R.L. Carson

Caliper and ultrasonographic measurements of bovine testicles and a mathematical formula for determining testicular volume and weight in vivo

This study quantified the relationship between calibrated caliper and ultrasonographic derived measurements of bovine testicles in vivo with actual testicular length, width, volume and weight. The prolate spheroid formula was tested to accurately predict testicular volume and a modification to predict weight. Ten bulls were employed to derive caliper and ultrasound testicle (n = 20) length and width measurements in vivo. Caliper length measurements were more reliable than ultrasound derived lengths, with correlations of r2 = 0.8023; P < 0.05 and r2 = 0.5111; P < 0.05, respectively. Width for both the calipers and ultrasound measurements when compared to actual width measurements were r2 = 0.7313; P < 0.05 and r2 = 0.8310; P < 0.05, respectively. The prolate spheroid formula is reliable in determining testicle (n = 116) volume (r2 = 0.8928; P < 0.05). Testicular volume and weight are highly correlated (r2 = 0.9776; P < 0.05); therefore, a modification of the prolate spheroid formula was used to predict weight (r2 = 0.9084; P < 0.05) against the actual weight. Caliper-derived length and width measurements used in the prediction of volume and weight had correlation coefficients against actual volume and weight of r2 = 0.5497; P < 0.05 and r2 = 0.6340; P < 0.05, respectively. Ultrasound in vivo measurements for prediction of testicular volume and testicular weight had a correlation of r2 = 0.3276; P < 0.05 and r2 = 0.6249; P < 0.05, respectively. A testicular (n = 116) length to width ratio of 1.8:1 (SEM = 0.01) was determined for both slaughterhouse and castrated animals. Caliper measurements are reliable, inexpensive and much simpler to obtain than ultrasound determinations for in vivo testicle length, width, volume and weight. The two-dimensional measurement of length and width would be a more accurate predictor of testicle volume and weight than the one-dimensional measurement of scrotal circumference (SC), especially in bulls with variation in testicular shape.

Testicular shape and its relationship to sperm production in mature Holstein bulls

This study was conducted to determine the relationship between testicular shape, scrotal circumference (SC) and sperm production. Twenty-seven mature Holstein bulls were evaluated subjectively and objectively for testicular shape as indicated by testicular length and width, then placed in 1 of 3 groups. Group 1 contained 17 bulls with a normal ovoid testicular shape and a length to width ratio of 1.61:1 +/- 0.01 (SEM). Group 2 was composed of 4 bulls with a long, slender testicular shape and a length to width ratio of 1.95:1 +/- 0.06 (SEM). Group 3 was comprised of 6 bulls with spheroid-shaped testicles and a length to width ratio of 1.3:1 +/- 0.03 (SEM). All the groups were statistically different for length to width ratios (P < 0.05). Length measurements from cranial to caudal pole of the testis proper were also different between groups (P < 0.05). Width or testicular diameter was different between Group 2 and Group 3 at P < 0.05; however, there was no difference between Group 1 and Group 2 or between Group 1 and Group 3. Predicted volumes and weights of testicles were not significantly different between groups. Scrotal circumference measurements were significantly different between groups (P < 0.05). Group 1 had an average SC of 43.07 +/- 0.36 cm (SEM), Group 2 of 39.33 +/- 1.18 cm (SEM) and Group 3 of 46.22 +/- 0.69 cm (SEM). Sperm production for a twice daily, 2-day-per-week collection schedule revealed a statistically significant difference for sperm output. A total of 2742 ejaculates was evaluated. A total of 1818 ejaculates was evaluated in Group 1, 440 ejaculates in Group 2 and 484 ejaculates in Group 3. The mean spermatozoal harvest per day for Group 1 bulls was 13.62 +/- 0.09 x 10(9) (SEM). Group 2 bulls with the longer-shaped testicles produced 14.82 +/- 0.18 x 10(9) (SEM) spermatozoa per day, and Group 3 bulls, with the more rounded testicle shape and the significantly larger SC produced 11.72 +/- 0.64 x 10(9)(SEM) sperm cells per day. All 3 groups were statistically different at the P = 0.05 level. The results suggest that prediction of sperm production may be dependent on factors other than SC, testicular volume, or weight. Testicular shape may influence sperm output in mature Holstein bulls.

Analytical sensitivity of assays used for detection of bovine viral diarrhea virus in semen samples from the Southeastern United States

Bovine viral diarrhea virus (BVDV) is a significant pathogen that can be shed in the semen of infected bulls. Thus, screening for BVDV in semen of bulls is recommended prior to their entry into an artificial insemination center. No previous research has compared the analytical sensitivity of reverse transcription-nested polymerase chain reaction (RT-nPCR) and virus isolation assays for detection of BVDV in semen from an infected bull. Therefore, the goals of this research were to compare the analytical sensitivity of RT-nPCR and virus isolation assays for BVDV in semen and to apply these assays to determine the prevalence in the Southeastern United States of bulls that lack viremia yet shed BVDV in semen. Semen collected from a bull that was persistently infected with BVDV was serially diluted (1/10) in semen from uninfected bulls and frozen in liquid nitrogen as raw, partially extended or fully extended semen. Subsequently, samples of semen were assayed by virus isolation and RT-nPCR. Viral detection was more sensitive in extended semen samples than in raw semen samples and more sensitive by RT-nPCR than virus isolation. After this evaluation of analytical sensitivity, serum and semen were collected from 558 post-pubertal bulls in our region. These samples were tested for BVDV by virus isolation. Partially extended semen was also assayed for BVDV by RT-nPCR. All samples were negative by all assays for BVDV. The application of analytically sensitive assays reveals a very low prevalence (</=0.54%) of BVDV in semen from bulls in the Southeastern United States.

Comparison of Tests for Detection of Bovine Viral Diarrhea Virus in Diagnostic Samples

Currently, a variety of tests are used to detect bovine viral diarrhea virus (BVDV) in persistently infected (PI) cattle. These tests include immunohistochemical staining (IHC), antigen capture enzyme-linked immunosorbent assay (ACE), virus isolation (VI), and reverse transcription-polymerase chain reaction (RT-PCR). However, a lack of methods standardization could compromise the ability to consistently identify animals infected with BVDV. This study evaluated the diagnostic proficiency of current methods for detecting BVDV in infected cattle using intra- and interlaboratory comparisons. Samples were collected from 4 animals more than 7 months of age (2 BVDV negative animals, a PI animal, and a PI animal that previously lacked detectable virus in serum as determined by VI). Samples were submitted to 23 participating diagnostic laboratories using the respective laboratorys standard submission protocol. Samples collected for submission included: 1) serum for ACE, RT-PCR, and VI; 2) whole blood for RT-PCR and VI; and 3) skin biopsies for ACE and IHC. The ACE performed on skin provided the greatest consistency in detecting positive samples and a perfect level of agreement among laboratories. Reverse transcription-polymerase chain reaction and IHC performed well by correctly identifying ≤85% of samples positive for BVDV. Virus isolation performed on serum yielded the lowest consistency in detecting positive samples and the lowest level of agreement. The level of agreement between laboratories for detecting BVDV in persistently infected cattle ranged from perfect to less than expected by chance. The variation between laboratories suggests a need for training opportunities in standardized laboratory protocols and proficiency testing.

The effects of ovarian hormones and ACTH on uterine defense to Corynebacterium pyogenes in cows.

Ovariectomized cows were treated with either estrogen, progesterone or adrenogorticotropic hormone (ACTH). Each cows uterus was inoculated with 1x10(6)Corynebacterium pyogenes organisms. The cows were evaluated by rectal examination for signs of uterine infection. Peripheral leukocytic phagocytosis was determined by chemiluminescence at the beginning (Day 4) and end (Day 21) of the experiment. Uterine cultures were obtained at the end. None of the estrogen-treated cows developed signs of uterine infection, but all the other cows did develop uterine disease. All the infected cows showed clinical improvement at the experimental end (Day 21). There were no differences between groups for leukocytic phagocytosis on Day 4, but on Day 21, values for progesterone-treated and control cows were similar but greater than those for estrogen or ACTH-treated cows, which were similar. Leukocytic phagocytosis values for all cows were lower on Day 21 than on Day 4. Most of the estrogen- and ACTH-treated cows had negative intrauterine cultures on Day 21 while most of controls and progesterone-treated cows had positive cultures.

Observations using the new bull-breeding soundness evaluation forms in adult and young bulls.

The new bull-breeding soundness forms were used to evaluate 1276 bulls; 62.85% of these bulls were deemed satisfactory. Unsatisfactory and deferred percentages were 28.92% and 8.23% respectively. Reasons for the various classifications were evaluated, and age and breed comparisons were made.

Epidemiology of prolonged testicular infections with bovine viral diarrhea virus.

Previously, bovine viral diarrhea virus (BVDV) had been found in prolonged testicular infections following acute infection of immunocompetent bulls. The primary purpose of this research was to evaluate the production and maintenance of prolonged testicular infections after exposure to BVDV of seronegative bulls in varying circumstances. The secondary objective was to initiate assessment of the potential for transmission of BVDV via semen of bulls exhibiting a prolonged testicular infection. In total, 10 research trials were conducted. The first trial examined the duration of detectable virus in semen after intranasal inoculation of peri-pubertal bulls. The second to fifth trials examined the potential for prolonged testicular infections resulting from natural exposure of seronegative bulls to persistently infected heifers. In the last five trials, the potential for viral transmission from bulls exhibiting prolonged testicular infections to a small number of exposed animals (n=28) was evaluated. Results of this research demonstrated that prolonged testicular infections could result in detection of viral RNA in semen for 2.75 years with infectious virus grown from testicular tissue 12.5 months after viral exposure. A type 1b strain of BVDV caused prolonged testicular infection after natural exposure of seronegative bulls to a persistently infected heifer. However, transmission of BVDV to susceptible animals was not detected in the final five trials of this research. In conclusion, BVDV can persist in testicular tissue after acute infection for several years, but the potential for viral transmission from these prolonged testicular infections appears to be low.

Effects of grazing endophyte-infected tall fescue on eCG and progestogen concentrations from gestation days 21 to 300 in the mare

Abstract The influence of grazing endophyte-infected tall fescue on endometrial cup formation and function, progestogen production, and embryonic and fetal development were examined in pregnant mares between Day 21 and Day 300 of gestation. Total immunoreactive progestogens and equine chorionic gonadotropin (eCG) concentrations were compared between untreated controls (endophyte-free, n = 12) and treated mares (endophyte-infected, n = 12). There were no differences in endometrial cup formation or function, as determined by eCG concentrations at Days 45, 60, 75, 90 and 120 (P > 0.05) between mares grazing endophyte-infected and endophyte-free tall fescue. Mares grazing the endophyte-infected tall fescue had lower total progestogen concentrations (P

Use of in vitro fertilization for production of calves from involuntary cull cows

PurposeThe main purpose of the study was to assess the feasibility of a combined system for in vitro maturation of oocytes, in vitro fertilization, and in vitro culture of embryos for production of calves from cows that have to be removed prematurely from production units.ResultsEighteen cows that were to be culled from experimental dairy production units were ovariectomized. An average of 45.7 oocytes per cow was collected from the ovaries. After in vitro maturation and fertilization of the oocytes, an average of 40.8 presumptive zygotes was placed into in vitro culture, with an average of 16.1 cleaving by day 2 and an average of 5.7 developing to morulae/blastocysts by day 6 or 7. A greater mean quantity of oocytes was collected from cows that were ovariectomized between day 5 and day 13 of the estrous cycle than from those that were ovariectomized between day 0 and day 3 of the estrous cycle. Correspondingly larger mean numbers of cleaved zygotes and morulae/blastocysts were produced from the cows that were ovariectomized between day 5 and day 13 of the cycle. Transferable embryos were produced from 17 of the 18 cows. Eighteen embryos from six oocyte donor cows were transferred to recipients. Six of the eighteen recipients were confirmed to be pregnant after 40 days. Three of the pregnant recipients delivered live calves at term. Two others remain pregnant but have not reached term. The sixth recipient aborted at approximately 120 days of gestation.ConclusionsResults from the preliminary study indicate that this system can be used for production of calves from cull cows. Although transferable embryos were produced from all except one cow, there was a high degree of variability among cows in total number of oocytes recovered and embryos produced. More donors need to be evaluated to determine the effects of age, breed, reason for culling, and source of semen.

Ultrasonographic examination and measurement of ram testicles.

Ten adult rams were used in a study to compare ultrasonographic and physical measurements of testicles. Scrotal circumference measurements were correlated with both physical and ultrasonographic measurements and with semen analysis results. Scrotal circumference correlated well with most of the physical and ultrasonographic measurements and with semen motility and percent abnormalities. Ultrasonographic measurements correlated with scrotal circumferences but not with the semen analysis. There were significant differences in physical and ultrasonographic measurements of testicle circumference and diameter, especially when the ultrasonographic measurements were made through the intact scrotal wall. There appear to be problems in the accuracy of ultrasonographic measurements of testicle size in rams.