Gulliksen S M, Lie K I, Løken T, Osterås O
Department of Production Animal Clinical Sciences, Norwegian School of Veterinary Science, Oslo, Norway.
J Dairy Sci. 2009 Jun;92(6):2782-95. doi: 10.3168/jds.2008-1807.
The aims of this study were to estimate mortality rates in Norwegian dairy calves and young stock up to 1 yr of age, identify risk factors for calf mortality, and evaluate the etiology of calf mortality based on postmortem analyses. The material comprised 3 data sets. The first data set included information on 289,038 offspring in 14,474 dairy herds registered in the Norwegian Dairy Herd Recording System (NDHRS) in 2005. The second included recordings on 5,382 offspring in 125 Norwegian dairy herds participating in a survey on calf health, and the third included results from postmortem analyses of 65 calves from 37 of the survey herds. The calf mortality rate during the first year of life in all herds registered in the NDHRS was 7.8%, including abortion (0.7%) and stillbirth (3.4%). The overall calf mortality rate in liveborn calves in the survey herds was 4.6%. Cows with severe calving difficulties had an odds ratio (OR) of 38.7 of stillbirth compared with cows with no calving difficulties. Twins and triplets showed an increased risk of stillbirth compared with singletons (OR = 4.2 and 46.3, respectively), as did calves born in free stalls compared with tie stalls (OR = 1.9). Respiratory disease increased the risk of death in all age groups with hazard ratios (HR) of 6.4, 6.5, 7.4, and 5.6 during the first week of life, 8 to 30 d of age, 31 to 180 d of age, and 181 to 365 d of age, respectively. Diarrhea increased the risk of death among calves younger than 180 d of age, but the influence was only significant during the first week of life and between 8 to 31 d of age (HR = 2.4 and 2.9, respectively). Calves born during the winter were more likely to die during the first week of life than calves born during the summer (OR = 1.2), and were more likely to die during the first month of life than calves born during the autumn (OR = 1.2). Calf mortality rates in all age groups increased with increasing herd size. Calves housed in a group pen from 2 wk of age were more likely to die during the first month of life than calves housed individually (HR = 1.5). Bronchopneumonia and enteritis were the most frequent postmortem diagnoses, with proportional rates of 27.7 and 15.4%, respectively.
本研究的目的是估计挪威奶牛犊及1岁以下幼畜的死亡率，确定犊牛死亡的风险因素，并基于尸检分析评估犊牛死亡的病因。材料包括3个数据集。第一个数据集包含2005年挪威奶牛 herd Recording System（NDHRS）登记的14474个奶牛群中289038头后代的信息。第二个数据集包括125个参与犊牛健康调查的挪威奶牛群中5382头后代的记录，第三个数据集包括37个调查奶牛群中65头犊牛的尸检分析结果。NDHRS登记的所有牛群中，犊牛出生后第一年的死亡率为7.8%，包括流产（0.7%）和死产（3.4%）。调查奶牛群中活产犊牛的总体死亡率为4.6%。与无难产的母牛相比，有严重难产的母牛死产的优势比（OR）为38.7。双胞胎和三胞胎与单胞胎相比，死产风险增加（OR分别为4.2和46.3），与栓系牛舍出生的犊牛相比，自由牛舍出生的犊牛也是如此（OR = 1.9）。呼吸系统疾病增加了所有年龄组的死亡风险，在出生后第一周、8至30日龄、31至180日龄和181至365日龄时的风险比（HR）分别为6.4、6.5、7.4和5.6。腹泻增加了180日龄以下犊牛的死亡风险，但仅在出生后第一周和8至31日龄时影响显著（HR分别为2.4和2.9）。冬季出生的犊牛在出生后第一周比夏季出生的犊牛更易死亡（OR = 1.2），在出生后第一个月比秋季出生的犊牛更易死亡（OR = 1.2）。所有年龄组的犊牛死亡率随牛群规模的增加而增加。2周龄起就饲养在群栏中的犊牛在出生后第一个月比单独饲养的犊牛更易死亡（HR = 1.5）。支气管肺炎和肠炎是最常见的尸检诊断结果，比例分别为27.7%和15.4%。
