An algorithm using only computer-based records to guide selective dry-cow therapy was evaluated at a New York State dairy farm via a randomized field trial. DairyComp 305 (Valley Ag Software, Tulare, CA) and Dairy Herd Improvement Association test-day data were used to identify cows as low risk (cows that might not benefit from dry-cow antibiotics) or high risk (cows that will likely benefit). Low-risk cows were those that had all of the following: somatic cell count (SCC) ≤200,000 cells/mL at last test, an average SCC ≤200,000 cells/mL over the last 3 tests, no signs of clinical mastitis at dry-off, and no more than 1 clinical mastitis event in the current lactation. Low-risk cows were randomly assigned to receive intramammary antibiotics and external teat sealant (ABXTS) or external teat sealant only (TS) at dry-off. Using pre-dry-off and postcalving quarter-level culture results, low-risk quarters were assessed for microbiological cure risk and new infection risk. Groups were also assessed for differences in first-test milk yield and linear scores, individual milk weights for the first 30 d, and culling and mastitis events before 30 d in milk. A total of 304 cows and 1,040 quarters in the ABXTS group and 307 cows and 1,058 quarters in the TS group were enrolled. Among cows to be dried, the proportion of cows that met low-risk criteria was 64% (n = 611/953). Of cultures eligible for bacteriological cure analysis (n = 171), 93% of ABXTS cured, whereas 88% of TS cured. Of the non-cures, 95% were contributed by the minor pathogens coagulase-negative staphylococci (n = 19/20). These organisms also accounted for 57.5% of new infections (n = 77/134). We found no statistical differences between treatment groups for new infection risk (TS = 7.3% quarters experiencing new infections; ABXTS = 5.5%), milk production (ABXTS = 40.5 kg; TS = 41.2 kg), linear scores (ABXTS = 2.5; TS = 2.7), culling events (ABXTS, n = 18; TS, n = 15), or clinical mastitis events (ABXTS, n = 9; TS, n = 5). Results suggest that the algorithm used decreased dry-cow antibiotic use by approximately 60% without adversely affecting production or health outcomes.

在纽约州的一家奶牛场，通过一项随机的田间试验评估了仅使用基于计算机的记录来指导选择性干牛治疗的算法。DairyComp 305（Valley Ag Software，加利福尼亚州Tulare）和奶牛改良协会的测试日数据用于确定奶牛是低风险（可能不会从干牛抗生素中受益的母牛）还是高风险（可能会受益的母牛） 。低风险奶牛具有以下所有特征：最后一次测试的体细胞计数（SCC）≤200,000个细胞/ mL，最近三个测试中的平均SCC≤200,000个细胞/ mL，干燥时没有临床乳腺炎的迹象关闭，并且当前哺乳期发生的临床乳腺炎事件不超过1次。低风险奶牛被随机分配在干奶时接受乳内抗生素和乳头外用密封剂（ABXTS）或仅乳头外用密封剂（TS）。使用干燥前和产犊后的四分之一水平培养结果，对低风险的四分之一进行了微生物治愈风险和新感染风险的评估。还对各组进行了评估，以评估初试牛奶产量和线性评分的差异，前30天的单个牛奶重量以及30天之前的淘汰和乳腺炎事件。ABXTS组共有304头母牛和1,040个季度，TS组共有307头母牛和1,058个季度。在要干燥的母牛中，符合低风险标准的母牛比例为64％（n = 611/953）。在符合细菌学治愈分析要求的培养物中（n = 171），有93％的ABXTS治愈了，而88％的TS治愈了。在非治愈病例中，有95％是由次要病原体凝固酶阴性葡萄球菌引起的（n = 19/20）。这些生物也占新感染的57.5％（n = 77/134）。我们发现治疗组之间在新感染风险（TS = 7.3％经历新感染的季度； ABXTS = 5.5％），产奶量（ABXTS = 40.5 kg； TS = 41.2 kg），线性评分（ABXTS = 2.5； TS）之间没有统计学差异= 2.7），剔除事件（ABXTS，n = 18； TS，n = 15）或临床乳腺炎事件（ABXTS，n = 9； TS，n = 5）。结果表明，所使用的算法将干牛抗生素的使用量减少了约60％，而不会对生产或健康结果产生不利影响。