With grass green-up and summer coming, feeder lambs are being put in the feedlot, on pasture or combination of both. Also, 4-H and FFA market lamb project members have, or soon will have, identified their county and state fair winners. Successful and economical market lamb production is dependent on proper health and nutrition management. One of these can not be neglected without affecting the other. A variety of health problems related to nutrition may affect the feeder lamb, with the more common problems addressed in this article. Understanding the nature of the problem is critical to assist the producer with identifying, treating and future prevention of problems.

Enterotoxemia type D (overeating disease) is caused by Clostridia perfringens type D and usually affects lambs over a month old. It is common in unvaccinated lambs with changes in feed and high concentrate diets. Its course is rapid and affected animals are frequently found dead without symptoms. Signs, if observed, are depression, abdominal pain, teeth grinding, twitching or convulsions. Diagnosis requires necropsy of a fresh animal via microscopic examination of the small intestine for the bacteria and toxin.

Treatment for those found alive is usually not rewarding. C. perfringens C & D antitoxin can be given and antibiotics administered very early in the course of the disease to be effective. However, prevention is relatively simple. Vaccination is effective and inexpensive. For the first time vaccination, two doses of Enterotoxemia toxoid type C & D at least two weeks apart are necessary for optimum protection. Lambs should be vaccinated around 4 weeks of age and again at 6 weeks of age. Also, lambs can receive protection colostrally through the milk of a vaccinated ewe, and only require one C & D toxoid vaccination around 4 weeks of age. Some producers always vaccinate prior to putting lambs on feed to avoid outbreaks.

White Muscle Disease (Vitamin E and/or Selenium Deficiency) is a degeneration of the skeletal and cardiac muscles of lambs. White muscle disease occurs in a wide range of climates and on many different types of soils and pastures. It is most common in areas of good rainfall or irrigation, and incidence is higher in lambs on high quality diets. The disease is caused by a deficiency of selenium, vitamin E or both. Generally, one or both nutrients are deficient in the diet, but deficiencies may be caused by other dietary factors interfering with the utilization of vitamin E and selenium.

Symptoms are stiffness of the hind legs with an arched back and tucked in flanks. While leg muscles often are affected first, the heart muscles can also be damaged. Both selenium and vitamin E are generally used in treatments, injected subcutaneously or intramuscularly. However, do not overdose with selenium, as toxicity may occur.

Acidosis (grain overload, founder) commonly occurs in feeder lambs when they are changed from roughage or grazing diets to one including concentrates (grain). Lambs consume an excess quantity of grain either by accident or during the adjustment period. Grain fermentation results in abnormally high levels of acid in the rumen, rumen pH falls to 4.0 to 4.5, rumen microbes are killed and the acid is absorbed in the system, disrupting the acid/base balance necessary for life. Clinical signs usually occur within 6 to 12 hours after grain ingestion, resulting in lambs going off-feed, with indigestion, dehydration, and distended, paralyzed rumen. As time progresses lambs show incoordination, become comatose and die. Surviving lambs have diarrhea, dehydration, sunken eyes and often founder.

Early treatment is essential to recovery and prevention of permanent rumen damage. Lambs should be drenched with an antacid and mineral oil. Electrolytes and buffers correct dehydration and acidosis. Acidosis is best prevented by careful management of concentrate intake, allowing the rumen to adjust to the change. Electrolytes via the water and bicarbonates mixed in the feed are helpful during the transition period.

Polio (Polioencephalomalacia) is a disease of the central nervous system. The B vitamins, especially thiamine, essential for normal nerve cell development and function, are synthesized in the rumen of normal animals. Some forages, such as brackenfern or kocias, are high in an enzyme called thiaminase which ties up or destroys thiamine produced on the rumen. Also, certain bacteria produce a large quantity of thiaminase and may become numerous in the rumen, thus causing the deficiency. Lambs with polio initially follow behind other lambs, stagger, appear disoriented, occasionally stare at the sky and become blind. Eventually the lamb will be unable to rise, becomes comatose and dies.

Treat early with thiamine hydrochloride intravenously and intramuscularly. If treated early, response should be seen in 1 to 3 days. Blindness may continue up to 7 days.

Rectal Prolapse incidence varies among feedlots, but is associated with genetics, high concentrate feeding, short docking and coughing precipitated by dusty conditions and poor health caused by viral infections and internal parasites. Implanting has also been incriminated as a contributing factor. Continuous coughing of individuals results in protrusion of the rectum. If unattended the condition will continue to worsen with the prolapsed rectum becoming swollen and inflamed.

If the lamb is in good physical condition, salvage by slaughter is the most economically feasible approach. If treatment is attempted, the lamb should be taken off feed and the rectum cleaned out with a warm water enema. One procedure is to put an elastrator band on the prolapsed rectum near the anal sphincter, with or without a tube inserted in the prolapsed rectum to keep the tract open during the few days it takes for the protruding rectum to slough. Another procedure calls for replacing the rectum, increasing the importance of cleaning the prolapsed rectum, and suturing in or using iodine to build up scar tissue to hold the rectum in place. It is recommended to cull replacement ewes or rams that rectally prolapse.

Urinary Calculi (water belly), a metabolic disease of rams and wethers, is characterized by the formation of calculi (stones) in the urinary tract. Blockage of the urethra by calculi causes retention of urine, abdominal pain, distention and rupture of the urethra or bladder and death. Common signs are straining, kicking at the belly, frequent attempts to urinate, dribbling, frequent getting up and lying down. The most common cause is rations with high phosphorous levels or nearly 1:1 calcium to phosphorous ratio.

Economic restraints usually restrict surgical treatment. However, if the calculus is located in the urethral process, simply snip off the process with scissors. If discovered prior to complete obstruction, feed can be withheld for 24 hours in conjuction with oral dosing of ammonium chloride which will acidify the urine and possibly dissolve the calculi. Prevention can be accomplished generally by making sure a ration has a 2:1 calcium to phosphorous ratio. Calcium chloride is more effective then ground limestone. Addition of common salt, 1 to 4 percent, is beneficial to increase water intake and decrease stone formation.

Bloat is the interaction of several factors in the rumen, a combination of reduction of gas elimination and/or increased gas production from fermentation. Bloat is associated with lush forage and/or changes in diet composition may result in bloat. Signs of bloat are distention of the rumen (left side of the animal). If the bloat progresses, lambs will show respiratory distress, profuse salivation, bluish mucous membranes and death from asphyxiation.

Treat bloat by removing the offending cause, usually feed. Relieve ruminal pressure with a stomach tube, and defoaming agents such as vegetable oils, Poloxalene or Therabloat. Prevent bloat by knowing and avoiding the circumstances leading to bloat. Pasture management, especially legume pastures, along with Poloxolene blocks, Bovatec in the concentrate and increasing salt intake to increase water intake can be effective.

Sources: SID Sheep Production Handbook: Nutritional Effects on Sheep Health, Dr. Helen Swartz

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The information and links in this page are maintained by Brad Gillmore,  Extension Agent (Livestock). If you have questions concerning this material or questions of a general nature regarding livestock production and management, please e-mail at bgillmore@co.weld.co.us or phone at (970) 356-4000 Ext 4481.