Stephan Wildeus and Joni Rae Collins
Small Ruminant Program, Virginia State University, Petersburg
Virginia State University established a Meat Goat Research Program in 1992. The program’s objectives were to identify and develop a superior meat-producing goat and to develop low-input management systems suitable for the environment of the Mid-Atlantic region. A research herd composed of five goat breeds with potential for meat production was initially established. It was subsequently decided that hair sheep would make a significant contribution to the program, and Katahdin hair sheep were added in 1997, followed by Barbados Blackbelly in 1998, and finally St. Croix in 1999. The effort was subsequently renamed “Small Ruminant Program” to reflect this expanded species composition. The facilities currently house 250 breeding females, representing seven breeds of goats and hair sheep on 60 acres of permanent and annual pastures, and include an extensive pen system, animal handling facilities, and on-farm laboratory.
The Barbados Blackbelly flock at VSU stems primarily from a very generous donation of 25 ewes and 5 rams by Dr. Claude Hughes and Ms. Linda Sakiewicz, owners and operators of Bracken Brae Farm in North Carolina. The rams from this acquisition were used to establish breeding lines to maintain some genetic diversity in the flock. Additional stock was acquired in 1999 through an importation of two Barbados Blackbelly ram lambs from the research flock of the University of the Virgin Islands. Again, these rams were used to establish additional breeding lines. Finally, three Barbados Blackbelly ewes were obtained from the dispersal of a flock in Ohio, that was established from an importation of two ewe lambs and one ram lamb from the University of the Virgin Islands research flock and subsequently maintained as a closed flock.
The Barbados Blackbelly flock is part of a mixed species herd of 150 sheep and goats. This herd is maintained as a single group, except during mating. Females are mated in pens using single sires, with two sire groups per breed for each mating. The herd is managed under an accelerated, 8-months breeding system, with 30-day mating periods in November, July, and March. Lambs are weaned at 9 weeks of age. The herd is maintained predominantly on forage (pasture and hay) with some supplementation dependent on stage of production (late gestation or lactation). There is limited control of gastrointestinal parasitism through anthelmintics to allow for the identification of breeds and individuals within a breed with high tolerance to internal parasites.
A major emphasis of our work with the Barbados Blackbelly sheep is their evaluation under the accelerated mating system. We recently completed the 6th and final, mating in a four year production cycle. As part of the project we recorded seasonal estrus and mating activity, pregnancy via ultrasonography, litter size at birth, and weaning. These records are used to determine embryonic mortality, and neo-natal and pre-weaning survival. Also recorded are lamb birth and weaning weights and ewe weights in 14 day intervals. This information is used to determine production efficiency (weight of lamb born and weaned in relation to ewe body weight) of the various breeds under the accelerated system and to identify unique breed characteristics.
Weaned lambs are used in feeding trials to determine performance on high forage diets. Sampling is currently in progress in a cooperative feeding trial with the University of Georgia and Louisiana State University evaluating growth rate, feed intake, carcass characteristics, and gastrointestinal parasite tolerance in Barbados Blackbelly, Katahdin, and St. Croix lambs maintained either on permanent pasture or in pens with hay-based diets and supplemented at 1.5% of body weight either with a low or high crude protein supplement. Body weight, fecal egg counts, and packed blood cell volume are being determined in 14-day intervals from April to September. Male lambs will be slaughtered to determine carcass characteristics and to record the gastrointestinal parasite burden. Findings are intended to confirm results from a smaller pilot trial conducted earlier.
Efforts are under way to establish a functional estrus synchronization protocol for hair sheep using the limited number of products currently available on the U.S. market for this purpose. Initial trials have looked at the estrus response and timing of estrus, ovulation rate, and fertility using melengestrol acetate (MGA) as a source of exogenous progesterone. Protocols are also being developed for the collection and freezing of hair sheep ram semen. Initial trials evaluated differences in ejaculate quality in samples collected either by artificial vagina or electroejaculation. Current trials look at the effect of freezing protocol on the post-thaw quality of frozen semen.
The Barbados Blackbelly sheep in the U.S. is a breed with a small population size (especially polled stock) and a narrow genetic base. It appears to have lost some of the unique characteristics that the breed displays in its Caribbean populations (large litters, good parasite tolerance). One of our goals is to introduce additional, original germplasm into our flock at VSU to continually expand its genetic base. Our research in assisted reproductive technologies is aimed to help us to effectively employ cryopreserved semen and artificial insemination to achieve this goal. We hope to involve interested breeders of polled stock in the U.S. in this effort.
A second goal is to design economical, forage-based production systems for Barbados Blackbelly sheep that capitalize on their ability to breed out-of-season, have multiple offspring, and tolerate parasites. Lambs produced under such a system will not fit the traditional lamb market, but they may have a role to play for ethnic niche market production or as organically produced meat. In order to maintain the Barbados Blackbelly as a viable breed in the U.S., they have to be established as a breed suited for economically feasible niche market production and/or for upgrading wool breeds towards a hair sheep composite.
Reprinted from BBSAI Newsletter, December, 2003.
Copyright 2003 BBSAI. All rights reserved.