The effect of stocking density on the performance and economic implications for broilers grown to 42 days in open sided house in Trinidad. (170)
Keywords:Marginal physical product, marginal value product, carcass yield, physiological parameters, humid tropics
AbstractStocking density used by broiler farmers in Trinidad with open- sided house was 0.1 m²/ bird ranging from 0.08 to 0.13 m²/ bird. Three stocking densities, were compared T1 (0.07 m2/bird), T2 (0.1 m2/bird) and T3 (0.14 m2/bird) to determine the effect of stocking density on broilers reared under Trinidad conditions. A total of 3000 commercial day-old (Abor Acres x Ross) broiler chicks obtained from a single broiler breeder flock grown in Trinidad were used for the study. Body weight (BW), feed conversion (FCR), and mortality were not significantly affected (p>0.05) by treatments at 0-7 days. BW ranged from 164g to 180g and BW values for 0-21 day period ranged from 595g to 722g. BW, FCR and mortality at 42 days were not affected (p>0.05) by stocking density. There was a significant reduction in feeding intake with increasing stocking density for both 0-21 days (p=0.007) and 0-42days (p=0.003). Response of feed conversion to stocking density gave a significant quadratic response (p=0.000, R2= 0.871) and indicated that 87 % of the variation of the feed conversion was explained by changes in the space allocated per bird. The result indicated that a stocking density of 0.105 m2 per bird would maximize the feed efficiency. Rectal temperature in the afternoon increased with increasing stocking density (p = 0.001). Stocking density had no effect on haemoglobin (Hb) (p =0.445), haematocrit (Hct) (p=0.457), or MCHC (p=0.813). Ca decreased with increasing stocking density (p=0.074), similarly for P (p=0.076). AST decreased with increasing stocking density (p=0.672). Blood glucose decreased with increasing stocking density (p=0.018). Plasma protein increased with increasing stocking density (p= 0.018). Potassium (K) level was significantly lower for the higher stocking density T1 =5.09 and T2 =4.78 vs T3 =5.69 mmol/L. Birds were harvested at 42 days for all stocking densities MVP and MPP were positive and greater than zero indicating that birds were harvested within stage 2 of the production phase. Based on bird performance, MVP and MPP it was concluded that broiler production can be done successfully at stocking density of 0.1m2/bird in conventional open sided, naturally ventilated housing in Trinidad when harvested at 42 days. However, consideration should be given to the microclimate within the broiler houses as birds were experiencing chronic heat stress.