Effect of Molting Method and Dietary Energy on Postmolt Performance, Egg Components, Egg Solid, and Egg Quality in Bovans White and Dekalb White Hens During Second Cycle Phases Two and Three

Abstract

Two experiments of 4 x 2 x 2 factorial arrangements of 4 dietary energy levels, 2 molting methods (feed withdrawal and no salt diet), and 2 strains (Bovans White and Dekalb White) were conducted to determine the effect of dietary energy and molting method on long-term postmolt performance of 2 strains of commercial Leghorns. In experiments 1 and 2, Bovans White hens (n = 576) and Dekalb White hens (n = 576) were randomly divided into 16 treatments (6 replicates of 12 birds per treatment). Experiment 1 lasted from 86 to 96 wk of age, and experiment 2 lasted from 100 to 110 wk of age. Bovans White hens had significantly higher egg production than Dekalb White hens, whereas Bovans White hens had significantly lower egg weight, percentage of eggshell, and egg specific gravity than Dekalb White hens. Based on improved feed conversion, dietary energy of 2,846 kcal of ME/kg appeared to be enough for optimal performance during second cycle phase 2. Based on BW of hens, dietary energy level for optimal performance should be less than 2,936 kcal of ME/kg during second cycle phase 3. There can be no fixed ideal dietary energy level for optimal profits for postmolt egg production. Molting method had no effect on egg production and egg mass during the early and middle stages of the postmolt production period. However, hens molted by feed withdrawal had significantly higher egg production and egg mass during the later stage of the postmolt production period compared with hens molted by a no salt diet. There was no significant difference in egg specific gravity due to molting method. Feeding a no salt diet resulted in reasonable long-term postmolt performance and eggshell quality, rather than optimal performance and eggshell quality.

Requirement of Sodium to Molted Laying Hens

“…However, approaching 100 weeks, there was a significant reduction on performance and egg quality. Normally, the molt procedure cause a significant increase on performance and egg quality at shortterm and these indexes tend to decrease according to the age of the bird due to the natural wear caused by constant egg production in industrial scale (Wu et al, 2007). Physiologically, there are great wear on oviduct tissues, and difficulty to absorb the nutrients and its transfer to the egg's composition (Newman and Lesson, 1999;Bar et al, 2001;Heflin et al, 2018;Elhamouly et al, 2019).…”

“…Different strains may to present different responses on performance after molt, especially on laying hens and semi-heavy hens (Said et al, 1984;Gongruttananun et al, 2017;Hu et al, 2019). There is very limited literature about the performance, egg composition, egg solids, egg quality, and profits of postmolt hens (Wu et al, 2007), especially at long-term, a period near or exceeding to 100 weeks. An induced molting not only may improve performance and eggshell quality, but also increase profits by optimizing the use of replacement pullets on commercial layer farms (Lee, 1982;Barker et al, 1981;Bell, 2003;Mazzuco et al, 2011;Gongruttananun, 2018) proving the importance to understand its effect at long-term.…”

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

“…La variable peso del huevo indicó que el peso del huevo no depende de la edad, ya que en condiciones normales, el tamaño y el peso del huevo tienden a aumentar después del pico de producción, debido al incremento del peso corporal del ave y la disminución en el nivel de producción (5,8,22). Todos los pesos obtenidos en el experimento fueron mayores a los datos reportados en la guía de manejo de la línea para las mismas edades (17), lo que confirma lo propuesto por Flemming(22) y Webster (20), quienes afirmaron que una de las ventajas de la utilización del DO es el aumento en el tamaño del huevo postmuda (Tabla 2).…”

“…Con respecto al cese de la producción, se ha considerado necesario para la regeneración del aparato genital (4,7) y rejuvenecimiento de la zona reproductiva (8)(9)(10), permitiendo la recuperación en el nivel productivo, no tan alto como el ciclo anterior, pero con un peso de huevo promedio mayor y una calidad de cáscara óptima (3,5,11). En resumen, la técnica del DO se utiliza para ayudar a manejar y sincronizar los ciclos de la producción de un lote de aves (1,2,); debido a que durante la muda suspenden la producción de huevos, pero luego de ser nuevamente estimuladas, retornan a la producción igualando o superando la respuesta productiva antes del estimulo inductor del cese productivo, este segundo ciclo puede durar entre 25 a 35 semanas (11,12).…”

Influence of nutritional strategies on growth performance and digestive tract traits of brown egg laying pullets and subsequent effects on egg production

“…In contrast, Harms et al (2000), Wu et al (2007), and Bouvarel et al (2010) reported that egg weight increased as the AMEn content of the diet increased. Under practical conditions, egg size depends primarily of the methionine, fat, and linoleic acid content of the diet (Safaa et al, 2008b).…”