What ‘Ewe’ Need to Know About Pregnancy Toxemia

Instructional Guide

This lesson focuses on helping students connect the physiology of pregnancy and digestion with practical strategies for animal care, ensuring healthy outcomes for both ewe and offspring.

Intended Grade Level

This lesson is designed for students in grades 9- 12. Students should already have a basic understanding of the ruminant digestive system and the function of each component. The included video can be offered as additional materials for a pre-class review

Learning objectives

• Explain what puts a sheep at risk for pregnancy toxemia (late gestation, less room for feed (multiple fetuses), obesity).
• Describe what conditions may lead to pregnancy toxemia (inadequate nutrition, not enough energy/low blood glucose).
• Explain how pregnancy toxemia can be avoided (more frequent meals, high energy feed, equitable access to water and feed, improving overall health and body condition).
• Demonstrate knowledge of why glucose is important to physiological functioning and complications of low blood glucose.
• Describe the impact of multiple fetuses on rumen function.

Lesson Format

This can be done in any size group. The material can be printed and disseminated.  Activities require computer access with internet.

• At the beginning of class the student groups can use “Think-Pair-Share” to review the ruminant digestive system and the importance of macromolecules.
• The student will then be assigned one of the pregnancy toxemia case studies to review in their groups. The goal will be to identify the causative factors and answer the attached questions.
• The class will end with a group discussion on the cases.
• A possible post-class assessment or project could assign student diseases or disorders that affect different parts of the ruminant digestive system and how they effect the animal’s overall health.

Lesson Background

Pregnancy toxemia, also known as ketosis or twin lamb disease, is a serious metabolic disorder that occurs in ewes during the last few weeks of pregnancy. It most commonly affects those carrying multiple fetuses and is especially dangerous when the ewe cannot meet her increased energy demands through diet alone.

During late gestation, the developing lambs take up more and more space in the ewe’s abdomen, leaving less room for the rumen to expand. This reduces how much the ewe can eat, even as her nutritional needs increase. Ewes that are overweight or under-conditioned are at greater risk because their metabolism is already unbalanced or their energy reserves are insufficient.

If the ewe is not getting enough high-energy feed, she will begin breaking down her body fat for energy. This process releases ketones into the bloodstream and can quickly lead to low blood glucose (hypoglycemia), liver failure, and even death if not addressed. Symptoms include poor appetite, weakness, tremors, and in severe cases, coma.

Pregnancy toxemia is preventable with good nutritional management. Strategies include:

• Feeding smaller, more frequent meals in late pregnancy

• Providing high-energy rations

• Ensuring all ewes have equal access to feed and clean water

• Monitoring and maintaining healthy body condition scores

Understanding the role of glucose is key. Glucose is the main energy source for both the ewe and her fetuses. When blood glucose is too low, not only does the ewe become weak, but fetal development can suffer, and pregnancy may be lost.

Finally, when a ewe is carrying twins or triplets, the enlarged uterus compresses the rumen, disrupting normal digestion. Reduced rumen capacity limits fiber breakdown and energy absorption, compounding the nutritional challenges during this critical time.

Activities

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Common misconceptions and challenge points

• Students may think that when an ewe is fat, she’s healthier and less likely to get sick. Obesity in pregnant ewes actually increases the risk of pregnancy toxemia. Fat ewes may eat less, mobilize fat too quickly, and overwhelm their liver with ketones.

• Students may think that if a sheep is eating, it must be getting enough nutrition. Remind students that eating alone isn’t enough—quality and energy content of the feed are crucial, especially when rumen space is limited late in gestation.

• Students may think that glucose is just for sugar and energy, so low blood sugar isn’t a big deal. Remind students that glucose is vital for brain function, fetal development, and cellular energy. Low glucose in pregnant ewes can cause weakness, coma, or fetal loss.

Assessment

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Further exploration

Other chapters within this textbook may be interesting for students. Some options can be found linked below: