The present study was designed to evaluate the longevity of canine cauda epididymal sperm in vitro at 40C. The testes were collected from 30 mixed breed dogs of average weight of 20-25Kg,presented to the clinics for sterilization. The testes were stored at 40C in normal saline in a refrigerator.The sperms were collected from the epididymis at different intervals of time (0, 4, 8, 12 and 24 hr) by taking 6 testes in each interval of time. The sperm quality was accessed at different intervals of time.The data analysed was analysed by ANOVA and the significant level was 5% (P= 0.05). The sperm concentration at different interval of time and storage at 40C did not show significant difference. On the other hand the sperm motility revealed significant difference between all the time intervals of sperm collection except at 8 and 12 hr of collection. There was significant difference of live sperm (%) at different intervals of sperm collection except at 8-12 hrs of sperm collection. The percentage of normal sperms was significantly different in between 0 to 24 hr interval of time but there was no significant difference either at 4 and 8hr or 12 and 24 hr of sperm collection. The acrosomal integrity was found statistically significant between 0-24 hrs of sperm collection and storage at 40C. There was significant difference in percentage of hypo- osmotic swelling between 0 hr (66.67 ± 2.11%), 4 hr (40.50 ± 6.21%), 8 hr (26.27 ± 2.25), 12 hr (11.50 ± 1.38%) and 24 hr (6.67 ± 1.05%). However, there was no difference between 8 and 12 hr of sperm collection from testes and storage at 40 C. The study concluded that the cauda epididdymal spermatozoa can be effectively stored and utilised for the purpose of assisted reproductive technology during emergency. These findings can be applied to the endangered wild canines and felines.

In the conditions of the Republic of Belarus there was analyzed the influence of the following paratypical factors on cow productive longevity: age of the first calving; milk yield at the first lactation; and a birth season. At the experimental animals there studied the indices of dairy efficiency: a lifelong milk yield (kg); a lifelong yield of dairy fat (kg); the total duration of the lactation period (days); duration of practical use (lactations). There was noted a tendency of increasing of a term of productive use and lifelong productive efficiency at the animals the practical economic use of which was begun in later terms. The insemination of these animals was approximately realized at the age older than 21 months. Also it was stated that in accordance with all investigated indices (except for a milk yield per one day of lactation) the highest indexes were typical for cows which had the least milk yield at the first lactation.

In the article showed results of the researches of the influence on productive longevity of cows of such factors, as a linear belonging, a genotype of the father, type of selection are stated. The lead researches have shown, that more longer duration of use characterized the animals belonging to line Siling Trajdzhun Rockit 252803 - 4,5 lactations. Among daughters of various bulls the greatest term of productive use daughters of the bulls the Silach 158 - 5,0 lactations differed. At the maximal deviation in efficiency of ancestors (6001-7000 kg of milk) longevity of their daughters was the greatest and has made 4,18 lactations. The greatest influence on duration of economic use of cows was rendered by specific features of bulls (32,2%) and a linear accessory -12,0%. While the selection variant practically does not influence longevity of animals - a share of influence of 3,7%