本試驗係在探討產蛋早期與高產對白色來亨新母雞與母雞血球相、血清動情素與助孕素濃度之影響。全部試驗分二個試驗進行，試驗一使用6 月齡新母雞40 隻，餵飼蛋雞商業飼料，採籠飼，水與飼料任飲食，並選取已開始產蛋與未產蛋之2 個雞群各10 隻後，由翼靜脈採取血樣。試驗二使用35 月齡母雞40 隻，飼養管理同試驗一，並從產蛋記錄選出高產與低產母雞之2 個雞群各10隻，由翼靜脈採取血樣。試驗一與試驗二所採集之血樣，分別測定血球相、 血清動情素與助孕素濃度，試驗結果顯示，尚未開產之白色來亨新母雞較早期產蛋者有顯著較高的紅血球數與血容比(P＜ 0.05)；正開始之產蛋母雞，其血液單核球與淋巴球數顯著較尚未產蛋者為低，而異嗜球數(H)、異嗜球與淋巴球數(L)之比值(H/L)，則以正開始產蛋的母雞顯著較未產蛋者為高(P ＜ 0.05)。在高產與低產母雞之紅血球相比較方面，除高產母雞之血紅素濃度較低產者為低 (P ＜ 0.05)外，其他紅血球相項目與白血球相分類比例在二者間均無顯著差異。開產白色來亨新母雞之血清動情素(E2)與助孕素(P4)之比值(E2/P4)較未開產者為低(P ＜ 0.05 )，而35 月齡高產與低產母雞之血清動情素與助孕素濃度及E2/P4 之比值均無顯著差異。綜合上述，從H/L 比值而言，新母雞進入產蛋係為一種生理緊迫，而老母雞則對產蛋緊迫已有適應性。另外，血清E2/P4 之比值對新母雞為產蛋之指標，但H/L 及E2/P4 比值對35 月齡母雞則非高產與低產之指標。
The objective of this study is to investigate the effect of early onset of lay and high egg production rate on blood cell profiles, sera estrogen and progesterone levels in white Leghorn pullets and hens. Two trials were conducted in this study. In trial I, forty of 6-month-old pullets were fed with commercial feed in cage, water and feed were supplied ad libutum. Each 10 pullets from laying and non-laying pullets were selected for wing vein blood withdrawn. In trial II, forty of 35-month-old hens were divided into high and low egg production groups according to their laying record. The animal management and sampling plan was the same as trial I. Blood samples were analyzed for blood cell profiles, sera estrogen and progesterone concentrations. The results indicated that non-laying pullets had higher erythrocyte number and hematocrit (P ＜ 0.05). Early laying pullets had lower monocytes and lymphocytes then non-laying pullets. The hetrophils and H/L ratio for early laying pullets were higher than those of non-laying pullets (P ＜ 0.05). There was no significant difference in erythrocyte and leukocyte profiles except for hemoglobin. The E2/P4 ratio for early laying pullets were lower than those of non-laying pullets (P ＜ 0.05). E2, P4 and E2/P4 ratio between high and low egg production in 35-month-old hens were not significantly different. Based on the change in H/L ratio, there exists a physiological stress for Leghorn pullets while entering laying phase; nevertheless, hens is considered adapted to the stress after laying for some time. In addition, the sera E2/P4 ratio can be used as an index of laying in pullets, but H/L ratio and E2/P4 ratio cannot be used as the index of high or low egg production rate for 35-month-old Leghorn hens.
