Diagnostic tests in canine andrology - What do they really tell us about fertility?

Dog breeders often require breeding soundness evaluations which include andrological examinations of the genital organs, hormone measurements, and semen analyses. During the past decades, a considerable number of research results have been published, allowing diagnoses of specific andrological conditions and fertility assessment. For specific examinations, however, no standard procedures have been defined and for some parameters different reference ranges have been published. Therefore, examination results from different facilities are difficult to compare and profound conclusions regarding health and fertility of a male dog are not always possible. Conventional semen examination, however, is still useful in identifying deviations or no deviations from normality, especially if confounding factors are taken into account and if the exam is repeated in case of inconclusive findings. A standardization of examination procedures and reference ranges would help to harmonize the exchange of examination results and interpretation of the findings.

Hypo-Osmotic Swelling Test (HOST) for Feline Spermatozoa: The Simplified Procedure and the Aspect of Sperm Morphology

Hypo-osmotic swelling test (HOST) is used to assess the functional integrity of sperm plasma membranes in many species. The primary aim of this study was to test a simplified HOST procedure for the evaluation of feline semen. The second objective was to check if sperm abnormalities can influence the results of this test. Urethral semen was collected from 19 male, domestic cats. In Exp. 1, HOST was performed in different media (50 mOsm/kg fructose or distilled water), temperature (37 °C or room temperature) and time (5 and 30 min). In Exp. 2, the potential effect of sperm abnormalities on HOST results was assessed by observing individual normal and abnormal spermatozoa microinjected into droplets of distilled water. The results showed no differences between the HOST results performed in different media, temperature and time. Viable abnormal spermatozoa were able to swell under hypo-osmotic conditions in the same manner as normal ones, except spermatozoa with distal droplets, which showed a higher frequency of ‘despiralization’. In conclusion, HOST can be reliably performed at 0 mOsm/kg for 5 min at room temperature, which may contribute to a wider use of this test under clinical environments. Viable abnormal spermatozoa are able to swell under hypo-osmotic conditions; therefore, their presence in the ejaculate would not bias the results of HOST when total coiling is calculated.

Short communication: Progressive motility of frozen-thawed canine semen is highest five minutes after thawing

Progressive motility is usually estimated by visual inspection using a light contrast microscope at X 100 immediately after semen collection or immediately after thawing frozen semen. Standard operating procedures have never been established for this test. The objective of this experiment was to examine time-dependent changes of motility after thawing cryopreserved canine semen. Semen of 35 dogs was collected, and volume, concentration, progressive motility, morphology, membrane integrity and HOS test were evaluated. For cryopreservation, CaniPRO^® Freeze A&B was used. Semen was thawed and diluted using CaniPRO^® culture medium. After thawing, semen was evaluated as before. In addition, every sample was evaluated for progressively motile sperm cells 0, 5, 20 and 60 min after thawing. Progressive semen motility was significantly highest five minutes after thawing.

Semen quality, testicular B-mode and Doppler ultrasound, and serum testosterone concentrations in dogs with established infertility

Retrospective examination of breeding records enabled the identification of 10 dogs of normal fertility and 10 dogs with established infertility of at least 12 months of duration. Comparisons of testicular palpation, semen evaluation, testicular ultrasound examination, Doppler ultrasound measurement of testicular artery blood flow, and measurement of serum testosterone concentration were made between the two groups over weekly examinations performed on three occasions. There were no differences in testicular volume (cm(3)) between the two groups (fertile right testis = 10.77 ± 1.66; fertile left testis = 12.17 ± 2.22); (infertile right testis = 10.25 ± 3.33; infertile left testis = 11.37 ± 3.30), although the infertile dogs all had subjectively softer testes compared with the fertile dogs. Infertile dogs were either azoospermic or when they ejaculated, they had lower sperm concentration, sperm motility, and percentage of morphologically normal spermatozoa than fertile dogs. Furthermore, infertile dogs had reduced sperm membrane integrity measured via the hypoosmotic swelling test. Infertile dogs had significantly lower basal serum testosterone concentrations (1.40 ± 0.62 ng/mL) than fertile dogs (1.81 ± 0.87 ng/mL; P < 0.05). There were subjective differences in testicular echogenicity in some of the infertile dogs, and important differences in testicular artery blood flow with lower peak systolic and end-diastolic velocities measured in the distal supratesticular artery, marginal testicular artery, and intratesticular artery of infertile dogs (P < 0.05). Notably, resistance index and pulsatility index did not differ between infertile and fertile dogs. These findings report important differences between infertile and fertile dogs which may be detected within an expanded breeding soundness examination.

Evidence-based Medicine in Animal Reproduction

With new knowledge being generated and published daily, the importance of evidence-based approaches in veterinary medicine is obvious. Clinicians must stay current or risk making poor decisions that clients may challenge. Especially in animal reproduction, several new substances and procedures to diagnose or treat reproductive disorders have been introduced in the last years. On the other hand, a closer look at the quality of published literature on animal reproduction reveals major deficits in methodology and reporting of many clinical trials. We strongly recommend systematically assessing the quality of scientific information when reading journal papers before using the given information in practice. The aim of evidence-based medicine (EBM) is to base the decisions in the practice of medicine on valid, clinically relevant research data. Therefore, we suggest that students should become familiar with the concepts of evidence-based veterinary medicine (EBVM) at the beginning of their veterinary education. Concepts and supporting tools such as checklists for literature assessment have been developed and validated. The purpose of this article is to review and discuss the importance of incorporating EBVM in animal reproduction. The need for further research that produces strong evidence in different fields of animal reproduction and better reporting of relevant study information is obvious.

Invited review: Antibiotic treatment of metritis in dairy cows: a systematic approach

Acute puerperal metritis (APM) is an acute systemic illness with fever ≥ 39.5 °C and signs of toxemia due to an infection of the uterus occurring within 21 d after parturition. Because of the infectious nature of APM, antibiotics are considered beneficial for its treatment. Each use of an antimicrobial drug, however, is associated with selective pressure for the emergence of resistant bacteria. Hence, there is a significant need to encourage prudent use of antibiotics and alternative therapies to antibiotics. Therefore, the objective of this study was to systematically review the current literature on treatment of APM. A comprehensive and systematic literature search was conducted utilizing the PubMed and CAB Abstracts databases to identify literature focusing on the antibiotic therapy of puerperal metritis in the cow. After application of specific exclusion criteria, 21 publications comprising 23 trials remained for final evaluation. Data extraction revealed that the majority of the studies (n = 19) were attributable to the highest evidence level. Of 21 studies controlled, 11 had an untreated group and 3 a positive control group. The majority of the studies (n = 17) applied ceftiofur for the treatment of APM. Concerning the efficacy of ceftiofur, 7 studies observed clinical improvement, whereas none found improved reproductive performance. Fewer than half of the studies (n = 10) performed a bacteriological examination and only 4 implemented an antibiotic susceptibility test. Also, 3 studies (13.0%) described a self-cure rate per se. Little attention was given to the issue of bacterial resistance (n = 3), the need for reducing the application of antibiotics (n = 2), or guidelines for prudent use of antibiotics (n = 1). Our findings demonstrate that implementation of bacteriological examinations, sensitivity testing, and determination of minimum inhibitory concentrations, as well as reporting and discussion of critical issues (e.g., self-cure rates, resistance, prudent drug use), were suboptimal. On the other hand, the quality of studies on the treatment of APM was good, as indicated by evidence level 1. Nevertheless, more high-quality research considering self-cure rates is necessary to address critical issues related to APM and crucial to the dairy industry, such as resistance, prudent use of antibiotics, animal welfare, and cost-benefit ratios.