The objective of this experiment was to determine the effect of intramammary calcitriol treatment on indicators of inflammation during an intramammary bacterial infection. Lactating Holstein cows were challenged with intramammary Streptococcus uberis. At the onset of mild or moderate mastitis, cows were randomly assigned to receive 10 µg of intramammary calcitriol (CAL, n = 7) or placebo control (CON; n = 6) after every milking for 5 days. Data were analyzed by ANOVA with mixed models using the MIXED procedure of SAS with significance declared at P ≤ 0.05. Milk somatic cells, mastitis severity scores, rectal temperatures, and milk bacterial counts did not differ between treatments. Calcitriol decreased the percentage of CD11b⁺CD14^- cells in milk compared with CON (CON = 81 vs. CAL = 61 ± 5%). Antioxidant potential and concentrations of 15-F_2t- isoprostanes in milk of infected quarters also were lower in CAL compared with CON. Transcripts for the 25-hydroxyvitamin D 24-hydroxylase and inducible nitric oxide synthase were greater in milk somatic cells of CAL compared with CON, but those for β-defensin 7, metallothionein 1 A and 2 A, thioredoxin and thioredoxin reductase did not differ between treatments. Although clinical signs of severity did not differ, CAL influenced the composition of milk somatic cells and redox activity in milk of infected quarters.

本实验的目的是确定乳房内骨化三醇治疗对乳房内细菌感染期间炎症指标的影响。哺乳期荷斯坦奶牛受到乳房内乳房链球菌的攻击。在轻度或中度乳腺炎发作时，奶牛被随机分配接受 10 µg 乳房内骨化三醇（CAL ，n = 7）或安慰剂对照（CON；n = 6），连续 5 天，每次挤奶后。使用 SAS 的 MIXED 程序通过混合模型的 ANOVA 分析数据，显着性声明为P  ≤ 0.05。乳汁体细胞、乳腺炎严重程度评分、直肠温度和乳汁细菌计数在治疗之间没有差异。与 CON 相比，骨化三醇降低了牛奶中^{CD11b +} CD14 ^-细胞的百分比（CON = 81 vs. CAL = 61 ± 5%）。与 CON 相比，CAL 中受感染地区牛奶中的抗氧化潜力和 15-F _2t - 异前列腺素浓度也较低。与 CON 相比，CAL 乳汁体细胞中25-羟基维生素 D 24-羟化酶和诱导型一氧化氮合酶的转录本较多，但 β-防御素 7、金属硫蛋白1 A 和 2 A、硫氧还蛋白和硫氧还蛋白还原酶的转录本在 CAL 和 CON 之间没有差异。治疗。尽管严重程度的临床症状没有差异，但 CAL 影响了受感染地区乳汁体细胞的组成和乳汁氧化还原活性。