Effects of Nutrient Density and Age at Photostimulation on Carcass Traits and Reproductive Efficiency in Fast- and Slow-Feathering Turkey Hens

Abstract

This study was conducted to compare BW gain, carcass composition, and reproductive fitness in fast- and slow-feathering turkey females between 29 and 56 wk of age. A total of 452 Hybrid standard fast-feathering (FF) and experimental slow-feathering (SF) hens (226/group) were fed either a control or a high-energy, high-protein diet. Birds were photostimulated at 29 or 31 wk. Data on BW and carcass characteristics (keel and shank, keel, breast muscle, fatpad, liver, ovary, and oviduct weight) and egg production were assessed. At photostimulation, FF birds had an increased shank length (2.6%) compared with SF birds. After photostimulation, FF birds were heavier than SF birds by 7.8%. Fast-feathering hens had greater ovary weight (49%), oviduct weight (52%), keel length (2.8%), and had one more large yellow follicle at the end of lay. The number of large yellow follicles was greater in birds photostimulated at 31 wk (8.3) compared with birds photostimulated 2 wk earlier (7.8). Absolute ovary weight and oviduct weight were increased by 21 and 18%, respectively, in birds photostimulated at 31 wk compared with 29 wk. These effects of delayed photo-stimulation were greater in SF birds. Ultimately, FF hens had a greater total hen-housed egg production (55 vs. 33%), peak egg production (76 vs. 68%), and laying sequence length (5.7 vs. 3.3 d). Although delaying photostimulation did not affect total egg production, it did reduce the number of double-yolked eggs. Nutrient density had minimal effects on production in this trial. These data indicate that despite having similar BW, fleshing, and conformation traits to FF birds, the SF strain had inferior reproductive efficiency traits. This problem will need to be remedied before an SF turkey strain can become commercially viable.