Corlett N J, Peters R R, Paape M J, Schultze W D
J Dairy Sci. 1984 Nov;67(11):2571-9. doi: 10.3168/jds.S0022-0302(84)81615-X.
Effectiveness of a polyethylene intramammary device against naturally occurring infections was evaluated in three Maryland herds over 2 yr. Treated cows [62] were fitted with intramammary devices in all quarters of udders. Control cows [62] were sham treated. Rates of new intramammary infection over single lactation in treated and control quarters of primiparous cows averaged 18 and 27%. Reduction of infection rate was due primarily to fewer Corynebacterium bovis infections. Infection rate between multiparous cow treatments were similar. In uninfected quarters cell counts in strippings averaged .11 to .13 X 10(6)/ml and in quarters fitted with intramammary devices concentrations were only .22 to .31 X 10(6) cells/ml. But in infected quarters with intramammary devices, cell counts of strippings were 1.38 to 1.48 X 10(6)/ml. Concentrations of somatic cells of strippings in infected quarters without devices averaged .48 to .63 X 10(6)/ml. Dairy herd improvement cell counts for primiparous and multiparous cows with and without intramammary devices were similar and averaged .2 X 10(6)/ml. Neither milk nor fat production differed. The intramammary device as currently designed is incapable of stimulating a leukocytosis sufficient in stripping milk to prevent intramammary infection.
在两年多的时间里，在马里兰州的三个牛群中评估了一种聚乙烯乳房内装置对自然发生感染的有效性。对62头经处理的奶牛的乳房所有象限都安装了乳房内装置。62头对照奶牛接受了假处理。初产奶牛经处理和对照象限在单个泌乳期内新的乳房内感染率平均分别为18%和27%。感染率的降低主要是由于牛棒状杆菌感染减少。经产奶牛处理组之间的感染率相似。在未感染的象限中，挤奶样中的细胞计数平均为0.11至0.13×10⁶/ml，而在安装了乳房内装置的象限中，浓度仅为0.22至0.31×10⁶个细胞/ml。但在安装了乳房内装置的感染象限中，挤奶样的细胞计数为1.38至1.48×10⁶/ml。未安装装置的感染象限中挤奶样的体细胞浓度平均为0.48至0.63×10⁶/ml。安装和未安装乳房内装置的初产和经产奶牛的奶牛群改良细胞计数相似，平均为0.2×10⁶/ml。牛奶和脂肪产量均无差异。目前设计的乳房内装置无法刺激白细胞增多到足以在挤奶时预防乳房内感染的程度。
