Discuss the effects of temperature on: (a) brooding of chicks; (b) reproduction in livestock; (c) milk production; (d) egg production.

Answer Details

Temperature is an important climatic (environmental) factor that strongly affects livestock performance. Its effects on the following are discussed.

(a) Brooding of chicks: Young chicks cannot regulate their own body temperature, so warmth must be supplied artificially during brooding. The correct temperature (about 35 degrees Celsius in the first week, reduced gradually) keeps the chicks comfortable, active and evenly spread under the brooder, and promotes good growth. If it is too cold the chicks huddle together and may be smothered or die of chilling; if it is too hot they pant, move away from the heat source, eat less and grow poorly.

(b) Reproduction in livestock: Moderate temperatures favour normal reproduction, but very high temperature (heat stress) reduces fertility. In males it lowers the quantity and quality of sperm produced, and in females it interferes with the oestrus cycle, weakens the signs of heat and can cause early embryo death and abortion. Very low temperatures also depress reproductive activity.

(c) Milk production: Dairy animals give the most milk within a comfortable (thermo-neutral) temperature range. Under high temperature the animals feel heat stress, eat less feed and use energy to keep cool, so milk yield and the butterfat content fall. Very cold weather also lowers yield because more feed energy is diverted to keeping the body warm.

(d) Egg production: Laying birds produce best at moderate temperatures. When temperature is very high the birds pant, drink more water, eat less and lay fewer eggs with thinner shells and smaller size. Very low temperature increases the feed needed for body warmth and can also reduce the rate of lay.