EFFECTS OF CLIMATE CHANGE ON POULTRY PRODUCTION
Poultry are birds such as the domestic fowl, Turkey, Duck, Goose, Ostrich e. t. c which are of economic importance to man. Their production is one of the livestock production with significant contribution to human food (Demeke, 2004). It is the primary supplier of eggs and meat as a source of income and employment to people compared to other domestic animals (Avila, 1985). They are raised with relatively low capital investment and readily available household labour. For instance poultry egg contains 74% water, it is a good source of high protein and it is often used by nutritionist as a standard reference for evaluating other ...view middle of the document...
Further, the fowl, like many other animals, can undergo a number of complex and imperfectly understood physiological changes which enable it to minimize the adverse effects of hot climates (Sykes and A1-Fataftah 1980). To understand better the relationship between elevated ambient temperature, nutrition and performance, the physiological mechanisms must also be considered. Acute physiological responses to high environmental temperatures are obviously directed to the maintenance of homeothermy, but small increases in body temperature may be tolerated (Fisher et al. 1985).The effects of high environmental temperatures are well documented; however, in view of the importance of ambient temperature in efficient poultry production, especially in areas where high ambient temperatures are prevalent for most of the year.
2.0 IMPLICATION OF CLIMATIC FACTORS ON PRODUCTION
Temperature is an important bio-climatic factor affecting the physiological function of layer-chickens (McDowell, 1972) though the effect on egg production rate depends on age of laying hens. The effect is more evident at old age when birds are exposed to cold climate. When temperature falls below the thermo neutral zone of below 12.8oC (which is rarely experienced in the tropics) egg production becomes uneconomical (Oluyemi and Robert, 1979). Charles (1980) opined that feed intake of a laying hen decreased by 1.5g a day for every degree rise in temperature above 30oC, decreased egg production by about one egg per bird a year for every degree rise in temperature above 25-30oC and that the depressive effect of environmental temperature by heat stress significantly increases water consumption, reduces egg production , egg weight , shell weight, shell thickness causing a significantly higher production of shellers or very thin-shelled eggs. The optimal laying temperature according to Kekeocha (1985) is between 11o and 26oC .
A humidity level above 75 percent will cause a reduction in egg laying. When ambient temperature is high, chickens have higher energy (feed) needs than when in thermo-neutral environments. Major losses result from a less efficient conversion of feed to meat, which detrimentally impacts poultry health and productivity (Olanrewaju et al., 2010). Poultry flocks are particularly vulnerable to climate change because there is a range of thermal conditions within which animals are able to maintain a relatively stable body temperature in their behavioural and physiological activities. Hence, birds can only tolerate narrow temperature ranges to sustain the peak of their production for human consumption and any unpredictable climatic changes will therefore trigger a series of adjustment and readjustments by livestock and poultry birds in the struggle for survival which may have negative consequence on the viability of poultry production.
Environmental temperatures above 30 °C in the rearing area cause high mortality of broiler chickens (De Basilio and Picard, 2002) or...