Environment and Management III

The effects of environmental temperature (ET) and dietary ME on core body temperature (CBT) and production efficiency were evaluated in broiler breeder hens. A total of 192 Ross 708 broiler breeder hens were individually caged in one of 6 temperature-controlled chambers (32/room) at 20 wk of age. A biotelemetry sensor was surgically implanted abdominally to measure CBT of 8 birds/tmt every 10 min. The experiment was a 4 × 2 factorial arrangement, with 4 ET treatments (15, 19, 23, and 27 C) and 2 dietary ME levels (HE, 2,900; LE, 2,700 kcal/kg). The ET were randomly assigned to the chambers for 2 wk periods with the constraint that each treatment was represented at least once per period and each chamber had equal exposure to all treatments. Standard breeder BW targets were maintained by daily feed restriction. Individual BW was measured twice/wk for adjustment of feed allocation. Daily feed intake, egg production and egg weight were recorded. Data were analyzed using ANOVA and difference between treatment means were considered significant at P < 0.05. Mean CBT was the highest (40.84 C) in the 27 C treatment. Mean CBT in the 23 C treatment (40.63 C) was higher than in the 19 C and 15 C treatments (40.51 C), which did not differ. Similar trends were observed for average daily maximum and minimum CBTs in the ET treatments, while the mean CBT in the LE hens was 0.02 C higher than in the HE hens. Feed intake was higher in the LE compared with the HE hens (141 and 133g/d, respectively). The LE hens consumed significantly more energy (9.35 kcal) and CP (0.540 g) per g of egg compared with the HE hens (8.79 kcal and 0.494 g CP), which likely contributed to the difference in egg weight (58.9 vs. 58.2g in LE vs. HE). As long as target BW gain is maintained, changing environmental temperatures (15 to 27 C) will not affect production traits in breeder hens.