CURRENT BEEF CATTLE PROJECTS
- Evaluation of composite and/or purebred cow productivity and profitability under stressful environmental conditions and subsequent progeny performance in the feedlot. D.W. Schafer and J.A. Marchello.
The V Bar V Ranch is currently evaluating various beef composites and/or purebreds for potential use in the arid Southwest. Data are being collected on the cattle from conception to consumption. Using Hereford cows, both registered and commercial, as our control population, other purebreds and/or composites are being introduced into the herd for evaluation not only on the ranch but also progeny performance in the feedlot and carcass. Currently, we have two composite groups that we are evaluating and one purebred breed that we are introducing for evaluation. The first composite is from the Bar T Bar Ranch in Winslow, AZ, comprising 25% Hereford, 25% Red &/or Black Angus, 25% Gelbvieh, 25% Barzona or Senepol. The second composite is the CGC Composite from the USDA Fort Keogh Research Laboratory in Miles City, MT. The CGC breed composition is 50% Red Angus, 25% Tarentaise, 25% Charolais. The purebred breed we are introducing is the African breed of Tuli. The experimental design is to introduce a minimum of 150 single source animals into the herd over a three-year period to reduce year effects. Each group is bred to its respective bull counterpart for the first calf and replacements are retained. The evaluation of each composite/purebred continues until less than 50 head remain in the herd at which time another composite/purebred is introduced. Each of the groups will be evaluated against constant control of Hereford cows which also provides ties to the national Hereford database. Additionally, through the donation of semen and cattle as well as the purchase of some cattle, the Hereford breed at the V Bar V is genetically tied to San Carlos Apache Tribe’s R-100 Ranch, the Colorado State University-San Juan Basin Research Center and the USDA Fort Keogh Livestock Research Laboratory allowing for direct comparison of the genotypes from these locations in a single environment.
- Development of Synchronization Methods for Arizona Production Systems. D.W. Schafer and S. Peder Cuneo
We have been evaluating new methods of improving and implementing existing synchronization protocols utilizing the University of Arizona V Bar V Ranch as a model for Arizona and Southwestern beef production systems. The scope of the ranch, both in numbers of cattle, and environmental factors, mimics a typical production scenario here in the Southwest. By evaluating the level of management on our own ranch, we can serve as a benchmark for other ranchers to help in improving the management of their own operations.
- Parentage Verification with Multiple Sires. D.W. Schafer and M. Ben Abdallah.
Much of the southwest is made up of large public lands ranches which do not have the ability to run cows in small single sire pastures. The V Bar V Ranch is no different. We must utilize a multi-sire breeding scheme due to the extensive nature of the ranch. However, in doing genetic research it is important to know the parentage of all offspring. Cows are easily paired with calves at birth but sires can be more difficult if more than one sire of a particular breed is being used. Therefore, we collect blood on all the calves at branding for DNA analysis and parentage verification and are evaluating methods of correctly identifying sires in a multi-sire system.
We have been experimenting with different methods of storing and extracting the DNA. Once blood is collected, DNA is stored as whole blood and on a FTA (Fast Technology for Analysis) card. We are then comparing the amplification we get from DNA stored on the FTA card versus the liquid DNA we get from whole blood. We use a single polymerase chain reaction (PCR) to amplify eleven microsatellite markers. Additionally, in efforts to minimize cost, we have optimized the PCR reaction multiplex using only 7 to 10 µl of reaction instead of the kit recommended 14 µl, thereby cutting our cost by nearly 50%.
Beef cattle microsatellite parentage assignment is commonly assessed using exclusion probabilities which estimate the probability that a particular sire can be correctly excluded as the sire of a specific offspring. One problem with this method is that more than one male may remain non-excluded or that the true sire may be excluded due to a typing error or mutation. Therefore, we have been assigning parentage using the maximum likelihood-based method with statistical confidence in natural populations in the Windows based computer program Cervus.
- Evaluation of Waguli Composite sired calves. D.W. Schafer, J.A. Marchello and M. Ben Abdallah.
A performance evaluation of the Waguli composite for use in southwestern breeding programs was initiated in 2003. The Waguli composite was formed in Texas by crossing Wagyu and Tuli lines of cattle. The Wagyu cattle exhibit extreme levels of marbling or intramuscular fat as well as good calving ease, good fertility, quiet temperament, adaptability, and early female maturity. The Tuli cattle are known for above average tenderness, heat and drought tolerance, docility, early maturity, good fertility, calving ease, tick resistance and adaptability. The Wagyu-Tuli cross offspring (Waguli) exhibit above average carcass characteristics while retaining their other good qualities for fertility and adaptability. Therefore, the Waguli may offer an alternative to Bos Indicus breeds which despite their being less tender, later maturing and less fertile are used extensively for their adaptability, heat tolerance and insect resistance in southwestern breeding systems.
In this experiment, Waguli bulls are being randomly mated to Hereford and Hereford cross females and to Bar T Bar and CGC composite females. Subsequent progeny performance will then be evaluated on the ranch, in the feedlot and ultimately the carcass. Additionally, half-blood Waguli females will be retained as replacements to evaluate the fertility and adaptability to Arizona range conditions.
