Jones K L, King S S, Griswold K E, Cazac D, Cross D L
Department of Animal Science, Food & Nutrition, Southern Illinois University Carbondale, Carbondale, USA.
J Anim Sci. 2003 Oct;81(10):2568-74. doi: 10.2527/2003.81102568x.
The aim of this study was to evaluate the effect of a dopamine antagonist, domperidone, in nonpregnant, reproductively cycling heifers consuming endophyte-infected (EI) fescue diets. Thirty crossbred heifers (Angus x Holstein or Hereford x Holstein) were assigned to one of three treatment groups (n = 10); endophyte-free (EF) fescue diet, EI fescue diet, or endophyte-infected diet and treated with domperidone (EID). Heifers fed EI diets had decreased weight gains compared with heifers fed EF or EID (P < 0.05) during a 21-d treatment period. Ovarian structures were monitored via transrectal ultrasound to determine follicle size and day of ovulation. Blood plasma samples were collected daily and analyzed for progesterone concentration to determine luteal function. Heifers ingesting EI diets had estrous cycles of shorter duration and lower mid-cycle progesterone concentrations than heifers in the EF or EID treatments (P < 0.05). Ovaries from a subset of heifers in each group (n = 3 per group) were harvested and in vitro secretion of progesterone from luteal tissue extracts was determined. No differences in progesterone concentrations were detected among luteal tissue incubates (P > 0.05). These results suggest that domperidone supplementation of heifers consuming EI fescue may ameliorate certain symptoms of fescue toxicosis.
本研究的目的是评估多巴胺拮抗剂多潘立酮对食用内生菌感染（EI）羊茅日粮的未怀孕、处于生殖周期的小母牛的影响。将30头杂交小母牛（安格斯×荷斯坦或赫里福德×荷斯坦）分配到三个处理组之一（n = 10）；无内生菌（EF）羊茅日粮组、EI羊茅日粮组或内生菌感染日粮并接受多潘立酮处理组（EID）。在21天的处理期内，与饲喂EF或EID日粮的小母牛相比，饲喂EI日粮的小母牛体重增加减少（P < 0.05）。通过经直肠超声监测卵巢结构，以确定卵泡大小和排卵日。每天采集血浆样本并分析孕酮浓度，以确定黄体功能。与EF或EID处理组的小母牛相比，摄入EI日粮的小母牛发情周期持续时间更短，周期中期孕酮浓度更低（P < 0.05）。采集每组一部分小母牛（每组n = 3）的卵巢，测定黄体组织提取物中孕酮的体外分泌量。黄体组织培养物中未检测到孕酮浓度的差异（P > 0.05）。这些结果表明，给食用EI羊茅的小母牛补充多潘立酮可能会改善羊茅中毒的某些症状。
