July Sheep Update
Livestock Update, July 1997
Steve Umberger, Animal and Poultry Sciences, Virginia Tech
1997 Virginia Performance Tested Ram Lamb Sale. The Virginia Performance Tested Ram Lamb Sale will be held at the Virginia Sheep Evaluation Station in Steeles Tavern on Saturday, August 23, starting at 1:00 p.m. The barn will open to buyers at 9:00 a.m. Breeds represented in this year's sale include Suffolk, Hampshire, Dorset, Finnsheep, Polypay, and Suffolk x Hampshire crossbred rams. The purpose of this sale is to provide top quality breeding rams at a time of the year when they're normally not available. A complete breeding soundness examination is performed on all of the rams before the sale, including scrotal circumference, palpation of the testicles, and a semen evaluation. All rams are sold as being sound, healthy, and fertile. Ram lambs not be expected to service as many ewes as mature rams, but should easily handle 25 ewes during a 40-day breeding period. Ram lambs should not be kept in the same breeding pasture as mature rams because of the dominance of the older, heavier rams over the younger rams. Ram lambs work well in a "clean-up" role after mature rams have been removed from the breeding flock. Through the purchase and use of ram lambs in the fall, they are given the opportunity to adapt to their new surroundings and are ready to use for breeding as yearlings in 1998. The Virginia Sheep Evaluation Station is located .5 mile east of I-81 at Exit 205. Steeles Tavern is approximately 20 miles southwest of Staunton, Virginia. For sale information, write or call Steve Umberger, Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA, 24061-0306, (540) 231-9159.
Hair Breed Crosses Make Good Commercial Ewes. A study comparing the performance of crosses of hair and wool breeds of sheep was conducted at the University of Illinois Dixon Springs Agricultural Center located in southern Illinois. Hair-breed rams (St. Croix and Barbados Blackbelly) and prolific wool-breed rams (Finnsheep, Booroola Merino, and Combo-6; a composite breed developed by the University of Illinois) were mated to Suffolk and Targhee ewes. Crossbred ewe lambs from those matings were bred to Dorset rams in September and October of 1987 through 1990, and lambed at approximately two and three years of age from 1988 through 1991. The reproductive traits measured on the crossbred ewes were fertility, prolificacy, lamb survival, lamb weaning weight, and total weight of lamb weaned per ewe exposed. Ewes sired by hair-breed rams had significantly shorter breeding to lambing intervals (7.1 fewer days), higher fertility (11.5% more ewes lambing), higher lamb survival (9.3% more lambs from birth to weaning), and weaned more pounds of lamb per ewe (10.3 pounds) than ewes sired by wool-breed rams. This study clearly indicates that hair-breed crossbred ewes have a number of advantages that might be considered useful in Virginia commercial flocks. During the 1980's, a small group of Dorset x Barbados Blackbelly ewes were lambed during the fall at Virginia Tech over a 5-year period. They exhibited pregnancy rates in excess of 90% and lambing percentages over 150%. From a reproductive standpoint, this would be very difficult to beat using other breeds or breed crosses.
High Tensile Smooth Wire Fence For Pasture Subdivision And Predator Control. When constructing new fence or modifying existing fence, the value of the fence for both improved pasture management and predator control should always be considered. Subdividing large grazing boundaries into smaller units provides more flexibility for altering grazing management and increasing hay production. The importance of properly constructed fence cannot be overstated as a tool for protecting livestock from dog and coyote predation. Highly effective, safe, and inexpensive electric fencing systems has made fencing for pasture subdivisions and predator control more practical. High tensile (HT) smooth wire electric fence is cheaper and easier to construct than most traditional types of fence. Electrified boundary fence is one of the most effective tools used for predator control, and provides the opportunity to tie in temporary electric fence to facilitate pasture subdivision for improved grazing management.
Boundary fence for sheep should consist of at least five strands of electrified HT wire. Internal fence for pasture subdivisions requires a minimum of three strands of wire. Internal fence may be permanent or temporary. Types of temporary electric fence include: 1) polywire; 2) polytape; and 3) electric netting. Some of the benefits for temporary fence are: 1) flexibility to subdivide pastures for certain times of the year rather than year-round; 2) the opportunity to experiment before settling on the best combination of temporary and permanent pasture subdivisions; and 3) the opportunity to fence in front of and behind sheep when strip grazing. Temporary fence will not carry a charge as far as HT fence, nor is it as effective in controlling predators.
Factors influencing the effectiveness of electrified HT fence include: 1) proper construction of fence; 2) sufficient grounding (noted as the most common error by fencing experts); 3) the amount of vegetative growth coming in contact with the fence; and 4) quality and power of the fence charger. All fence chargers are not built to the same specifications. Unfortunately, a uniform set of standards for comparison of various makes and models of chargers is not available. Only high energy, low impedance chargers should be used. When purchasing a charger, producers should be familiar with the reputation of the company, their product, their warranty, and their dealer's service record. The company representative should be willing and able to assist the producer in determining the charger that best meets their needs. In general, electric fence intended to control sheep and deter predators should average 4000 to 5000 volts and carry a minimum charge of 2000 volts at all times.