Department of Internal Medicine, College of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo 05508-270, Brazil.
Biological Institute, 1252 Conselheiro Rodrigues Alves Ave, Vila Mariana, São Paulo 04014-900, Brazil.
Viruses. 2020 Jul 15;12(7):760. doi: 10.3390/v12070760.
The aim of this study was to evaluate secondary clinical disease, milk production efficiency and reproductive performance of heifers and cows persistently infected (PI) with bovine viral diarrhea virus type 2 (BVDV type 2). PI animals ( = 25) were identified using an antigen capture ELISA of ear notch samples. They were distributed into three age groups: ≤ 12 ( = 8), 13 to 24 ( = 6) and 25 to 34 ( = 11) months old. A control group of BVDV antigen ELISA negative female cattle that were age matched to the PI animals was utilized from the same herd. The PI group had a 1.29 higher odds ratio for diarrhea than controls ( = 0.001, IC95% = 1.032-1.623) and 1.615 greater chance of developing bovine respiratory disease (BRD) ( = 0.012, IC95% = 1.155-2.259). The age at first insemination ( = 0.012) and number of insemination attempts required to establish the first pregnancy ( = 0.016) were both higher for PI than controls. Milk production was higher for control cows than PI cows during most of the sampling periods. Somatic cell counts (SCC) were higher in PI cows than the controls at all sampling points across lactation ( ≤ 0.042). PI cattle had a higher incidence of disease, produced less milk, a higher SCC, and poorer reproductive performance than control cattle in this study.
本研究旨在评估持续感染牛病毒性腹泻病毒 2 型（BVDV 2 型）的小母牛和奶牛的继发临床疾病、产奶效率和繁殖性能。通过耳标样本的抗原捕获 ELISA 来鉴定持续感染动物（=25）。它们分为三个年龄组：≤12 月龄（=8）、13-24 月龄（=6）和 25-34 月龄（=11）。从同一牛群中选择 BVDV 抗原 ELISA 阴性的年龄匹配的雌性奶牛作为对照组。PI 组发生腹泻的几率比对照组高 1.29 倍（=0.001，95%CI=1.032-1.623），患牛呼吸道疾病（BRD）的几率高 1.615 倍（=0.012，95%CI=1.155-2.259）。PI 组的首次配种年龄（=0.012）和首次妊娠所需的配种尝试次数（=0.016）均高于对照组。在大多数采样期间，对照组奶牛的产奶量高于 PI 组奶牛。在整个泌乳期，PI 组奶牛的体细胞计数（SCC）在所有采样点均高于对照组（≤0.042）。在本研究中，PI 牛的疾病发病率更高，产奶量更低，SCC 更高，繁殖性能更差。
