If you’ve ever stood among your sheep and felt like quitting, this one is for you. Writing this has taken me months, as it's an invisible problem with only tough choices for solutions. It could happen to any sheep farm unless you have already tackled Maedi Visna and I’m sharing what happened so you can learn from our heartbreak.
If you have read the cost of production post for 2023, then you know it was not a great year. Our flock was down to 190 adult ewes at one point in the year even though we had started the year with over 300 ewes. That was not an accident, but it was not an easy or happy decision either. We decided to tackle the difficult task of eradicating Maedi Visna (MV) from our flock. This did not happen overnight and will not be completely resolved for a long time.
If you are not familiar with the Maedi Visna (MV) virus, please take some time to read the following article. This article is essentially part 3 of the series on Maedi Visna and I will be referring to materials in prior articles.
The Breaking Point
In the winter of 2021, we participated in a study for paratuberculosis (Johne’s disease). The study took random samples from a quarter of our flock and included MV tests for all the samples. The study also involved tracking our cull ewes and deaths for a year, after which we would get all the results. December 6th, 2022 was a devastating day when we learned that a third of the ewes sampled were positive for MV. There was no indication that our flock had paratuberculosis.
We went looking for those ewes that weekend. And we could not find most of them. The list of culls and deaths came in very handy, there were 79 deaths and cull sales in 2022. Most of the ewes had died from “listeriosis” or at least the symptoms of that. While some ewes had been sold as culls due to performance, most of them were dead. Our adult ewe mortality that year was approximately 13%. The average age was 3.
We knew something was wrong. The prior 18 months were marked with noticeable performance issues within the flock. Random issues were becoming chronic problems. Our lamb mortality after tagging jumped from 3% to 18%. We went from 90-110 days to get a lamb to market weight to over 200 days. The average daily gain for our lambs declined from 0.7 lbs per day down to 0.3 lbs. We used to routinely get lambs that gained well over 1lb per day, and these were getting rarer. The ewes were not bouncing back in good condition after lambing despite making serious efforts to improve nutrition.
Roughly 20% of the ewes in each lambing group were not around by the next group. We were keeping back 40-80 ewe lambs, even over 100 at one point and we could not seem to grow our flock past the 225 ewe mark. At one point the growth rates on the lambs were so poor that we opted to buy in replacement ewe lambs in hopes that new genetics would help. Spoiler alert, almost all of those ewe lambs never made it past their second lambing.
The Decision
Knowing that we had a high rate of MV in the flock was both a relief and awful at the same time. We were left with three options:
Keep trying to improve our management and hope it goes away
Cull the entire flock, and start over or get out of sheep entirely
Sign up for the MV program and get the virus under control
Getting out was not a serious option though we considered it because going to the barn at that point was not fun anymore. However, the sheep are paying the bills. Additionally, we have limited other options to farm here given land constraints. Our barn is built to be multi-purpose but sheep still make the most sense at this time.
We did do detailed calculations for replacing the entire flock. This was not financially feasible given our preferred breeds and overall costs. There’s only one tested flock of Katahdins in Canada. Only a handful of Dorper breeders are enrolled in the MV programs and there’s very limited genetic diversity. High-quality, tested Romanov ewe lambs are incredibly expensive. Since it would be highly unethical to sell positive and high-risk sheep to other breeders, selling the entire flock for meat would not generate enough revenue to buy back a sufficient number of ewes.
And thus, we ended up signing up for the MV Program as we felt that was our only reasonable option. MV is a fatal, incurable disease that spreads like wildfire through a flock, especially one that is indoors. It’s invisible, and very hard to detect without blood tests. Just staying the course and ignoring MV seemed insane, at this point we’ve probably been battling this problem for ages.
The Testing Process
We could not do the initial test until April. After signing up for the program and ensuring we met all the biosecurity protocols, we had to quarantine the entire flock for 4 months. Every sheep over the age of 6 months had to be tested. Testing took two days due to the number of sheep that had to be processed. We were able to test roughly 63 sheep per hour with 4-5 people plus the veterinarian on hand.
All in all, testing for the first year ended up costing $7,120. This included purchases of additional equipment, testing fees and paying for friends and family to come help test. The actual testing was $7.60 per head on average for test fees and veterinary services. Quebec does subsidize the testing costs through CEPOQ. Testing for bringing in new rams costs more as new sheep have to be isolated and tested twice separately.
Once the results are available, the program requires you to remove the positive sheep within 30 days. They can either be sold for meat or housed in a separate facility. After speaking with several farms who had already gone through the process, we opted to cull any positive sheep as soon as possible. We did end up having to lamb some ewes out because they were already bred and due just mere weeks after testing.
We moved the positive sheep immediately to another barn. Despite being on the same rations and management, the mortality in the positive barn was 40% and the last lambs finally went to market this January. It was not worth having a separate flock with those kinds of results. We skipped an entire lambing group to ensure everything was open or just recently exposed for the second round of testing. Every single positive sheep was gone within two weeks of the blood tests being taken.
Current Status
We were counselled to expect over 40% of our flock to be positive based on the sample from the study. By the second round of testing, we had dropped to 5% positive. There’s a noticeable difference in the flock in just 9 months. We recently finished lambing the first group of low-risk ewes (two negative tests). There’s a massive improvement even though that group was arguably the worst managed we’ve had in years due to personal health issues. Lamb mortality after tagging is almost non-existent.
Our main objectives with the changes we made are to increase the number of lambs sold per ewe to grow revenue and improve feed efficiency to lower costs. This is already proving to be the case, the rate of gain has jumped back up to an average of 0.65 lbs per day. Lossing fewer lambs will contribute to the second goal of having more lambs to sell.
We didn’t have to medicate a single sheep in the last four months. We have not seen any of the random health issues we used to deal with since the first test. Our ewe mortality since the April test is less than 2%. I can count the dead ewes on one hand. Testing every 6 to 8 months is stressful, however, the results so far are encouraging.
Lessons Learned
The vast majority of our positive sheep were young. We did not have many skinny ewes or frequent cases of mastitis. We didn’t have huge numbers of bottle lambs. Our ewes still had milk but likely significantly reduced production. There were not many signs that we had such a high infection rate. Much like the UK case study referred to in earlier articles on MV, we mostly saw declining production despite investing in better genetics and providing improved nutrition.
Based on the symptoms recorded and later witnessed in the positive barn, we likely have the neurological strain of MV most frequently. Other observations we made from the positive ewes and their data included:
low weaning weights, any ewes that weaned lambs that were more than 10 lbs lighter than the average had a higher likelihood of being positive
uneven growth in twins, if a ewe had twins that were more than 10 lbs different in weight at weaning, she was almost definitely positive
body condition score was not an indicator of MV status at all
The majority of our positives were young, with the highest percentage in the replacements. We ended up culling 120 ewes and rams. We lost entire bloodlines. It’s going to be difficult going forward to buy new genetics, we will not be able to easily ever buy new Katahdin bloodlines again. Our breeding management has to change entirely so we can raise both ram and ewe replacements.
Despite all of this, we believe we made the right decision. Going to the barn is enjoyable again. Our lambs are growing consistently, and the whole flock looks better. Turns out, a sick sheep is more likely to be MV-positive than anything else.
Thanks for reading! This was not a fun article to write; what happened makes me feel like a complete failure as a sheep farmer. We have no idea at which point the virus entered our flock as we purchased 3 complete flock dispersals to build our flock. If reading this convinces even just one other producer to take MV seriously and do something about it then it was worthwhile.
I too, recall, after doing my first testing for MV, all the 'mastitis' seemed to disappear. I was lucky, in that I only had 12 or 13 positives out of 300, so a very small %. Paula Menzies did the testing in the pilot program and she was shocked that an indoor flock had such a low incidence.
But since the subsidy from CFIA was removed, I had to pay all the testing costs myself, so I did it my own way. The research stated that a mere 1/3 of the lambs from positive ewes tested positive themselves. The official program required me to pay to test all of them from 6 mos old and up when those results are unreliable until after 1 yr of age, so a waste of time, stress and money. The official program also said that I had to cull all lambs born from positive ewes, and I didn't do that either. I just raised them separate from the ewes from 2 mos old, in their own age group, like I had always done previously. All the lambs were separated at weaning (2 mos) into male/female groups and most of the males were marketed as meat anyway.
I just tested every animal over 1 yr of age every year, shortly after shearing, so we had better access for the blood draw. It took a Vet Tech and a Vet student 2 days to draw blood on the whole flock. 3 of us.
My g/f Liz Dobinson, of Whispering Pines Farm up in Sundridge, ON has Katahdins. Some registered, some not. She is organic. May be a source of some new genetics for you.
https://www.facebook.com/whisperingpinesorganicfarm