Effects of ultrasound on sexual maturity in the domestic hen, 1
2002
Ishino, S. (Wakayama-ken. Agricultural Experiment Station, Kishigawa (Japan))
The present study was conducted to investigate effects of ultrasound on precocious sexual maturity in White Leghorn pullets. Birds were divided into 2 groups at 70d - old and reared in individual cages under 14L/10D. The birds of one group were exposed to ultrasound for 3hr/day from 93d and another group served as control. Age at the onset of lay and egg laying performance afterward were compared between two groups. The age when 50% of individuals revealed the first egg lay was 136d in ultrasound group and 144d in control. The age showing 50% egg laying in each group was 141d and 145d, respectively. Egg production rate during 2wk afterward was 4% higher in the ultrasound comparing with the control. Throughout the experimental period, plasma progesterone (P sub4 ) and estradiol (E sub2 ) concentrations were measured using EIA. Plasma P sub4 level elevated around the day of first egg lay, while E sub2 increased 2 to 3 weeks before the first lay. The changing patterns of these hormone levels, however, resembled each other in the both of ultrasound and control. These results indicated that ultrasound was effective to induce a precocious sexual maturity in the chickens.
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