Jasmin Bambi H, Boston Ray C, Modesto Rolf B, Schaer Thomas P
University Laboratory Animal Resources, Department of Clinical Studies, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, USA.
J Am Assoc Lab Anim Sci. 2011 Jan;50(1):27-32.
Little information is available on normal ruminal pH values for domestic sheep (Ovis aries) housed in a research setting and fed a complete pelleted ration. Sheep maintained on pelleted diets undergoing surgical procedures often present with postoperative anorexia and rumen atony. To determine the relationship between diet and postoperative rumen acidosis and associated atony, we studied dietary effects on ruminal pH in an ovine surgical model. Sheep undergoing orthopedic surgical procedures were randomized into 2 diet groups. Group 1 (n = 6) was fed complete pelleted diet during the pre- and postoperative period, and group 2 (n = 6) was fed timothy grass hay exclusively throughout the study. Measures included ruminal pH, ruminal motility, and rate of feed refusal, which was monitored throughout the pre- and postoperative periods. The 2 groups did not differ significantly before surgery, and the ruminal parameters remained largely within normal limits. However, a downward trend in the strength and frequency of rumen contractions was observed in pellet-fed sheep. After surgery, the pellet-fed group showed clinical signs consistent with ruminal acidosis, supported by decreased ruminal motility, anorexia, putrid-smelling ruminal material, and death of ruminal protozoa. Intervention by transfaunation in clinically affected sheep resulted in resolution of signs. Our findings suggest that sheep fed grass hay appear to have a more stable ruminal pH, are less likely to experience anorexia and rumen atony, and thereby exhibit fewer postoperative gastrointestinal complications than do sheep on a pellet diet.
关于在研究环境中饲养并喂食完全颗粒饲料的家养绵羊（Ovis aries）的正常瘤胃pH值，目前可用信息较少。接受手术的绵羊若持续食用颗粒饲料，术后常出现食欲不振和瘤胃弛缓。为确定饮食与术后瘤胃酸中毒及相关弛缓之间的关系，我们在绵羊手术模型中研究了饮食对瘤胃pH值的影响。接受骨科手术的绵羊被随机分为2个饮食组。第1组（n = 6）在术前和术后期间喂食完全颗粒饲料，第2组（n = 6）在整个研究期间仅喂食提摩西草干草。测量指标包括瘤胃pH值、瘤胃蠕动和采食量拒绝率，在术前和术后期间均进行监测。两组在手术前无显著差异，瘤胃参数基本保持在正常范围内。然而，喂食颗粒饲料的绵羊瘤胃收缩强度和频率呈下降趋势。手术后，喂食颗粒饲料的组出现了与瘤胃酸中毒一致的临床症状，表现为瘤胃蠕动减弱、食欲不振、瘤胃内容物有腐臭味以及瘤胃原生动物死亡。对临床受影响的绵羊进行瘤胃微生物移植干预后，症状得到缓解。我们的研究结果表明，与喂食颗粒饲料的绵羊相比，喂食干草的绵羊瘤胃pH值似乎更稳定，更不容易出现食欲不振和瘤胃弛缓，因此术后胃肠道并发症也更少。
