Components of feed efficiency in broiler breeding stock: influence of water intake and gastrointestinal contents.
An experiment was conducted with 3 lines of broilers to evaluate the potential roles of water intake and fill of the gastrointestinal (GI) tract on feed conversion ratio (FCR) as measured in a 1-wk FCR test. Birds were reared to juvenile selection age (41 d) and subsequently selected, with the best 18 to 29% of male chicks placed into cages for FCR testing. Feed and water intake were highly correlated in all lines, with each in turn highly correlated with weight gain on test. Although filling of the GI tract differed between the top and bottom halves of the FCR distribution, FCR as measured and corrected for weight of GI tract contents were highly correlated (r = 0.59 to 0.93). Differences between FCR classes were striking for weight gain, but differences between FCR class groups were subtle for starting weight and feed intake. These subtle differences are difficult to detect in a single generation, but may add up through generations of selection. Based on the results of the current and previous studies, it appears that selection for improved FCR works at multiple levels to improve efficiency of feed conversion in broiler breeding stock.
Skinner-Noble
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Oklahoma State University, Department of Animal Science, Stillwater, Oklahoma 74078, USA.
Teeter
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D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001947:Breeding; D002645:Chickens / Q000235:genetics / Q000502:physiology*; D004064:Digestive System / Q000378:metabolism*; D004068:Digestive System Physiological Phenomena; D004326:Drinking; D004435:Eating; D008297:Male; D012641:Selection, Genetic; D015430:Weight Gain