EFFECT OF AMBIENT TEMPERATURE AND CAGE ENRICHMENT ON THE PERFORMANCE AND SLAUGHTER YIELD OF RABBITS

Abstract

The effects of ambient temperature and cage enrichment on the performance, dressing percentage and carcass traits were studied in Botucatu rabbits. Forty-eight rabbits weaned at 35 days were housed, four per cage, either in a natural temperature chamber or in a refrigerated chamber, up to 70 days of age. In each chamber, half the cages had the floor partially enriched with straw. All cages were equipped with two feeders and two drinkers, one at each end. A completely randomized design with a 2 x 2 factorial arrangement was adopted. As sample size was relatively small due to the chambers physical limitations, differences with associated probability of type I error less than 0.10 (P<0.10) were considered significant. Average air temperature and relative humidity were: 20.6°C and 70.9% in the refrigerated chamber and 23.5° C and 78.1%, in the natural chamber. There was an effect of the temperature x enrichment interaction, but not of the main affects, on mean live weight from 35 to 70 days and on slaughter weight. In the natural chamber, weights were higher in the absence of enrichment (1,514 vs. 1,453 g and 2,066 vs. 1,951 g, respectively), whereas in the refrigerated chamber no difference between enriched and non-enriched cages was detected (1,529 vs. 1,491g and 2,065 vs. 2,000 g, respectively). Average feed consumption was smaller in the natural temperature chamber (107.3 vs. 116.2 g/ day), and also in the feeders located on the enriched side of cages (52.6 vs. 59.1 g/day), independently of the chamber. No effects of the interaction or of the main factors were detected on feed conversion, whose overall mean was 3.17. Relative weights of skin, distal parts of legs, thoracic viscera and kidneys were higher in the refrigerated chamber (263.0 vs. 251.4 g; 69.6 vs. 66.9 g; 26.7 vs. 22.6 g; and 11.4 vs. 10.7 g; respectively). Cage enrichment resulted in relatively heavier heads and less dissectible fat (127.0 vs. 122.9 g; 23.1 vs. 28.3 g; respectively). Cage enrichment with straw favors rabbit growth in amenable ambient temperature, but not when the temperature is higher. Its effect on the reduction of dissectible fat, however, deserves to be further investigated.