131-139The present study was aimed to develop a most effective extender for long term storage of Labrador dog semen at 4oC. Tris-citric acid-fructose was supplemented with egg yolk (TEY), egg yolk plasma (TEYP), low density lipoproteins (TLDL) and coconut water (TCW) @10, 15 and 20; 10, 15 and 20; 11-15; and 25, 50 and 75 percent, respectively. Extended semen was stored at 4oC and analyzed for sperm attributes and lipid peroxidation. Values for motility, viability and plasma membrane integrity remained significantly (p < 0.05) higher in 15% TEY, 15% TEYP, 13% TLDL and 25%/50% TCW from 0 hr to 72 hrs of storage. It indicated superiority of 15% TEY, 15% TEYP, 13% TLDL and 25% /50% TCW over other concentrations for storage of Labrador dog semen at 4oC. A significant (p < 0.05) decline in motility, viability and membrane integrity was observed from 0-72 hrs of preservation in all extenders, but sperm attributes were still >50% at 72 hrs of preservation. Decline was comparatively less in 15% TEY, 15% TEYP, 25%/50% TCW and 13% TLDL compared to other concentrations. Values for acrosome integrity also differ significantly (p > 0.05) among different concentrations of extenders except TEY. Lipid peroxidation did not vary among different extenders except TEY. In conclusion, both 15% TEY and 15% TEYP were better than 13% TLDL and 25% TCW. TEY extender may be substituted with TEYP for preservation of dog semen at 4°C and further interventions may improve TLDL and TCW extenders
