Consistent estimates of boar fertility potential from objective semen evaluation could be a valuable tool for boar selection. The objective of this study was to evaluate semen characteristics of Kolbroek and Large White boars following computer aided sperm analysis ® (CASA). Eight ejaculates were collected separately from individual Kolbroek (n = 4) and Large White (n = 4) boars using the gloved-hand technique. Following semen collection, semen was evaluated for macroscopic and microscopic characteristics. Analysis of variance (ANOVA) was used to test the differences between the breeds (P<0.05). The bodyweight of Kolbroek (154.7 ± 8.5) was significantly lower compared to Large White (189.9 ± 7.7) boar. There was also a positive correlation between bodyweight and semen volume of both Kolbroek (r = 0.2197) and Large White (r = 0.2577) boar. However, no significant differences were observed in Kolbroek and Large White boar semen volume (140 and 170 ml), sperm concentration (0.727 and 0.761 × 10 9 sperm cell/ml), pH (7.0 and 7.0), total motility (95 and 91%) and morphology (84 and 82%). In conclusion, the bodyweight of Kolbroek and Large White boar was positively correlated with ejaculated semen volume. Sperm characteristics of both Kolbroek and Large White boar were similar. Sperm class analyser ® provided a precise and more objective information of sperm motility characteristics.

The choice of the short-term extender is important to preserve the quality of the diluted South African indigenous Kolbroek boar semen during short-term storage prior to artificial insemination. The aim of this study was to identify the suitable extender for short-term storage of Kolbroek boar semen at 17°C. Five ejaculates were collected separately from five Kolbroek boars using the gloved-hand technique in a 300-mL glass beaker. The filtered sperm fraction were sealed with a gauze filter inside a prewarmed (39°C) insulated thermos flask. Following semen collection, the semen was evaluated for macroscopic characteristics; semen volume, pH, and concentration. Sperm cells morphology was evaluated using eosin-nigrosin staining solution using fluorescent microscope system. Only ejaculates with >75% motile sperm and <15 abnormalities were used. The semen was pooled and diluted with five different short-term extenders, namely: Beltsville Thawing Solution (BTS), Kobidil+, Hungarian Standard, Citrate, and Tris-based extenders at a ratio of 1:1 (v/v). Sperm cells motility parameters were evaluated using a sperm class analyzer (SCA) at 0, 3, 24, and 48 h intervals. The data were analysed by SPSS. The results demonstrated that sperm cell motility rate did not differ when stored at 0 (88.9 ± 8.3) and 3 (93.8 ± 4.4) h irrespective of extender. However, semen that was diluted with Hungarian extender and Tris-based extender maintained higher proportion of sperm cells motility (90.0 ± 2.5 and 87.8 ± 4.8, respectively) for a longer period during storage for 24 h as compared with the other extenders. In conclusion, the study demonstrated that prolonged storage of boar sperm cells reduces motility rates. However; Hungarian Standard and Tris-based extenders preserved sperm motility rate better than the other extenders when stored up to 48 h at 17°C. Thus, this study suggests that Kolbroek sperm cells can be transported within 24 to 48 h in South African regions without adversely affecting motility rates when diluted with Hungarian Standard and Tris-based extender at 17°C without cryopreserving them. This study was funded by the Department of Agriculture Forestry and Fishery, ARC, DST (RT19000), and National Research Foundation (NRF, Grant. No. RT21 and 24000).

The choice of ideal permeable cryoprotectant for cock semen equilibration and freezing is critical. The aim of this study was to compare three different cryoprotectants [dimethyl sulfoxide (DMSO), ethylene glycol (EG), and propanediol (PND)] following cryopreservation. The abdominal massaging technique was used for semen collection from 5 Venda cocks. Individual ejaculates were diluted with modified Kobidil+ (mK+) extender (fraction A) at a ratio of 1:2 and equilibrated for 2 h at 5°C. Semen samples of 5 μL were taken at 0, 60, and 120 min and evaluated by CASA for spermatozoa motility parameters (rapid, medium slow, static, NPM and PM) and velocity. Semen was further diluted at 1:1 volume ratio with mK+ supplemented with 8% DMSO, EG and PND (fraction B), and equilibrated for additional 2h at 5°C and evaluated at 60 and 120 min for motility and velocity. Cooled semen were then transferred into 0.25-mL straws and placed into a programmable freezer. The temperature of the chamber was decreased in a stepwise manner, from 5°C to -20°C, at the rate of 1°C/min until it reached the target temperature. The straws were exposed to liquid nitrogen (LN2) vapor and then plunged into LN2 (-196°C). The semen straws were stored into LN2 tank at -196°C. After 3 months of storage, semen straws were thawed at 5°C and evaluated by CASA for spermatozoa motility and velocity. Data were analyzed by ANOVA. There were no significance differences between DMSO and EG regarding the survival and motility rate of frozen/thawed semen; however, these parameters were lower compared with the fresh semen. The PND was not a suitable cryoprotectant to cryopreserve Venda spermatozoa. In conclusion, ethylene glycol was found to be a suitable cryoprotectant to cryopreserve spermatozoa of South African Venda cocks. Department of Agriculture Forestry and Fisheries, NRF,ARC, Department of Science & Technology.

The Nguni breed of South Africa is small, hardy, disease-tolerant, thrives on poor pasture, and was regarded as an inferior breed in the past. For optimizing routine fresh and freezing of Nguni bull semen analysis, 3 different concentrations of glycerol (7, 10, and 14%) were examined. Ten ejaculates were collected from each 6 Nguni bulls using electro-ejaculator at ARC, Irene, South Africa. Following semen collection, semen was examined for macroscopic (volume, pH, and concentration) and microscopic (motility) parameters. The semen was extended with Tris + 10% egg yolk diluent at a ratio of 1 : 2 (v/v) and frozen at different concentrations of glycerol (7, 10, and 14%). The semen was then evaluated using the sperm class analyzer (SCA; CASA system) for progressive motility parameters. Fresh and frozen-thawed were fixed and stained with Nigrosin-Eosin for morphology (dead and live). Data were analyzed by ANOVA. There was a significant difference among individual Nguni bull spermatozoa volume and concentration. Analyzed frozen-thawed Nguni spermatozoa resulted in a significant (P < 0.05) difference of spermatozoa motility parameters frozen in 10% glycerol (68%) compared with 7 (41%) and 14% glycerol (30%). In conclusion, Nguni spermatozoa can be cryopreserved successfully when 10% of glycerol concentration is used. The results of this study will improve the viability of cryopreserved Nguni bull spermatozoa following the development of a South African semen cryo-gene bank. This study was supported by grants from National Research Foundation (NRF), Hungarian, South African Bilateral Scientific and Technological (TETNo. OMFB-00302/2008, RT24000) collaborative project. Department of Agriculture Forestry and Fisheries (DAFF, RPPP15).