Trail Notes from the Ag Extension Office

        The end of January left with a blast of arctic cold. When tractors and feed trucks gel up and fingers stop being flexible enough to grip a pitch fork, it can take every ounce of a rancher’s effort to get animals fed. This work becomes even more critical as gestating females enter the third trimester, where the bulk of fetal growth occurs. The demands of cold temperatures and pregnancy increase the nutritional requirements of ewes and cows, and this is especially the case for young animals that are still making gains toward their own mature body size. The 2022 University of Wyoming Extension bulletin “Supplementation Considerations for Ewes Managed on Dormant Winter Pastures and Rangelands” contains an excellent overview of nutritional requirements of sheep during this period with critical environmental and physiological burdens. On the beef cattle side, the 2015 University of Nebraska-Lincoln Extension bulletin “Supplementation Needs for Gestating and Lactating Beef Cows and Comparing the Prices of Supplement Sources” contains a similar overview for the bovine. Find these publications online or stop by your local Extension office to request a printed copy.

            Supplementing with alfalfa, distiller’s grains, or range cake will supply rumen degradable protein (RDP), formerly known as degradable intake protein (DIP). This protein boosts the rumen microbes that break down low quality forages and helps the animal access energy that would otherwise be locked up in cellulose.

        When forage is low in quality it can become physically impossible for animals to consume enough of it to meet their energy or protein needs. The growing fetus restricts the rumen and capacity for feed intake. Without proper management, the animal can go into a negative energy balance and begin to metabolize stored energy in the form of body fat reserves. This puts the body into a state of ketosis. Sustained for long periods, ketosis can develop into the metabolic disease known commonly as pregnancy toxemia. This is not the result of a calcium or magnesium deficiency, as in milk fever or tetany, respectively. Pregnancy toxemia is most likely to present late in gestation in sheep and goats carrying multiple offspring or obese individuals due to the restrictions imposed on feed intake. Less frequently observed in cattle, it is most likely at or near peak lactation in high milking capacity individuals fed poor quality diets.

        Common symptoms of pregnancy toxemia include an animal going off feed and showing lethargic behaviors progressing to recumbency and death in severe cases. Neurological signs such as head pressing or circling may also occur as a result of ketone buildup in the blood. As you make your daily animal checks, look closely for any individuals that appear depressed and “out of it.” Are their ears up and eyes bright? Are they keeping their heads up when you approach? These are basic livestock husbandry observations, but catching any problem animals early can lead to the best outcomes.

        If pregnancy toxemia is suspected, work with your veterinarian to develop a treatment plan. Since the cause is a deficit in available energy, supplementation with glucose is often the simplest and least invasive therapy. Many over the counter oral drenches are available to counter the effects of ketosis, but be sure that the product you have is labeled for use in the correct species. In extreme cases, a veterinarian can administer an intravenous glucose infusion. Watch affected animals closely for secondary infection during recovery from pregnancy toxemia.

            While treatments are available, it is ultimately best to prevent pregnancy toxemia from occurring in the first place. Ensure that animals consume a high-quality, balanced diet and have access to clean water. Use body condition scoring to maintain breeding females in moderate flesh (BCS 3-4 for sheep, BCS 5-6 for cattle). Utilize concentrate supplements as appropriate, especially to provide sufficient protein when grazing dormant winter range, as animals enter the third trimester of gestation (days 100-150 of gestation for sheep, months 7-9 for cattle), or to counter the effects of severe winter weather.

        For the rancher, nutritional management is one of the most powerful tools to prevent disease and enhance productivity. Work with your local UW Extension educator if you have questions about your winter livestock rations. Wishing all a safe, easy, and quick lambing/calving/kidding season!