EFFECTS OF HOLDING TIME AND TEMPERATURE ON PERFORMANCE IN COMMERCIAL BROILER-CHICKENS UNDER TROPICAL ENVIRONMENT

Studies were conducted for 8 weeks to assess the responses of commerci al broiler chickens to a pre-placement holding time of 48 h in chick b oxes at 19 and 26 degrees C. Two hundred and seventy imported chicks w ere involved in a completely randomized experimental design with three treatments at three replications each. The delayed placement treatmen ts produced significant (p < 0.05) reductions in pre-placement bodywei ght, gastrointestinal tract (GIT), liver and heart weights as well as blood sugar level. The concentration of sodium in the blood was signif icantly (p < 0.05) increased, while blood potassium was unaffected. Su bsequent feed consumption was depressed by both delayed placement proc edures during the first 2 weeks of age only. Similarly, reductions in live body weight of the birds persisted for 4 weeks, but at a decreasi ng rate, suggesting a waning effect of delayed placement with age. Per cent mortality was significantly (p < 0.05) increased by the pre-plac ement holding procedures only during the first week of age. Average da ily gain was significantly decreased during the second week, while hea rt and GIT weights were increased at the 8th week. Overall assessment showed that delayed placement of commercial broiler chickens for 48 h under tropical conditions did not produce any apparent enduring impair ment on subsequent performance traits at about market age.