Bertoni Emiliano, Barragán Adrián A, Bok Marina, Vega Celina, Martínez Marcela, Gil José F, Cimino Rubén O, Parreño Viviana
Área de Investigación en Salud Animal, IIACS-CIAP, INTA EEA Salta, Cerrillos A4403, Argentina.
Veterinary Extension, Field Investigation & Research, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, State College, PA 16801, USA.
Animals (Basel). 2021 Sep 9;11(9):2652. doi: 10.3390/ani11092652.
Scours is the most common disease in dairy calves, and it is a multifactorial syndrome complex. sp. (C. sp.), rotavirus group A (RVA), and bovine coronavirus (BCoV) are the three main pathogens associated with scours. The objective of this study was to identify potential factors associated with scours, C. sp., RVA, and BCoV infections in preweaned dairy calves from Lerma Valley in Salta Province, Argentina. A total of 488 preweaned calves from 19 dairy farms located in the Lerma Valley were enrolled in this observational study. One fecal sample was collected from each calf between one week and two months of age for assessment of C. sp., RVA, and BCoV infection status. sp. oocysts and RVA and BCoV antigens in fecal samples were assessed using microscopic observation and indirect enzyme-linked immune sorbent assay (iELISA), respectively. A voluntary questionnaire was developed and used to collect data regarding management practices from the participants' farms. The data were analyzed using multivariable logistic regression models. Scours incidence was 35.4%, and a greater proportion of calves younger than 20 days were affected. Of the fecal samples, 18% and 9.5% tested were positives for C. sp. and RVA, respectively, while BCoV was detected only in two calves. Furthermore, 84.2% and 63.1% of the farms tested positive for sp. and RVA, respectively. In addition, the following variables were associated with higher odds of having scours: (1) herd size (>300 milking cows; OR = 1.7), (2) calf age (<20 days of age; OR = 2.2), (3) RVA and C. sp. test (positive test; RVA OR = 2.6; C. sp. OR = 3), calf feeding practices (feeding milk replacer; OR = 1.81), and newborn calf management practices (calf moved from maternity pen <6 h after calving; OR = 1.7). Concerning RVA infection, calves less than 20 days of age (OR = 2.6) had a higher chance of testing positive for RVA, while calves that remained in the calving pen for less than 6 h after calving had a lower chance (OR = 0.3). On the other hand, for C. sp. infection, large farm size (>300 milking cows; OR = 1.2) and young calf age (<20 days of age; OR = 4.4) indicated a higher chance of testing positive for C. sp., while calves belonging to farms that fed frozen colostrum (OR = 0.2) had a lower chance of becoming infected with C. sp. The result of this study indicated that scours is a prevalent disease in farms of the Lerma Valley, Salta, Argentina, and that RVA and C. sp. infections, along with specific farm management practices, might be important contributing factors that could increase the chance of NCS in dairy farms.
腹泻是奶牛犊牛最常见的疾病，是一种多因素综合征。梭状芽孢杆菌（C. sp.）、A组轮状病毒（RVA）和牛冠状病毒（BCoV）是与腹泻相关的三种主要病原体。本研究的目的是确定阿根廷萨尔塔省莱尔马山谷断奶前奶牛犊牛腹泻、C. sp.、RVA和BCoV感染的潜在相关因素。本观察性研究纳入了位于莱尔马山谷的19个奶牛场的488头断奶前犊牛。在犊牛1周龄至2月龄期间，从每头犊牛采集一份粪便样本，以评估C. sp.、RVA和BCoV感染状况。分别使用显微镜观察和间接酶联免疫吸附测定（iELISA）评估粪便样本中的C. sp.卵囊以及RVA和BCoV抗原。编制了一份自愿调查问卷，用于收集参与者农场的管理实践数据。使用多变量逻辑回归模型对数据进行分析。腹泻发病率为35.4%，20日龄以下的犊牛受影响比例更高。在粪便样本中，分别有18%和9.5%的样本检测出C. sp.和RVA呈阳性，而仅在两头犊牛中检测到BCoV。此外，分别有84.2%和63.1%的农场检测出C. sp.和RVA呈阳性。此外，以下变量与腹泻几率较高相关：（1）牛群规模（>300头泌乳奶牛；OR = 1.7），（2）犊牛年龄（<20日龄；OR = 2.2），（3）RVA和C. sp.检测（检测呈阳性；RVA的OR = 2.6；C. sp.的OR = 3），犊牛饲养方式（饲喂代乳品；OR = 1.81），以及新生犊牛管理方式（犊牛在出生后<6小时从产房转出；OR = 1.7）。关于RVA感染，20日龄以下的犊牛检测出RVA呈阳性的几率更高（OR = 2.6），而在出生后在产房停留时间少于6小时的犊牛检测呈阳性的几率较低（OR = 0.3）。另一方面，对于C. sp.感染，大农场规模（>300头泌乳奶牛；OR = 1.2）和犊牛年龄小（<20日龄；OR = 4.4）表明检测出C. sp.呈阳性的几率更高，而属于饲喂冷冻初乳农场的犊牛感染C. sp.的几率较低（OR = 0.2）。本研究结果表明，腹泻在阿根廷萨尔塔省莱尔马山谷的农场中是一种普遍疾病，RVA和C. sp.感染以及特定的农场管理实践可能是增加奶牛场犊牛腹泻几率的重要因素。
