Fertility of Ryujin-Jidori under different light treatment schemes
2019
Itami, T. (Livestock Experiment Station, Wakayama Prefecture, Hidaka-Gun (Japan). Laboratory of Poultry) | Hashimoto, N. | Matsui, N.
The goal of this study was to determine the effects of light treatment (forced turning) on the fertility of "Ryujin-Jidori" chickens. The Ryujin-Jidori chickens were raised in a cage within a windowless poultry house and allocated into one of 12 breeding groups (I to XII; 337-1665 days old), according to age. Light treatment was carried out as follows: October 10-11, 2016, 14 h light period; October 12-14, decreased by 1 h per day; October 15-November 7, 10 h light period; November 8-10, increased by 1 h per day; November 11 onward, 14 h light period. Egg laying had stopped in all groups by October 17, 2016. The indoor temperature and egg production rate between November 22, 2016 and April 30, 2017 were monitored. Furthermore, we determined the fertilization rate and hatching rate from November 22-December 5, 2016 and April 17-April 30, 2017. The egg-laying rate peaked in December in each group, and gradually decreased thereafter. In groups with young females (I-III), egg laying was continuous, and a maximum egg production rate exceeding 70% was observed. In six groups (VII-XII), egg laying stopped during the investigation period; particularly, the egg production rates in groups IX-XII did not exceed 20%. The fertilization rate was over 50% in two groups (I and II) in 2016, and over 80% in all groups in 2017. The hatching rate was over 45% in these groups in 2016, and over 87.5% in two groups (I and V) in 2017. Males were fertile up to 1420 days of age; however, in females, the hatching rate declined after 1129 days of age. Both the fertilization rate and hatching rate were high in 2017. We believe that the results of this study will help the continued preservation of the Ryujin-Jidori chicken breed.
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