Mastitis in the transition period: identification of potential blood markers

ABSTRACT This study identified potential blood markers associated with mastitis in dairy cows under different dry therapies during the transition period, using a logistic regression model. Thirty-four Holstein dairy cows were divided into three groups: untreated controls (13 cows, 42 quarters); animals that received an antimicrobial at drying-off (10 cows, 40 quarters); and animals that were administered an internal teat sealant at drying-off (11 cow, 44 quarters). Blood and quarter milk samples were collected 60 days before the expected day of calving, on the day of calving, and three, seven, 15, 21, and 30 days after calving. Milk samples were submitted for bacteriological analysis and somatic cell count. Blood samples were collected for analyses of the following: the erythrogram and leucogram; plasm fibrinogen concentration; hepatic and renal functions; metabolic profile; serum calcium and phosphorous levels; total serum protein and albumin concentrations. The concentration of total serum proteins was associated with a high somatic cell count. Similarly, the concentrations of total serum proteins and triglycerides were associated to milk bacteriological positive samples during the transition period. Thus, the occurrence of mastitis in dairy cows during the transition period was greater in animals that showed higher concentrations of serum total proteins and triglycerides, in contrast to the use of dry cow therapy.

摘要 本研究采用逻辑回归模型（logistic regression model），筛选过渡期内接受不同干奶疗法（dry cow therapy）的荷斯坦奶牛（Holstein dairy cows）乳腺炎（mastitis）相关潜在血液标志物。本研究共纳入34头荷斯坦奶牛，分为3组：未干预对照组（13头奶牛，42个乳区）、干奶期施用抗菌药物组（10头奶牛，40个乳区），以及干奶期施用乳房内密封剂（internal teat sealant）组（11头奶牛，44个乳区）。分别于预期产犊日前60天、产犊当日，以及产犊后第3、7、15、21、30天采集血液与乳区奶样。奶样用于细菌学分析（bacteriological analysis）与体细胞计数（somatic cell count）；血样则开展以下检测：红细胞象（erythrogram）与白细胞象（leucogram）检测、血浆纤维蛋白原（plasma fibrinogen）浓度测定、肝肾功能（hepatic and renal functions）检测、代谢谱（metabolic profile）分析，以及血清钙、磷水平检测、总血清蛋白与白蛋白浓度测定。研究发现，总血清蛋白浓度与高水平体细胞计数呈显著关联；同理，过渡期内总血清蛋白与甘油三酯（triglycerides）浓度亦与细菌学检测阳性奶样存在关联。综上，相较于采用干奶疗法的奶牛，血清总蛋白与甘油三酯浓度较高的奶牛，其过渡期乳腺炎发生率更高。