165 The effect of different extenders and storage period on sperm quality of Nguni bulls semen equilibrated at 5°C

M. R. Ledwaba; M. L. Mphaphathi; M. A. Thema; M. D. Sebopela; N. C. Negota; M. M. Seshoka; T. C. Chokoe; H. A. O’Neill

doi:10.1071/RDv37n1Ab165

RESEARCH ARTICLE

165 The effect of different extenders and storage period on sperm quality of Nguni bulls semen equilibrated at 5°C

M. R. Ledwaba ^A ^B , M. L. Mphaphathi ^A , M. A. Thema ^A , M. D. Sebopela ^A , N. C. Negota ^C , M. M. Seshoka ^D , T. C. Chokoe ^E and H. A. O’Neill ^B

+ Author Affiliations

- Author Affiliations

^A Agricultural Research Council, Animal Production, Irene, South Africa

^B University of the Free State, Department of Animal, Wildlife, and Grassland Sciences, Bloemfontein, South Africa

^C University of Venda, Department of Animal Science, Reproduction, and Physiology, Thohoyandou, South Africa

^D Northern Cape Department of Agriculture, Environmental Affairs, Rural Development and Land Reform, Vaalharts Research Station, Jan Kempdorp, South Africa

^E Department of Agriculture, Land Reform and Rural Development, Pretoria, South Africa

Reproduction, Fertility and Development 37, RDv37n1Ab165 https://doi.org/10.1071/RDv37n1Ab165

The Nguni cattle breed exhibits a significant level of genetic variation, which has been cultivated over many generations. The preservation of their semen is crucial for conservation initiatives. An appropriate semen extender is necessary for effectively preserving bull semen as it supplies the necessary energy sources for sperm metabolism. The aim of this study was to evaluate the effect of different extenders and storage period on sperm quality of Nguni semen equilibrated at 5°C. A total of 18 ejaculates (6 replications/bull) were collected from three Nguni bulls aged 4 to 5 years, using an electro ejaculator. Collected raw semen samples were transported to the laboratory and evaluated for sperm motility. Semen was randomly diluted with three different semen extenders (AndroMed®, egg yolk citrate [EYC], and Tris). Diluted semen was stored at 5°C and evaluated at 0, 3, 6, 24, and 48 h after collection. A computer-aided sperm analyzer system was used to evaluate sperm motility and velocity traits of semen at different hours. Data were analyzed using GenStat® statistical program with the General Linear Model procedure. Treatment means were separated using Fisher’s protected t-test least significant difference at a 0.05 level of significance. Our data revealed that semen diluted with AndroMed and EYC extenders significantly maintained a high percentage of sperm total motility (TM) at 3 h (84.3 ± 10.4 and 77.0 ± 19.0) and 6 h (79.9 ± 19.7 and 82.0 ± 6.5), respectively (P > 0.05). The Tris semen extender significantly decreased sperm TM after 48 h (28.5 ± 16.0) as compared with AndroMed (72.3 ± 4.8) and EYC (85.7 ± 13.3; P > 0.05). A high percentage of sperm moving progressively and rapidly was recorded on EYC (53.6 ± 16.4, 50.9 ± 5.4) at 48 h as compared with the AndroMed (25.8 ± 9.4, 38.7 ± 20.6) and Tris (7.1 ± 4.6; 11.3 ± 11.2) extenders (P > 0.05). For velocity parameters, no significant difference was observed on sperm with curvilinear velocity for the extenders at different hours of storage. The EYC significantly maintained sperm with straight-line velocity (58.0 ± 8.8) and average path velocity (73.6 ± 7.0) and sperm moving in straightness (78.4 ± 5.3) at 48 h as compared with AndroMed (34.9 ± 9.1; 58.0 ± 12.2; 60.6 ± 11.0) and Tris (25.8 ± 1.9; 43.2 ± 7.4; 60.7 ± 8.2) extenders (P > 0.05). In conclusion, the EYC extender provides better sperm motility and velocity traits up to 48 h without any detrimental effects.