| dc.description.abstract | A study was carried out to assess the performance, cost of production and carcass characteristics of New Zealand White (NZW), California White (CAL) and NZW x CAL crossbreed (ZxC) growing rabbits under two feeding regimes (Concentrate based diet and forage based diet supplemented with varying amounts of the concentrate). The parameters assessed were feed intake, weight gain, time taken to reach the average market weight of 2kg and the cost of weight gain. Twenty females of each NZW and CAL breed were mated to obtain the purebreds litters. To obtain the crossbreed (Z×C) litters, another 20 NZW females were mated with CAL males to produce 60 litters with a target of 360 kits for the two feeding levels study. The experimental animals were recruited at weaning done at (6) weeks of age. A completely randomized design (CRD) with a 3 × 2 factorial arrangement of treatments (two genetic groups plus their cross) and two feeds (Concentrate or forage based diet) was applied with the breed and feeding regime as the treatments. At the end of the feeding experiment, 30 rabbits, 5 from each breed and feeding system were slaughtered and the carcass characteristics evaluated. The parameters assessed were live weight at slaughter, dressed weight, drip loss, meat to bone ratio, carcass fat and internal organs weights. The animals on concentrate based diet reached the 2 kg target weight faster (12 weeks) than those on forage based diet (17 weeks). The crossbred rabbits also attained the 2kg target weight 1 week and 2 weeks earlier than the purebreds under the concentrate and forage based diets respectively. The total feed intake was lowest (P < 0.05) for the Z×C group under both feeding regimes explained by the shorter time to the market weight of 2kg. The daily weight gain across
the breeds was not significantly different (P > 0.05) within a feeding regime and ranged between 23 to 36gd-1 for concentrate based diet and 10 to 30gd-1 for forage based diet. The FCR ranged from 3.97 to 4.82 and 6.27 to 7.39 under the concentrate and forage based diets respectively and was significantly different (P < 0.05) across the breeds for concentrate based diet. The rabbits dressed at weights ranging from 1061 to 1294g and weight of internal organs did not differ (P>0.05) across the breeds, between or within the feeding regimes. Of the other carcass parameters only dressing percentage, full gut, perirenal fat and the drip loss were different (P<0.05). The estimated total cost per unit weight gain (N kg–1 gain) differed significantly (P < 0.05) within breeds and between the feeding regimes and was higher on the concentrate based diet at Sh.213.3, Sh.187.7 and Sh.178.4 for NZW, CAL and Z×C respectively. The respective cost with the forage based diet were Sh 167.7, 178.7 and 155. Though production costs were higher on the concentrate based diet, the economic returns were also significantly higher due to an improved off-take. The conclusions from the study were that the crossbreed was better for meat production regardless of the feeding regime and carcass characteristics of the rabbits were similar when slaughtered at the same weight of 2 kg. | en_US |
