The only time I tried to self wean my Zwartbles, lambed in January, I had to take the lambs away to put the ram in. The ewes were still feeding them. Maybe if they had over wintered together and the ewes only bred from alternate years it would have worked. The other alternative would have to put the lambs in lamb but that would have been to their father.
Having had a mare that arrived with her 3 year old son still feeding from her I am doubtful that with such a milky breed self weaning would have worked in every case.
I’d agree. Dairy cows tend to milk on until specifically dried up, pure suckler mostly self-wean at 9-10 months or when the grass stops growing or when the new calf is a month away. Although they don’t all, and we have had the occasional suckler feeding last year’s as well as the newborn, so we have had to intervene.
Not all ewes will self-wean, and they absolutely can and do cycle and get pregnant while still feeding. So weaning lambs is a function of your system - if you want the lambs to benefit from the fogs after haymaking, you probably want to wean them first; if you don’t tup ewe lambs then the girls need weaned off before the tup, and so on.
It’s not correct to say that all commercial farmers wean. On the Cumbrian hill farm, we sold the vast majority of our lambs fat straight from their mothers, always getting any entire males away first, then mostly wethers and finally ewe lambs not required for replacements, so weaning the remainder - replacement ewe lambs and slower maturing lambs - when it happened a month before tupping was no major drama. Some years we might wean earlier; if there wasn’t enough good grass and the lambs would need fed better than their mums, for instance. Because stressing lambs causes them a check in growth, most say of two weeks, then for us it made more economic sense to not wean unless we needed to.