J. Anim Sci., doi: 10.2527/jas.2007-0068
©Copyright, 2007, The American Society of Animal Science
The value of DNA paternity identification in beef cattle: examples from Nevada's free range ranches
L. Gomez-Raya 1*,
K. Priest 1,
W. M. Rauw 1,
M. Okomo-Adhiambo 1,
D. Thain 1,
B. Bruce 1,
A. Rink 1,
R. C. Torrell 2,
L. Grellman 1,
R. Narayanan 3,
C. W. Beattie 1
1 Department of Animal Biotechnology, University of Nevada, Reno 89557
2 University of Nevada Cooperative Extension Livestock Specialist, 701 Walnut, Elko, Nevada 89801
3 College of Agriculture, Biotechnology and Natural Resources, University of Nevada, Reno. Reno, NV 89557
* To whom correspondence should be addressed. E-mail: lgomezraya{at}cabnr.unr.edu.
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Abstract |
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The feasibility and economic value of DNA paternity identification were investigated and illustrated using Nevada beef cattle operations. A panel of 15 microsatellites was genotyped in 2,196 animals from 8 ranches with a total of 31,571 genotypes. Probabilities of exclusion for each marker within ranch and across ranches were computed. Joint probabilities of exclusion for the 15 microsatellites were also determined, resulting in values over 0.99 for any individual ranch and across ranches. Dropping 1 or 2 microsatellites with the lowest probabilities of exclusion resulted in joint probabilities higher than 0.99 and with marginal reduction when compared to the probabilities with 15 microsatellites. Formulae for benefit-cost analysis for a DNA paternity identification program in beef cattle were derived. Genotyping 15 microsatellites with 20 calves per sire resulted in benefits of $1.71 and $2.44 per dollar invested at bull culling rates of 0.20 and 0.30, respectively. The breakpoints for the program to be profitable occurred when the ratio of the price of 1 kg of calf liveweight over the cost of genotyping 1 microsatellite was higher than 1.1 for a bull culling rate of 0.30. Benefit-cost analysis was also derived under incomplete DNA paternity identification using a lower number of DNA-markers than necessary to achieve joint probabilities of exclusion of 0.99. Approximately a 20% increase in benefit-cost ratio was achieved using 10 versus 12 microsatellites with incomplete paternity identification. The higher the number of bulls in the operation, the lower the benefit-cost ratio of the paternity testing program. Low probabilities of exclusion and a high number of bulls in the beef operation reduced the benefit-cost ratio dramatically. DNA paternity identification programs are feasible and may be profitable for free range beef cattle operations.
Key Words:
beef cattle, benefit-cost analysis, DNA-marker, paternity test
