Feed Technology and Health of Foot Pads in Broilers

摘要

This study aimed to test potential effects of the physical form of diets based on same ingredients and chemical composition on the health of foot pads in broilers.Three consecutive trials were done with 306 of one-week-old broiler heing reared over 4 weeks.In each trial,the birds were divided randomly int0 4 groups.Each floor pen was littered with wood shavings(1 kg/m2 ).All birds were fed ad libitum a diet based on identical ingredients(％,64 wheat; 30 toasted soybean; 2 soy oil; 2.5 mineral and vitamin mixtures and l.5 CaC03).For diet 1 ingredients were ground finely(hammer mill,h.m.),for diet 2 ground coarsely(roller mill,r.m.).diet 3 contained 22％ unground wheat,diet 4 was prepared as an extrudate.However,all diets had about an identical chemical composition.External assessment of foot pads was done weekly.Inspite of identical ingredients and identical chemical composition of the diet there were significant effects of feed technology.Extrudate diet resulted in increased development and severity of foot pad dermatitis (FPD)whereas the finely ground pelleted diet decreased it significantly.No significant differences of FPD scores were found between diets 2 and 3.It has to be emphasized that severity of FPD scores was correlated to dry matter contents of the litter(estimated at the end of 3 trials in whole litter).It is supposed that the effects of feed technology are mediated by changes in the water:feed intake ratio and its consequences on the dry matter content of the litter ; presumably there are further effects due to changes in the water release from the litter(drying of the litter surface?); this property of the litter could also be influenced by the water binding capacity of undigested carbohydrates.