|CHENG, HENG WEI|
Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 2, 2007
Publication Date: N/A
Technical Abstract: The aim of this work was to evaluate the efficacy of molting diets at inhibiting egg production in layers (Hy-Line W36). In total, 96, pair-housed, 60-wk-old, hens were assigned to one of four diet treatments (n=12/trt): control (C, 15.4%); low energy (LE, 12.9% CP); low salt (LS, 15.4% CP, 0.05% Na) and; FW for 10 d. C birds always received a layer ration. LE and LS had ad libitum access to their diets for 28 d followed by a return to a layer ration. FW were feed deprived for 10 d then reintroduced to a pullet developer diet (16 % CP, 3034.6 ME kcal/kg) for 14 d prior to returning to a layer ration. Egg laying ceased in the FW group on d 5, on d 7 in the LE birds, and on d 12 in the LS group. From d 12 to d 26, only C birds continued to lay. FW began laying again on d 27, LS on d 35 and LE on d 43 after start of molt. Egg numbers were lower in molted birds until d 54 (d 26 post molt) (P<0.01). There was an immediate effect of diet on feed intake (FI) in LE with intake falling by >50% on d 1 (P<0.001). By d 3, LE intake averaged 19g/bird/day compared to 95g/bird/d for C (P<0.001). For the 1st 7 d of molt, LS intake was intermediate to that of LE and C. However, FI was considerably lowest in the LS, and intermediate in LE, between d 23 and d 28 (P<0.05). After reintroduction of normal layer diet on d 28, FI was highest in LE and lowest in LS (P<0.001). Thereafter, there was little in the way of difference across treatments. FI rapidly returned to near normal levels in the FW group after the reintroduction of feed on d 11. Changes in body weight (BW) emerged by d 3 in FW and LE and by d 9 in LS relative to C (P<0.05). Overall, FW lost 26% of their BW by d 10 whereas LE and LS lost 23% and 17% respectively of BW during their 28 d molt. BW tended to remain higher in C birds until d 41 (d 13 post molt). Decreases in BW and egg production occurred more rapidly in the FW group. LE birds, however, exhibited a similar overall loss in weight to FW and took longest to re-commence laying. All treatments inhibited egg laying and further work is ongoing to evaluate treatment impact on welfare and productivity during the 2nd laying cycle.