The Pattern of Growth of Exotic Pullets Raised in a Tropical Wet Climate: The Need for a Renewed Feeding Programme.

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Essien A.I.
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Fifty growing pullets of Harco strain of chickens were weighed weekly from setting to liveweight, to study the changes in liveweight from 31.11 ± 0.45 g at one day of age to 1791.62 ± 27.40 g at 168 days of age. The weights obtained were fitted into three growth functions namely the simple linear function, Y = ax; the Brody function, Y = aeb'; and the Schmachausen function, Y = axb • Prediction equations were derived from growth functions for the different growth phases (0-56, 56-112, 112-168, and 0-168 days). Generally, the simple linear model predicted live-weight growth better than either the Brody or the Schumalhaussen function. The widest range of daily growth rate (2.46 - 6.09 g d-I) occurred in the chick (0-56-day) phase. The growth pattern within the grower phase indicated a stable rate of growth and a narrower range (6.09 - 7.73 gd-I) in the early grower phase (112-168 days), which had a range of 7.83-10.48 dol. The mean daily rate of liveweight gain in the early grower phase was significantly (p~0.01) lower than that in the later growth phase. This diphasic growth pattern suggests a need to feed pullets in the lower growth phase two levels of protein (phase feeding). This would ensure earlier attainment of the desired body weight and sexual maturity for the onset of egg production.
East African Agricultural And Forestry Journal, 59 (No. 3), p. 261-267