Middle East Journal of Agriculture Volume : 05 | Issue : 04 | Oct.-Dec. | 2016 Research Pages: 655-665 ISSN 2077-4605 Evaluation of Different Force Molting Methods on Layers Performance during Molting Period Mosaad F. Taboosha and Mohammed Sh. Abougabal Animal Production Department, Faculty of Agriculture, Al-Azhar University, Cairo, Egypt. Received: 30 November 2016 / Accepted: 30 December 2016 / Publication date: 31 December 2016 ABSTRACT This study was conducted to compare four induced molting methods and to determine the preferable method which achieves the main goals of molt in laying hens during molt period. Two hundred and forty Lohmann Brown-Classic commercial layers (73 weeks old) were used. The hens were randomly and equally divided into 5 treatment groups (four experimental and one control) of 45 hens each in three replicates. Experimental groups were as follow; T1) non-molted group and served as control (CONT), T2) molted by California method (CAL), T3) Conventional method (CONV), T4) Standard (STD) method and T5) High zinc diet method (HZD). Body weight, weight loss, mortality, egg production cease, carcass traits, digestive tract and reproductive system organs were determined before and after molting period. The results of this study indicated that, force molting by fasting methods (CAL and CONV method) achieved most main goals of induced molt method. Moreover, California force molt method recorded the best values in productive traits during molt period. California treatment at the end of molting period, recorded maximum body weight loss (27%), lower mortality percent (4.4%), fewer days to cease egg production (7 d.) and minimum body weight (1299 g) followed by CONV, STD and HZD treatments. So it seems that, California method can be used successfully as force molting method because it more suitable, simple to implement, least in cost, resulted low mortality and achieved most objectives during molt period. Nonetheless, further experimentation is suggested to enhance the efficiency of the molting methods for improvement of egg production, egg quality during the subsequent laying cycle. Key words: Force molt methods, molting period, laying hens Introduction Force molting is a management tool adopted by farmers to give the rest at the end of a long period of egg production and extend the productive life of flock to 110 weeks or longer (Aygun, 2013 and UPE, 2016). The practice of molting continued to increase and spread widely in the most of egg production countries of the world with the time as a tool to rejuvenate the spent hens, (Bell, 2003). The decision of using a force molting program depends on several factors, such as: price of replacement new flock, egg quality, egg price, feed cost, maximum facility use and employed molting method, (Gracia et al., 2001 and Reddy et al., 2008). Methods conventionally used for induce molting in commercial layer can be classified in three main ways: limination or limitation of food and/or water; feeding the birds low nutrient rations deficient in protein, energy, calcium or sodium; administration of drugs, hormones, and metals including prolactin, chlormadinone, and progesterone; and high levels of iodine, dietary aluminum, and zinc (Bell and Kuney, 1992), coincided with some variations and modifications, such as length of the treatment, lighting schedule and the age of molt (Bell, 2003). The conventional feed withdrawal/deprivation (fasting) procedure is most widely used in poultry production because it is simple, practicable and economical technique that can be used in combination with light and/or water restriction (Koelkebeck et al., 2001; Bell, 2003 and Khoshoei and Khajali, 2006). Fasting is the most frequently used method to induce molting due to its low cost and high efficiency (Rodrigues et al., 1995). The increasing public awareness of the animal stress associated with feed withdrawal has led researchers to investigate alternative molting processes (Brake, 1993; Park et al., 2004 and Aygun, 2013). Mineral induced molting programs were also adopted. The uses of higher levels of either aluminium salt (Yousaf and Ahmad, 2006) or dietary zinc (Koelkebeck and Anderson, 2007) have been successfully Corresponding Author: Abougabal, M. Sh., Animal Production, Dept. Faculty of Agric. Al-Azhar University, Nasr City, Cairo, Egypt E-mail: [email protected] 655 Middle East J. Agric. Res., 5(4): 655-665, 2016 ISSN 2077-4605 practiced. Also, the use of low sodium diet was found to be an effective procedure for molt induction (Naber et al., 1984). It was observed that molt induction by feeding hens a diet containing high levels of zinc oxide or zinc acetate resulted in stoppage of egg production within 5 days (Keshavarz and Quimby, 2002). Several non-feed removal procedures were used to induce molting in hens. Ideally, a good molting method should: get the flock out of production within 5- 6 days, keep flock out of production until it has rested, bring it back into production when needed, simple to implement, low in cost, result low mortality and lead to high subsequence performance (Koelkebeck et al., 1992). Hence, the objectives of this study were comparison of four induced molting methods and determining the preferable method which achieves the main goals of molt in caged laying hens during molt period. Materials and Methods This study has been performed in the Poultry Experimental Station, belong to Animal production department, Faculty of Agriculture, Al- Azhar University, Cairo, Egypt during Spring of 2015. A total number of 240 Lohmann Brown-Classic hens (aged 73 wk) were used. Birds were individually weighed and allocated to each treatment group and housed in caged laying metal batteries with one bird per cage (35 x 35 x 35 cm) and 2 weeks were allowed for acclimation. During this period, birds were given vitamins supplementation, and allowed full access to a complete layer ration (Soybean-corn diet contain: 18% CP, 2750 ME/kg and 3.8% calcium) and water via nipple drinkers. The hens were exposed to a 16L:8D h photoperiod daily before the start of the experiment. The mean temperature of the house was 27 - 31 °C. After acclimation, 15 birds were slaughtered (at day 0) to estimate liver and abdominal fat (g or %), digestive tract (intestine and ceca weight and length) and reproductive system (ovary weight, oviduct length and mature follicles). Molting period: Layers were randomly divided to five treatment groups (control and four different molting methods described in Table (1) with three replicates consisting of 45 hens in each treatment (15 layers/replicate). These five treatments were designed as follows; T1: Control, non-molted group, where the hens fed daily 150 g of layer ration without additives. T2: California method (CAL), in this method the feed was withdrawn for 10 days, and hens were fed with cracked corn diet and limestone (1:1) ad-libitum from 11 to 28 day. T3: Conventional method (CONV), the hens in this group were deprived of feed and water for 2 days followed by 8 days of skip-a-day (feed and water) feed restricted to 45 g of feed per hen and they were provided 75 g (50 % of control ration) of a layer diet from day 11 to 28. T4: Standard (STD) method (Recommended in Hisex Commercial Layers, Management Guide, 2008), the hens in this method were fed with 45 g of cracked corn and wheat bran (1:1) from day 1 to 28. T5: High zinc diet method (HZD), the hens in the this group were fed with full feed ration containing high level (3000 mg/kg) of Zn as ZnO for first 10 days and they were provided 75 g ( 50 % of control ration) of a layer diet from day 11 to 28. Three day before the beginning of molt period, layer hens were exposed to 24 hours photoperiod for 3 days and reduced to natural day light (12.15 - 12.30 hrs). During molting period, hens were weighed individually at day 0 (initial live body weight), 10, 20 and at day 28 (final live body weight) to estimate body weight loss. The number of days to cessation of lay of each group of birds and dead birds were also recorded. At the end of molting period (28 d), 30 birds were slaughtered (6 hens / group) to estimate carcass traits, digestive tract and reproductive system organs using an electronic weighing scale. Body weight loss (%) was calculated [(on the basis of body weight at 28 days [(W2) – body weight at 0 days (W1) / (W2)] * 100. The number of days to resumption of lay of each group of birds was also recorded. Statistical analysis: Data were subjected to analysis of variance using SPSS software program package (SPSS, 2005, version 16.0). All data were analyzed by using one way ANOVA and presented as means±SE. Duncan,s multiple range test was applied to identify significant differences among groups, (Duncan, 1955). 656 Middle East J. Agric. Res., 5(4): 655-665, 2016 ISSN 2077-4605 Table 1: Procedure of different force molting methods (Feeding, water and lighting program) for experimental groups: California Conventional Standard High Zinc diet Days of Light (CAL) (CON) (STD) (HZD) procedure hrs. Feed Water Feed Water Feed Water Feed Water 1 × × × 2 × × × 3 × 45 gm/bird libtum 4 × - × × 5 × Ad 45 gm/bird 12.30 hrs.) 6 × × × - 7 × 45 gm/bird (3 gm / kg diet) 8 × × × Natural Day light (12.15 (12.15 9 × Lime stone 45 gm/bird 10 × × × feedFull diet + Zinc oxide 11 45 gm / bird lib. - 12.30 hrs.) - Ad Corn Cracked + wheat barn (1:1) lime stone ( 1:1 ) Natural Day light (12.15 Feed Restricted (75 gm/bird) on layer ration Feed Restricted on 50 % of (75 (75 gm/bird) on layer ration 28 Full feed on cracked Corn + Full feed on layer Full feed on layer Full feed on layer Full feed on layer 14 → 28 - ∞ ration + ration + ration + ration + 16 water water water water hrs.