The Effect of Incubator Type on Hatchability and Chick Survival of Emu Dromaius Novae Hollandiae (Le Souef 1907)

Abstract

The population of wildlife is declining due to unsustainable harvest for meat. There is need to increase animal protein to fill the gap between the demand and supply from conventional sources through production and management of non-conventional sources of meat like Emu Dromaius novaehollandiae. In this study hatchability and chick survival due to the use of two different types of incubators examined. Sixteen birds aged 20 month were managed in eight pens (25m by 25m each) under semi intensive system at Ajanla farms, Ibadan at the rate of one male to one female per pen. They were fed with pelleted feed and Tridax procumbens. Eggs were collected daily for viability test before setting and hatching in two different types of incubators; electric cabinet and kerosene incubators. Both were maintained at a temperature of 40°C and 25% relative humidity. Hatched chicks were monitored for the first six weeks of life to determine chick survival. Data obtained were analyzed using ANOVA. Proximate analysis of the diet revealed that it contained 45% crude protein. Average production for three years was 62 + 2.4 eggs, with a total average of 35 + 18.2 eggs per hen during the breeding period. The mean weight recorded for Emu eggs was 625 + 2.59g. Fertility percentage was 75.4%. Average hatchability of 60.4%, 70.1% and 65.4% observed for kerosene-operated incubator for 2002, 2003 and 2004 respectively were significantly higher (P<0.01) than 17.5%, 16.1% and 18.2% respectively for the electric incubators. For both incubators, incubation period was 50 days. The average weight of newly hatched chick was 414g. Mean weight of hatchings from kerosene and electric incubators were 418.5g; 409,6g respectively. Mortality recorded in hatchlings from electric incubator was 30% while that for kerosene incubator was 10%. There was low hatchability in electric incubator compared to kerosene incubator. @ JASEM Wildlife is a natural resource that represents the principal source of animal protein for the rural majority in most African countries (Ajayi 1979, Ayeni et al, 1982). The supply of bush meat from wildlife stands out to bridge the gap between livestock production and human population growth. Ajayi (1971) reported that in developing countries livestock production is increasing at a rate of 1.25-2.0% per annum while protein demand is expected to grow at 5% per annum over the period to 1985. Hatchability depends on good incubation condition, all other things being equal. Artificial incubation of emu eggs needs to aim at creating condition such as incubation humidity and temperatures to stimulate the natural condition. The average hatchery sequence for the chick to break into air cell is at 47 day of incubation while to pip the eggshell is at 49 day and to complete hatching at 50 day. However, the time interval is subject to normal biological variations. Hatchability problem could be due to heavier egg and hyperthalmia,that is, when the egg temperature is higher than ambient temperature by 2°C towards the end of incubation. Incubation problems can be categorized into infertility of eggs, early embryonic death [up to fourteen days of incubation] and late term embryonic death [29-50 day of incubation] and dead in shell [at time of hatching]. MATERIALS AND METHOD Sixteen (16) adult emu, twenty months old each at the ratio of one male to one female were managed, at Ajanla farm for the study. The birds were weighed before the start of the experiment. The average weight of the birds in each pen was 68 + 1.12kg. Any bird with the following physical disability was excluded from stocking: Curvature of the spine or neck, Eye infections, dull feathers, emaciation and other signs of illness, Excessively wild birds (prone to injury). Blood in stool, which indicates problems. Extremely dome shapely back and obesity. Pairs of Emu (one male to one female) were housed in eight pens. A horse-wire was used to fence each pen. The height of the pens was 1.8m tall supported with a top rail for greater strength. All the fasteners were turned outwards so as to avoid scrape or injury of birds' neck. Eggs were collected in the morning during feeding time in order to cause the least amount of stress. As the breeding season continued, males were found sitting on the fresh eggs. The eggs were collected at night by moving quietly without flash light around the birds. Males were gently lifted by grasping one of the legs tucked under them, and the eggs removed. Usually the male was already in a state of trance-like incubation state and did not offer any resistance when being lifted and put down again. Eggs were collected into a clean container that had been cushioned with clean hay to ensure eggs do not roll. Eggs were marked (numbered and dated) with a white coloured pencil. This method was useful in identifying the eggs laid from the eight different pens used for the study. All eggs laid and collected were not treated with any chemical or washed. Dirts were removed from eggs by using a small dry brush prior to incubation. Eggs were also checked for morphology and the abnormally shaped eggs are removed from the collection before incubation. Soft-shell, cracked /