• Asian-Australasian Journal of Animal Sciences
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• v.18 no.5
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• pp.686-691
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• 2005

Prolactin is considered to influence the taking of pauses in between ovulatory sequences in White Leghorn hens. Therefore modulating concentrations of prolactin using bromocriptine - a dopamine agonist during early life (17 to 36 weeks of age) could overcome the inhibitory effects of high concentration of prolactin on ovarian activity. The effect of modulation of prolactin concentration on egg production, sequence length and inter sequence pauses were studied by analyzing the oviposition records from 19 to 72 weeks were studied and compared with untreated controls. Bromocriptine administered subcutaneously (100 $\mu$g kg$^{-1}$ body weight or orally through feed (640 $\mu$g day$^{-1}$ bird$^{-1}$) resulted in a steady and sustained decrease in prolactin levels (p<0.01) during and after the withdrawal of treatment up to one reproductive cycle (72 weeks of age). The treated birds had comparatively longer sequences (p<0.01) and fewer pauses (p<0.01). Egg production increased (p<0.01) by fourteen per cent through subcutaneous administration and eleven per cent through oral feeding, over the control birds. It is concluded that the physiological pauses that occur during ovulatory sequences can be disrupted effectively using bromocriptine. Prolactin levels are modulated which may interfere with the follicular recruitment and subsequent oviposition thereby improve egg laying potential of the bird.