Egg Production, Feed Consumption, and Maintenance Energy Requirements of Leghorn Hens as Influenced by Dietary Energy at Temperatures of 15.6 and 26.7 C

Diets (H) and (L) containing 2830 and 1980 kcal/kg were fed to groups of Leghorn hens kept at 15.6 and at 26.7 C ambient temperatures. The average metabolizable energy (ME) intakes per day were 231 kcal and 287 kcal at 15.6 C; and 200 kcal and 242 kcal for the (L) and (H) diets, respectively. Within this temperature range the feed intake decreased by 1.21% and 1.41% per 1 C rise in ambient temperature for the (L) and (H) diets, respectively. Neither egg production nor shell thickness was influenced by the treatments, but egg weight was significantly depressed at 26.7 C as compared to those at 15.6 C. The maintenance energy requirements (MEm) were significantly lower at the two ambient temperatures when hens were fed the (L) diet as compared with the (H) diet. The MEm values for the respective diets were 132.6 and 171.3 kcal/kg.75/day at 15.6 C; and 114.9 and 140.2 kcal/kg.75/day at 26.7 C. The energetic efficiency was increased for the conversion of ME intake to egg energy either by increasing the ambient temperature or by lowering the dietary ME.