Global Advanced Research Journal of Agricultural Science
June 2012 Vol. 1(6), pp. 148-155
Copyright © 2012 Global Advanced Research Journals

Full Length Research Paper

Phenotypic and genetic parameter estimates for grasscutter production traits. 1. (Co) variance components and heritability

S.Y. Annor^1,2,4#, B.K. Ahunu², G.S. Aboagye², K. Boa-Amponsem³ and J.P. Cassady⁴.

¹Department of Animal Science Education, College of Agriculture Education, University of Education, Winneba, P.O. Box 40, Mampong-Ashanti, Ghana.

²Department of Animal Science, College of Agriculture and Consumer Sciences, University of Ghana, P.O. Box LG 571, Legon, Accra, Ghana.

³Animal Research Institute, Council for Scientific and Industrial Research, P.O. Box AH 20, Achimota, Accra, Ghana.

⁴Department of Animal Science, College of Agriculture and Life Sciences, North Carolina State University, Campus Box 7621/232B Polk Hall, Raleigh NC 27695-7621, North Carolina, USA

Corresponding Author E-mail: sayannor@yahoo.com

Accepted 25 June, 2012

Abstract

The objectives of this work were to estimate genetic variation and heritability of traits in the Thryonomys swinderianus. The study was conducted at the grasscutter section of the Department of Animal Science Education, University of Education, Winneba, Ghana, from 2005 to 2010. Data were obtained from a random mating population and consisted of records of 502 kids born by 136 does and 40 sires over a period of 5 years. Data were analyzed by mixed model methodology using a full animal model and all known genetic relationships, in single trait analysis, using the MTDFREML programme. Body weight and growth rate showed the greatest additive genetic variation, with reproductive and survival traits, and feed intake showing relatively low additive genetic variation. Most traits had moderate maternal genetic variation. Body weight and growth rate had medium to high direct heritability (0.30-0.84). Medium direct heritability was obtained for feed intake (0.30) and feed efficiency (0.38). All reproductive traits, apart from those associated with weight, and survival traits had low direct heritability (0.02-0.06). Maternal heritability for most traits were low to high (0.13-0.99). Direct-maternal genetic correlations for traits was low negative to high negative (-0.01 to -0.95). Based on the results it was concluded that opportunity exists for fast genetic gains in the improvement of growth and body weight traits, whilst slow genetic progress may be made in reproductive and survival traits. It was also concluded that maternal effects are important in the glasscutter, and must be accounted for in breeding value estimations.

Keywords: Thryonomys swinderianus, cane rat, rodent, phenotypic and genetic parameters, domestication