Humer E, Ghareeb K, Harder H, Mickdam E, Khol-Parisini A, Zebeli Q
Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, 1210 Vienna, Austria.
Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, 1210 Vienna, Austria; Faculty of Veterinary Medicine, South Valley University, 83523 Qena, Egypt.
J Dairy Sci. 2015 Dec;98(12):8788-99. doi: 10.3168/jds.2015-9893.
The present study aimed to investigate changes in the reticuloruminal pH and temperature dynamics in periparturient dairy cows. Reticuloruminal pH and temperature measurements were conducted from 7 d before until 8 d after parturition using indwelling sensors. Nine Simmental and 4 Brown Swiss dairy cows were fed a close-up total mixed ration (52.5% neutral detergent fiber, 5.68MJ of net energy for lactation per kg of dry matter) with additional 1kg/cow per d concentrate mixture (29.5% neutral detergent fiber and 6.25MJ of net energy for lactation per kg of dry matter), starting from 2 wk before the estimated calving date. Postpartum, all cows had free access to the same close-up diet and were gradually fed increasing amounts of a concentrate-rich total mixed ration for early-lactation cows (32.7% neutral detergent fiber, 7.22MJ of net energy for lactation per kg of dry matter). Data showed depressed reticuloruminal pH early postpartum, but only in the group of cows defined as subacute ruminal acidosis (SARA) susceptible (n=8), which had a higher duration time of pH <5.8 (753±82min/d) compared with SARA-tolerant cows (n=5; 15±6min/d). Also, compared with SARA-tolerant cows (112±91min/d), the SARA-susceptible group showed longer (1,049±75min/d) duration time of pH <6.0. When compared by breed, mean reticuloruminal pH tended to be lower in Simmental (6.16±0.03) than in Brown Swiss cows (6.25±0.05), but no differences were observed in the duration of pH <5.8 between breeds. Simmental cows produced more milk (30.4±1.2kg/d) compared with Brown Swiss cows (27.9±1.3kg/d). Neither total dry matter intake nor milk yield were different between SARA-susceptible and SARA-tolerant groups. However, SARA-tolerant cows consumed greater amounts of the close-up total mixed ration than their SARA-susceptible counterparts, whereas no difference was observed in the intake of the early-lactating total mixed ration between the groups. Reticuloruminal temperature was not affected by breed or SARA susceptibility. Interestingly, the mean reticuloruminal temperature and the time duration of temperature >39.5°C abruptly dropped from d 2 to 1 before calving by 0.35°C and 430min/d, respectively. In conclusion, the strong inter-animal variation in reticuloruminal pH responses suggests the need for more careful monitoring and differentiated feeding management of cows during the transition period, whereby the SARA-susceptible cows may require particular attention regarding feeding management and diet composition. The abrupt decrease in reticuloruminal temperature the day before parturition may enable this noninvasive method as a management tool for prediction of parturition time.
本研究旨在调查围产期奶牛瘤网胃pH值和温度动态变化。使用植入式传感器在分娩前7天至分娩后8天进行瘤网胃pH值和温度测量。从预计产犊日期前2周开始，给9头西门塔尔奶牛和4头瑞士褐牛饲喂预产全混合日粮（中性洗涤纤维含量52.5%，每千克干物质泌乳净能5.68MJ），并额外每天每头奶牛添加1千克精料混合物（中性洗涤纤维含量29.5%，每千克干物质泌乳净能6.25MJ）。产后，所有奶牛可自由采食相同的预产日粮，并逐渐增加富含精料的早期泌乳奶牛全混合日粮的饲喂量（中性洗涤纤维含量32.7%，每千克干物质泌乳净能7.22MJ）。数据显示产后早期瘤网胃pH值降低，但仅在被定义为易患亚急性瘤胃酸中毒（SARA）的奶牛组（n = 8）中出现，与耐SARA奶牛（n = 5；15±6分钟/天）相比，该组pH值<5.8的持续时间更长（753±82分钟/天）。此外，与耐SARA奶牛（112±91分钟/天）相比，易患SARA的组pH值<6.0的持续时间更长（1,049±75分钟/天）。按品种比较时，西门塔尔奶牛（6.16±0.03）的瘤网胃平均pH值往往低于瑞士褐牛（6.25±0.05），但品种间pH值<5.8的持续时间未观察到差异。西门塔尔奶牛的产奶量（30.4±1.2千克/天）高于瑞士褐牛（27.9±1.3千克/天）。SARA易患组和耐SARA组之间的总干物质摄入量和产奶量均无差异。然而，耐SARA奶牛比其易患SARA的同组奶牛消耗更多的预产全混合日粮，而两组之间早期泌乳全混合日粮的摄入量未观察到差异。瘤网胃温度不受品种或SARA易感性的影响。有趣的是，瘤网胃平均温度和温度>39.5°C的持续时间在分娩前2天至1天分别突然下降0.35°C和430分钟/天。总之，瘤网胃pH值反应在动物之间存在很大差异，这表明在过渡期需要更仔细地监测奶牛并进行差异化饲养管理，因此对于易患SARA的奶牛，在饲养管理和日粮组成方面可能需要特别关注。分娩前一天瘤网胃温度的突然下降可能使这种非侵入性方法成为预测分娩时间的管理工具。
