Components of feed efficiency in broiler breeding stock: energetics, performance, carcass composition, metabolism, and body temperature

Two experiments were conducted to identify factors influencing feed conversion in broilers. The first experiment was conducted to develop a test for body temperature (BT) under mild handling stress. In the first experiment, BT was recorded periodically with birds briefly restrained after they had be...

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Bibliographic Details
Published in:Poultry science 2003-07, Vol.82 (7), p.1080-1090
Main Authors: Skinner-Noble, D O, Teeter, R G
Format: Article
Language:English
Subjects:
Animal Nutritional Physiological Phenomena
Animals
Basal Metabolism
Body Composition
Body Temperature
Breeding
Chickens - physiology
Digestion - genetics
Eating
Energy Metabolism
Fasting
Female
Male
Photoperiod
Weight Gain
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Summary:Two experiments were conducted to identify factors influencing feed conversion in broilers. The first experiment was conducted to develop a test for body temperature (BT) under mild handling stress. In the first experiment, BT was recorded periodically with birds briefly restrained after they had been removed from feed with either continuous lighting or 16L:8D. Body temperature was affected by photoperiod and declined following feed removal. The second experiment was conducted to investigate metabolic-physiologic differences existing between good (G) and poor (P) converting broilers, initially classified in a commercial breeding company's feed conversion (FCR) test. Basal metabolic rate (BMR) and BT were measured at the beginning and end of the FCR test following appropriate time without feed. Heat production (HP) was recorded throughout the study both for BMR calculations and to measure net energy (NE). Excreta were collected for measurement of AME, and at study termination, birds were analyzed for carcass composition. The G and P converters, however, had similar BMR and feed consumption but differed in AME (58 kcal/kg) and total NE (184 kcal/kg). Generally, G and P broilers had similar starting BW, but the G broilers gained more weight on the same amount of feed than did P broilers. The two BT measurements recorded in the present study were correlated with each other. The BT was also correlated with subsequent gain and FCR, indicating potential use as an indicator trait for feed conversion. Further, the data indicated that processes other than basal metabolism (measured as average hourly HP) may impact FCR. These might include variability in fear response during BT measurement or variations in bird activity level.
ISSN:0032-5791
1525-3171
DOI:10.1093/ps/82.7.1080