Parasite control and sheep in Iowa’s cold

Regular readers might recall that the summer of 2016 was an unusual one for the bloom of parasites in our region: weather conditions were perfect for the dramatic rise of internal parasite larvae in our pastures which resulted in illness and death in many of our youngest flock members. We initiated a plan to reduce the number of parasites in our sheep that fall and hoped for wickedly cold conditions to help reduce the parasite load over the winter of 2016-2017 – but that cold never came. As a result, we kept our sheep off of each our pastures for six months during 2017, using only two pastures in the first half of the year, and then opening up the other five pastures for the second half of the growing season. This plan made a huge difference in the health of our sheep and llamas, although our sheep went into breeding season this fall a bit thin because of the quality of the grass (over-mature grasses are much lower in protein, and therefore less helpful in getting our sheep back up to their pre-gestational weights). Yet, I know that we are much better off now than one year ago – our parasite control plan is working and this spring, our sheep will have access to high quality grasses once more.

Yet, there is an aspect of this plan that we hoped for last year, but didn’t get – until recently, that is. Parasite eggs are quite resilient, able to survive both exceptional heat and bitter cold. Yet, The larvae is much more temperature selective; hot dry temperatures or very cold temps when the ground is not protected by snow or thick vegetative cover will both hit these parasites hard. The bitter temperatures that Iowa has recently endured are just the thing we needed, since they make not only our lives miserable, but the lives of the parasites in the fields, too.

I do get emails from readers wondering about our sheep in the sub-zero temperatures, but we don’t usually worry too much about them this time of year – for two reasons. First of all, they are receiving extra rations of hay for the duration of the cold – basically all the hay they can eat. The fermentation of hay in their digestive systems creates heat – the extra hay is meant to create an internal furnace, providing both a warming effect from the fermentation plus extra calories to put towards warming of the body. Also, our ewes are currently in full fleece, due to be sheared in only a couple of weeks. This time of year, we are generally more concerned about how warm they are than how cold. Our ewes have access to the barn to get in out of the wind and cold, but most remain outside, often panting to eliminate excess body heat because of their heavy wool coats. In this situation, wind can dramatically increase cooling, but remember that our sheep are coated – in order to help cool the sheep, the wind must make it past not only a densely woven sheep coat, but also up to eight inches of wool coat beneath. Believe me, our sheep are not cold, even when we are freezing!

There is another risk this time of year that most people don’t consider, however, and that is specifically related to the amount of wool that some of our sheep carry. Because the Romney breed can be slower-maturing, there are still a number of young Romney ewes (who will be yearlings in a few months) who are small and have a fairly light body weight. The Romneys are knows for their long, lustrous locks that can reach up to nine inches in a year – and that amount of wool can be quite heavy. Also, consider if you were wearing a 9″ thick wool coat: your ability to maneuver easily would be very limited. It is possible that these little ewe lambs would lie down in a slight depression in the ground and end up cast (unable to get up). Their top-heavy weight due to their heavy wool coats in addition to their limited mobility can create a life-or-death situation. This time of year, we are constantly monitoring our young Romneys to make sure that they can get up and down and move around the barn to get in out of the cold. After shearing in a couple of weeks, they will be both much lighter and much more mobile. I am told that there are people who believe that shearing sheep is abusive, but honestly, watching them in such heavy coats makes me look forward to shearing day and their freedom from their wool! They are always thrilled by their newfound lighter and freer lives! After all, these young lambs have never been sheared before – they only know life with their heavy wool coats.




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  • Jane M says:

    Trying to wrap my mind around “shearing is abusive” and completely failing….

    • Dee says:

      Well, we actually had a girl scout troop come out once because the ASPCA started a new program at that time using the catchy phrase of “Save a sheep – don’t wear wool.” The leader wanted to bring the girls out to show them how very abusive we are to our sheep. We, of course, let them come and called our sheep to the troop with a box of graham crackers so that the girls could feed the ewes. By the end of the afternoon, I think the girl scouts decided that, given the choice, they would rather be sheared than carry around an additional 20 pounds of wool every year – but the leader was standing strong in her position that sheep are abused. Unless we educate the public, these types of misconceptions will continue – and that’s one of the reasons for this blog!

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