Repeatability Estimate of Egg Weight, Egg Number and Body Weight of Tortoise (Pelusios casteneus) Breeds in Lowland Ecological Zone, Nigeria

Abstract

The study was conducted to determine the repeatability estimate of Egg Number (EN), Egg weight (EWT) and body weight (BWT) in tortoise (Pelusios casteneus) were estimated based on daily basis for EN and weekly basis for EWT and BWT.  Tortoises were measured from 32 to 52 weeks of rearing period. A total of fifty (50) tortoises were purchased from rural farmers for the study. The tortoises were reared on the deep litter and fed ad libitum with concentrate feed, clean and cool water. At end of 52 weeks of age, data collected on EWT, BWT and EN were analyzed for fixed effect of repeatability estimate. The result reveals a range from 0.071 to 0.084, 0.084 to 0.096 and 0.075 to 0.084 for EWT, BWT and EN, respectively. Therefore, the repeatability for entire estimate for egg traits varies from 0.070 to 0.096. There is inconsistent increase and decrease in the repeatability estimate for the traits as laying age progressed. However, there is low repeatability in general for all the traits implying that the tortoises are not productive. Also, the expected relative genetic gain increases with increasing number of records used on all individuals at all ages. The decrease in the repeatability of each trait indicates that more records will be required to adequately characterize the inherent transmitting capacity of the females as laying age progresses. However, increase in the repeatability implies that fewer records will be adequate to characterize the inherent producing ability of the female’s tortoise.