Worming 101

Discussion in 'Sheep' started by lisarichards, Feb 24, 2005.

  1. lisarichards

    lisarichards Well-Known Member

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    Can we do worming 101?

    We got two separate small herds (7 Icelandics and 6 Shetlands) last fall, both up to date on worming and vaccinations. We'd never had critters of any kind on our land. It's been a pretty snowy and cold winter, and my understanding is that the worm life-cycle needs temps above freezing to start, and that I should begin worming and moving the herd to different pastures in the spring.

    So we will probably still be snow covered for another 6-8 weeks, though it could be as short as 4. When do I start worming? Where do I buy the meds? What do I need? to get started?
     
  2. lisarichards

    lisarichards Well-Known Member

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    This is from Vermont, which has a similar environment, so seems like a good place to start: (http://www.ext.vt.edu/news/periodicals/livestock/aps-03_06/aps-237.html)

    Tips for Successful Internal Parasite Control
    Internal parasites are a potential source of economic losses for sheep producers during the spring and summer months. Parasitic infestation can result in decreased production of ewes and lambs on pasture through reduced milk production and poor weight gains, and even mortality in extreme cases. The two most significant parasite impacting sheep in Virginia is Haemonchus contortus. These worms thrive under warm and moist conditions of late spring and summer, which emphasizes the importance of an effective parasite control program as sheep go to pasture. Approved dewormers for use in sheep include Levamisole (Levasole and Tramisol), Ivermectin (Ivomec Sheep Drench), and Albenazole (Valbazen). Keep in mind that all other products are currently not labeled for sheep, and must be prescribed and administered under veterinary direction. Following are a few tips for a successful sheep deworming strategy:

    1. Deworm the flock on a regular basis. Be sure to record the date of treatment so a schedule can be followed. This is especially important when the dose and move system is not applicable due to limited pasture availability. Normally sheep should be treated every three to four weeks. Frequency of deworming will be related to stocking rate, age of sheep, breed of sheep, weather, and pasture worm load. In many cases, deworming only a few days late can result in anemia and reduced performance, particularly in lambs.

    2. Use pasture management to enhance the effectiveness of a deworming program. The practice of "dose and move" can reduce the dependence on anthelmentic drugs to prevent and treat parasites by reducing the number of parasites sheep are exposed to. Using the dose and move technique, sheep are moved to a clean pasture after treatment. A clean pasture may be one that has been harvested for hay, previously grazed by cattle, or been without sheep for a year. A clean pasture does not ensure that infective larvae are not present, but has infectivity low enough that susceptible sheep do not become infected rapidly. A strategic deworming protocol must still be followed after moving the sheep.

    3. Lower stocking rates will reduce the intensity of the deworming program. Fewer sheep result in fewer shed worm eggs within a given area, thereby reducing parasite loads. This in turn may reduce the frequency of deworming, and help minimize developed resistance.

    4. Administer the proper dose. Be sure to estimate the weight of the sheep accurately. Dose the sheep for the heaviest in the group, not the average. Dosages given that are inadequate for the body weight of the sheep are not only less effective on decreasing worm loads, but may also enhance parasite resistance to the drugs.Rotate dewormers annually. This means that if you used Ivermectin last year, switch to Levamisole this year. Rotating anthelmentics on an every other year basis will help prevent parasites from developing resistance to the product.

    5. Deworm the entire flock (or group of sheep grazing the same pasture). For a parasite control program to be effective, it is important to include all of the sheep. Lambs should be treated beginning at around six weeks of age. Mature ewes are more tolerant to high worm loads than are lambs.

    6. When introducing new sheep to the flock, deworm with the most effective product available. New sheep should be isolated a minimum of 30 days prior to introduction. Mixing untreated sheep with sheep on the deworming program may destroy earlier efforts to minimize worm loads in the flock.
     

  3. MorrisonCorner

    MorrisonCorner Mansfield, VT for 200 yrs

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    Actually, this is based on information coming from Virginia. For New England farmers this is an important distinction. Parasite control has become such an issue in some of the southern states that to control worms during the critical weeks after lambing shepherds have begun resorting to dry lot feeding, where sheep are on bare ground (or cement) and not allowed to forage off the ground, thus putting at least a short term stop to the worm cycle.

    In the Northeast we pretty much haven't had to deal with this level of infestation. Bless those northern winters!

    There are two schools of thought here... one is "on a schedule" the other is "as needed." The down side of worming on a schedule, particularly if your sheep don't actually need it, is that you're building a resistance to the wormers.

    Sheep who are having problems with a parasite load will show it in their eyes and gums, they'll be pale as a heavy worm load leads to anemia. You can also have the fecal material tested for worm load. We do record when we worm, and we do worm automatically after lambing, but worming on a steady schedule may not be helpful, and may in fact not be beneficial.

    The other thing that will reduce worm load is not allowing waste to build up, particularly on slopes or in pasture areas. Unfortunately, we discovered this a wee bit too late!

    Our worming program consists of handling the sheep daily, or at least being able to observe them closely. If we see one with an issue, we dose the lot. We do hit the ewes after lambing, and the entire flock before breeding because we don't worm while the ewes are pregnant. During the summer I think we hit them twice more... once more than I think was strictly necessary but we were nervous after a friend nearly lost a good ram through inattention.

    T
     
  4. ovsfarm

    ovsfarm Well-Known Member Supporter

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    I am chiming in from another perspective. We manage our flock organically. I will be quick to add that we have many things going for us that not everyone enjoys. We have fresh ground that has not had sheep for at least 50 years. We have a very small stocking rate. We have primitive sheep known for their vigor and disease resistance.

    We wormed them all heavily with the herbal wormer from Hoeggers when we first got them (including the llamas). Then we keep up with the basic schedule for giving the wormer free choice once a week. The sheep seem to love it (Woo hoo! Friday night, wormer in the feed!) The llamas hate it and will only eat it if they have to go through it reluctantly to get to the sweet feed.

    I take samples to our vet in the early spring, after lambs are weaned, at the end of summer, and in the mid Fall. So far all the samples have come back either minimal strongyles or -0- evidence. We do have white tailed deer in and around our pastures, and probably plenty of other scurvey little wild critters too.

    I have heard from our local vets/Extension people that there are now many ivermectin resistant parasites in our region. They attribute that to people who worm on schedule and miss the most vulnerable cycle of the parasites or those who fail to retest after using medication to fight a heavy infestation and apply a second dose as needed--either practice of which is supposed to leave some live parasites that have been exposed to a minimal dose of the chemical, which kills the more fragile ones and leaves the "super bugs" to be the ones that replicate.

    In my vast experience (3 years with sheep), we have been very successful going the organic route. We have seen others have terrible problems going organic and at the same time seen some following the chemical schedule to a T, and have the same or even higher mortality. I guess the main thing is to stay on top of it. To keep a close eye on the condition of the animals and to intervene quickly, monitor the success of the intervention, and to keep at it until the fecal tests come back at acceptable or clean levels. I am willing to consider other opinions, though.

    Lori