Pregnancy toxemia in ewes and does
When a pregnant ewe takes ill, a likely cause is pregnancy toxemia. Pregnancy toxemia goes by several other names including pregnancy disease, twin lamb disease, lambing paralysis, and ketosis.
Pregnancy toxemia is a metabolic disorder caused by low glucose concentrations in the blood and excessive breakdown of body fat to compensate. "Ketones" are the toxic by-product produced during this rapid breakdown of fat, and it is possible to test for their presence in the ewe's urine.
Inadequate nutrition during the last one-third of pregnancy is the primary cause of low blood sugar/pregnancy toxemia, as ewes cannot consume enough feed (energy) to meet the demands of their growing fetus(es). This is because approximately 70 percent of fetal growth occurs during the last 4 to 6 weeks of pregnancy.
Over-conditioned (condition score 4/5 or more) ewes are susceptible to pregnancy toxemia because of fat in their abdominal region –- there simply isn't enough room in the gut for the ewe to eat enough –- and excessive fat resources for breakdown. Under-conditioned (condition score 2 or less) ewes are susceptible because they cannot eat enough to meet their own nutritional needs, let alone the added burden of developing fetuses.
Ewes carrying multiple births are also at high risk for pregnancy toxemia. Ewes carrying twins require 1.9 times the dry matter intake as ewes with singles. Ewes with triplet fetuses require 230% more energy than ewes with singles. In fact, anything that affects the ewe's ability to eat enough during late gestation can result in pregnancy toxemia: multiple fetuses, fat ewes, thin ewes, small ewes, timid ewes, granny ewes, dental disease, parasitism, and lack of exercise.
The symptoms of pregnancy toxemia are vague and can be similar to other diseases, especially hypocalcemia (or milk fever). Milk fever can be differentiated from pregnancy toxemia by the affected ewe's response to calcium therapy.
Ewes in early stages of pregnancy toxemia will go off feed and appear lethargic. Their heads droop and they lag behind the rest of the flock and walk aimlessly. Teeth grinding and twitching is common. Eventually, affected ewes become depressed, weak and have poor muscle control. In latter stages, they lie down and are unable to rise. If left untreated, coma and death result.
Successful treatment of pregnancy toxemia requires early detection and steps to quickly meet the energy (glucose) needs of the affected ewe. The most common treatment is to drench ewes with 2 to 3 ounces of propylene glycol 2 to 3 times daily. Yogurt mixed with water will also provide energy
and bacteria to stimulate the rumen. Intravenous glucose is another possibility, but harder for producers to do on the farm.
Force feeding and/or injections of multiple B vitamins can help stimulate the ewe's appetite. Antibiotics can be administered to prevent pneumonia. In advanced cases, a caesarian section may need to be performed to remove the fetuses and save the ewe's life. If the lambs are near term, oftentimes, they too, can be saved. The nutrition of the entire flock should be suspect anytime a ewe shows indications of pregnancy toxemia.
Of course, like other diseases, it makes more sense to prevent pregnancy toxemia than to treat it. To achieve this, it is absolutely essential that ewes be provided adequate energy in their ration during the last 4 to 6 weeks of gestation. Good quality hay should be provided, along with grain supplementation, beginning at .5 lbs and increasing to 1 ½ to 2 lbs. per head per day until the time of parturition. Grain and molasses are excellent sources of energy. Hay alone usually doesn't provide enough energy for ewes carrying twins and triplets. Exercise is also deemed important in the prevention of pregnancy toxemia.
Abrupt feed changes must also be avoided, and ewes should not be stressed during late pregnancy. There must be adequate feeder space so that all ewes can fit around the feeders and get their fair share of hay and grain. Producers should strive to have ewes in moderate body flesh (condition score of 3+) prior to lambing. Ewes should be prevented from becoming obese during early pregnancy, and thin ewes should be separated and receive extra feed until they achieve the desired condition score.
References and further reading
Pregnancy toxemia (ketosis) in does and ewes - University of Missouri
Pregnancy Disorders (Metabolic) in Transition Ewes - Ontario, Canada
Pregnancy Toxemia and Ketosis - Goat Connection
Pregnancy toxemia - Navajo Sheep Project
Ketosis or Pregnancy Toxemia in the Doe - SweetLix Livestock Supplement System
This article was written in 2002 by Susan Schoenian.