RESUMEN

Utilizou-se o teste hiposmótico (HO) para estudar a capacidade de preservação da membrana plasmática do sêmen eqüino resfriado em diferentes meios. Estimou-se a correlação entre os resultados do teste HO e os exames de rotina aplicados ao sêmen, usando-se sêmen de sete garanhões. Cada ejaculado foi diluído em três meios, Kenney (K), Baken com 3% de gema (B3) e Baken com 10% de gema de ovo (B 10), e resfriado a 5°e. Avaliaram-se a motilidade total (MT), a motilidade progressiva (MP), o vigor espermático (V), a porcentagem de espermatozóides morfologicamente normais (NOR) e os resultados do teste HO no sêmen fresco e a cada 24 horas pós-resfriamento. A longevidade espermática foi considerada como o tempo de manutenção da motilidade espermática progressiva superior a 10% do sêmen diluído e resfriado. Maior longevidade espermática foi obtida nas amostras diluídas em meio B3. Os resultados do teste HO sugerem que os diluidores à base de gema de ovo preservaram melhor a membrana plasmática. Foram obtidos valores de correlação (P<0,05) entre o teste HO e a motilidade espermática (MT=0,57; MP=0,59), e correlação baixa entre HO e NOR (0,16).

Asunto(s)

RESUMEN

Utilizou-se o teste hiposmótico (HO) para estudar a capacidade de preservação da membrana plasmática do sêmen eqüino resfriado em diferentes meios. Estimou-se a correlação entre os resultados do teste HO e os exames de rotina aplicados ao sêmen, usando-se sêmen de sete garanhões. Cada ejaculado foi diluído em três meios, Kenney (K), Baken com 3% de gema (B3) e Baken com 10% de gema de ovo (B10), e resfriado a 5ºC. Avaliaram-se a motilidade total (MT), a motilidade progressiva (MP), o vigor espermático (V), a porcentagem de espermatozóides morfologicamente normais (NOR) e os resultados do teste HO no sêmen fresco e a cada 24 horas pós-resfriamento. A longevidade espermática foi considerada como o tempo de manutenção da motilidade espermática progressiva superior a 10% do sêmen diluído e resfriado. Maior longevidade espermática foi obtida nas amostras diluídas em meio B3. Os resultados do teste HO sugerem que os diluidores à base de gema de ovo preservaram melhor a membrana plasmática. Foram obtidos valores de correlação (P<0,05) entre o teste HO e a motilidade espermática (MT=0,57; MP=0,59), e correlação baixa entre HO e NOR (0,16).(AU)

The hypoosmotic test (HO) was used to evaluate plasmatic membrane integrity of equine chilled semen and to estimate the correlation between the results of the HO test and those from applied routine exams of semen. The semen of seven stallions was preserved at 5ºC in three different extenders. Each ejaculate was diluted in three extenders, Kenney (K), Baken with 3% of egg yolk (B3) and Baken with 10% of egg yolk (B10), and chilled at 5ºC. The total motility (MT), progressive motility (MP), spermatic vigor (V), normal spermatic morphology (NOR) and HO test were used to evaluate semen immediately after collection and at 24 hour-intervals. Spermatic longevity was defined as the time taken to the progressive motility to decline under 10%. Semen diluted in B3 had the best longevity. The results of the HO test suggest that extenders made with egg yolk preserved the membrane plasmatic. Correlation (P<0.05) between HO test and spermatic motility (MT=0.57; MP=0.59), and low correlation between HO and NOR (0.16) were observed.(AU)

Asunto(s)

RESUMEN

Semen characteristics of first and second successive ejaculates from 6 jacks were evaluated weekly for 12 mo. The semen was collected at 4-h intervals, using an artificial vagina with a female in either natural or induced estrus. The statistical analysis was done by factorial delineation 2 x 2 in randomized blocks. Due to some ejaculation failures, the data had to be divided into 2 Groups (A and B) for statistical analysis: Group A - ejaculates preceded by 2 ejaculates in the previous week and Group B - ejaculates preceded by only 1 ejaculate in the previous week. If no statistical difference was observed between the groups in a given parameter, the data was grouped together. Semen characteristics for the first and second ejaculates, respectively, showed the following mean +/- SEM: gel-free semen volume 29.2 +/- 2.2 and 31.7 +/- 2.2 ml; progressive motility 71.0 +/- 1.6 and 72.9 +/- 1.6%; sperm vigor 3.8 +/- 0.1 and 4.1 +/- 0.1; live spermatozoa for Group A 82.6 +/- 2.1 and 82.3 +/- 2.1%, and for Group B 84.6 +/- 1.4 and 86.6 +/- 1.4%; total number of spermatozoa for Group A 10.6 +/- 0.8 x 10(9) and 5.8 +/- 0.8 x 10(9), and for Group B 13.3 +/- 1.2 x 10(9) and 9.6 +/- 1.2 x 10(9); head abnormalities for Group A 1.2 +/- 0.3 and 1.4 +/- 0.3%, and for Group B 1.6 +/- 0.3 and 1.9 +/- 0.3%; mid piece abnormalities 7.7 +/- 0.7 and 6.1 +/- 0.7%; tail abnormalities 7.3 +/- 0.7 and 6.8 +/- 0.7%; pH 7.6 +/- 0.0 and 7.6 +/- 0.0. Significant differences (P < 0.05) were observed between the animals for all sperm characteristics except for sperm vigor. The means for the first and second ejaculates were significantly different (P < 0.05) for the total number of spermatozoa in all the animals, while the percentage of mid piece abnormalities was significantly different in only 1 jack. Seasonal effects on sperm parameters were observed only for semen pH.

RESUMEN

The courtship of 5 jacks was evaluated weekly for 12 mo. The characteristics of sexual behavior were recorded before the collection of 2 ejaculates, at 4-h intervals, into an artificial vagina in the presence of a female in either natural or induced estrus. The maximum time given to the jack to perform the ejaculatory mount was 1 h. If the jacks did not ejaculate, another attempt was made the following week. At the time of collection, the male and female remained free in a paddock (20 m2). The data presented in this study is based on results in which the first and second ejaculates occurred successively. Statistical analysis was done by a 2 x 2 factorial design in randomized blocks. The mean +/- SEM of sexual behavior characteristics for the first and second ejaculate were, respectively: time until first mount = 0.7 +/- 0.2 and 0.9 +/- 0.2 min; time until first erection = 11.9 +/- 1.1 and 11.6 +/- 1.1 min; time until ejaculation = 15.0 +/- 1.2 and 13.6 +/- 1.2 min; frequency of partial exposure of penis = 3.4 +/- 0.4 and 3.2 +/- 0.4; frequency of total exposure of penis = 1.0 + 0.2 and 1.1 +/- 0.2; frequency of flehmen responses = 6.6 +/- 0.5 and 4.6 +/-0.5; frequency of erections = 1.3 +/- 0.1 and 1.2 +/- 0.1; frequency of retreats away from the female = 1.8 +/- 0.2 and 1.0 +/- 0.2; frequency of mounts with erection but without ejaculation = 0.3 +/- 0.1 and 0.1 +/- 0.1; frequency of mounts without erection = 2.0 +/-0.1 and 1.2 +/- 0.1 ; and frequency of pelvic copulatory movements = 4.8 +/- 0.4 and 4.4 +/- 0.4. Individual differences were observed (P<0.05) for partial and total exposure, flehmen responses, mounts without erection and pelvic copulatory movements. The variables flehmen responses, retreats away from the female and mounts without erection showed significant differences (P<0.05) between ejaculates. Seasonal effects on sexual behavior characteristics were not found. However, a monthly effect was noted for flehmen responses, partial exposure of the penis, mounts without erection, retreats away from the female and pelvic copulatory movements when the 2 ejaculates were combined.