Productive and physiological performance of local laying hens as affected by force molting methods

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Abstract: This study was conducted to determine the effect of two force molting procedures (zinc oxide and fasting) on economical traits, egg quality, some internal organs and some blood parameters in the two local strains of Gimmizah and Mamourah.
One hundred and eight hens 60 weeks old (54 hens from each strain) were used. Birds of each strain were randomly assigned to 3 equal treatment groups of 18 birds each. The three treatments were non-molted (control), 20.000 ppm zinc oxide / Kg diet, and Fasting, respectively. The application of force molting treatments continued for 10 days.
Gimmizah hens had significantly higher body weight loss after treatments than Mamourah ones. The Gimmizah hens were earlier in egg laying cessation during force molting than Mamourah hens. Generally, Mamourah strain had better values for economical traits (Egg production rate, egg weight, egg mass and feed conversion), egg quality traits (Egg shell weight and haugh unit scores) and blood parameters (Calcium, cholesterol and progesterone) than Gimmizah strain. The differences in the percentages of internal organ weights between both strains were not significant except oviduct length which was significantly (P<0.05) higher in Gimmizah hens than Mamourah ones at the end of study.
The hens of zinc oxide and fasting treatments lost 19.2 and 18.4% of their premolt body weight in comparison to the control one. The force molting treatments had significant (P<0.05) effect on the days of laying cessation, egg production rate, egg production rate at peak, egg weight, egg mass and feed conversion during the second laying cycle. The best values of the last characteristics were recorded by zinc oxide treatment followed by fasting and control groups. Force molting treatments slightly improved egg quality traits (egg shell weight and thickness and haugh unit scores) and significantly (P<0.05) affected on internal organs studied. The control group had significantly (P<0.05) better values of liver, ovary and oviduct percentages and oviduct length than force molted groups after treatments while, the opposite was true at the end of study.
Similarly, the control group had significantly (P<0.05) higher plasma concentration values of total protein, albumin, calcium, inorganic phosphorus, AST, AL T, cholesterol and progesterone after molting treatments, meanwhile, the opposite was found at the end of experiment.
Therefor, from this study it could be recommended to use zinc oxide procedure of 20.000 ppm for molting to maximize the productivity of laying parent stocks of both local strains during the egg laying second cycle.

Publication year

2005

Pages

12-31

Availability location

معهد بحوث الانتاج الحيوانى-شارع نادى الصيد- الدقى - الجيزة

Availability number

Organization Name

Animal Production Research Institute (APRI)

serial title

Egyptian Journal of Applied Science

ISSN