Objectification of methods for quality prediction in boar semen

The relations between spermatozoa membrane resistance, evaluated by means of the osmotic resistance test (ORT), and respiratory activity in boar semen (ZO2), determined by the polarographic method, were tested. Both studied parameters were evaluated in regard to preservation ability and survival of spermatozoa diluted in the ratios 1:2 and 1:4 by the dilution medium DISURIN. The ejaculates of three boars of the White Meaty breed at the age of 24 months were evaluated. They were collected 11 times in successive order once a week. Besides the basic spermatologic parameters there was also evaluated the respiratory activity using the oxygen detector of Clark's type. ZO2 expresses O2 consumption in micro l of 10** (8) spermatozoa per hour at 37 deg C (Redenz, cit. Mann, 1964). The osmotic resistance test (ORT) was performed by a method described by Schilling and Vengust (1985). It expresses the average proportion of spermatozoa with NAB (normal acrosomal border) during incubation in isotonic solution (300 mOsm.kg** (-1)) for 15 minutes, and in hypotonic solution (150 mOsm.kg** (-1)) for 120 minutes. Each ejaculate was soluted at the same time in ratios of 1:2 and 1:4 with the dilutant DISURIN with added Ampicilin (250 mg/l). The survival of diluted semen was evaluated at intervals of 24, 48, and 72 hours by thermic test after 15, 60, 180 and 300 minutes of incubation at the temperature of 39+-0.5 deg C. Basic parameters of the fresh semen after collection are given in Table I. ZO2 value represented 3.5 micro l with ORT 58.5 %. No significant differences in survival were observed between the dilution ratios in spite of apparently higher values with lower dilution ratio (Table II). Statistically significant correlations were calculated between ZO2 and ORT (r=0.50) as well as between these parameters and survival in thermic test (Table III). These results document that the values of ORT and ZO2 of fresh semen are in significant mutual correlation, as well as in correlation to survival of insemination doses of the tested boars irrespective of the semen dilution degree. Therefore it is supposed that the values ZO2 and ORT can objectify the evaluation of boar semen quality and predict its preservation ability on the level of calculated correlation coefficients. Higher reliability of the estimate is achieved with both tests applied at the same time.