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Abstract
| 1. | From 1992 to 2003, selected (S) and control lines (C) of the laying Brown Tsaiya duck (Anas platyrhynchos) were simultaneously maintained under the same standardised conditions of feeding and management. | ||||
| 2. | The selection objective was to increase the number of fertile eggs after a single artificial insemination (AI) with pooled Muscovy semen. From generations G1 to G11, 2452 and 2022 female ducks, in S and C lines, respectively, were measured and recorded. In the S line, the percentage selected varied between 20·2 and 34·3% in females and between 7·2 and 20·8% in males. | ||||
| 3. | Selection for number of fertile eggs had a correlated effect of increasing the parameter τ of the logistic curves which fitted the daily variations (d 2 to 15) in fertility or hatchability on the basis of eggs set. The differences S − C for the estimates of the times of half maximal fertility and hatchability increased by 0·41 and 0·37 d per generation between G1 and G11, respectively. | ||||
| 4. | The highest increases of fertility per day rates after a single AI were observed between d 5 and 11. Moreover, in the selected line, fertility rate was higher than, or equal to, 90% in d 2 from G8. The same tendencies were observed for the changes in the evolution of hatchability on the basis of eggs set. | ||||
| 5. | Selection increased fertility and hatchability according to the egg set rates, especially for d 2 to 8 after AI. Hatchability of fertile eggs was not impaired, confirming that selection for one AI per week was possible in this strain of laying ducks. | ||||
Acknowledgements
The selection experiment was started in 1992 and carried out as a cooperative research programme between the Livestock Research Institute, Council of Agriculture (LRI-COA) and the Institut National de la Recherche Agronomique, Station d’Amélioration Génétique des Animaux du Département de Génétique Animale (INRA-SAGA). We would like to thank all staff at LRI-COA and INRA-SAGA for their help in carrying out this research, and the National Science Council (NSC81-0409-B-061-504; NSC82-0409-B-061-016; NSC84-2321-B-061-004; NSC85-2321-B-061-002; NSC86-2321-B-061-005) and LRI-COA for their financial support.