Welfare assessment of breeder hens supplemented with zinc and vitamin C during the cold winter period
2013
Bozakova, N., Thrakia University, Stara Zagora (Bulgaria) | Gerzilov, V., Agricultural University, Plovdiv (Bulgaria) | Atanasov, A., Thrakia University, Stara Zagora (Bulgaria) | Uzunova, K., Thrakia University, Stara Zagora (Bulgaria) | Chukacheva, I., Thrakia University, Stara Zagora (Bulgaria)
The purpose of the study was to evaluate the poultry welfare of three groups New Hampshire hens – control, supplemented either with 35 mg zinc/kg feed or a combination of 35 mg zinc/kg feed with 250 mg/kg vitamin C during the cold winter period. Eighty seven New Hampshire breeders at the age of 48 weeks were divided in three groups - n=29 and were reared under a free range system sleeping pens and outdoor walking yards. The welfare of flocks was scored on the basis of their behaviour, plasma corticosterone and several blood biochemical parameters, as well as microclimatic rearing parameters during the cold winter and thermoneutral period. The behaviour of breeders was recorded with a video camera for 12 h during 4 consecutive days accounting the number of birds engaged in specific forms of behaviour: ingestive, gregarious, sexual and agonistic. The plasma corticosterone levels were assayed by commercial ELISA kit. Blood biochemical indices were determined on an automated biochemical analyzer Cobas mira. During the cold period, the poultry welfare - PW score of control breeders was PW=40 %, of the Zn-supplemented flock – PW=60 % and of zinc and vitamin C supplemented flock – PW=73.33 %. The poultry welfare improvement was due to the stress-reducing effect of both Zn and vitamin C supplements. The combined supplement had a better alleviating stress effect due to synergic action of its ingredients.
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