Sheep Update

Livestock Update, December 2000

Scott Greiner, Extension Animal Scientist, Sheep, Virginia Tech

Shepherd's Symposium Scheduled for January 5 & 6, 2001
The annual Virginia-North Carolina Shepherd's Symposium will be held Friday and Saturday, January 6 & 7, 2001 at the Sheraton Four Points Hotel and Rockingham County Fairgrounds in Harrisonburg. Speakers will cover a range of production, management, and marketing topics. Highlights of the Friday program include an in-depth session on lamb marketing, and the annual banquet featuring Dr. Keith Inskeep who will discuss out-of-season breeding. The program on Saturday at the Rockingham County Fairgrounds will include hands-on workshops, a youth stockman's contest, and the Virginia Commercial Bred Ewe Sale will round out the days events. The detailed program is as follows:

Virginia Commercial Ewe Lamb Development Program Begins
The Virginia Sheep Producer's Association has initiated a new commercial ewe lamb development and marketing program for Fall 2000. The purpose of the program is to provide a source of quality replacement ewes with documented health, management, and genetics for Virginia commercial flocks. The program is being conducted at the Virginia Sheep Evaluation Station, located at the Virginia Tech Shenandoah Valley Agriculture Research and Extension Center located near Steeles Tavern. A total of 97 commercial crossbred ewe lambs (various crosses of Dorset, Suffolk, Columbia, Finn, and Rambouillet breeding) were delivered to the station on September 6. Ewe lambs are being developed on grass with supplemental grain mix provided to optimize growth and reproductive performance during the development program. Ewes have been allocated to breeding groups based on age, weight, and breed. Ewes will be mated to purebred rams, which have all been tested on the 2000 Virginia Performance Ram Lamb Test. Two Suffolk and two Dorset rams will be utilized, with approximately the same number of ewes mated to each ram breed. Rams will be placed with the ewes October 1 through mid-December. Breeding dates will be recorded on all ewes, and pregnancy status will be determined on all ewes in late December via ultrasound. Ewes will be sold Saturday, January 6, 2001 at the Rockingham County Fairgrounds in Harrisonburg. Ewes will be sold in groups of 3-5 based on breed, service sire, and pregnancy status/due date. For more information, contact the Virginia Sheep Producers Association at 540-231-9163.

Late Gestation Ewe Management
Proper management during the last four to six weeks of gestation are critical to ensure a healthy, vigorous lamb crop. Approximately two-thirds of the growth of an unborn lamb occurs the last six weeks of gestation. During this time, the ewe should gain approximately .5 pounds/day. Proper management during this last portion of gestation will help prevent pregnancy disease, promote strong lambs at birth, enhance milk production, and prevent disease. Following are a few points to consider during late gestation:

Nutrition:
Energy/Protein: Requirements for both energy and protein increase during the last 4 to 6 weeks of gestation. Mature ewes weighing 150 to 175 pounds require a diet of approximately 65% TDN and 11.5% crude protein. In most cases, energy is the deficient nutrient during late gestation. Feeding high quality grass/legume hays normally provide adequate protein concentrations for the late gestation ewe. However, hay samples should be analyzed to make appropriate ration formulations. General recommendations include supplementing 1 pound of corn or barley during the last 4 to 6 weeks of gestation. It is important to gradually work ewes up to the 1 pound/day: 1/2 pound per day 4 to 6 weeks prior to lambing increasing to 1 pound by 2 to 4 weeks prior to lambing. Grain should be introduced gradually to prevent enterotoxemia, and appropriate bunk space should be provided to prevent crowding and potential injury to unborn lambs. If hay supplies are short, 1 pound of corn may substitute for approximately 2 pounds of hay. It is important that ewes receive a minimum of 2 pounds of roughage per day to maintain rumen health. Additionally, supplemental protein will likely be necessary if grain is used to replace a significant portion of the roughage in the diet. Inadequate energy during late gestation may result in small, weak lambs at birth as well as decreased milk production in the ewe. Additionally, pregnancy ketosis may occur as a result of a diet deficient in energy during late gestation.

Selenium: Virginia is largely a selenium deficient state. Deficiencies in selenium result in weak lambs and white muscle disease. Ewes should have access to a selenium fortified trace mineral salt (up to 90 ppm selenium) during late gestation. Providing selenium mineral mixes specifically formulated for sheep should meet the ewes' requirements. If feeding a selenium mineral is not feasible, injections of selenium and vitamin E can be given. Ewes should receive 2.5 to 3 mg of selenium per 100 pounds of bodyweight. Injections of selenium/vitamin E are not recommended when a selenium mineral mix is being fed as high levels of selenium may be toxic.

Vaccinations/Health:
Enterotoxemia and Tetanus: Vaccinate ewes for overeating and tetanus approximately four weeks prior to lambing. Vaccination at this time will provide passive immunity to the lambs at birth through the ewe's colostrum.

Antibiotics: Vaccines for prevention of abortion diseases (vibrio and chlamydiosis) have not been widely available. Chlortetracycline (Aureomycin) fed at a level of 80 mg/head/day (approved dosage) during the last six weeks of gestation has been shown to aid in prevention of these diseases. Injections of oxytetracycline (LA 200) at 2 week intervals the last 4-6 weeks of gestation have also been recommended as a preventative measure.

Deworming: Ewes should be dewormed 2 weeks prior to lambing. Research has documented that worms increase egg shedding just prior to and continuing after lambing. During this time, the ewe has a reduced ability to deal with the increased worm load. Therefore, deworming prior to lambing is an important aspect in an effective parasite control program.

General Management:
Shearing: Shearing prior to lambing has several advantages: facilities remain cleaner and drier, ewes require less space, ewes about to lamb are easier to identify, and the newborn lamb and ewe are easier to manage. Shearing prior to lambing does require that adequate facilities be made available, especially immediately after shearing so that ewes have protetion from adverse weather. Cold weather will increase the energy requirements of the ewe the first couple of weeks after shearing. Shorn ewes are more apt to seek shelter for lambing in adverse weather. Shearing can be done up to one week before lambing. Shearing ewes very close to lambing may result in some premature births. If shearing is not feasible prior to lambing, ewes can be crutched. Crutching involves the removal of wool aroung the dock and udder of the ewe. Although crutching enhances the shepherd's ability to manage the ewe and her newborn lambs, it will not enhance the lambing barn environment or reduce space requirements needed for the ewes.

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