Abstract:
The aims of the study were to compare super ovulatory response, fertilization rate and evaluate embryo quality recovered from super ovulated Nguni stud cows and heifers. Nguni cows (n = 15) and heifers (n = 10) aged 4-6 and 2 years, respectively, were used as embryo donors. Embryo donors were synchronized for estrus before superovulation. For superovulation donors were administered with 350 mg of FSH (Folltropin®-V) divided into 2 injections daily 12 h apart for 4.5 days on a decreasing dosage. Semen was collected from two Nguni bulls (bull 1 and 2) using an Electro Ejaculator (EE) and semen characteristics (volume, motility, viability, concentration and morphology) were recorded and motility parameters were assessed by computer aided sperm analysis before Artificial Insemination (AI). Donor cows and heifers were inseminated randomly with semen straws from either bull 1 or bull 2. Embryos were flushed 7 days after AI using a nonsurgical technique and were evaluated under microscope for quality. Data were analyzed using one-way ANOVA and linear or quadratic relationships were used to determine effects of semen traits on fertilization rate and embryo quality. No significant differences were observed on the super ovulatory response rate of Nguni cows and heifers (P>0.05). Furthermore, no significant differences were recorded on fertilization rate between cows (67.5%) and heifers (63.5%) (P>0.05). Embryo quality between Nguni cows (code 1, 2.5±1.00; code 2, 1.3±0.59) and heifers (code 1, 0.8±0.41; code 2, 1.0±0.36) was similar. There was no significant difference between bull 1 (93.7%) and bull 2 (90.5%) on total sperm motility rate (P>0.05). The Super ovulatory response, fertilization rate and embryo quality between Nguni cows and heifers was similar.
