Effects of testicular biopsy in clinically normal bulls

Thermographic Screening of Beef Cattle Metatarsal Growth Plate Lesions

Simple Summary

Young beef bulls are predisposed to develop diseases of the growing skeleton, especially growth plate lesions. These lesions jeopardize both welfare and production, often leading to anticipated culling and diminished weight gain. However, beef cattle are prey animals and do not exhibit signs of pain and lameness until the disease becomes extensive and severe. Fast methods to screen for growth plate lesions presence could therefore lead to prompt treatment of the affected animals, enhancing recovery and diminishing losses. The aim of the present study was to examine the potential of infrared thermography as a non-invasive tool for rapidly screening beef bulls for the presence of growth plate lesions. Here, 20 Charolais and Limousine beef bulls affected by growth plate lesions were screened using infrared thermography. A difference in maximum, mean, and minimum temperatures was detected between healthy and affected growth plate areas, and a difference in mean and maximum temperatures was detected globally in the affected limbs against healthy ones. Infrared thermography could therefore serve as a reliable tool for screening growth plate lesions in beef bulls, permitting rapid detection at pen level and aiding fast and targeted treatment, thus improving animal welfare and production.

Abstract

Lameness represents one of the main causes of decreased productive performance and impaired animal welfare in the bovine industry. Young beef bulls are predisposed to develop diseases of the growing skeleton, especially growth plate lesions. Early diagnosis is indispensable for ensuring correct treatment, fast recovery and reduction losses. However, when dealing with beef cattle, this is not always possible. Fast and reliable diagnostic imaging techniques are necessary to improve dealing with lameness in beef animals. The aim of the present study was to examine the potential of thermographic imaging as a non-invasive tool for rapidly screening beef bulls for the presence of growth plate lesions. Here, 20 Charolais and Limousine beef bulls affected by growth plate lesions in one of the rear limbs were selected. IRT was performed on both hind limbs using a digital infrared camera (ThermaCam T420 Model, Flir Systems, Boston, MA, USA), prior to radiographic imaging and clinical examination. The temperature of healthy and affected limbs was measured in two regions: the area correspondent to the growth plate (AR01) and the whole area of the metatarsus (AR02). Growth plate lesions were found to increase the maximum, mean, and minimum temperatures in AR01; and the mean and maximum temperatures in AR02, therefore, indicating the potential of IRT as a reliable, practical tool for screening growth plate lesions in beef bulls.

Evaluation of Stallion Testicular Cell Types by Flow Cytometry

Flow cytometry procedures can be used for evaluation of both spermatogenic efficiency and diagnose disorders of stallion spermatogenesis. Aims of this study were to compare two testicular sample acquisition techniques (needle aspirate-N and tissue wedge-T) and results when using flow cytometry and histology procedures. Testicular cell types were stained with acridine orange, and nine regions (R2 to R10) were identified and enumerated following acquisition by either N or T. Testes were also grouped and analyzed by size and sexual maturity (Small [immature] compared with Large [mature]) and used to determine if flow cytometry procedures could be used to detect differences. For both N and T, percentages of 2n cell types were greater in the Small than Large testes, whereas percentages of 1n cell types in N were greater in the Large than Small testes (P < .05). Testicular cell types in N regions were correlated to similar T regions (r between 0.51 and 0.99; P < .05) in both groups. Flow cytometry and histology scores were correlated in both groups (r between -0.95 and 0.93, P < .05). There were small differences in number of testicular cell types from N and T. With both sample acquisition methods, there was discrimination between the Small and Large testes, therefore, evaluation of testicular cell types using flow cytometry procedures might have clinical applications. Results with comparison of flow cytometry to histology procedures indicate that flow cytometry can be applied clinically to identify changes in testicular cell types of stallions using a needle aspirate.

Histological Comparison of Testicular Needle Biopsy and En Bloc Samples in Abattoir Calves

the aim of this study was to test whether a single testicular needle biopsy could provide histological results comparable to en bloc resection histology and whether one biopsy was sufficient to reflect the histology of an entire pair of testicles. Two methods of sample collection were tested on 32 bull calves aged five to eight months to compare histological parameters of needle biopsy with those of en bloc resection samples. One testicular needle biopsy of the right and three en bloc samples of both testicles were collected and compared for the number of tubular cross sections, tubules with elongated spermatids (ES), outer/inner diameter of tubules, thickness of tubular wall, and number of Sertoli cells (SC). Additionally, animal data were considered. No significant differences were found between the left and right testis or among the individual locations of en bloc samples. However, histologically significant differences (Bonferroni-adjusted significance level: p < 0.05/6 = 0.0083) were found between the needle biopsy and en bloc resection regarding the tubular cross sections per visual field (p < 0.05), the outer (p = 0.01) and inner diameter and the thickness of the tubular wall (both p < 0.01). In the SOX9 immunohistochemical staining, no significant differences (p > 0.05) could be observed for SC numbers between needle biopsy and en bloc samples. In conclusion, results of testicular needle biopsy do not have the same validity as the en bloc resection histology. Furthermore, one biopsy is insufficient to reflect the histology of the entire testicular pair.

The prevalence of ultrasonographic abnormalities and histopathologic lesions is high in testes of yearling tropical hair rams

Ultrasonography is commonly used to examine testes as part of a breeding soundness examination in sheep, especially, in cases of infertility or when gross testicular abnormalities are present. A descriptive, prospective, prevalence study was conducted to characterize the ultrasonographic, histopathologic, and spermatozoal morphology abnormalities present in a group of yearling tropic hair rams on the island of St. Kitts. Hyperechoic and shadowing abnormalities increased over a 6 month study period. Hyperechoic abnormalities were present in one or both testes in 89% (25/28) of yearling rams and 71% (40/56) of testes at castration. Shadowing abnormalities were present in one or both testes in 46% (13/28) of rams and 34% (19/56) of testes at castration. Shadowing was present more with moderate and severe hyperechoic abnormalities, with few testes in the mild category having any shadowing. As hyperechoic and shadowing abnormalities increased in severity, so did the severity of microscopic lesions including increased interstitial cellularity/fibrosis, interstitial mineralization, seminiferous tubules mineralization (hyperechoic only), and chronic lymphoplasmacytic orchitis. There were no spermatozoal morphologic abnormalities other than an increase in distal cytoplasmic droplets. The study findings detail a pathologic event in this group of yearling rams that has an unknown etiology. Potential causes may include scrotal insulation, trauma, infectious causes, immunity alterations, nutritional imbalances, and ingestion of a toxin. Further studies are required to elucidate the causative agent.

The value of trans-scrotal ultrasonography at bull breeding soundness evaluation (BBSE): The relationship between testicular parenchymal pixel intensity and semen quality

Bull breeding soundness evaluation (BBSE) is commonly undertaken to identify bulls that are potentially unfit for use as breeding sires. Various studies worldwide have found that approximately 20% of the bulls fail their routine prebreeding BBSE and are therefore considered subfertile. Multiple articles describe the use of testicular ultrasound as a noninvasive aid in the identification of specific testicular and epididymal lesions. Two previous studies have hypothesized a correlation between ultrasonographic testicular parenchymal pixel intensity (PI) and semen quality; however to date, no published studies have specifically examined this link. The aim of this study, therefore, was to assess the relationship between testicular parenchymal PI (measured using trans-scrotal ultrasonography) and semen quality (measured at BBSE), and the usefulness of testicular ultrasonography as an aid in predicting future fertility in bulls, in particular those that are deemed subfertile at the first examination. A total of 162 bulls from 35 farms in the South East of Scotland were submitted to routine BBSE and testicular ultrasonography between March and May 2014, and March and May 2015. Thirty-three animals failed their initial examination (BBSE1) due to poor semen quality, and were re-examined (BBSE2) 6 to 8 weeks later. Computer-aided image analysis and gross visual lesion scoring were performed on all ultrasonograms, and results were compared to semen quality at BBSE1 and BBSE2. The PI measurements were practical and repeatable in a field setting, and although the results of this study did not highlight any biological correlation between semen quality at BBSE1 or BBSE2 and testicular PI, it did identify that gross visual lesion scoring of testicular images is comparable to computer analysis of PI (P < 0.001) in identifying animals suffering from gross testicular fibrosis.

Thermal imaging of normal and cranial cruciate ligament-deficient stifles in dogs

OBJECTIVE

To investigate the capability of thermography for differentiation between normal stifles and those with cranial cruciate ligament (CCL) rupture in dogs, initially with a full hair coat and 1 hour after clipping the hair coat.

STUDY DESIGN

Prospective study.

ANIMALS

Labrador Retrievers (n=6) with normal stifle joints (controls) and adult dogs (n=10) with CCL rupture.

METHODS

Thermography was performed before, and 60 minutes after, clipping the hair coat from the pelvic limb. Stifle images were classified as normal or abnormal, then subclassified as clipped and unclipped hair coat. CCL deficiency was confirmed at surgery and thermographic images subsequently classified as abnormal before analysis with image processing software.

RESULTS

Using image recognition analysis, differentiation between normal and CCL-deficient stifles in both clipped and unclipped dogs was 85% successful on cranial images, medial, caudal, and lateral images were between 75% and 85% successful. Although there were significant increases in skin temperature after clipping in both groups (P<.0002-.0001), there were no significant temperature differences between normal and CCL-deficient stifles when the entire stifle was examined.

CONCLUSION

Thermography was successful in differentiating naturally occurring CCL-deficient stifles in dogs, with a success rate of 75-85%. Clipping is not necessary for successful thermographic evaluation of the canine stifle.

CLINICAL RELEVANCE

Thermography may be a useful imaging modality for diagnosis of CCL deficiency in dogs when CCL rupture is suspected but stifle laxity is not evident.

Noncytopathic bovine viral diarrhea virus can persist in testicular tissue after vaccination of peri-pubertal bulls but prevents subsequent infection

The objectives of this research were to evaluate the risk of prolonged testicular infection as a consequence of vaccination of peri-pubertal bulls with a modified-live, noncytopathic strain of BVDV and to assess vaccine efficacy in preventing prolonged testicular infections after a subsequent acute infection. Seronegative, peri-pubertal bulls were vaccinated subcutaneously with an approximate minimum immunizing dose or a 10x standard dose of modified-live, noncytopathic BVDV or were maintained as unvaccinated controls. Forty-nine days after vaccination, all bulls were intranasally inoculated with a noncytopathic field strain of BVDV. Semen and testicular biopsies collected after vaccination and challenge were assayed for BVDV using virus isolation, reverse transcription-nested PCR, or immunohistochemistry and the identity of viral strains was determined by nucleotide sequencing of PCR products. The vaccine strain of BVDV was detected in testicular tissue of vaccinated bulls as long as 134 days after immunization. Prolonged testicular infections with the challenge strain were detected only in unvaccinated bulls as long as 85 days after challenge. Whereas vaccination caused prolonged testicular infection in some bulls, it did prevent subsequent infection of testicular tissue with the challenge strain. This research demonstrates that subcutaneous vaccination of naïve, peri-pubertal bulls with a noncytopathic, modified-live strain of BVDV can result in prolonged viral replication within testicular tissue. The risk for these prolonged testicular infections to cause venereal transmission of BVDV or subfertility is likely to be low but requires further investigation.

Detection of bovine viral diarrhea virus in semen obtained after inoculation of seronegative postpubertal bulls

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 (RT-nPCR) 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.

Evaluation of the safety and efficacy of testicular biopsies in llamas

Evaluation of the reproductive function of Lama glama is generally considered to be a challenging task due to the difficulty of obtaining representative semen samples. One method that has been proposed for evaluation of testicular function in these animals is histologic examination of testicular needle biopsies. This study was undertaken to examine the safety and efficacy of using needle biopsies to assess testicular function in this species. One randomly selected testicle from each of 16 sexually mature llamas was biopsied with a 14-gauge self-firing biopsy instrument. The llamas were evaluated over a 6-week period with thermography for temperature changes of the scrotum. At the end of the 6-week trial, the llamas were castrated and sections of each testis were fixed in Bouin's solution for histologic examination. Immediately prior to castration, an additional biopsy was taken from each testis to compare the tissue obtained via biopsy with sections from the corresponding testis obtained after castration. A qualitative grading scale was used to compare the seminiferous tubules from each testis. No difference was found between the biopsied and the nonbiopsied testes (P = 0.69). The percentage of normal tubules between the biopsied and the nonbiopsied sides also did not differ (P = 0.70). Furthermore, the percentage of normal seminiferous tubules did not differ between the needle biopsy samples and the corresponding tissue samples obtained at castration (P = 0.48). The number of round seminiferous tubules counted in each biopsy section ranged from 3 to 67. There was no significant difference in the thermographic images of the scrotum between the biopsied and the nonbiopsied testes. This study supports testicular biopsies as a safe and useful procedure in the evaluation of testicular function.