International Journal of Animal and Veterinary Advance 2(1): 26-30, 2010 ISSN: 2041-2908 © Maxwell Scientific Organization, 2009 Submitted Date: November 26, 2009 Accepted Date: December 09, 2009 Published Date: February 10, 2010 Corresponding Author: Anil Joshi, Division of Animal Physiology and Biochemistry, Central Sheep and Wool Research Institute, Avikanagar, via Jaipur, Rajasthan-304501, India 26 Comparative Semen Evaluation of Malpura and Bharat Merino Rams by Computer-aided Sperm Analysis Technique Under Semi-Arid Tropical Environment Davendra Kumar, Anil Joshi and S.M.K. Naqvi Division of Animal Physiology and Biochemistry, Central Sheep and Wool Research Institute, Avikanagar, via Jaipur, Rajasthan-304501, India Abstract: The present study was conducted to compare sperm motion characteristics of adult Malpura and Bharat Merino rams by the computer-aided sperm analysis (CASA) technique. Malpura is a hardy native sheep breed of the semi-arid tropical environment and Bharat Merino is a crossbred evolved in the same environment by crossing native sheep with exotic rams. Semen was collected from 8 donor rams of each breed at the onset of autumn season on 5 occasions at three days interval. The data were analyzed by analysis of variance using the general linear model repeated measures procedure. The CASA parameters which differed significantly (p<0.05) between the breeds were rapid motile sperm, medium motile sperm, slow motile sperm, linearity, straightness, curvilinear velocity, average path velocity, straight-line velocity, amplitude of lateral head displacement, beat frequency, sperm head area and sperm head elongation with higher values in all traits in Malpura breed. The semen volume and sperm concentration were higher in Bharat Merino breed but the differences were not significant. The body weight of rams had significant (p<0.05) effect on mass motility, curvilinear velocity and amplitude of lateral head displacement. The mass motility was higher in rams of more than 50 kg body weight while curvilinear velocity and amplitude of lateral head displacement was higher in rams of less than 50 kg body weight. A significant (p<0.05) influence of age of rams was observed on linearity and amplitude of lateral head displacement. The linearity was higher in rams of less than 3.5 years of age whereas amplitude of lateral head displacement was higher in rams of more than 3.5 years of age. In conclusion, CASA derived sperm motion characteristics revealed that the semen quality of native Malpura rams was better compared to crossbred Bharat Merino rams during major breeding season in a semi-arid tropical climate. Key words: Bharat berino, breed, computer-aided sperm analysis, malpura, semi-arid climate and sheep INTRODUCTION Sheep farming plays an important role in agrarian economy by providing a major source of livelihood to large number of small, marginal and landless farmers in hilly, arid and semi-arid regions of India. Malpura is a hardy native sheep breed of the semi-arid tropical environment and is reared for wool and mutton production. Breed characteristics of Malpura sheep have been reported under farm (Arora et al., 1975; Acharya, 1982) and field conditions (Mehta et al., 1995). Mishra et al. (2005) have compiled in-depth information on genetic attributes, reproduction and production performance characteristics of this breed. Malpura ewes have been used for developing a prolific germplasm by introgression of fecundity gene (FecB) via artificial insemination (AI) using semen of small sized rams of prolific Garole sheep of West Bengal (Naqvi et al., 2002; Sharma et. al., 2004). Bharat Merino sheep has been evolved for fine wool production by crossbreeding native ewes (Nali, Chokla, Malpura and Jaisalmeri) with exotic Rambouillet/Soviet Merino rams and stabilizing the population at 75% exotic inheritance (Singh et al., 2006). The Bharat Merino sheep has shown potential to perform well under semi-arid and sub-temperate agroclimatic conditions in India and act as a promising import substitute for exotic fine wool breeds expressed in terms of growth, reproduction, survivability and wool quality at par with exotics (Singh et al., 1999; Dixit et al., 2002). Genetically superior rams of these breeds are in great demand by the sheep owners and developmental agencies for improvement of farmer’s flocks by natural mating. AI is an important management tool for optimizing production performance and maximizing the use of high value rams. One important element for selection of breeding rams for either natural mating or AI relies on semen quality evaluation. Subjective evaluation of semen quality attributes is simple but do not provide accurate estimates for correlating it with fertility (Rodriguez- Martinez, 2003). Computer-aided sperm analysis (CASA) quantifies wide range of parameters of sperm motility and provides a rapid and objective method for assessing the motility of ram spermatozoa (Joshi et al., 2003; Kumar et al., 2007; 2009). The aim of the present study was