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.
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.