Rear harness for Bullmastiff gait support

Your vet is right to steer you away from a collar for gait support — on a large, heavy dog like a Bullmastiff with rear-end weakness, a collar puts all the load in completely the wrong place and can actually throw their movement off further. A full rear harness is the right call. To make sure we get the fit correct, can you tell me roughly how much your dog weighs right now, whether the weakness is more in one leg or both equally, and whether he's still getting around under his own steam or needing quite a bit of lift assistance?

That's a classic picture — bilateral rear weakness with enough muscle left to keep him moving, but you need something you can hold onto when he sways or stumbles. At 58kg he's a big lad, so you need a harness built for serious weight, not a lightweight hiking design that'll twist under load. What does he do for daily exercise at the moment — short garden walks, longer outings, or is he mostly pottering around the house?

Good to know. The sliding-and-panicking on hard floors is often what accelerates the decline — one bad scramble can set a dog like this back weeks. For what you're describing, I'd recommend the Ruffwear Web Master Harness. It's a full five-point harness with a padded belly strap, chest panel, and a reinforced grab handle over the back that's genuinely strong enough to steady or partially lift a dog his size. It distributes load across the whole trunk rather than just the hindquarters, which suits a dog who still has some drive from the front but needs rear stability. It goes up to fit a chest of about 97cm and at his build he'll likely sit in the Large or XL — Bullmastiffs tend to have the deep chest so measure that first before ordering. It's available on Amazon UK and well-reviewed by owners of large dogs with mobility issues. The handle is firm and close to the body, which is exactly what you want when you're catching a 58kg dog mid-sway.

It's reasonably quick once you've done it a few times — there are buckles on each side of the chest and belly, so you can loosen it fully, lay it over him, and clip in rather than pulling it over his head. That matters a lot with a dog who already has limited rear mobility, because you're not asking him to step through loops or lift his legs awkwardly. Worth doing a dry run at the kitchen table before you use it on him so you're not fumbling at the front door. One tip: go a size up if he's between sizes — snug is good but you don't want it compressing his belly, which can happen with deep-chested breeds.

Good plan. Measure around the widest part of his ribcage, not just behind the front legs — Bullmastiffs often catch people out because their chest is deep front-to-back as well as wide. Once you've got it fitted, give him a few minutes in it indoors before you try it on the walk, just so he's not dealing with a new sensation and slippery floors at the same time. If the vet wants to see how he's moving in it, the grab handle also makes it easy to do an assisted walk alongside him for assessment. Hope he takes to it well.