ウシの妊娠末期における夜間給餌が血漿中プロスタグランジンE_2およびコルチゾール濃度に及ぼす影響 [in Japanese] Effect of Night-Time Feeding on Plasma Prostaglandin E_2 and Cortisol Concentrations on Teminal Stage of Pregnancy in Cow [in Japanese]
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To describe the mechanism of increasing day-time calving by night-time feeding, plasma concentration of Prostaglandin E<sub>2</sub> (PGE<sub>2</sub>) and cortisol were determined during a prepartum period. Fifty-five Holstein Friesian cows in the late pregnancy were divided into two groups, 28 cows were fed for 97.99% of TDN 7.35kg per cow in the evening, while other 27 cows were fed regularly in the morning and afternoon and served as controls. Blood was collected twice a day, in the morning between 4:00 and 5:00 and in the evening between 18:00 and 19:00 from 23 of the 55 cows for the measurment of PGE<sub>2</sub> and cortisol. Percentage of cows delivered in the day-time was 64.3% in the night-time feeding group and 51.9% in the regular-feeding group. In the night-time feeding group of cows, plasma PGE<sub>2</sub> in the evening was not specifically increased and plasma PGE<sub>2</sub> was higher in the morning than in the evening during the last 7 days of pregnancy, while no such a trend was seen in the regular feeding group. Among cows with night-time feeding the diural pattern of plama PGE<sub>2</sub> was more apparent in cows which delivered in the day-time than those calved in the night-time. Changes of plasma PGE<sub>2</sub> in cows during a prepartum period are closely associated with plasma cortisol. The results indicate that a restraint of plasma PGE<sub>2</sub> increasing in the evening and a rise of plasma PGE<sub>2</sub> in the morning after night-time feeding plays an important role in increasing day-time calving.
- Nihon Chikusan Gakkaiho
Nihon Chikusan Gakkaiho 69(2), 133-139, 1998-02-25
Japanese Society of Animal Science