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Sheep - AgRIS

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containing diluents enriched with additives did not show results better than milk diluent alone<br />

and Cornell University Externder. Keeping quality of ram semen in these diluents showed<br />

significant seasonal variations but generally superior values of motility could still be observed<br />

in spring, rainy and autumn season. Effect of higher dilutions (1: 10 to 1 :100) in these diluents<br />

upto 72 h of storage interval showed that there has been deterioration in keeping quality of ram<br />

semen with the increase of dilution rates beyond 1:10 and effect was more pronounced in egg<br />

yolk citrate as compared to glycine yolk and Cornell University Extender diluents on storage at<br />

5-7°C upto 72 h. However, Tiwari, et al. (1968) observed better survival upto 30 h in dilution<br />

rates varing from 1:3 to 1:10 depending upon the room temperature in different seasons it could<br />

be possible to utilise diluted semen within 34 h after collection and dilution for artificial<br />

insemiantion and glucose saline without egg yolk may be used for dilution of semen to be<br />

utilised quickly within 2 h of storage at 30°C.<br />

Ram semen preservation studies (Sahni and Tiwari, 1972), were further carried out, on<br />

efficacy of the dilution rates, storage temperature, additives, semen container storage media,<br />

cooling rates etc. Results revealed higher spermatozoal survival in egg yolk citrate glucose<br />

diluent (EYCG) as compared to EYC, heated cow milk, milk + egg yolk at 8, 24, 48,72 h of<br />

storage interval. Irrespective of storage media, (refrigerator, semen shipper) and the diluents<br />

higher spermatozoal survial have been observed in glass screw capped vials. Out of all the<br />

diluents testes, EYCG gave higher satisfactory results at different storage interval which was<br />

mainly due to better buffering capacity of the diluent. Further studies were then confined to the<br />

EYCG diluents only. Significant differences were observed in percent spermatozoal survival<br />

and pH duet to variation in nurnber of live and normal spermatozoa (25-400xl0 6 ) in 0.1 ml of<br />

diluted semen. However, such differences were non-significant upto 24h of storage intervals<br />

and irrespective of number of live sperrnatozoa per inseminating dose (0.1 ml) about 70-80 per<br />

cent sperm motility have been observed upto 24 h of storage interval. This shows that<br />

concentrated ram semen could be stored successfully upto 24 h and could be utilized for<br />

breeding operations. Indigenous rams did not differ among themselves in relation to<br />

spermatozoal survival. However, difference between breeds was found to be significant.<br />

Indigenous and halfbred rams showed relatively higher sperm survival than exotic rams at each<br />

storage. interval. Differences between Rambouillet and Soviet Merino were nonsignificant.<br />

Addition of 1,3 and 5 per cent gelatine and polyvenyle alcohol in EYCG diluent did not provide<br />

significant beneficial effect on spermatozoal survival and pH during storage.<br />

In other studies carried out by Singh and Saxena (1965) and Saxena and Singh (1967) it<br />

has been observed that motility and percent live sperrnatozoa was highest in skim milk yolk<br />

followed by egg yolk glucose bicarbonate diluent than EYC and CUE upto 168 h of storage at<br />

3°C. However, during storage there was no automorphological changes in sperrnatozoa as<br />

reported earlier in EYC diluent upto 72 h of storage, (Joshi and Singh, 1968a,b,c) in a<br />

comparative study on the efficacy of the diluents have reported higher sperm survival in yolk<br />

containing diluents enriched with fructose, tomato juice and glycine, skim milk diluent<br />

containing yolk, glucose or fructose. Beneficial effect of caproic acid on sperm motility during<br />

storage has been observed by Honmode (1972).<br />

Sahni and Roy (1972c) studied the effect of deep freezing (79°C) on post thawing revival<br />

of sheep and goat sper natozoa using various levels of glycerol, different equilibration time and<br />

rate of freezing in EYC and cow milk diluent. The post thawing survival varied from 10-14<br />

percent in different trials and considerable variation between rams with respect to freezability<br />

was noted.<br />

The efficiency of EYCG was further compared with diluents prepared from some known<br />

buffers by Tiwari et al. (1978). Out of many, the percent motility and live spermatozoa was<br />

relatively better in diluents prepared form the Mcillvain and Tris buffer containing yolk and<br />

glucose similar to that of EYCG. Over the above in better survival, the most common<br />

characteristics in these diluents were the absence of sperm clustering (Sperm agglutination)<br />

which was about 20-30 percent in EYCG at 24 h of storage and also relatively better buffering<br />

capacity. This shows that these diluents might be able to give better fertility as compared to<br />

EYCG diluent.<br />

Factors affecting long term preservation are:<br />

408

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