Sheep Update

Livestock Update, April 2007

Scott Greiner, Ph.D., Extension Animal Scientist, Beef, VA Tech

New Dates for Eastern Stud Ram Show and Sale

The 2007 Eastern Stud Ram Show and Sale will be held at the Augusta Expoland near Staunton May 18 & 19.  The show and sale has moved to May to better suit the needs of Mid-Atlantic producers and youth.  This annual event draws breeders from Virginia and across the United States.  The show will be held on Friday, May 18.  The show and sale will include registered breeding sheep (Hampshires, Southdowns, Dorsets, Suffolks), Wether Sires and Dams (registered and crossbred), and Club Lambs.  A sale addition for 2007 will be boer goats (billies, does, and wethers).  The sale begins at 9:00 a.m. on Saturday, May 19.  Yearling rams and ewes of each breed will sell, as well as fall and spring-born ram and ewe lambs.  For more information contact the Virginia Sheep Producers Association, phone
540-231-9163 or Willoughby Sales online at www.willoughbylivestocksales.com.

Spring Breeding and the Ram Effect

Fall-born lambs marketed November through February have commanded high prices in recent years.  These high prices have been the result of strong demand for lambs during these months coupled with relatively low supplies (particularly for lambs weighing 50 to 100 pounds).  Consequently, production systems that utilize spring breeding (fall lambing) warrant consideration.  However, the reproductive seasonality inherent to the biology of sheep makes this practice challenging, since many breeds are anestrous from April through July.  Fertility in both the ewe and ram are affected by season of the year.  Successful spring breeding starts with the utilization of genetics that have out-of-season capability.  Breeds noted for this ability include Dorset, Polypay, Rambouillet, Finnsheep, hair breeds (Katahdin, St. Croix, Blackbelly), and crosses of these breeds.  Considerable variation exists within these breed for fall lambing potential, and selection for this trait needs to be a priority for operations that utilize an extended breeding season.

Genetics, coupled with proper nutrition and management, are key components for spring breeding success.  One such management practice- the “ram effect” is commonly utilized to induce ovulation in anestrous ewes that have been previously isolated from rams.  The ram effect is an effective, inexpensive, practical means to increase percentage of ewes lambing out of season.  Utilization of the ram effect requires ewe isolation from rams for a minimum of one month, and preferably longer.  Isolation from rams needs to be complete by avoiding fenceline contact and any association with rams (sight, smell, touch).  Upon joining rams with ewes that have been previously isolated, ewes will ovulate within 7 days after introduction of the rams.  However, less than 20% of the ewes will be in heat during these first 7 days (silent heat).  Active estrus (heat) and ovulation will occur 17 to 24 days after introduction of rams, resulting in pregnancy.  Breed of ewe is an important factor in response to the ram effect.  Ewes will be more responsive to the ram effect as they reach the end of anestrous (are ready to start cycling), and therefore ewes with the genetic propensity to breed out-of-season respond most favorably to the ram effect in the spring.  Vasectomized teaser rams are frequently used during the first two weeks since there is a delay in estrus with the ram effect.  Fertile rams need to be placed with the ewes after 14 days.  Aggressive rams (both fertile rams and teasers) with high libido are most effective in eliciting a response in the ewe.  It is important that rams receive a breeding soundness exam prior to spring breeding to ensure fertility.

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