The major deaths of newborn lambs are starvation, hypothermia, scours, and pneumonia. A study at the Sheep Experiment Station showed that 46 percent of lamb mortality is caused by scours (diarrhea), 20 percent by starvation, and 8 percent by pneumonia. Lambs that experience difficult and prolonged birthing episodes are more susceptible to health problems, as are those that do not consume adequate colostrum.
Hypothermia (chilling) is defined as low body temperature. To maintain its body temperature, a newborn lamb must produce as much heat as it is losing to the environment. If it cannot do this, its body temperature will start to fall. A smaller lamb will chill faster than a larger lamb. Lambs with thicker coats will lose less heat. For this reason, hair sheep lambs are generally colder tolerant.
The quicker a ewe licks off the lamb, the less vulnerable it will be too chilling. Lambs born in drafty pens or outside with no shelter from the wind will lose body heat quicker. Lambs born in colder temperatures obviously lose body heat more quickly than those born during moderate weather.
Lambs with hypothermia appear weak, gaunt, and hunched up. In severe cases, the lamb may be unable to hold its head up. The ears and mouth may feel cold. The lamb may lack a suckling response. The normal body temperature for lambs is 102-103°F. Lambs with temperatures below 100°F are considered hypothermic. A rectal thermometer can be used to assess body temperature.
It is important to get colostrum in newborn hypothermic lambs to elevate the body temperature. Tube feeding is an effective means of doing this. It may also be necessary to move the lamb to a warmer environment to elevate the body temperature. In fact, if the lamb’s temperature is 99 degrees F or less, it should be warmed first.
There are several ways to warm a lamb. If the lamb is wet, dry it off and wrap it in a towel. A hairdryer can be used to warm a lamb. The lamb can be put into a warming box. Heat lamps do not provide enough heat for hypothermic lambs. They are also a fire hazard.
In newborn lambs, hypothermia usually results from exposure. In lambs over 24 hours of age, hypothermia is usually a result of starvation. Older lambs should be handled in a similar manner, except they do not need colostrum. Milk replacer can be fed with a bottle or tube feeder. More milk should be fed at one time.
Lamb starvation is the number one killer of baby lambs. There are many causes: inadequate intake of colostrum, rejection by the dam, mastitis, teats that are too large or close to the ground, inadequate milk production, joint injury or illness, sore mouth, and/or difficult birth. Starvation typically occurs during the first three days of life.
A lamb will be found standing with its head down, ears drooping back, or it may become too weak to stand. Hungry lambs frequently bleat. The stomach would be empty upon palpation. Shivering, shaking and hypothermia may follow but this hypothermic lamb is typically over 12 hours of age. The obvious treatment for starvation is nutrition. Some lambs can be fed with a bottle; others will require tubing.
Baby lamb scours can be due to one of several bacteria: e. coli, salmonella, or clostridium perfringins type C. Adequate intake of colostrum is the best protection against scours. Strict sanitation is also important. Sloppy lambing conditions predispose lambs to many potential health problems.
Bacterial scours can be treated with antibiotics and fluid therapy. Spectinomycin oral pig pump is a preferred treatment for baby lamb scours. Its extra-label use requires veterinary approval. There are vaccines for e. coli scours (“watery mouth”) and clostridium perfringins type C.
Baby lamb pneumonia is caused primarily by the bacterium Pasteurella hemolytica, sometimes mycoplasma. It is characterized by fever, increased respiratory rate, failure to nurse, and death in untreated cases. Lambs appear gaunt and lethargic. Lambs that do not consume adequate colostrum are particularly at risk for developing pneumonia.
Ventilation problems are commonly associated with outbreaks of pneumonia. Drafts and dampness contribute. Pneumonia is much more common with housed sheep than those raised on pasture. Tightly closed barns often lack adequate ventilation. Pneumonia is usually treated with antibiotics: penicillin, tetracyclines, and others. Fluid therapy can hasten recovery.
Unfortunately, vaccination of pregnant ewes with parainfluenza (PI3) has not been shown to reduce pneumonia levels in newborn lambs. Some breeds seem to be more susceptible to respiratory problems (e.g. East Friesian).