Ensure a Healthy Lamb Crop
Dr Simon Kenyon, School of Veterinary Medicine, Purdue University, Spring 1999
|Proper care of the ewe in mid to late
pregnancy and care of the lamb in the first few hours are the essential components of
ensuring a healthy lamb crop. Vaccination and supplementation of the ewe are also
efficient ways of ensuring the health of the lamb.
CONDITIONS AFFECTING THE EWE IN LATE PREGNANCY
Twin Lamb Disease (Pregnancy Toxemia). Pregnancy toxemia - is a condition in which the ewe is unable to support the energy needs of multiple fetuses in late pregnancy.
Clinical signs: Last month of pregnancy, obviously pregnant animal (multiple fetuses), poor body condition, showing neurologic signs: recumbent, blindness, lapping, head pressing, tremors and convulsions
Diagnosis: Clinical signs, strong positive urine test for ketones.
Treatment: Intravenous glucose, propylene glycol as a drench or by stomach tube (4 ounces twice a day), oral rehydration solution, e.g Biolyte, by mouth every 6 hours, encourage to eat, If non responsive requires cesarean operation to deliver lambs. Immediate supplemental feeding of the rest of the flock.
Prevention: This is a preventable condition! It is important to feed late term ewe according to their increased energy requirements, and recognize the fact that they are likely to have reduced dry matter intake because of the space occupied by the pregnant uterus. Feed ewes in groups based on number of fetuses (use ultrasound for selection at time of pregnancy diagnosis), monitor body condition and assess if energy intake is sufficient. In Indiana the most common cause is ewes that are too fat going into the last two months of pregnancy. These ewes need to be carefully managed and kept on a rising plane of nutrition.
Hypocalcemia and Hypomagnesemia are easy to confuse with Twin Lamb
Since these three disorders appear clinically similar a blanket treatment for all three conditions can be given e.g. intravenous fluids containing glucose, calcium and magnesium.
Not clear what causes it. If it replaces when ewe stands up simply tie wool across the opening of the vulva. Otherwise requires suturing of the vulva or insertion of an of an aluminum or plastic retainer. Watch carefully for signs of lambing. Consider culling since 40% of these ewes will prolapse next year and there may be an hereditary component.
Preparing the Ewe
Clostridial Vaccines (Cl. Perfringens C and D, Cl. Tetani). Give boosters 2-3 weeks before lambing.
Crutch or shear ewes reduces contamination of the lamb with E. coli and Clostridia from the fleece.
Start coccidiostats 30 days before lambing (Bovatec or Deccox). Has dramatic effect on coccidia shedding and reduces coccidia dose to newborn lambs.
Vitamin E and Selenium. Almost all Indiana soils are marginal or deficient in Selenium. Sheep should be supplemented to the limit of 0.3 ppm permitted by FDA. If the selenium is provided in loose salt the label should show 90 ppm. Vitamin E/Selenium injections may be given to the ewe but note that Bo-Se now carries a warning against use in pregnant ewes. Alternatives are to give Vit. E injection to the ewe or Bo-Se to the lamb after birth (1/2 cc).
Check the udder of the ewe, and strip some milk. Watch for asymmetry and behavior change. Mastitis treatment: milk out and treat once a day with a dry cow mastitis treatment e.g. Cefadry, Tomrrow, Orbenin Dry Cow, or LA-200
Watch for "hard bag" (OPP)-both sides swollen, no milk.
Be sure lamb is dry in first hour of life. Lambs lose body heat very rapidly if wet, not sheltered and have not nursed. They rapidly become hypothermic and hypoglycemic (starvation hypothermia). Starvation, mis-mothering and exposure are by far the commonest causes of death in newborn lambs. If the ewe doesnt have enough colostrum give 2-4 ozs colostrum from another ewe, a cow or a goat.
If the lambs temperature is below 100F, warm with warm air and tube with colostrum. Give 20cc 5% dextrose under the skin.
Weak lambs: Use esophageal feeder to give colostrum (3 times in first 12 hours, 60 ccs/ feeding). Hypoglycemic lambs will not nurse.
Goat colostrum from CAE free goats may be used. Cow colostrum may be used but requires about 30% more to meet requirements. Do not feed cow colostrum after 36 hours because of the danger of developing immune mediated anemia. Some cows have antibodies in their colostrum against sheep red blood cells.
Milk replacer: Lamb milk replacer available with 30% fat and 24% protein.
This is caused by an E. coli organism and usually strikes within the first three days of life. Dull, won't suck, salivates, rattles when shaken because of gas in the gut, die within 24 hours. Often have low temperature and low blood sugar, so need to differentiate from starvation hypothermia.
Treatment: oral fluid therapy, warming, antibiotics. Not usually successful.
Prevention: Ensure adequate colostrum intake.
Good hygiene in lambing area
Prophylactic oral antibiotics widely used in problem flocks.
Docking & castration:
Elastrator bands after 24 hours of age but before one week.
Tail docking with scalpel and Burdizzo, and castration with scalpel at 7 days. Tetanus protection required particularly if using rubber bands.
If the ewes were vaccinated against tetanus remember that colostral antibodies only last about 4 weeks.
Dock at end of caudal fold.
Vaccination of lambs
Give two doses of Clostridial vaccine 2 weeks apart starting at 6 weeks of age. Cl. perfrigens C&D and Cl. tetani are essential.
Outbreaks of coccidiosis are usually treated with sulfa drugs and amprolium. The treatment for the outbreak of the disease should not be confused with the drugs used for control. Bovatec (lasalocid) and Dccoex (decoquinate) have been approved for the prohylactic treatment of sheep against coccidia. These drugs are used as a preventative, not a treatment.
Pasteurella pneumonia is probably the main killer of lambs that survive to two weeks of age. Dead lambs are usually the first sign of an outbreak and it needs to be distinguished from overeating disease (pulpy kidney) by post mortem examination. Oxytetracycline is the drug of choice for this disease and it is usual to treat the whole group of lambs with long-acting oxytetracycline if an outbreak is in progress. Vaccines are available, but like all Pasteurella vaccines the response is variable.