F. V. Ramukhithi

Oestrous synchronisation and pregnancy rate following artificial insemination (AI) in South African indigenous goats

The study evaluated the effect of duration of progestagen treatment and breed on response to oestrous synchronisation and pregnancy rate following AI in 47 Boer and 27 unimproved indigenous goats. Each breed was subdivided into two groups, based on the duration of progestagen treatment. In the long-term progestagen treatment, controlled internal drug release dispensers (CIDRs) were inserted for 16 days, while in the short-term progestagen treatment, CIDRs were inserted for 9 days. Oestrous detection was performed for a period of 72 h, starting at CIDRs withdrawal. AI was performed 48 h following CIDRs removal with raw or frozen/thawed semen. Pregnancy diagnosis was performed at day 35 following AI. Boer goat exhibited a significantly (p <0.05) higher oestrous response (100%) than unimproved indigenous goats (88.9%). Breed had no effect on the onset of oestrus. Boer goat does recorded a longer duration of the induced oestrous period, compared to the unimproved indigenous goats. No significant difference was observed between short or long-term progestagen, with respect to the oestrous response, onset and duration of the induced oestrous period. The pregnancy rate was not affected by breed and semen cryopreservation. However, long-term progestagen treatment drastically reduced pregnancy rate. In conclusion, breed had an effect on oestrous response and the duration of induced oestrous period. The interaction of breed and duration of progestagen treatment had no effect on response to oestrus and onset of oestrus. The pregnancy rates of the current study were generally low and were affected by the duration of progestagen treatment.

Cryopreservation of South African Indigenous Goat Semen

®V10 software. South African indigenous goats had total sperm cell motility rate of 83.1%, progressive sperm cell motility of 49.3% and non-progressive sperm cell motility of 33.9%. Moreover, acidic semen pH of 6.4 and low sperm cell concentration (663.6 × 10 6 /ml) were obtained. Removal of seminal plasma and semen cryopreservation significantly decreased pH (5.8 ± 0.1 and 5.7 ± 0.1 for frozen-thawed washed and not-washed, respectively) and sperm cell motility rates of South African indigenous goats. Reduction in the sperm cell motility after freeze/thawing is still a problem and requires further research on the diluents and techniques that give protection to sperm cells during cryopreservation.

Comparative study on semen characteristics of Kolbroek and Large White boars following computer aided sperm analysis ® (CASA)

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. Key words : Sperm, Large White, Kolbroek, motility rate, boar.

Pre-Weaning Growth Performance of Piglets at Smallholder Farms in Gauteng Province

The objective of the study was to determine pre-weaning performance of piglets born following artificial insemination (AI) at smallholder farms of Gauteng province. Data from 496 piglets originating from 73 multiparous crossbred sows were used in the study. Litter size, number of piglets born alive, number of piglets weaned, birth and weaning weights were recorded. Data was analysed using the Proc Univariate procedure of SAS. The average litter size was 11.8. The average birth weight and weaning weights were 1.9 and 6.2 kg, respectively. No significant differences were found between male and female piglets for all the growth performance characteristics. Piglets born during winter had a significantly higher (P 0.05). The interaction between sex and season was only confirmed on the total number of weaned piglets (P < 0.01). A highly significant positive correlation was found between litter size and number of piglets born alive (r = 0.86) and total number of piglets weaned (r = 0.50). A highly significant correlation was found between total number of piglets born alive and total number of piglets weaned (r = 0.55). In conclusion, season of birth had the greatest impact on birth and weaning weight, with the highest birth and weaning weights recorded during winter season. However, sex did not affect the pre-weaning performance of piglets.

15 QUANTIFICATION OF BULL SPERM TRAITS AS ASSESSED BY COMPUTER-ASSISTED SEMEN ANALYSIS AND THE RELATIONSHIP TO PREGNANCY RATE FOLLOWING CONTROLLED BREEDING

The bulls contribution through artificial insemination to reproductive efficiency is of great biological importance. The objectives were (1) to compare the oestrous synchronization response of Bonsmara and Nguni cows; and (2) to find the relationship between cows conception rate (in vivo and in vitro fertilization) and bull sperm motility rate assessed by computer-assisted semen analysis (CASA) following AI. For the in vivo sperm fertility test, 100 Bonsmara and 482 Nguni cows were randomly selected and subjected to oestrous synchronization protocol and AI with frozen-thawed assessed semen by CASA before AI. Briefly at Day 0, cows were inserted with an intravaginal CIDR® (1.9g), which was removed on Day 7. Prostaglandin was then administered (2mL) on Day 8 and a heatmount detector was placed on the hindquarter of each cow. For the in vitro sperm fertility test, collected oocytes from slaughterhouse were in vitro matured (n=360) and in vitro fertilized (sperm/mL) in 100-µL droplets (final volume) of BO-IVF medium per treatment bulls (Bonsmara or Nguni bull). The frozen/thawed semen straws of Bonsmara and Nguni bulls were randomly selected and used under the same IVF conditions. The thawed bulls sperm characteristics were examined by CASA before in vitro fertilization. Data were analysed using ANOVA. Treatment means were compared using the Fishers protected least significant difference t-test. There was no significant difference in oestrous response for the Bonsmara (83.0%) and Nguni (90.8%) cows, respectively. The Bonsmara cows recorded a significantly higher pregnancy rate (59.0%) compared with the Nguni (37.1%) cows (P<0.05). Sperm traits such as total motility (TM), progressive motility and rapid were found to be positively correlated with conception rate (r=0.06, 0.03, and 0.08, respectively; P<0.01), although correlations were low. There was no difference in the average frozen-thawed sperm TM rate of Nguni (92.2%) and Bonsmara (81.0%). There was a lower fertilization rate following IVF with Bonsmara and Nguni bull sperm. In conclusion, Nguni cows had similar oestrous response as Bonsmara cows. The sperm traits from Bonsmara and Nguni bulls were found to be related to in vivo conception and in vitro fertilization rate when sperm cells were assessed by CASA technology. However, the pregnancy rate was lower in Nguni cows.