Help for sheep suffering from "something bad inside"

It’s a running joke among sheep farmers that 99% of a sheep farmer’s job is saving these wooly beasts from the 1,001 ways they try to die. After a few years owning sheep, I am still surprised by the silly ways they get into a pickle, but there’s likely nothing more frustrating than losing a sheep to a mysterious cases of SBI, “something bad inside.”

The truth is, sheep don’t really deserve the trying-to-die reputation — most cases of SBI are often nutrition or parasite-related – but due in part to a lack of training and knowledge transfer, sheep farmers often scramble to treat sheep with online advice and the few tools at their disposal.

Laurie Maus, a farmer and soon-to-be-retired purebred sheep breeder in eastern Ontario, doesn’t think it has to be this way, and she’s launched a new company to work with sheep farmers to put some power back in their hands. So often, internal parasite loads in sheep drag down production and lead to suddenly dead sheep, leaving the farmer confused and feeling defeated, she says. It’s also common that when sheep are looking poorly out on grass, the first thing a farmer asks is which dewormer to use, but that’s actually backwards. Dewormers are a valuable tool in parasite management, but should be one of the last points in a parasite management plan. Instead, decreasing total parasite loads and culling those animals highly susceptible to parasites will get a farmer further ahead, says Maus.

Maus has been hosting fecal egg counting workshops at her Hawk Hill Farm at Dunvegan for several years, taking the opportunity to show farmers how to monitor parasite loads in their flock and evaluate dewormer effectiveness. During the workshop, farmers learn about parasite life cycles, how parasite resistance to dewormers happens, and how to select for parasite tolerance in their ewe flock. It’s typically an eye-opening day for many, especially when they learn that pasture needs close to 60 days without sheep in order to effectively decrease parasite re-infection risk.

A new venture, No-Sheep Sherlock, builds on the fecal sampling workshop and takes parasite management one step further, Maus says. The expanded service includes an on-farm tour and advising to develop a whole-farm parasite prevention plan. Too often, Maus says, farms may have set up rotational grazing but use common areas every day, or are under-dosing sheep  when they do use a dewormer. The one-on-one training means farmers can ask all the questions they have, and perhaps save those sheep from “something bad inside.”

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Listen below to Laurie Maus explain how No Sheep Sherlock came to be, and how sheep farmers can take parasite management to the next level on their farms. 

Parasite management 101:

  • I rarely use the term “never” with anything in agriculture, but this might be the exception —never treat all of your sheep all at once and never with the same drug. Always leave some untreated animals as a refugia to reduce the pace of worms becoming resistant to the product you’re using. You can’t eliminate worms entirely, and leaving healthy animals untreated means there’s a worm population left that remains susceptible to the product, because its never been exposed.
  • How do you decide who to leave and who to treat? Treatment should be based on a combination of factors: body condition score, fecal sample,  stage of production (i.e. lambs, lambing stress), FAMACHA score (an estimation of anemia), grazing history, time of year, and other symptoms, such as diarrhea or bottle jaw.
  • Treat with an approved dewormer and for the most likely culprit. For sheep, the list of approved wormers is actually very short. Consult your vet for any off-label use — you’ll need their input on withdrawals for each un-registered product.
  • Make sure you give the right dose. Don’t guess the weight of your sheep, either. Weigh them! It’s ideal to do a fecal re-test to evaluate the dewormers effectiveness
  • Remember that the worms are in the environment more than in your sheep. Pasture management is going to go much farther in protecting your sheep than a dewormer. Prevention is the name of the game. The biggest culprits? Set stocking densities (i.e. leaving sheep in the same field for an extended period of time where there’s always enough to eat), or rotational over grazing (grazing the crop down to below four inches in height). Not only is this hard on the pasture, but this is when parasite loads build up and sheep returning to a paddock within 30 to 60 days are at risk of picking up parasite loads
  • A healthy sheep is better able to withstand a parasite load. Test your feed, and ensure you’re feeding an adequate mineral supplement
  • Select for genetic resistance to parasites —though it’s easier to cull for the opposite and you’ll likely make gains faster this way, Maus says (as in, it’s easier to identify and remove very susceptible animals than it is to identify those with resistance.) Maus notes that selecting for resistance does not replace a fully integrated management plan — an animal with resistance will still succumb to parasites under high-load conditions.

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