Seasonal effects on semen quality in Black Baladi and White New Zealand rabbit bucks.

Abstract

A total of 32 sexually mature rabbit bucks (at 6 th month of age) were used in this experiment to study the effects of breed (Black Baladi -BB-vs. White New Zealand -WNZ-) and season (summer vs. winter) on libido and seminal parameters. The experimental design was completely random with four groups arranged factorially (two breeds and two seasons) with eight rabbits in each group and three months per season. The results obtained from this study indicated that, libido (14.5 vs. 21.9 sec) and physical semen characteristics represented by the volume of semen per ejaculate without gel fractions (0.70 vs. 0.49 mL), sperm-cell concentration (703 vs. 597×10 6 /mL), total sperm output (513 vs. 293×10 6 /ejaculate), sperm abnormalities (11.6 vs. 14.0%), acrosomal damages (8.6 vs. 11.5%), dead spermatozoa (13.9 vs. 16.0%), and advanced sperm motility (63.2 vs. 57.1%) were signifi cantly (P<0.01) better on BB rabbit bucks than on WNZ breed. In addition, these parameters proved to be signifi cantly (P<0.01) better in winter season (15.8 sec, 0.68 mL, 702×10 6 /mL, 487×10 6 /ejaculate, 10.7%, 8.4%, 12.7%, and 65.6%, respectively) than in summer (20.6 sec, 0.52 mL, 598×10 6 /mL, 319×10 6 /ejaculate, 15.0%, 11.7%, 17.3%, and 54.7%, respectively). Following the hypo-osmotic swelling test (HOST) at 75 mOsmol/L during incubation at 37 o C for 20 min, the percentages of sperm motility, swollen spermatozoa, and spermatozoa with coiled tails were higher for BB bucks (16.98, 44.08, and 39.13) than for the WNZ breed (7.2, 32.3, and 26.0). This was also the case in the winter season (14.4, 42.7, and 38.5) when compared to summer (9.8, 33.7, and 26.6), respectively. We concluded that, under Egyptian conditions, both libido and semen quality in BB bucks seems to be better than those displayed by the WNZ bucks. Nevertheless, overall semen characteristics were better in winter than in the summer season.

Effect of seasonality on quality and fertility of cryopreserved New Zealand white rabbit semen under Egyptian conditions

“…The results of the present work evidently demonstrated that the success of cryopreservation mainly depends on the effect of seasonality on fresh semen from the beginning of semen processing. The results for fresh and cryopreserved semen (Table 1, 2) revealed that there was no significant difference between semen quality parameters during autumn, winter and spring seasons, but the highest values of the total motility, live sperm, functional membrane integrity and acrosome integrity were yielded in winter, which is in agreement with previous studies by Marai et al (2002) and Safaa et al (2008). This may be attributed to the fact that rabbits can tolerate up to about 27°C degrees without heat stress or adverse effect on semen characters.…”

Semen characteristics and sexual hormones of Hy-Plus rabbit bucks influenced by a dietary multi-enzymes additive

“…In the present study, the EZ0 rabbit bucks presented a lower sexual drive than the EZ-supplemented rabbit bucks, coincident with a linear increase in blood testosterone levels with ascending levels of the diet EZ additive. The reaction time of rabbit bucks was much longer than the 4.2 s observed by Ogbuewu et al (2009) with New Zealand white×Chinchilla rabbit bucks and 14-21 s reported by Safaa et al (2008) in Black Baladi and White New Zealand rabbit bucks. This may be due to the testosterone and estradiol, which act synergistically to stimulate male sexual behaviour (Cross and Roselli, 1999).…”

Climate Changes Effects on Rabbit Production

“…El-Sawy et al, (2017); Lavara et al, (2013) and Safaa et al, (2008) reported that the libido, mating activity and the physical semen quality of NZW rabbit bucks during the winter season were highly significant (P≤0.01) better than those observed in the summer season. Semen volume increased and motility indexes decreased during summer (Roca et al, 2005).…”