THE INFLUENCE OF BREED, AGE OF BOARS AND EXPLOITATION SEASON ON THEIR LIBIDO IN CONDITIONS OF THE INSEMINATION STATION
In this study it was defined the influence of breed, age and season on libido of boars exploited in insemination station. It was found that libido of hybrids (Duroc x Pietrain), (Pietrain x Duroc) and PIC is indeed higher than that of pure breed boars Pietrain, Duroc, wbp and pbz. Boars of Pietrain and pbz breed showed changes of sexual activity according to the exploitation season. Libido of boars was significantly higher in summer and autumn. The reaction of breeders to phantom in mention seasons was 2,75 min. The fastest reaction to phantom (2,4 min.) and the indeed shortest time to start ejaculation (4,6 min.) comparing to remaining age groups was shown by boars in ages above 36 months. Specimen in this age group didn’t shown any significant changes in sexual activity in each exploitation season. Received results can find use in practice. The acquaintance of boar’s libido will permit on his rational exploitation and improvement of organization of collecting the semen.
The effect of season on semen parameters in cross-bred boars and phenotypic correlations between semen characteristics in different seasons
The study evaluated ejaculates of cross-bred boars produced by reciprocal crossbreeding of the breeds Duroc and Pietrain, as well as the effect of the season of the year on qualitative and quantitative parameters of the semen of these boars. Phenotypic correlations between semen characteristics in particular seasons of the year were estimated as well. The analysis included a total of 1156 ejaculates from 2-year-old boars, collected manually at 3-4-day intervals. The following traits were evaluated: ejaculate volume (ml), sperm concentration (x106 x ml-1), percentage of live sperm (showing progressive motion) (%), total number of live sperm in the ejaculate (in billions), number of sperm per insemination dose, and the number of insemination doses obtained from one ejaculate. No significant differences were noted in the semen characteristics of boars produced by reciprocal cross-breeding of the Duroc and Pietrain breeds. The season of the year significantly affected the characteristics of the ejaculates. Ejaculates collected in the spring had the greatest volume, while the highest sperm concentration and sperm count were noted in the ejaculates collected in the autumn and winter. The volume of the ejaculates decreased substantially in the summer, together with the sperm count, resulting in fewer insemination doses obtained per ejaculate. The value of the phenotypic correlations between semen characteristics was not significantly affected by the season of the year.
Male sex behavior and testosterone concentrations in gilts administered testosterone propionate.
Two gilts were administered testosterone propionate and their subsequent plasma testosterone concentrations and male sex behavior were recorded. These were compared to testosterone concentrations and male sex behavior in boars. Testosterone propionate (75 mg) was administered to the gilts every other day for 20 days (induction scheme) and every 10 days there-after (maintenance scheme). Concentrations of testosterone in plasma were elevated to concentrations detected in the boars during the induction scheme. During the maintenance scheme, concentrations of testosterone appeared to be lower than in boars. At 20, 30 and 40 days following the first injection, sniffing, nosing and mating song behaviors were exhibited by the testosterone treated gilts similar in frequency to the boars. Mounting behavior was first detected 30 days following the first testosterone propionate injection, and by day 40, the frequency of mounting was greater than observed in boars.