The objectives of the current study were to evaluate the estrous response and pregnancy rate following timed artificial insemination (TAI) with frozen-thawed semen in cows. The study was carried out in cows at different villages of KwaZulu-Natal (KZN; n = 160) and Limpopo provinces (L; n = 171). Cows were selected randomly as presented by the farmers, regardless of parity, age, breed and body weight following pregnancy diagnosis. The cows were grouped according to breed type and body condition score (BCS) on a scale of 1-5. Selected cows were inserted a controlled intravaginal drug release (CIDR ®) and removed on day 8, followed by administration of prostaglandin. Heat was observed on day 9 with the aid of heat mount detectors (HMD) that were placed on the individual cow's tail head. Cows on heat were then inseminated twice at 12 hours interval. Pregnancy diagnosis was performed by an ultra-sound scanner and rectal palpation 90 days after TAI. Data were analyzed using SAS 2006. Estrous responses were 100% in KZN and 99% in Limpopo.

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.

Improving techniques for liquid storage of cock semen can increase the efficiency of AI programs in the poultry industry. The aims of the present study were (1) to compare storage of cock sperm for 24 h at 5 and 25°C and (2) to test the cryotolerance of sperm cell motility in individual Venda cocks. Semen was collected with the abdominal massage method, from 6 indigenous Venda cocks. Cocks were 26 weeks of age and were kept under the same conditions. After macroscopic analysis, semen was pooled and diluted (1:2) with Kobidil+ extender and divided into 3 equal parts. Part 1 was evaluated immediately (0 h), part 2 was stored at 5°C and part 3 was stored at 25°C and evaluated for sperm motility and velocity parameters at 4, 8, 12 and 24 h of storage. For cryopreservation, semen was diluted (1:2) with modified Kobidil+ extender supplemented with 8% of dimethyl sulfoxide. Individual ejaculates were equilibrated at 5°C for 4 h and then loaded into the programmable freezer. Then, semen straws were thawed at 5°C. Sperm motility and velocity parameters were evaluated using the Sperm Class Analyzer® system. Six replicates were done per trial. Data were analysed using the statistical programme GenStat®. Treatment means were separated using Fisher's protected t-test least significant difference (P < 0.05). Total sperm cell motility rate was 87.5% and decreased significantly during in vitro storage and was <31% after 24 h at 25°C. Semen samples stored at 5°C showed a total sperm cell motility rate of above 50% after 24 h. There was a slight linear decrease in the percentage of sperm with progressive motility and rapid velocity as the storage period increased, irrespective of the storage temperature. The rapid and medium motility percentages were higher in fresh semen and significantly decreased (P < 0.05) during the incubation period. There was variation in the total sperm cell motility of fresh and frozen semen among cocks. There was no significant difference in variation in non-progressive and medium percentage (P > 0.05) motility in diluted fresh or frozen sperm cells or in the percentage of sperm with rapid motility in thawed semen. There was variation in <25% of the cocks in total sperm motility rate. In summary, cryopreservation reduced sperm cell motility and velocity rates in all the cock semen donors. We found that cryotolerance of cock sperm does vary among males. Furthermore, the lower temperature 5°C was suitable for semen storage of Venda cocks. This temperature (5°C) could potentially improve methods of semen equilibration before cryopreservation. The study was supported by an Agricultural Research Council Parliamentary Grant, Department of Agriculture Forestry and Fisheries and National Research Foundation-GUN No RT21 and 24000 (NRF). The Germplasm Conservation & Reproduction Biotechnologies (GCRB) group is thanked for their support.

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).