Ram Management
It is important not to turn new rams in with the ewes as soon as they are brought to the premises. Separate the rams from the ewes for at least two weeks, treat for external parasites, and observe them carefully for contagious diseases before allowing them to breed any of the ewes.
The rams should be strong and in good condition at breeding time. If a ram is thin, or if he appears to be losing weight during the breeding season, it may be necessary to feed him separately from the ewes. Ordinarily, 1 to 1.5 pounds of oats or a grain concentrate mixture with good quality hay is sufficient. Ram lambs may need more concentrate. Also, shear rams about a month before the breeding season.
Lambing Methods
The ewes may be lambed in a lambing shed. With an abundance of high-quality pasture, it is possible to lamb successfully on pasture. Normally, however, a higher percentage of the lambs can be saved when ewes are lambed in a shed or other closely confined area. Lambing method depends on available labor, available facilities, and relative returns.
Shed Lambing. Shed lambing requires adequate space to house lambing pens for at least 10 percent of the ewe flock. Lambing pens are usually 4 x 4 foot or 4 x 5 foot enclosures (jugs or jails). Large breeds may need 5 x 5 foot pens. Very often, machinery sheds or other existing buildings on the farm can be used during the lambing season.
Lambing pens should be in a draft-free area of the shed or barn. Prior to lambing, thoroughly prepare the lambing area. Clean the area, erect lambing pens, install necessary heat lamps, and obtain medication.
Gestation typically ranges from 147 or 152 days. However, some ewes may lamb a week early, so it pays to be ready.
Pasture Lambing. Compared with shed lambing, feed costs are generally lower for pasture lambing. However, it is usually not possible to save as many lambs because it is impossible to observe all the ewes closely and frequently. However, even when lambing in the pasture, ewes not claiming their lambs or ewes that have extremely weak lambs should be placed in lambing pens. It is usually not advisable to lamb yearling ewes on pasture unattended. However, in New Mexico this is often the only practical method. When yearling ewes are lambing on pasture, graze them in a pasture where they can be observed relatively frequently, such as a trap close to the house or corrals.
Shearing
In New Mexico it is a good practice to shear ewes at least four weeks before lambing. This makes it easier for lambs to nurse and improves sanitation. Fleeces are cleaner and freer of stains if the ewe is shorn prior to lambing. Plus, it is easier to tell when a shorn ewe is about to lamb, and more ewes can be maintained in a smaller area of the shed. Occasionally, if shearing is done immediately before lambing and the ewes are handled roughly, some lambs may be born prematurely and some ewes may experience ketosis. If the ewes are not shorn before lambing, the area around the dock and udder, and between the legs should be shorn. This procedure is called crutching or tagging.
Management at Lambing Time
Lambing time is probably the most critical period in the year. The higher the percentage of lambs kept alive, the higher gross and net return. Observe ewes closely during the lambing period. Many producers check their ewes frequently during the night as well as during the day. Give the ewe assistance if she is unable to deliver naturally. It is always best if the ewe is allowed to have her lamb naturally. Occasionally, pulling a lamb makes a ewe reluctant to claim the lamb.
If the ewe is having difficulty lambing, wash your hands thoroughly with soap and water and apply some lubricant before examining the ewe via the vagina. Lambing difficulties can result from the lambs being too large, the ewe having a small pelvic area, or both. Quite often, however, lambs are in an abnormal position. The normal position is with the head between and slightly above the front feet. If the lamb is coming forward with one or both legs turned back, or the head is turned back, first straighten the legs and neck. It is preferable to have both legs straight, but many lambs can be delivered with the head and one leg forward.
If the back legs are presented first, the delivery should be made in this position as rapidly as possible. Remove membranes and mucous from the lamb's face and mouth immediately after delivery, and lift the lamb by its hind legs to clear mucous from the nose. Applying gentle pressure to the rib cage can stimulate breathing. Blowing into the lamb's mouth may also be effective. As soon as the lamb is breathing properly, allow the ewe to lick the lamb clean. Then treat the navel with a 7 percent iodine solution; strip each teat on the ewe to remove the plug and to be sure that the ewe has colostrum available.
If it is extremely cold, a heat lamp over the lambing pen may be beneficial. Only use heat lamps long enough to dry the lamb. Prolonged use of heat lamps tends to increase a lamb's susceptibility to pneumonia.
The first few hours of a lamb's life are the most critical. If the lamb does not nurse shortly after birth, it will weaken rapidly. The lamb should only receive assistance to nurse if it is necessary. Best results are obtained if the lamb is allowed to nurse naturally, without assistance. Occasionally, very weak lambs may need supplemental colostrum. Colostrum must be available to provide energy, protein, minerals, vitamins, and essential antibodies that provide the lamb with vital resistance to disease. Very weak lambs may be fed with a stomach tube. Weak lambs may also be revived with a subcutaneous injection of 25 to 50 mL of a 5 percent dextrose solution.
It is essential to know that the lamb consumes colostrum soon after birth. Starvation is the major cause of death in very young lambs. Therefore, keep the ewe and lamb or lambs in a lambing pen until the lambs are strong and healthy and no problem is observed with the ewe. Often, a ewe with a single lamb can be removed from the lambing pen in 24 hours; ewes with twins usually can be removed after two days. The ewe and her lamb should be identified with corresponding numbers if possible. Overall flock production efficiency will also be enhanced if ewes with single lambs are separated from ewes with twin lambs, and fed accordingly. Ewes nursing a single lamb should receive approximately 1 to 1.25 pounds of grain concentrate daily, while ewes nursing twin lambs should receive 1.50 pounds or more of grain concentrate daily.
Grafting Lambs
If a lamb is not receiving enough milk from the ewe (because of triplet lambs, ewes with bad udders, or some other reason), it is a good management practice to graft the lamb onto another ewe or to feed the lamb artificially.
There are several methods of grafting lambs, such as using special sprays to make the ewe accept the lamb. The most successful method is as follows: locate a ewe in the process of lambing a single lamb. After her lamb is delivered, check to be sure that she is not going to have another lamb. Do not let her get up until the lamb to be grafted has been brought over and thoroughly saturated in the placental fluids the ewe has just excreted. Then rub the lamb that is being grafted together with the newborn lamb. Tie the legs of the newborn to the lamb that is being grafted. Then allow the ewe to get up and lick the lambs. If the grafted lamb is thoroughly saturated and rubbed together with the newborn lamb, the ewe usually cleans both lambs and readily accepts both.
Then place the ewe and the two lambs in a lambing pen, keeping the lambs tied together until she has thoroughly cleaned both lambs. The lambs can then be untied and allowed to nurse. It may be necessary to restrict the older grafted lamb from nursing too much until the newborn lamb has had a chance to receive its share of the colostrum.
Occasionally, ewes refuse to claim their lambs. This is more common with ewes lambing for the first time. If ewes tend to do this year after year, they should be culled. There is not a best method of getting a ewe to claim her offspring. However, one method is to put the ewe in a stanchion and tie the ewe with a halter until she allows the lamb to nurse.
Tail-Docking and Castration
Lambs should be tail-docked and castrated at about 7 to 10 days of age. There is less bleeding and lambs heal more quickly when these operations are done at an early age. Elastrator rings may be used, but they are painful and there is a greater likelihood of tetanus. A pocket knife, emasculator, or burdizzo is very effective.
Cut off tails about 1 inch from the body. A good place is at the end of the caudal folds on the underside of the tail. Push the skin on the tail toward the body before cutting to allow enough loose skin to cover the end of the stub. If tetanus is a problem, vaccinate the lambs for this disease. (Your county Extension agent has more detailed instructions for these operations.)
Colostrum
Colostrum, the first milk produced by the ewe, is essential to the newborn lamb. Colostrum contains high levels of antibodies that are necessary to combat infections. It is also rich in various vitamins and minerals. Lambs must be provided colostrum within the first eight hours after birth for protection with the antibodies. If colostrum is not available from the ewe, the lamb can be allowed to nurse another ewe that just lambed, or colostrum can be obtained from heavy-milking ewes, goats, or cows and frozen in ice-cube trays in preparation for the lambing season. The colostrum cubes can be thawed (not in a microwave) and used as needed. Feeding 4 to 6 ounces of colostrum per lamb every four to six hours during the first 18 hours after birth has proven satisfactory. In the event that natural colostrum cannot be obtained, a synthetic colostrum may be used. One popular formula consists of 24 ounces of cow's milk, 1 beaten egg, 1 teaspoon cod liver oil, and 1 heaping tablespoon of sugar. Feed this formula at the rate of 6 ounces per lamb, four times daily. This substitute colostrum is more valuable than no colostrum, but it does not contain the necessary antibodies.
Artificial Rearing of Lambs
Orphan lambs can be successfully raised on milk replacer, goat's milk, and, occasionally, cow's milk. However, cow's milk contains less fat than ewe's milk. Milk goats can raise several orphan lambs each. Commercial milk replacers are available for lambs. These contain 30 to 32 percent fat, 22 to 24 percent crude protein, and 22 to 25 percent lactose. Do not use calf milk replacer on lambs.
If only a few lambs are to be raised on milk replacer, they can be bottle fed, if labor is available. However, they must be fed every four hours during the first week and then every six to eight hours until they are weaned.
With newly developed systems, it is possible to feed several lambs at the same time. A milk dispensing system provides milk free-choice. In this situation, mix a new batch of milk replacer each day. Generally, milk-feeding systems use the lam-bar nipple (a rubber teat connected to a polyethylene tube). The teats are connected through a hole in a metal plate inside the lamb pen panel with tubes leading to a bucket of milk outside the pen. As the lambs stop nursing, there is no leakage from the nipple because the milk returns to the bucket by gravity flow.
Research shows that feeding cold milk is much more beneficial than feeding warm milk when the lambs are on a self-feeding system. The cold milk is not as likely to spoil and lambs do not overeat, so they have fewer digestive disorders. Keep the milk cold by placing plastic jugs full of ice in the feeding unit.
Offer creep feed to the lambs soon after they have started on liquid milk replacer. Soybean meal is an excellent feedstuff to include in creep feed for very young lambs. The starter creep should contain 17 to 20 percent protein. Ordinarily, lambs are weaned from the milk replacer in four to six weeks.
Space Requirements for Sheep Production
The amount of space required for efficient sheep production varies with the breed, level of productivity, drainage, and management system. See table 4 for the average space requirements under most conditions, according to the 1974 Mid-West Planning Service's Sheep Handbook.
Table 4.
