RED DEER – Careful observations and diligent care are necessary to help ewes wean more lambs, says a University of Guelph veterinarian.
Good management starts before lambs are born, Paula Menzies said at the Alberta Sheep Symposium in Red Deer Nov. 17.
“Some people get into sheep because they think they are easier to take care of than cattle,” Menzies said.
“That is not true. They need to be closely observed, especially at lambing time.”
A recent survey in Ontario showed 12 percent of lambs die before weaning. Late-term abortions, stillborns, disease, poor mothering, hypothermia and predators are among the main causes of death.
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Proper care of ewes is crucial.
Ewes may have a late trimester abortion due to bacterial infections or mineral deficiencies.
Pregnancy toxemia in ewes may result in premature lambs and the mother may die.
Ewes can get infections from dental problems so producers are encouraged to check incisors and molars.
“Older ewes are more at risk of dental disease, but we have seen some pretty bad teeth in four and five-year-old ewes,” she said.
Too much competition around the feed trough may occur if ewe lambs are mixed with older ewes, or if different breeds are mixed. Poor water intake can also set off a toxemia outbreak in the flock.
“They are often riding the line and then you added something else that set them over the edge and can give you an outbreak.”
Vaginal prolapses, which can happen three weeks before lambing, are a major problem in many flocks. The main cause is poor quality forage, which forces ewes to overeat.
“They don’t have much room in them because they are full of lambs,” she said.
“If they have a full rumen too, they lie down and out comes the vagina.”
Avoid feeding a ration that has more than one-third red clover hay or alfalfa.
These legumes carry compounds that relax the ligaments and make ewes more prone to prolapse. It is better to save that type of hay for the lactation period.
Some producers believe that ewes experiencing this problem came from a mother suffering from prolapse.
It may also happen when tails are docked too close, which affects muscle tone. A docked tail should cover the vagina.
Ewes that must stretch to get to a feed bunk intended for cattle are also at risk.
“Make sure they don’t have to stand on their tip toes to get something to eat.”
Pregnant ewes require good nutrition.
For example, ewes carrying twins require 1.9 times more energy than what is required for regular maintenance.
Good feed is needed during the first 90 days of pregnancy when the placenta is forming.
Ewes should be sorted before lambing and should get exercise.
They should receive a booster shot of multi-clostridial vaccine two to four weeks before lambing to boost disease immunity in lambs. Ewes should also be wormed before lambing.
Keep frozen colostrum from healthy ewes on hand for lambs in trouble. Cow colostrum may be substituted, but there are some disease risks between the two species.
Crutch the ewes by removing wool from the perineal area. It is also easier for lambs to nurse if the udder is clean.
Lambing areas should be covered with straw rather than shavings because it is cleaner. A cold, wet environment is one of the greatest threats to newborns.
Some lambs die at birth because they were too large for the birth canal or because malpresentation occurred. There may have been a case of tangled twins. The lamb may have been breech or legs were pushed back and intervention did not come soon enough. Struggling to be born may result in a ruptured liver, fractured bones or lack of oxygen to the brain.
Lambs may suffer a variety of birth defects that lead to death. An undershot jaw may prevent it from nursing.
Badly crippled legs or blindness also affect the lamb’s ability to survive because it struggles to move around and nurse. Others may be born with a cleft palette or no anus.
Mismothering and starvation are common.
The mother may only accept one lamb from a pair of twins and the rejected one cannot feed.
Some producers place the family together in a small pen so the mother can learn to accept the extra lambs.
Cold, wet weather can lead to hypothermia. A lamb is chilled if it is sitting tucked up and depressed with a temperature less than 37.5 C. These lambs can be warmed and fed colostrum from a tube to give them necessary maternal antibodies in the first hours of life. If a lamb can’t suckle and is warm, it is probably sick and will die.
Move cold lambs less than five hours old to a warming box. A lamb more than five hours old is apt to be hypoglycemic and needs glucose. It could go into convulsions and die if warmed without glucose.
Some lambs develop septicemia in two to seven days because they failed to absorb colostrol antibodies.
White muscle disease in lambs under 30 days of age can cause sudden death.
A copper deficiency occurs from birth to four months of age. The lambs are swaybacked and crippled.
They can also pick up parasites and bugs like E. coli, salmonella, coccidiosis or cryptosporidia, causing serious diarrhea.
Coccidiosis infection is common and leads to a pot bellied lamb that passes pasty feces.
Lambs can die suddenly from pneumonia.
Menzies suggests producers conduct a post mortem to determine causes of death in young lambs.
Look for meconium stains. They indicate mismothering because the ewe did not clean it off. Check for deformities and signs of dehydration and starvation.
Look at the colour of the lungs and fat. Pink lungs with no brown fat around them indicate the lamb may have starved to death.
Sometimes there is dirt in the rumen as it struggled to find something to eat.
