Productive performance of naked neck, frizzle and dwarf laying hens under various natural climates and two nutritional treatments

Abstract

The productive performance of major genes for feather reduction (naked neck and frizzle) and body size reduction (dwarf) in a dual-purpose layer strain was evaluated in the subtropical coastal region of southeast Africa (Maputo, Mozambique). The experimental material consisted of eight different genetic groups, two diets (14.4 and 16.2% crude protein) and two climatic seasons. Birds were caged individually in a laying house with natural light and ventilation. Traits measured were: temperature and relative humidity, body weight, age at first egg, egg number and weight, feed intake and mortality. The following were calculated: persistence, egg mass, feed efficiency, feed conversion, biological efficiency (EMD/BW 0.75 ) and productivity (EN/BW 0.75 ). The main results show that: (1) none of the feather-reducing genes significantly improved egg production or feed efficiency, although the naked neck (Na) excelled in terms of biological efficiency and productivity; (2) the dwarf gene (dw) was associated with delayed sexual maturity, production of fewer and lighter eggs, higher persistence, better feed conversion and higher survivability; (3) elevated temperatures restrained voluntary feed intake, egg number and weight, and body weight gain; (4) the lower dietary protein content resulted in decreased body weight. It was concluded that the genes were not equally responsive to the environments, which offers the opportunity for selective breeding.

Diallel Analysis for Bodyweight Involving Three Genotypes of Nigerian Indigenous Chickens

“…Naked-neck and frizzle birds have been found to be thermally stress tolerant compared with their normally feathered counterparts (Nwachukwu et al, 2006). The naked-neck and frizzle genes have been found to be associated with heat tolerance, and therefore in areas with high ambient temperature, birds with these genes are superior to their normally feathered counterparts for feed efficiency (Garces et al, 2001). According to Fayeye et al (2006), birds with the naked-neck and frizzle genes have better adult bodyweights than their normally feathered counterparts.…”

Haematological studies on frizzled and naked neck genotypes of Nigerian native chickens

“…The naked neck gene reduces feather coverage in chickens by 20% and 40% in heterozygous (Nana) and homozygous (NaNa) states, respectively (Deeb and Cahaner 2001). Garces et al (2001) reported that Ffchickens showed a reduced density of feather coverage, which provides some heat tolerance to egg-type chickens. The NNC represent valuable resources for local poultry development because their extensive genetic diversity allows for rearing of these chickens under varied environmental conditions, providing a range of products and functions (Yakubu et al 2009).…”

Influence of major genes for crested-head, frizzle-feather and naked-neck on body weights and growth patterns of indigenous chickens reared intensively in Kenya

“…However, genotypes possessing the nakedneck and frizzle-feather genes, either singly or in combination have increased growth rates, body weights, feed conversion, egg production and disease tolerance in tropical environments (Fraga 2002;Missohou et al 2003;Mahrous et al 2008). The dwarf gene has been associated with feed efficiency and egg mass production (Garces et al 2001;Yeasmin et al 2003) while the ptylopody gene has been shown to increase body weight and egg mass (Fayeye et al 2006). These genotypes need to be exploited and utilized so as to increase production to meet the everincreasing demand for indigenous chicken products and to conserve them for present and future use.…”