Stevenson J S, Knoppel E L, Minton J E, Salfen B E, Garverick H A
Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506-0201.
J Anim Sci. 1994 Mar;72(3):690-9. doi: 10.2527/1994.723690x.
Angus x Hereford multiparous cows were assigned to four treatments: 1) mastectomized+calf weaned at birth (MCW; n = 7); 2) mastectomized+calf presence restricted to noninguinal contact (MCR; n = 7); 3) mastectomized+unrestricted calf presence (MCP; n = 7); and 4) udder-intact cows+unrestricted calf presence (UICP; n = 8). Except for MCW cows, cow-calf pairs were penned together individually from parturition (d 0) until d 35 when calves were weaned. On d 7, calves in MCP and UICP treatments were separated overnight from their dams, and before and upon reunion, blood samples were collected from the cows to assess changes in oxytocin, cortisol, and prolactin. Calves in the MCP and UICP treatments attempted to or suckled their dams for a similar duration upon reunion, respectively. Concentrations of cortisol and percentage of change in oxytoxin and prolactin were increased (P < .05) for up to 12 min in MCP cows after reunion with their calves. Average concentrations of serum LH in samples collected on d 14, 21, 28, and 35 did not differ in noncyclic cows among treatments within day postpartum (except for greater [P < .05] LH in MCW cows on d 21). However, MCP cows had more (P < .05) LH pulses (d 21), greater (P < .05) variability in LH pulses (d 21), greater (P < .05) variability in LH concentrations, and greater (P < .05) average maximum concentrations of LH than UICP cows after d 14. Intervals to first ovulation were similar in MCW and MCR cows but shorter (P < .01) than those in MCP and UICP cows. Attempted suckling of mastectomized dams by their calves was associated with increased serum cortisol and percentage of increase in serum oxytocin and prolactin. Despite increased LH in MCP cows, intervals to first ovulation did not differ from those of UICP cows.
1）乳房切除 + 犊牛出生时断奶（MCW；n = 7）；2）乳房切除 + 犊牛存在但仅限于非腹股沟接触（MCR；n = 7）；3）乳房切除 + 犊牛无限制存在（MCP；n = 7）；4）乳房完整的母牛 + 犊牛无限制存在（UICP；n = 8）。除了MCW组的母牛外，母牛 - 犊牛对从分娩（第0天）开始单独圈养在一起，直到第35天犊牛断奶。在第7天，MCP和UICP处理组的犊牛与它们的母亲分开过夜，在重聚之前和重聚时，从母牛采集血样以评估催产素、皮质醇和催乳素的变化。MCP和UICP处理组的犊牛在重聚时分别试图或吸吮它们的母亲的时间相似。与犊牛重聚后，MCP组的母牛在长达12分钟的时间内，皮质醇浓度以及催产素和催乳素的变化百分比均升高（P < 0.05）。在产后第14、21、28和35天采集的样本中，非发情周期的母牛在产后当天各处理组之间血清促黄体生成素（LH）的平均浓度没有差异（除了第21天MCW组的母牛LH更高 [P < 0.05]）。然而，在第14天后MCP组的母牛比UICP组的母牛有更多（P < 0.05）的LH脉冲（第21天）、更大（P < 0.05）的LH脉冲变异性（第21天）、更大（P < 0.05）的LH浓度变异性以及更大（P < 0.05）的LH平均最大浓度。MCW和MCR组的母牛到首次排卵的间隔相似，但比MCP和UICP组的母牛短（P < 0.01）。犊牛试图吸吮乳房切除的母牛与血清皮质醇增加以及血清催产素和催乳素增加的百分比相关。尽管MCP组的母牛LH增加，但到首次排卵的间隔与UICP组的母牛没有差异。
