Adrian Chiles traces the recent history of dog owners picking up their dog’s poo, starting from New York (I’ve been thinking a lot about dog poo, 14 January). Certainly in this country it is now possible to go for a walk in the countryside or in towns without having to watch your step.

However, quite often a footpath or bridleway is made impassable due to large dumps of horse manure. Dog owners have taken on their duty to clear up after their pets, always armed with dog-poo bags. Why are horse owners and riders allowed to make much larger, smellier and long-lasting heaps of horse excrement? I can imagine that it would be inconvenient for a horse rider to dismount so as to clear up the poo, but I don’t see why the riding stables should not have this duty. I look forward to the day when walkers can enjoy the environment free of dog and horse-made hazards.
Ros Ward
Durham

Adrian Chiles is right about the “seismic cultural shift” in dog-poo etiquette, but as a Dutchman housesitting across rural England, I’ve noticed that the revolution stopped at the stirrups.

​Recently, while I was performing the civic duty of scooping a modest deposit from the dog I was looking after, a rider trotted past. Her horse promptly left a steaming mountain of manure directly in the centre of the track. With a polite nod, she moved on, leaving me – bag in hand – contemplating the Great British poo divide.

​It seems that if your beast has paws, you’re a social pariah for a missed scoop. If it has hooves, the carefree “leave-it-where-it-lands” era of the 1950s lives on. Until I see an equestrian dismount with a shovel, I’ll assume the status of the “doo” depends entirely on the owner’s place in the class system.
Jan Veenstra
Terherne, the Netherlands