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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether a polymerase chain reaction (PCR) assay could be used to detect Eperythrozoon wenyoniin the blood of cattle.

Design—Prospective study.

Animals—95 cattle from various herds in Alabama and Georgia and 96 bulls enrolled in Auburn University's Alabama Beef Cattle Improvement Association Bull Test program.

Procedure—Blood samples were collected by means of venipuncture of the median caudal vein and submitted for a CBC and PCR assay. Blood smears were made immediately after blood collection and examined by means of light microscopy.

Results—Three of 95 cattle from herds in Alabama and Georgia and 5 of 96 bulls enrolled in the Bull Test program had positive PCR assay results. Organisms were seen in blood smears from only 5 of these 8 animals. Organisms were not seen in blood smears from any animals for which results of the PCR assay were negative.

Conclusions and Clinical Relevance—Results suggest that a PCR assay may be an effective method for detecting E wenyoni infection in cattle and that the PCR assay may be a more sensitive test than evaluation of blood smears. (J Am Vet Med Assoc 2001; 219:1432–1434)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate persistence of bovine viral diarrhea virus (BVDV) in semen after inoculation of postpubertal bulls.

Animals—Three 2-year-old bulls and five 6-month-old calves.

Procedure—3 seronegative 2-year-old bulls were inoculated intranasally with BVDV. Serum and semen samples were obtained at regular intervals until 7 months after inoculation. Serum samples were tested for BVDV by use of virus isolation (VI) and reverse transcription-nested polymerase chain reaction (RTnPCR) tests. Semen samples were tested for virus by use of VI and RT-nPCR tests. Testicular biopsy specimens were obtained 7 months after inoculation and tested for BVDV by use of immunohistochemical analysis and VI and RT-nPCR tests. Semen samples collected from 1 bull immediately before and 5 and 7 months after inoculation were administered IV to seronegative calves, which were monitored for subsequent viremia and seroconversion.

Results—Use of VI and RT-nPCR tests detected transient virus in serum of all bulls. The VI test detected BVDV in semen of 2 bulls for < 21 days after inoculation, whereas RT-nPCR assay detected BVDV until 7 months after inoculation. Virus was detected in testicular biopsy specimens of these 2 bulls by use of immunohistochemical analysis and RT-nPCR assay but could only be isolated from the biopsy specimen of 1 bull. Of the calves administered semen IV to detect infectious virus, only the recipient of semen collected 5 months after inoculation of the adult bull was viremic and seroconverted.

Conclusions and Clinical Relevance—Bovine viral diarrhea virus can persist in semen of acutely infected bulls for several months after exposure. (Am J Vet Res 2003;64:428–434)

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in American Journal of Veterinary Research

Abstract

Objective—To determine whether testicular needle biopsy is detrimental to testicular function in clinically normal bulls.

Design—Prospective study.

Animals—6 mixed-breed mature bulls.

Procedure—A randomly selected testicle from each bull was biopsied with a 14-gauge needle biopsy instrument. Bulls were then evaluated over a 90-day period for changes in scrotal temperature and thermal patterns, ultrasonographic appearance, and quality of spermatozoa. At the end of the 90-day study, bulls were castrated, and testicles were examined grossly and histologically.

Results—Changes were detected in scrotal temperatures and thermal patterns and in the breeding soundness examination results during the first 2 weeks of the study. However, there were no long-term changes in semen quality over the course of the experiment. Hyperechoic areas were detected on ultrasonographic examination and corresponded to the areas of penetration by the biopsy instrument. Microscopic lesions that were indicative of testicular dysfunction were not found.

Conclusions and Clinical Relevance—Results indicate that testicular biopsy is a safe procedure in bulls. Testicular biopsy could possibly be used to further examine bulls that have less than satisfactory results for breeding soundness examinations. (J Am Vet Med Assoc 2002;220:507–512)

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in Journal of the American Veterinary Medical Association