Phenotypic Characterization of Guinea Pigs (Cavia porcellus) in the Middle belt of Ghana.

Abstract

This study was conducted to investigate the phenotypic characterization of Guinea pigs in the middle belt of Ghana. The study specifically looked at the socioeconomic characteristics of Guinea pigs farmers, production systems, morphological characteristics, the relationship between body weight and linear body measurements, as well as the cost of production. Two studies were conducted. The first study was a survey of Guinea pig farmers, while the second phase of the work was a performance evaluation experiment on the production of Guinea pigs. Fifty-four (54) Guinea pig farmers were interviewed using a semi-structured interview and questionnaire, and 310 Guinea pigs were sampled in the middle belt of Ghana using the snowball sampling method. In phase two (field experiment), fifty-four (54) Guinea pigs of about four (4) weeks old were reared for four (4) months for performance traits measurements in Goaso, Ahafo region. The effects of colour, location Sex and body measurements were analyzed and phenotypic correlations among the various body measurements were measured. A simple linear regression equation was used for body weight and linear body measurements. All data analysis was carried out using R statistical software version 4.2.1 and SPSS version 21.0. The results of study one showed that Guinea pigs with two (2) eye colours were found to be black and red, of which the black eye colour recorded the highest (91.61 %) value. Thirteen (13) colour categories were revealed. Black-brown-white had 34.84 % as the highest presentation, and greyish-brown and gold-black-white scored the same 0.32 % as the least. Four colour categories formed were monochrome, dichrome, trichrome and multi-chromatic. Out of the four colour categories formed, trichrome was the largest presentation of 51.29 % and multi-chromatic scored 4.84 % out of the entire sampled population. The effect of colour categories in Guinea pigs influenced significant (p ≤ 0.05) variation for head length, hind leg length and fore leg length. The body measurements of Guinea pigs in the study area were highly significant in terms of hind leg length and fore leg length (p ≤ 0.01), and the linear body measurements did have a significant effect (p > 0.05) on cavies. Also, both sexes did not have significantly different (p > 0.05) figures for all the linear body measurements. The highest correlation value (0.91) was between body length and heart girth, the second highest correlation figure of 0.87 was recorded between body weight and body length, and also among hind leg length and fore leg length. The least correlation value (0.21) was found between body weight and foreleg length. In respect to the simple linear regression equation, body length (BL), heart girth (HG), height-at-withers (HW), and head length (HL) were the best predictors of body weight in guinea pigs, with an R2 of 0.80. The best time to predict the body weight of a Guinea pig was in week 2. Provision of good production systems and management practices, such as pen, quality feed, watering and health care, contributed positively to the growth and reproduction of cavies. The birth weights of young Guinea pigs were between 85 - 110g, and weaned at 14 days with weights between 120-200g. Matured local Guinea pigs have an average body weight of 405.19 g at 90 days old. Indigenous Guinea pigs were small in size, with the Ahafo region being superior in body weight and linear body measurements. The production cost of raising one cavy from birth to maturity (90 days) was GH¢ 32.16 (US$ 5.53). However, the overall revenue from the sales of Guinea pigs yielded GH¢ 66.04 (US$ 11.35), with GH¢ 33.88 (US$ 5.82) as the profit on each animal. It was concluded that local Guinea Pigs in the middle belt of Ghana are moderate in size, have many colour categories, females are superior to males, have a high growth rate and prolific, and are easy to produce by classes of people, provide valuable food and income, require small capital to start and have an appreciable return on investment.