Contents The aim of the present study was to compare the influence of room temperature (27 degrees C) and 4 degrees C during glycerol addition on canine semen cryopreservation and verify the effect of different post-thawing dilutions on canine semen. Ten ejaculates from five stud dogs were collected by digital manipulation. Semen samples were evaluated and further divided into two aliquots. The first aliquot was extended in Tris-egg yolk-glycerol at 27 degrees C and the second one received glycerol at 4 degrees C. Samples were frozen and stored in liquid nitrogen. After 1 week, samples were thawed and submitted to evaluations of progressive sperm motility, morphology, acrosomal integrity, hypo-osmotic swelling (HOST) and thermoresistance tests. For thermoresistance test, aliquots were divided in two portions: one portion was kept undiluted (1 : 0) and the other one was diluted in a 1 : 4 ratio (one part semen to four parts extender). No differences were observed between temperatures for glycerol addition regarding seminal parameters evaluated. Furthermore, post-thawing dilutions demonstrated similar effect on canine semen longevity. Correlations among post-thaw sperm motility and HOST and results from thermoresistance test were observed for both temperatures for glycerol addition. In conclusion, glycerol could be added to canine semen at room temperature (27 degrees C) or at 4 degrees C. Moreover, there is no need to extend canine semen after thawing for the thermoresistance test, but if we need to increase the inseminating volume for artificial inseminations, the addition of extender will not damage the semen.

ContentsThe reproductive potential of male animals is commonly evaluated using a breeding soundness examination incorporating B-mode ultrasound examination of the testes and recently Doppler ultrasound examination of the testicular arteries. These techniques may detect testicular normality or pathology, and while some measured parameters are associated with semen quality at the time of ultrasound examination, few studies have investigated the relationship with future semen quality. We hypothesized that B-mode and Doppler ultrasound measurements would correlate with future semen quality. Within two studies, we investigated the relationship between ultrasound measured testicular volume, testicular echogenicity, testicular homogeneity, subjective assessment of the testicular parenchyma, testicular artery resistance index, and pulsatility index with subsequent semen quality. Fifty-five normal fertile dogs of which 29 had stable semen quality and 26 had a subsequent decline in semen quality were examined during a 6-month period commencing 62 days after the ultrasound examination.Statistical analysis showed that no ultrasound parameters were predictive of future total sperm output or percentage live normal sperm. However, mean testicular echogenicity was positively related to future sperm motility (t = 2.202, p = .039). We conclude that quantitative ultrasound assessment of the appearance of the testicular parenchyma has potential for the evaluation of future semen quality in dogs.

No abstract

To determine whether the effects of different concentrations of insulin on the development of canine preantral follicles in vitro were associated or not with FSH, secondary follicles were isolated and cultured. In Experiment 1, follicles were cultured in the following media: modified minimum essential medium (CtrlMEM) alone; CtrlMEM plus 5 ng mL⁻¹ insulin (Ins5ng); CtrlMEM plus 10 ng mL⁻¹ insulin (Ins10ng); and CtrlMEM plus 10 μg mL⁻¹ insulin. In Experiment 2, follicles were cultured in the same media but in the presence of sequential FSH (i.e. CtrlFSH, Ins5ngF, Ins10ngF and 10μgF, respectively). Increasing concentrations of FSH (100, 500 and 1000 ng mL⁻¹) were added sequentially to the culture medium on Days 0, 6 and 12 of culture. Viability were assessed at the end of culture and follicular diameter and the antrum formation rate at four time points (Days 0, 6, 12 and 18). In Experiment 1, the high insulin concentration significantly increased follicular viability (P<0.05). In contrast, in Experiment 2, viability was not affected by the inclusion of insulin. In addition, viability was significantly better in follicles cultured in CtrlFSH (P<0.05). The diameter of follicles in the high-insulin group in Experiment 1 and high-insulin plus FSH group in Experiment 2 was superior to other groups tested. In experiment 2, the Ins10μg and Ins10μgF groups exhibited significantly higher antrum formation rates than the other groups. In conclusion, in the absence of FSH, high concentrations of insulin have beneficial effects on follicular viability. However, to promote the growth of canine preantral follicles in vitro, it is recommended that a combination of insulin and FSH be added to the medium.

No abstract