Is the length of productive life a concern in the U.S. Katahdin ewes?

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Sheep GEMS News Brief 15 – June 2025 Ewe productive longevity, which is the number of days between a ewe’s first and last lambing, positively impacts flock profitability in at least three ways. It reduces annual ewe replacement costs. It increases ewe output by increasing the proportion of mature ewes in the flock. And lastly, ewes that live longer usually have fewer reproductive and health issues, which are major reasons for early culling. As part of Sheep GEMS, we are investigating ewe longevity using information on ewes in flocks enrolled in the National Sheep Improvement Program (NSIP). Our aim is…

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Understanding How the Heat Beats Your Sheep

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Have you felt pretty beat up by the heat when you work outside for long hours in the summertime? Well, let me tell you that the summer heat does not only affect us, but also our flock. Imagine that you are training for a marathon at 100 degrees Fahrenheit with a quilted puffer jacket on. That is exactly how our animals feel when experiencing heat stress conditions. Heat stress is defined as when the ambient temperature and relative humidity increase to a point where it affects the animal’s capacity to dissipate their internal heat to the exterior, causing an increase…

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What’s Next for Eco-Management Clusters?

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Sheep GEMS News Brief 14 – May 2025 Previously, we introduced the concept of eco-management cluster—groups of flocks that share similar climate and management practices. These clusters are the foundation of our approach in Sheep GEMS for building genetic evaluations that more closely consider production environments. We are still exploring the makeup of eco-management clusters, as they undoubtedly differ among breeds. However, one of their important uses is in our study of genotype-by-environment interactions (G×E). G×E occur when the ranking of animals based on their genetic potential changes depending on the production environment in which they are managed. As an…

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Understanding Eco-Management Clusters

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Sheep GEMS News Brief 13 – April 2025 Sheep producers across the U.S. operate in a wide range of environments—from humid grasslands to dry, high-elevation rangelands. These environmental differences, along with varied management practices, mean that a “one-size-fits-all” approach to genetic selection often falls short. In other words, the animals that perform best across all environments may not be the same, which could have implications when selecting breeding animals. To help address this challenge, our team in the Sheep GEMS project has developed a tool — coined eco-management clusters —designed to help producers select animals that are best suited to…

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Evaluating Breeding Animals

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Unfortunately, defects show up in some of our animals and even though those animals might be exceptional in other areas, for the betterment of the breed we should not propagate these defects. Always check your animals before keeping them as replacements or selling them as breeding stock. Bite In lambs the bottom teeth should “bite” into the dental pad. They should not extend in front of it (monkey mouth, undershot), nor be too far backwards (parrot mouth, overshot). If a bite is VERY off you can easily see that the bottom jaw is markedly longer or shorter than normal at…

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When lack of pasture parasites challenges your EBV’s, try an artificial infection

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An inherent problem with FEC EBV is having a sufficient population of pasture parasites to generate a FEC in your flock. The timing of lambing, climate and production scheme can affect the presence of infective worm larvae. These complications limit our ability to identify parasite resistant lambs using FEC, particularly at weaning. Weaning or post-weaning FEC EBV are based on samples collected from animals that have had an opportunity to be exposed to strongylid parasites (e.g.: Haemonchus, Trichostrongylus and Telodorsagia). Each of these parasites have their own ideal climatic conditions, but generally they desire warm and humid environments. Often these…

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Finding the Right Ram for You

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Ram selection and breeding decisions have lasting impacts on your flock. When replacement females are retained, these decisions can quickly account for a significant majority of your genetics. Just because a ram is a crowd favorite at a sale or a leader in a particular trait or two does not mean it is the right ram for your operation at that given time. The following steps should be taken to carefully evaluate your flock and make accurate ram selection decisions. Establish Goals: The first step to finding the right ram is determining goals for your flock. These goals should take…

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Sick Sheep? Let Us Inspect Their Earwax.

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Reprinted with permission. Ambrook Research publishes original research and stories on issues facing modern agriculture, to read more:  Ambrook Research A USDA lab devised a way to ID toxins from common poisonous plants using “non-traditional” bodily excretions. Recently, Raye Walck recounted for this inquisitive journalist a grim story from some high-desert grazing lands in Grand Junction, Colorado. “I had a case a couple of years ago where these sheep came off the range and were brought into a dry lot situation, into a bunch of old pens,” the director of the Western Slope Veterinary Diagnostic Laboratory at Colorado State University (CSU)…

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Genetic Approaches to Parasite Control

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Sheep GEMS News Brief 12 – March 2025 In the last Sheep GEMS news brief, we talked about the impact of parasites on production, and it was eluded that genetic selection can be a very promising means to manage worm parasites. Continuing with the Sheep GEMS theme of breeding for climatic resilience and robustness across environments, parasite resistant sheep express improved fitness. Determining fecal egg counts (FEC) at the time of weaning and post-weaning is a measure of parasite resistance already included in the National Sheep Improvement Program (NSIP). Collaboration with the GEMS innovation flocks and 3 USDA ARS facilities…

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How do Parasites Affect Production?

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Sheep GEMS News Brief 11 – Late February 2025 Gastrointestinal parasites are one of the main health concerns for grazing sheep because available dewormers are largely ineffective due to dewormer resistance. Parasitic worms are a year-round problem in tropical and sub-tropical environments affecting millions of small ruminants world-wide. However, resistance to multiple deworming drugs is common in small ruminants. Infection with gastrointestinal nematode parasites can cause reduced weight gains, fertility, fiber and milk production, as well as cause anemia, diarrhea, and death. The most pathogenic worm species is barber pole worm or Haemonchus contortus is a blood sucker and can…

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