one nearby with a saddle.

I've got ~8-10 on the Plains outside the base, 6-8 in my taming pit, another 4-5 in the Meadow behind the Plains base, in view, and about another 10 in a walled enclosure in the Meadow just beyond the grazing herd there, so quite a few Lox tamed and grazing nearby.

You definitely have to tend the herd with cloudberries from time to time...or you will begin to lose more than a few quickly; it also keeps them happy and breeding so it pays to tend your herds of tamed Lox.

Throw a few workbenches on top of the walls or some raised platforms. Dollars to donuts it is fulings. Lox can generally manage to kill deathsquitos, but if you have a fuling spawn, one where they throw down a campfire, that can really be dangerous to lox. Usually if there is a fuling campfire spawn, there is a spear & fire (torch) wielding fuling, and you know how weak lox are to fire.

Your probably losing them to deathsquitos if they're in the plains?

Do they drop meat/skins?
If the pit is in Plains or on the border, they might get ravaged by deathsquitos or spear-throwing fulings that patrol at night.
Spend a couple of nights nearby, see what's going on.

Yes, they drop meat and skin. We even had a wooden spike walls up too. I'll do some guard duty to see what's going on. Thank you for the quick reply. :)

Raise a 3-4m wall around the pit, with vertical walls so that enemies couldn't climb it.
If the top of the pit is level with the ground, the loxes can easily be sniped by fulings or whatever raids your base while unable to fight back.

Are you still having the problem my friend? For God's sake feed them, tamed animals only regenerate their health when fed as of this update, it is no longer like how it used to back then when your animals keeps on getting the regen effect even when hungry.

And Lox's been nerved. Still strong for a single one vs one fight, can even beat Eikhtyr solo, but Lox can no longer fight is prolonged time with multiple waves of enemies.
Yes, no more One Man Army Lox, hence why i breed couple of them and with 5 Lox in the vicinity, they can keep each other from harm.