Wednesday, January 6, 2010

Saving hypothermic lambs

By Bill Fosher
Copyright 2010

In winter lambing flocks, hypothermia and starvation of newborn lambs can account for nearly all of the pre-weaning death loss of lambs. It’s a serious problem that can often be avoided, if not eliminated entirely via management of the ewe flock and its environment.

However, even under the best management in the best environment, there will still be some cases of hypothermia and starvation in most winter lambing flocks. It’s important for shepherds to know how to recognize, treat, and, most importantly, learn from each case.

In most cases, the problems that lead to hypothermia are difficult to fix during lambing. They go back months to the level of nutrition in early gestation, or to barn design, or the availability of bedding. That’s why it’s important to keep records about the causes of any hypothermia cases – once lambing is over, it’s easy to put those problems out of your mind and forget to fix them for next time. Make a habit of reviewing your lambing records well before the next breeding season so that you have time to make any changes or cull any ewes to reduce problems in the next lambing.

In the meantime, you need to try to save as many cold lambs as possible. Here’s a step-by step guide to the process. The goal of this guide is to help you make sound decisions about how to treat a lamb when you’re tired, busy, and probably a little upset. All the steps are aimed at getting the lamb back with its mother as soon as possible, and are based on the assumption that the mother has adequate milk to sustain the lamb. If that is not the case, the lamb will need to be raised as an orphan.

Ideally, if a lamb needs to be removed from its mother, the dam should be left penned by herself where she cannot try to claim other lambs. If a ewe has more than one lamb, consider removing not just the chilled lamb, but all of them. The process of warming a lamb can take several hours, and during that time, a ewe may forget about one of her lambs. She will not forget about all of them. However, you must return the non-chilled lamb or lambs to the dam to suckle regularly – probably every 20 minutes to half hour.

The warming box that I refer to here is a contraption that can be as simple or complicated as you want it to be as long as it provides a constant, gentle heat to the lamb. I have rigged up hair dryers blowing into dog crates, and one pasture lambing operation that I have heard of uses insulated coolers with hot water bottles. The main thing is that you don’t want to heat the lamb directly; just keep it in a very warm environment. Heating a lamb too fast is just as lethal as leaving it cold.

Step 1. Evaluate
Determine lamb’s age: is it more or less than five hours old?
Determine lamb’s body temperature
Determine lamb’s general condition: able to stand, suck and swallow? Unable to swallow? Unable to stand?

Step 2. Act

If the lamb’s temperature is over 99 degrees F., regardless of age
Collect milk or colostrum from the mother if possible to use in feeding the lamb
feed by stomach tube
return to mother.

For lambs with temperatures lower than 99 degrees F.

More than five hours old, unable to hold up head or swallow
Give IP injection of glucose
Move to warming box
Collect milk or colostrum from the mother if possible to use in feeding the lamb
Check temperature every 20 minutes until it reaches 99 degrees F.
Feed by stomach tube
Return to mother

More than five hours old, able to hold head up and swallow
Move to warming box
Collect milk or colostrum from the mother if possible to use in feeding the lamb
Check temperature every 20 minutes until it reaches 99 degrees F.
Feed by stomach tube
Return to mother

Less than five hours old, able to hold up head and swallow
Move to warming box
Collect colostrum from the mother if possible to use in feeding the lamb
Check temperature every 20 minutes until it reaches 99 degrees F.
Feed by stomach tube
Return to mother

Step 3. Follow up
If any lamb remains weak, it may need to be kept in draft-free, gently heated environment and fed by stomach tube regularly until it is strong enough to return to its mother. If at all possible, use milk or colostrum from the lamb’s own mother for all feedings, as this will increase the likelihood that the lamb will be accepted when returned to her.

Submerge the lamb in warm water.
Warm a lamb with low blood sugar.
Overheat a lamb

Step 4. Find the cause
Hypothermia and starvation cause a great deal of death loss and their treatment greatly increases labor requirements at lambing time. Shepherds should set a goal both for economic and animal welfare reasons to reduce hypothermia and starvation as much as possible. Each case should be noted in the lambing records of the dam, and the shepherd should attempt to pin down the cause of each case. After the crush of lambing is over, these records can be reviewed to look for patterns that might suggest management changes or culling of individual ewes.

Well-fed and -conditioned ewes can deliver and keep lambs fed and warm under fairly extreme temperatures, provided that they sheltered from wind, drafts, and moisture. Temperature alone should not a cause of lamb hypothermia-starvation in shed lambed ewes unless the air temperature is below 0 degrees F.

Some management-related causes of hypothermia-starvation in shed-lambed ewes would include:
-- poor maternal nutrition in early gestation when placental development takes place, leading to low birth weights and low milk production.
-- poor maternal nutrition in late gestation, reducing fetal development and resulting in low birth weight and weakness in newborn lambs
-- inadequate bedding; ewes lambing on wet or frozen pen floors
-- drafts at floor level
-- overcrowding of ewes leading to mismothering, grannying, or lost and wandering lambs.
-- inadequate pen construction allowing lambs to wander away from their mothers.

Some disease-related causes of hypothermia-starvation would include:
-- Ovine progressive pneumonia, which can cause reduced (or absent) colostrum.
-- Any of the several abortion diseases, leading to weak newborn lambs.
-- Mastitis, causing the ewe to refuse to allow the lambs to suckle, or past mastitis causing one or both sides of the bag to fail completely or partially.

If causes related to management and disease are ruled out, the most common cause of hypothermia and starvation in lambs is maternal inattention. Good mothering ability includes the skill of keeping track of your lambs and not allowing them to starve. In some rare cases, teat size and placement on the ewe can also be a factor. Be particularly attentive for ewes with excessively large or low teats. Sometimes there can be plenty of milk that the lambs simply can’t get to.

With attention to detail, hypothermia and starvation can be reduced to very low rates even in flocks that lamb in the dead of winter in very cold climates. In most sheep production systems, the majority of the cost of producing a finished market lamb is already spent when the lamb is born (in the form of feed and keep for the breeding flock), so saving chilled lambs is an important way to protect your investment. Preventing it from happening in the first place is even more important.