Dinsmore R P, Stevens R D, Cattell M B, Salman M D, Sundlof S F
Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523, USA.
J Am Vet Med Assoc. 1996 Nov 15;209(10):1753-5.
To establish the maximum concentration and duration of oxytetracycline residues in milk from cows with retained fetal membranes given the antimicrobial via intrauterine infusion, and to investigate whether the number of infusions or the presence of fever (> 39.7 C) affected the duration of residues.
Prospective study.
54 Holstein cows with retained fetal membranes on a single 1,400-cow commercial dairy.
Cows were treated once a day with 5 g of oxytetracycline (50 ml of 100 mg/ml solution in a povidone base) by intrauterine infusion for at least 2 days, or until the membranes were expelled. Cows that became febrile (rectal temperature > or = 39.7 C) were also given 20,000 IU of procaine penicillin G/kg of body weight, i.m., for 2 to 4 days. Milk samples were collected at 24-hour intervals during treatment. and at 12-hour intervals after the last treatment. All samples were frozen and submitted every 2 weeks for high performance liquid chromatography analysis for oxytetracycline.
Oxytetracycline was detected in milk of all cows during treatment, at a maximum concentration ranging from 47.2 to 1,804.6 micrograms/kg (mean, 316.9 micrograms/kg). Duration of oxytetracycline residues after the last infusion ranged from 0 to 144 hours (mean, 52.3 hours). Neither the number of infusions received, nor development of rectal temperature > 39.7 C, affected the maximum concentration or the duration of oxytetracycline residues in milk.
Milk obtained from cows that had been treated for retained fetal membranes by intrauterine infusion of oxytetracycline should be discarded to avoid illegal residues.
确定经子宫内输注抗菌药物的胎膜滞留奶牛所产牛奶中土霉素残留的最高浓度和持续时间，并研究输注次数或发热（>39.7℃）是否会影响残留持续时间。
前瞻性研究。
来自一个拥有1400头奶牛的商业奶牛场的54头患有胎膜滞留的荷斯坦奶牛。
奶牛每天经子宫内输注5克土霉素（50毫升100毫克/毫升的聚维酮溶液），持续至少2天，或直至胎膜排出。发热（直肠温度≥39.7℃）的奶牛还按每千克体重20000国际单位的剂量肌肉注射普鲁卡因青霉素G，持续2至4天。在治疗期间每隔24小时采集一次牛奶样本，并在最后一次治疗后每隔12小时采集一次。所有样本均冷冻保存，每两周提交一次，用于土霉素的高效液相色谱分析。
治疗期间所有奶牛的牛奶中均检测到土霉素，最高浓度范围为47.2至1804.6微克/千克（平均316.9微克/千克）。最后一次输注后土霉素残留的持续时间为0至144小时（平均52.3小时）。输注次数和直肠温度>39.7℃均未影响牛奶中土霉素残留的最高浓度或持续时间。
通过子宫内输注土霉素治疗胎膜滞留的奶牛所产的牛奶应予以丢弃，以避免非法残留。
