Between male variation in semen characteristics and preliminary results on the dilution of semen in the ostrich

Abstract This study is part of an ongoing project on artificial insemination in ostriches. The physical output of neat semen from four ostrich males was investigated and the effect of reconstituting semen with: 1) seminal plasma of the same male (SPS); 2) seminal plasma of another male (SPD), and 3) Dulbecco's Modified Eagles Medium (DMEM). Semen was collected daily from one or two pairs of males using the dummy female method, each pair being replicated twice. Spermatozoa viability in neat semen, SPS, SPD and DMEM was assessed using nigrosin-eosin staining and the proportions of live normal, live abnormal and dead sperm were determined. Semen volume (mean ± SE) was 1.27 ± 0.13 mL, the concentration of spermatozoa 3.68 ± 0.17 x 10 9 /mL and the number of spermatozoa 4.92 ± 0.64 x 10 9 /ejaculate. Furthermore, the live normal, live abnormal and dead spermatozoa in the neat semen were 61.2 ± 4.5%, 21.2 ± 2.7% and 17.7 ± 4.3% respectively. The ejaculate volume and the number of dead spermatozoa were not affected by collection time. However, the number of live abnormal spermatozoa increased through the day causing a reduction in live normal spermatozoa. Furthermore, re-suspending spermatozoa in DMEM reduced the number of live normal (31.4 ± 4.6%) and live abnormal spermatozoa (11.0 ± 2.7%) and increased the number of dead spermatozoa (57.6 ± 4.4%). In contrast, numbers of live spermatozoa were higher when suspended in seminal plasma and similar in SPS (53.9 ± 4.6%) and SPD (50.7 ± 4.6%). These are the first crucial steps to determining the optimum semen collection time and to improving the viability of diluted spermatozoa

The effect of temperature and pH on the motility and viability of ostrich sperm

As the chemical environment of semen diluents can have a profound effect on sperm quality, we examined the effect of temperature and pH on the motility and viability of sperm in the ostrich. Semen was collected from four males, each male being replicated three times. Ejaculates were diluted and incubated for 10 min at 20 degrees C and 40 degrees C in four different buffers, temperature adjusted at pH 6, 7, 8 and 9 respectively. Average path velocity (VAP), curvilinear velocity (VCL), straight-line velocity (VSL), linearity (LIN), beat cross frequency (BCF) and amplitude of lateral displacement (ALH) were then recorded for each sample using CASA. The viability of sperm was assessed using nigrosin-eosin staining. Sperm incubated at 40 degrees C had higher motility parameters, except for ALH. At 40 degrees C, VAP, VSL and LIN increased with pH while VCL, BCF and ALH were higher for lower pHs. The viability of sperm was not affected by temperature but decreased at pH values > 7. A pH in the neutral range appeared to yield higher quality sperm after in vitro storage at 20 degrees C. However, the effect of different pH levels and temperatures on sperm longevity needs to be investigated further to develop viable ostrich specific diluents. (C) 2012 Elsevier B.V. All rights reserved

Predicting ejaculate quality and libido in male ostriches: Effect of season and age.

The success of artificial breeding program depends largely on the reproductive performance of males. Male performance can vary with season and age impacting on quality and quantity of semen collected for artificial insemination purposes and therefore fertility of inseminated females. We examined variation in semen output and male libido of seven male ostriches (aged 2-5 years) over a period of 24 months. We collected ejaculates using a dummy female and measured semen characteristics (ejaculate volume, sperm concentration, number of spermatozoa per ejaculate, sperm motility and morphology) and male libido (willingness to mount the dummy). A total of 1006 ejaculates were collected. Across months, the volume of semen (mean±SEM) ranged from 1.03±0.12mL to 1.85±0.07mL, the sperm concentration from 3.21±0.12×10(9)/mL to 4.16±0.74×10(9)/mL, and the number of spermatozoa from 3.42±0.28×10(9) to 7.66±0.47×10(9). The largest volume of ejaculates and the highest number of sperm were collected in spring. Ejaculates with higher number of normal sperm were also collected in spring-early summer, whereas ejaculates with higher numbers of live abnormal and dead sperm were collected in winter. Sperm motility was relatively constant over months, despite a reduction in summer (January-February), while male libido peaked in winter (June-July) and spring (October-November). Furthermore, we observed high individual variation between males for all variables tested, except for motility. These results indicate that collections conducted in spring yield higher number of spermatozoa, when the libido of males is also at a maximum. Therefore in this species seasonal variation in semen quality should be considered in breeding programmes by artificial insemination to maximise fertility