Artificially rearing lambs
One of the results of having a high lambing percentage (e.g. more than 200%) is that you will likely have some lambs that will have to be reared artificially. While some ewes are able to raise triplets (even quads), sometimes it is necessary (and/or wise) to remove lambs from large litters in order to obtain more satisfactory weight gains. There are also instances when a ewe cannot raise all of her lambs due to disease (e.g. mastitis or OPP) or death. Artificial rearing is a standard practice on most dairy sheep enterprises. Pet lambs are often reared artificially.
If/when choosing lambs for artificial rearing, there are different opinions as to which offspring should be removed. Traditionally, it was recommended that the bigger, stronger lamb(s) be removed for artificial rearing; however, experience has shown that these lambs do better on their dams, and the smaller weaker lambs do better if they are artificially reared. Regardless, in a group of three lambs, it makes sense to remove the odd one, leaving a balanced (size or sex) set of lambs on the ewe. Sometimes, you don't have a choice as to which lamb(s) require artificial rearing. Some lambs will not survive without human intervention.
Before initiating artificial feeding, you should try to graft the "extra" lamb(s) onto another ewe that has sufficient milk to raise another lamb (or two). Ewes that have lost their lamb(s) are usually good candidates. The best way to graft newly-born lambs is to rub the fetal membranes and fluids from the foster ewe's lamb(s) onto the lamb you wish to graft. You can also skin a dead lamb and place the skin on the lamb you wish to graft.
As with any newborn animal, it is important that newborn lambs consume enough colostrum during their first 18 to 24 hours of life. Colostrum is the first milk produced by the dam after birthing. It is rich in nutrients and antibodies. Research has indicated that a newborn lamb should receive 3 ounces of colostrum per pound of body weight, divided into several feedings. A lamb should consume 10 percent of its body weight in colostrum during its first day of life.
Many lambs will drink colostrum from a nippled bottle. Others may need to be fed with an esophageal feeding tube. If colostrum is not available from the dam or another ewe on the farm, cow or goat colostrum can be substituted. When cow colostrum is used, approximately 30 percent more should be fed to lambs, due to the low fat content of cow's milk as compared to ewe milk. You need to pay close attention to the source of colostrum, as CAE, OPP, and Johne's disease can all be transmitted via infected colostrum.
Artificial colostrum can also be used. Several companies (e.g. Land O'Lakes) sell colostrum substitutes for lambs that contain protective antibodies (IgG). Products marketed as colostrum supplements are highly nutritious but lack the protective antibodies of colostrum substitutes. Howver, they are preferable to no colostrum at all.
Nutrient content of milk
It is common to store frozen colostrum in ice cube trays. Frozen colostrum should be thawed at room temperature or in a hot water bath. High heat or microwaves should not be used to thaw colostrum because they will destroy the antibodies in the milk. The best way to thaw colostrum is at room temperature.
After colostrum feeding, lambs should be fed a high quality milk replacer that has been formulated specifically for lambs. Some lambs may do okay on generic (multi-species) or calf milk replacers, but they will do best if they are a fed species-specific milk replacer.
Milk replacer powder should be reconstituted (mixed) according to the manufacturer's instructions. It should never be diluted more than recommended. Because of the high fat content of lamb milk replacer, it should be mixed in warm water, then cooled and stored at 35 to 40° F before being fed. It is essential that milk replacer be mixed properly. Lumps can contribute to abomasal bloat. The addition of yogurt to the milk may help to prevent bloat. Formalin has also been added to milk replacers to prevent abomasal bloat.
Cow's milk is another option for artificially rearing lambs. One source might be "waste" milk from antibiotic-treated cows. This milk is otherwise discarded. When cow's milk is fed, additional fat or oil should be added, due to the nutritional differences between the milks. Store-bought cow's milk is another possibility, as it can be much less expensive than lamb milk replacer. Research has proven that whole powdered cow milk can be a cheaper and safe alternative for feeding lambs. If it can be obtained, goat's milk is another option for feeding lambs. As with cow's milk, additional fat or oil should be added. Cross-transmission of OPP and CAE is possible with goat's milk.
After the first few days, it is recommended that milk be fed cold, about 40°F (~4°C). With cold milk, there is less tendency for lambs to overeat, thus helping to prevent (abomasal) bloat, diarrhea, and other digestive upsets. Feeding cold milk is important if milk will be offered free choice. Milk can be kept cold in the summer by putting frozen plastic water bottles in the bucket.
For the first few days of life, lambs should be fed frequently. After they are a few days old, the frequency of feedings can be reduced. There are numerous protocols for feeding. Generally, the lambs should be fed more frequently when they are younger, and as they get older the amount of milk per feeding is increased, while the frequency of feedings is reduced (usually to 2). Lambs generally need to consume 10 to 20 percent of their body weight per day. More frequent feedings will help to prevent overeating and bloat. When hand rearing lambs, it is important to have a consistent feeding schedule.
Small numbers of lambs can be fed using individual bottles fitted with rubber teats. Pritchard teats are especially popular for feeding lambs. A nipple bucket can also be used to feed multiple lambs. For larger numbers of lambs, an automatic feeding station can be set up. Biotic markets several automatic feeders (e.g. Lak-Tek) for lambs. Lambs will drink cold milk from a lamb bar at frequent intervals, much like they would if they were nursing their dam. An open vessel (bucket or trough) can also be used to feed fresh milk.
Regardless of the feeding method utilized, hygiene is of primary importance. Feeding equipment should be cleaned frequently. Any unused milk should be refrigerated immediately or discarded.
Lambs should be put in a warm, draft-free area for artificial rearing, ideally away from sight and hearing distance of the ewes. Small groups of lambs are usually best. Lambs of significantly different ages should not be mixed. A light over the pen will encourage feeding.
In order to wean lambs at an early age, it is essential to get them consuming dry feed as soon as possible. The feed that is fed to nursing lambs is called creep feed. Creep feed should be highly palatable and digestible. It should contain 18 to 20 percent all-natural crude protein. Young lambs will consume more feed if is coarsely ground, though a pelleted ration may also be fed. Soybean meal makes a good starter feed. Particle size is small, and it is very palatable. It is a good idea to include a coccidiostat in the feed.
Ample, fresh water should be available at all times. There are differing opinions as to whether artificially-reared lambs should be offered hay. A common practice is to wait until lambs are about three weeks old before feeding them any hay. Hay, especially alfalfa, can cause bloat. Some producers do not feed hay until after weaning.
Lambs should be vaccinated for overeating disease and tetanus by the time they are six weeks of age, followed by a booster three to four weeks later. They should be vaccinated earlier (3 to 4 weeks of age), if they did not receive adequate protection through the colostrum.
Earlier vaccinations may not be effective due to the immature immune system of young lambs. It may be advisable to give other injections, such as vitamin A-D-E, iron dextran, and selenium/vitamin E.
There are numerous reasons why early weaning is recommended for artificially-reared lambs. Milk replacer is expensive. Hand feeding is labor intensive. Artificially-reared lambs are at increased risk for various health problems, especially digestive disturbances. Six weeks is the most common weaning age for artificially-reared lambs. Weaning at 30 days of age is common with dairy lambs and is possible if the lambs are big enough and are consuming adequate dry feed. At weaning, lambs should weigh at least 25 to 30 pounds or approximately 3 times their birth weight.
Weaning should be abrupt, and lambs should be left in familiar surroundings at the time of weaning to minimize stress. They may initially lose some weight, but eventually they will regain the weight as a result of compensatory gain.
If orphan lambs are properly fed and managed, they should gain similarly as lambs being raised on their dams. However, it is important to understand that artificially-reared lambs are often more vulnerable to diseases, such as coccidia, worms, and pneumonia, especially if their start-in-life was compromised.
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