Erskine R J, Eberhart R J
Department of Veterinary Science, Pennsylvania State University, University Park 16802.
J Am Vet Med Assoc. 1990 Apr 15;196(8):1230-5.
Twelve dairy herds that had participated in the Pennsylvania Dairy Herd Improvement Association (DHIA) program for at least 12 months, that had a 12-month mean DHIA somatic cell count greater than 700,000 cells/ml, and that had greater than 25% of lactating cows infected with Streptococcus agalactiae participated in a herd blitz treatment program. Initially, quarter milk samples for bacteriologic culturing were collected from all lactating cows. Subsequently, all cows identified as infected with Str agalactiae were treated, using a commercial penicillin-novobiocin intramammary infusion product. In addition, a herd mastitis management program of postmilking teat dipping and treatment of all cows at the start of the nonlactating period was instituted. Thirty days after the initial herd visit, samples from all lactating cows were again cultured, and cows infected at that time were treated. Twelve months after the initial herd visit, samples from all lactating cows were again cultured. Mean prevalence of infection with Str agalactiae decreased (P less than 0.05) from 23.0% of quarters and 41.6% of cows initially to 3.4% of quarters and 9.3% of cows at 30 days and 1.6% of quarters and 4.2% of cows at 1 year. Mean herd DHIA somatic cell count decreased (P less than 0.05) from 918,000 cells/ml initially to 439,000 cells/ml at 30 days and 268,000 cells/ml at 1 year.(ABSTRACT TRUNCATED AT 250 WORDS)
12个奶牛群参与了宾夕法尼亚奶牛群改良协会（DHIA）项目至少12个月，其12个月的平均DHIA体细胞计数大于700,000个细胞/毫升，且超过25%的泌乳奶牛感染无乳链球菌，这些奶牛群参与了一项群体突击治疗项目。最初，从所有泌乳奶牛采集用于细菌培养的四分位乳样。随后，所有被鉴定感染无乳链球菌的奶牛都使用一种商用青霉素-新生霉素乳房内灌注产品进行治疗。此外，实施了一项挤奶后乳头药浴和在非泌乳期开始时对所有奶牛进行治疗的牛群乳腺炎管理项目。首次访查牛群30天后，再次对所有泌乳奶牛的样本进行培养，并对当时感染的奶牛进行治疗。首次访查牛群12个月后，再次对所有泌乳奶牛的样本进行培养。无乳链球菌感染的平均患病率（P小于0.05）从最初季度的23.0%和奶牛的41.6%降至30天时季度的3.4%和奶牛的9.3%，以及1年时季度的1.6%和奶牛的4.2%。牛群平均DHIA体细胞计数（P小于0.05）从最初的918,000个细胞/毫升降至30天时的439,000个细胞/毫升和1年时的268,000个细胞/毫升。（摘要截短至250字）
