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Kansas State University

 

Beef Research News
Brought to you by Kansas State University College of Veterinary Medicine - Farm Animal Section
September 2007

 

 

 

Contents:

K-State Bovine Castration Survey

AVMA Food Supply Veterinarian Maps

Factors affecting feeder calf price in Arkansas

Testing with PCR & Culture for Tritrichomonas foetus

Reproductive effects of leptospira vaccine and oxytetracycline

DNA paternity identification in beef cattle

 

 

K-State Bovine Castration Survey
Based on the number of steers reported annually by the USDA NASS there are approximately 16 million bovine castrations performed in the US each year; yet little is known about which methods of castration are most commonly used in the industry. Since "Position Statements" on bovine castration are currently being drafted by various organizations, we believe that it would be helpful to establish benchmarks for the profession identifying the most common methods of castration and how these procedures are typically performed.

In order to evaluate Bovine Castration in the United States we invite you to participate in a survey of beef and dairy practitioners conducted by the Beef Cattle Institute (BCI) at Kansas State University. We expect our online survey to take about 15 minutes. By completing the survey, you will be giving us permission to use your anonymous responses in written and oral reports, which may be published. This study is been examined by the Institutional Review Board at Kansas State University and deemed to be exempt from any further review (KSU IRB #4406). The AABP Animal Welfare Committee has also had an opportunity to review and comment on this survey prior to circulation.

To take the survey, please click on the link below:

https://surveys.ksu.edu/TS?offeringId=73959

If you would like additional information about this study or have questions before you participate, please feel free to contact Dr. Hans Coetzee at the College of Veterinary Medicine, Kansas State University, Manhattan KS 66506, by email (jcoetzee@vet.k-state.edu) , or by telephone at 785-532-6354 or 515-231-7688.



AVMA Food Supply Veterinarian Maps
The American Veterinary Medical Association (AVMA) recently added a web tool to visualize the number of food animal veterinarians in each geographic region relative to the number of cattle in that area. The site displays maps comparing USDA cattle inventory numbers by county to the number of food supply veterinarians in each county. These maps can be found at: http://www.avma.org/fsvm/maps/default.asp

For more information on the potential shortage of food supply veterinarians, look at the AVMA’s website ( www.avma.org ) and click on the Food Supply Veterinary Medicine link.



Factors affecting feeder calf price in Arkansas
Data were collected from 15 Arkansas livestock auctions to determine factors affecting selling price. Data included how calves were sold (single or groups), gender, breed or breed type, color, muscle thickness, horn status, frame score, fill, body condition, age, health, BW, and price. Data were randomly collected on 52,401 lots consisting of 105,542 calves. Selling prices for steers ($124.20 ± 0.07), bulls ($117.93 ± 0.12) and heifers ($112.81 ± 0.07) were different from each other (P < 0.001). Hereford x Charolais feeder calves sold for the highest price ($122.66 ± 0.14) and Longhorns sold for the lowest price ($74.52 ± 0.46). Yellow feeder cattle received the highest selling price ($96.47 ± 0.12), and spotted or striped feeder cattle received the lowest ($83.84 ± 0.23). The selling price of singles was lower than the selling price for those sold in groups of 6 or more ($117.26 ± 0.06 vs. $122.61 ± 0.21; P < 0.001). For cattle classified as muscle scores 1, 2, 3, and 4, selling prices were $120.45 ± 0.05, $111.31 ± 0.09, $96.28 ± 0.44 and $82.21 ± 1.87, respectively. Polled feeder cattle sold for $118.57 ± 0.05, and horned feeder cattle sold for $114.87 ± 0.14 (P < 0.001). Interactions (P < 0.001) were detected between frame score and BW groups and muscle score and BW groups on the selling price of cattle. A number of management and genetic factors affected selling price of feeder cattle.

Barham, B.L., T.R. Troxel. Factors affecting the selling price of feeder cattle sold at Arkansas livestock auctions in 2005. J. Anim Sci. 2007. Doi:10.2527/jas2007-0340.



Testing with PCR & Culture for Tritrichomonas foetus
The sensitivity (Se) and specificity (Sp) of different testing schemes were estimated for detecting Tritrichomonas foetus (T. foetus) in smegma samples from experimentally infected bulls. Culture and polymerase chain reaction (PCR) on smegma samples were evaluated alone and in parallel testing. Mature dairy bulls (n=79) were intrapreputially inoculated with T. foetus (n=19); Campylobacter (C.) fetus venerealis (n=13); both T. foetus and C. fetus venerealis (n=11); Tetratrichomonas spp. (n=9); C. fetus fetus (n=8); or were not inoculated (n=19). For each bull, smegma samples were collected for 6 week post-inoculation and tested for T. foetus by In Pouch TF® culture and PCR. Most T. foetus-inoculated bulls became infected, according to culture (86.7%), PCR (90.0%), and both tests together (93.3%). In T. foetus-inoculated bulls, both tests combined in parallel on a single sample had a Se (78.3%) and Sp (98.5%) similar to two cultures (Se 76.0%, Sp 98.5%) or two PCR (Se 78.0%, Sp 96.7%) sampled on consecutive weeks. The PCR on three consecutive weekly samples (Se 85.0%, Sp 95.4%) and both tests applied in parallel on three consecutive weekly samples (Se 87.5%, Sp 95.6%) were similar to the current gold-standard of six weekly cultures (Se 86.7% and Sp 97.5%). Both tests used in parallel six times had the highest Se (93.3%), with similar Sp (92.5%). Tetratrichomonas spp. were only sporadically detected by culture or PCR. In conclusion, we have proposed alternative strategies for T. foetus diagnostics (for the AI industry), including a combination of tests and repeat testing strategies that may reduce time and cost for bull surveillance.

Cobo, ER, PH Favetto, VM Lane, A Friend, K VanHooser, J Mitchell, RH BonDurant. Sensitivity and specificity of culture and PCR of smegma samples of bulls experimentally infected with Tritrichomonas foetus. 2007 Theriogenology 68(6) 853-860.



Reproductive effects of leptospira vaccine and oxytetracycline
The objective of this field study was to determine whether a commercially available monovalent Leptospira borgpetersenii serovar hardjo type hardjo bovis vaccine coupled with systemic oxytetracycline treatment to clear carriers would improve the reproductive performance of beef cows. One thousand four hundred and forty six Angus cross-bred beef cows in eight locations were randomly assigned to treatment and control groups. Cows received two doses, 4 weeks apart, of a commercial leptospira monovalent vaccine (n=741). Cows that received the vaccine were also treated with 9mg/lb BW of oxytetracycline SC at the time of the second injection of vaccine. Serum antibody titers and urine samples were examined to detect presence of leptospira on farms prior to treatments. Farms were categorized as positive or negative for leptospira based on the presence of leptospiruric cows. Cows were synchronized for fixed time artificial insemination (FTAI) and bulls were introduced 14 days later to breed non-pregnant cows following FTAI. Outcome measures evaluated were FTAI pregnancy rate and over-all (season-long) pregnancy rate (based on rectal palpation) for treatment and control group and for cows living in leptospira positive (N=1183) and negative (n=264) farms. Data were analyzed with a statistical software program (SAS Version 9.1 for Windows, SAS Institute, Cary, NC, USA). General Linear Model was used to examine the effects of vaccination on FTAI and over-all pregnancy rates. Variables included in the model were treatment (yes or no), farms status for leptospira, season (fall and spring), age (2, 3-6, >6 years) and body condition score (<4, 5 and 6, >7). All possible interaction effects were also tested. No significant differences in the FTAI pregnancy rate and over-all pregnancy rate between treatment and control groups were observed. The FTAI pregnancy rate for cows in the leptospira positive farms was significantly less than the cows in the leptospira negative farms [55.1% (651/1182) versus 61.7% (163/264)]. Among treatment groups, there was no significant difference in the FTAI pregnancy rate for cows in the leptospira positive and negative farms [55.4% (336/606) versus 59.3%(80/135)]. Similarly, among control groups, there was no significant difference in the FTAI pregnancy rate for cows in the leptospira positive and negative farms [54.8% (316/576) versus 63.6 (82/129)]. There were no significant differences in the over-all pregnancy rate for leptospira positive and negative farms. The presence of leptospira on the farm affected the FTAI pregnancy rate. The monovalent leptospira vaccine coupled with oxytetracycline treatment did not improve the reproductive performance in beef cows.

Kasimanickam, R, W. Whittier, J. Hall, J. Currin, K. Pelzer, B. Inman. The effect of a monovalent leptospiral vaccine and parenteral oxytetracycline treatment against Leptospira borgpetersenii servor hardjo type hardjo on the reproductive performance of beef cattle – A field study. 2007 Theriogenology 68(3) 493-493.

 

DNA paternity identification in beef cattle
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.

Gomez-Raya, L., K. Priest, W. M. Rauw, M. Okomo-Adhiambo, D. Thain, B. Bruce, A. Rink, R. C. Torrell, L. Grellman, R. Narayanan, and C. W. Beattie The value of DNA paternity identification in beef cattle: examples from Nevada’s free range ranches.
2007 J. Anim Sci. published 18 September 2007, 10.2527/jas.2007-0068



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Beef Research News is produced by the Farm Animal section at Kansas State University. To modify your subscription to this service please email Erin Evanson ( eevanson@vet.ksu.edu   )

For more information please contact:
Brad White
Beef Production Medicine
Q211 Mosier Hall
Manhattan, KS 66506
bwhite@vet.ksu.edu