Miles Asha M, McArt Jessica A A, Leal Yepes Francisco A, Stambuk Cassandra R, Virkler Paul D, Huson Heather J
Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, 14853, United States.
Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, United States.
Prev Vet Med. 2019 Feb 1;163:7-13. doi: 10.1016/j.prevetmed.2018.12.010. Epub 2018 Dec 15.
Our primary objective was to identify udder and teat conformational risk factors associated with the occurrence of elevated somatic cell count (SCC) and clinical mastitis using a prospective cohort study design with careful assessment of exposure and disease outcomes. Mastitis prevalence was evaluated by parity across 6 sampling periods representing key physiological transitions during lactation: 0-1 day in milk (DIM), 3-5 DIM, 10-14 DIM, 50-60 DIM, 90-110 DIM, and 210-230 DIM. Cows were scored for front and rear teat length, width, end shape, and placement, fore udder attachment, udder cleft, udder depth, rear udder height, and rear udder width. Two independent multivariable logistic regression models were used to generate odds ratios (OR) for elevated SCC (≥ 200,000 cells/ml) and farm-diagnosed clinical mastitis. We identified that loose fore udder attachment (reference level: strong fore udder attachment, OR = 2.1, 95% confidence interval (CI) = 1.2-3.8) and flat teat end shape (reference level: round teat end shape, OR = 1.4, 95% CI = 1.1-1.9) increased the odds of an elevated SCC event, whereas a negative California Mastitis Test score at 0-1 DIM decreased the odds of an elevated SCC event (OR = 0.6, 95% CI = 0.4 to 0.8). Loose fore udder attachment (reference level: strong fore udder attachment, OR = 3.7, 95% CI = 1.3-10.7), flat teat end shape (reference level: round teat end shape, OR = 1.5, 95% CI = 1.0-2.4), low rear udder height (reference level: intermediate rear udder height, OR = 2.8, 95% CI = 0.3-6.2), and increasing rear teat width (OR = 2.2, 95% CI = 1.2-4.4) heightened the odds of developing clinical mastitis. We identified that within our study cohort, loose fore udder attachment and flat teat ends had an important association with increased odds of both an elevated SCC event and clinical mastitis diagnosis. The identification of these udder and teat conformational risk factors for mastitis can provide farmers an effective and inexpensive tool to manage mastitis.
我们的主要目标是采用前瞻性队列研究设计，通过仔细评估暴露因素和疾病结局，确定与体细胞数（SCC）升高及临床型乳腺炎发生相关的乳房和乳头形态风险因素。通过胎次评估乳腺炎患病率，涵盖泌乳期6个代表关键生理转变的采样时间段：产犊后0 - 1天（DIM）、3 - 5 DIM、10 - 14 DIM、50 - 60 DIM、90 - 110 DIM以及210 - 230 DIM。对奶牛的前后乳头长度、宽度、末端形状和位置、前乳房附着情况、乳房裂、乳房深度、后乳房高度以及后乳房宽度进行评分。使用两个独立的多变量逻辑回归模型生成SCC升高（≥200,000个细胞/毫升）和农场诊断的临床型乳腺炎的比值比（OR）。我们发现前乳房附着松弛（参考水平：前乳房附着牢固，OR = 2.1，95%置信区间（CI）= 1.2 - 3.8）和平坦的乳头末端形状（参考水平：圆形乳头末端形状，OR = 1.4，95% CI = 1.1 - 1.9）会增加SCC升高事件的几率，而在0 - 1 DIM时加利福尼亚乳腺炎检测评分呈阴性会降低SCC升高事件的几率（OR = 0.6，95% CI = 0.4至0.8）。前乳房附着松弛（参考水平：前乳房附着牢固，OR = 3.7，95% CI = 1.3 - 10.7）、平坦的乳头末端形状（参考水平：圆形乳头末端形状，OR = 1.5，95% CI = 1.0 - 2.4）、较低的后乳房高度（参考水平：中等后乳房高度，OR = 2.8，95% CI = 0.3 - 6.2）以及后乳头宽度增加（OR = 2.2，95% CI = 1.2 - 4.4）会增加发生临床型乳腺炎的几率。我们发现在我们的研究队列中，前乳房附着松弛和平坦的乳头末端与SCC升高事件和临床型乳腺炎诊断几率增加均有重要关联。确定这些乳腺炎的乳房和乳头形态风险因素可为奶农提供一种有效且低成本的乳腺炎管理工具。
