The frequency of collection and semen production in Muscovy ducks

1. Semen was collected by artificial vagina from 40 Muscovy drakes at frequencies of twice daily; once daily; once every 2 d; and once every 3 d for 24 consecutive days. 2. The total mean semen volume over a 24-d period increased linearly and significantly from 2-15 to 9 x 40 ml as the frequency of collection increased from once every 3 d to twice daily, but the average semen volume per collection decreased linearly and significantly from 1 x 07 to 0 x 78 ml. 3. The total number of spermatozoa produced by the drakes increased significantly as the collection frequency increased but became asymptotic at the higher frequencies. 4. Although twice daily collection gave the highest total semen volume, there was little difference between once daily and twice daily collection in the total yield of spermatozoa (10 x 206 x 10(9) versus 11 x 794 x 10(9). It seems that daily collection was the most efficient for production of spermatozoa for artificial insemination during the period under study.