INFLUENCE DU RYTHME DE RÉCOLTE SUR LA PRODUCTION DE SPERMATOZOÏDES CHEZ LE JEUNE BÉLIER ROMANOV

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Abstract
The influence of an increase of the frequency of collection on the concentration, volume and total number of spermatozoa of the ejaculates obtained from 4 Romanov ram-lambs was studied. The animals, born Feb. 8-10, 1972, were trained to the A.V. (artificial vagina) from the age of 5.5 mo. Aug.) and semen was regularly collected weekly at different frequencies according to their age. The effect of the season on the testicular development was also studied using measurement of the maxiumum antero-posterior diameter of the testicles between the age of 12-18 mo. (Feb.-Aug.). The mean monthly ejaculate volume (1st or 1st and 2nd ejaculate) increased regularly irrespective of the rhythm of collection. Its progression was closely related to that of the physical development (r = 0.91). The concentration and the total number of spermatozoa increased significantly during the 4 wk after changing of frequency of collection, from 2 to 4. When the frequency reached 6 ejaculates/wk, these 2 characteristics were not significantly modified. The mean weekly sperm output was multiplied by 2.39 and 1.52 when the frequencies of collection were increased from 2 to 4 and 4 to 6. With 6 ejaculates/wk, sperm production reached 30.28 .times. 109 spermatozoa. The antero-posterior diameter declined from Feb. to June (6.47 cm to 5.90 cm, P > 0.05) and increased thereafter. Increasing the frequency of collection produced in the Romanov ram a more than proportional elevation of the sperm output in subjects trained to the A.V. At the age of 12-18 mo., sperm production depended upon the influence of photoperiodism. This influence was less important than that observed in the adult.

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