Effect of Age at Molting on Postmolting Performance

Abstract

Molt was induced at the 431, 501, or 571 d, in Lohmann (L) and Hy-Line W-77 (H) hens, by 8 or 14 d, respectively, of feed withdrawal followed by a rest period of 16 d. Induced molt resulted in increases in egg production, numbers of intact eggs, egg mass per housed or surviving hen, and shell quality and in decreases in egg breakage (not significant), mortality, and culling. Egg weight was only slightly affected by molt, and the EW of hens induced to molt at 431 or 501 d of age were slightly lower than those of the unmolted hens or of those induced to molt at 571 d. Both strains reacted similarly to molt, although the L hens responded better, and expressed their responses more intensively when induced to molt earlier (431 d). This finding suggests that although different breeds have some effects of molt in common, molt protocols should be finely tuned for each breed. Total intact egg production and egg mass of the molted hens became higher than those of the unmolted hens at 650 to 728 d, which suggests that no benefit would be achieved by rearing molted hens for less than 700 to 730 d.

Changes in eggshell mechanical properties, crystallographic texture and in matrix proteins induced by moult in hens

“…These results confirm previous findings on the improvement in egg production and in shell quality after induction of an artificial moult by zinc oxide with or without restriction of light (Berry and Brake, 1987;Ramos et al, 1999;Bar et al, 2001). Garlich et al (1984) and Table 7.…”

“…The restorative effects of an induced moult on shell quality and the productivity of old laying hens is well substantiated (Berry and Brake, 1987;Bar et al, 2001). Thus, the aim of the current study was to explore the origin of the enhanced shell quality after moult and to use this model for establishing a possible relationship between the organic matrix components, shell microstructure and its mechanical properties.…”

Eggshell quality and calcium utilization in feed of hens in repeated laying cycles

“…Bar et al (2001) showed that induced moulting resulted in increases of egg production, egg mass per housed or surviving hen, numbers of intact eggs and shell quality. Alike Wu et al (2007) reported that hens moulted by feed withdrawal had significantly higher egg production and egg mass during the later stage of the post-moulting production period compared with hens moulted by no-salt diet.…”

Respuesta productiva de gallinas semipesadas inducidas al descanso ovárico en diferentes edades

“…El desempeño productivo de las aves en el segundo ciclo, se comienza a evaluar con los días improductivos a partir de la aplicación del DO, lo cual indica que el período improductivo aumenta a medida que el ave envejece, que bien podría interpretarse como una menor velocidad de recuperación del tracto reproductivo del ave a medida que aumenta la edad, aspecto expresado por Bar (19), quien recomienda no realizar inducciones al DO en aves con una avanzada edad, ojalá con menos de 100 semanas de vida.…”