Journal of Applied Biosciences (J. Appl. Biosci.) [ISSN 1997 - 5902]
Volume 55: 4028 - 4035. Published July 27, 2012.
Determination of grasscutter age (Thryonomys swinderianus, Temminck 1827) based on morphometric characters.
1SACRAMENTO Tèniola Isabelle, 2AIZOUN Frédéric, 2SINABARAGUI Olivier Sourokou, 2FAROUGOU Souaïbou, 2YOUSSAO Issaka, 3MENSAH Guy Apollinaire, 1*ATEGBO Jean-Marc
1Department of Animal Physiology, Faculty of Science and Technology, University of Abomey-Calavi, BP 526 Cotonou, Benin.
2Department of Animal Production and Health, Biotechnology Research Unit of Production and Animal Health, Polytechnic School of Abomey-Calavi, 01 BP 2009 Cotonou, Benin
3National Institute of Scientific Research, Research Center of Agonkanmey, Abomey-Calavi.
ABSTRACT
Objectives: In order to determine the grasscutter (Thryonomys swinderianus TEMMINCK, 1827 age, in Benin, a study was conducted on some of its morphometric characters such as Body Length (LTC), Tail Length (LQ), Ear Length (LO), Hind leg Length without Claws (LPPG), the Neck Perimeter (PC), Head Perimeter (PT), Chest Perimeter (Pth) and Body Weight (BW).
Methodology and Results: In this study, 202 male grasscutters aged from 2 weeks to 12 months were used. A strong correlation was obtained firstly between the different characters with a determination coefficient ranging between 0.764 and 0.968.alsoA between the animal age and these characters was a determination coefficient ranging between 0.858 and 0.98. The best age prediction equation in males with a single character, given by Simple Linear Model (SLM) was: Age = 1.094 + 0.013 PV, with R2 = 0.96; with two characters is: Age = - 10.162 + 0.078 LQ + 0.009 PV, with R2 = 0.98; with three characters is: Age = -9.981 + 0.006 LTC + 0.072 LQ + 0.009 PV with R2 = 0.98. The best obtained by Generalized Linear Model (GLM) with a single character was: Age = exp (-2.069 + 0.020 Pth) with AIC = 1053.2; with two characters is: Age = exp (- 1.458 + 0.006 LQ + 0.011 Pth), with AIC = 1016.6; with three characters is: Age = exp (-1.170 + 0.001 LTC + 0.006 LQ + 0.010 Pth) with AIC = 1017.
Conclusions and application of findings: Prediction equations developed can be used to estimate grasscutter age based on linear body measurements (LTC, LQ, LO, LPPG, PC, PT, Pth) and body weight (PV). The classification of equations in order of reliability for the two models used appears that the more equation expresses age based on several characters, the more reliable it is.Breeders, veterinarians and rural supervisors can use the equations found in this study to determine grasscutter age for better breeding, monitoring and management..Researchers can also use these equations to determine the age of game and for rearing grasscutter
Keywords: Grasscutter, morphometric characters, Age Estimation, Correlation, Regression Model, Prediction equations, Benin
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