Anyone got any experience of Johne's disease in sheep?
I think (hope) that actually our skinny Zwart will recover her condition, but we are still treating her as under suspicion of having Johne's until she really clearly improves.
This all began, this time around, when our one remaining Zwart ewe, usually an excellent producer of twins, lost a lot of condition over summer. She was rearing Shetland x lambs, so not having to work that hard, and running with the other lambed ewes on good grass all summer. We lambed 3-4 weeks later this year, late April, so that there would be plenty of grass for the ewes to make milk and - if the weather played ball, which it did - we wouldn't have to cake them until the grass came in, as we had had to do several times in the past, when lambing late March.
So, Gwenneth, usually an excellent sheep, keeping decent condition while producing two good strong lambs, became a hat rack this summer, when no-one else in her group did. She looked a bit lacklustre too, so she had the works - worm, fluke and vitamins. (There was no diarrhoea, no cud spilling, and she seemed to be eating well, although she never looked as
full on the lefthand side as the others in the group.) She perked up in herself but remained skinny, in fact got more skinny, so I separated her and dried her off, and she's now been on decent grass with the last of the 2019 lambs for a couple of weeks. When I handled her lambs at weaning, they were happy enough but ever so slightly skinny themselves, whereas every other year, Gwenneth's lambs have been strapping great things and very fit. Every other lamb in the group is fit to a fault, all bar one are twins, all to the same dad, and all to smaller ewes than Gwenneth. All the other ewes in the group are between okay - CS 2.5 or thereabouts - and fit as fleas.
What made me think of Johne's? Well, when I came here, there was a Zwartbles ewe in similar shape, skinny as a hat rack, eating okay but a bit listless, no diarrhoea, no cud spilling, teeth all fine, being pumped full of meds and racking up quite a vet bill. In the end we all agreed she wasn't rallying, and sent her off for mince (after the withdrawal period, of course!) Gwenneth reminded me of Mavis so I started to look into what else it could be.
I knew that sheep could get Johne's, and knew a little about Johne's in cattle, where it is almost always accompanied by very liquid faeces and I knew that diarrhoea was not a symptom in sheep, so I read up about it some more. Onset is typically at 3-4 years old. Gwenneth is 2015 born (so this is her 4th crop, all twins; Shetland 1st time, then Romney then Romney x Wensleydale then Shetland again), Mavis was exactly the same age and stage when she went downhill, having had either pure Zwartbles or Texel x lambs each time.
In sheep, as well as often not coming with diarrhoea, Johne's is a pig to diagnose in an individual. You may be able to get a positive diagnosis post mortem, but an absence of identifiable markers is not conclusive of not being Johne's.
Things that are distinctive, and which fit, include that the sheep is eating normally, the rest of the group - being managed the same - are not skinny, there is no diarrhoea (at least, after any necessary worming, there isn't) or other obvious cause or sign, but despite feeding, rumen fill is sub-par. I had noticed that Gwenneth appeared to graze and to cud the same as everyone else, but whereas others looked full to bursting on our good grass this year, Gwenneth looked not only skinny but also
not full - a distinct hollow in front of the hips on the left hand side, whereas everyone else was so round with their rumens full to bursting, I had been almost been anxious about bloat once or twice. (Not really, but they were very,
very round.)
There is usually a deterioration in the fleece too, which is actually hard for me to tell as I don't rate Gwenneth's fleece at the best of times :/. But that had most definitely been true in Mavis' case.
A week ago we were all quite glum and planning to send Gwenneth off, and trying to decide if we should get a PM so we might know for sure (although a negative pm doesn't mean it wasn't Johne's), and whether we dare risk keeping one of her daughters to keep the Zwartbles genes going, for those here who have an attachment to them.
The last couple of days I have thought Gwenneth was back to her old bouncy self, and when I handled her (after being away from Trelay for 10 days, and hadn't handled her since weaning), I thought I maybe could think her slightly less of a hatrack. She is now getting a little bit of cake by hand of an evening too, which will make her pushy and a nuisance very quickly
So we have agreed to give her another month, keep her well-fed and keep note of where she is kept, make sure she isn't pastured with young keeping lambs - or cattle - and that they don't follow her until spring at the earliest, to graze hard after her with the ponies (which would eat off any bacteria on the grass) and maybe to graze that ground with the ponies first in spring too, so that any bugs in the soil hopefully also get eaten off.
So, the game plan is, if she gains condition then we assume it wasn't Johne's but that she needs cake even if she lambs onto good grass and has plentful good grass all summer. If she doesn't gain condition after another month on decent grass, with a little bit of cake (and she will get some good haylage too if the weather stays cold and overcast), then we will think the worst and send her off. We are going to ask the vet at the abattoir if they would be able to look at her innards and see if they can positively diagnose Johne's, or otherwise a cancer or something else which could explain the failure to thrive.
As to keeping a daughter, we don't have to decide immediately because the daughters, if infected, are unlikely to be infect
ious until they lamb themselves. So we can keep one or even both for now, and see what we learn if we do send Gwenneth away. Personally, if we did get a positive diagnosis then I don't want her daughters on the farm longer term as they are likely to have been infected, if not in utero then through the milk. But it would be a harder call if there is no positive diagnosis of any cause for her skinniness.