乳房内感染对撒丁岛绵羊体细胞评分和产奶量的影响。

Effects of intramammary infections on somatic cell score and milk yield in Sarda sheep.

作者信息

Cuccuru C, Meloni M, Sala E, Scaccabarozzi L, Locatelli C, Moroni P, Bronzo V

机构信息

Department of Veterinary Pathology and Clinic, University of Sassari, Sassari, Italy.

出版信息

N Z Vet J. 2011 May;59(3):128-31. doi: 10.1080/00480169.2011.562862.

DOI:10.1080/00480169.2011.562862

PMID:21541886

Abstract

AIM

To evaluate the effects of intramammary infections (IMI) on somatic cell score (SCS) and milk yield in dairy ewes.

METHODS

Monthly milk samples were collected from a flock of 202 Sarda sheep, over a period of 7 months, for bacteriological culture and measurement of somatic cell counts (SCC). During the same period, milk yield was measured daily using electronic milk meters connected to each half-udder cluster of the milking machine. SCC was transformed to SCS using a base-2 log transformation. One SCS is equivalent to a SCC of 25,000 cells/ml, and each increase of 1 in SCS is associated with doubling of the SCC. IMI was defined by the presence of five or more colonies of similar morphology isolated from a milk sample (≥500 cfu/ml). The effect of IMI on SCS and milk yield was assessed using a generalised estimating equation (GEE).

RESULTS

There were 1,186 udder halves with IMI from 2,828 milk samples, a prevalence of 41.9%. The distribution of bacterial species within the 1,186 culture-positive samples was comprised of 476 (40.1%) Staphylococcus epidermidis, 172 (14.5%) Staph. chromogenes, 38 (3.2%) Staph. caprae, 134 (11.3%) Staph. simulans, 114 (9.6%) Streptococcus uberis, 123 (10.4%) Strep. dysgalactiae, and 129 (10.9%) Strep. equi subsp. zooepidemicus. SCS was greater in udder halves with IMI (mean 7.71; SD 0.82) than in udder halves without IMI (mean 5.53; SD 1.02) (p<0.01). IMI due to streptococcal species were associated with greater SCS (mean 8.24; SD 0.62) than those due to staphylococcal species (mean 7.48; SD 0.79) (p<0.01). Milk yield from udder halves with IMI was lower (mean 439 (SD 162) ml/half udder/day) than from udder halves without IMI (mean 602 (SD 170) ml/half udder/day) (p<0.01). IMI due to staphylococcal species was associated with a lower milk yield (mean 399 (SD 167) ml/half udder/day) than IMI due to streptococcal species (mean 427 (SD 156) ml/half udder/day) (p<0.01).

CONCLUSIONS

These findings provide sheep milk producers with information on the losses associated with subclinical mastitis, which can be used to evaluate the economics of prevention and treatment protocols concerning udder health in ovine dairy flocks.

摘要

目的

评估乳房内感染（IMI）对奶用母羊体细胞评分（SCS）和产奶量的影响。

方法

在7个月的时间里，每月从一群202只撒丁岛绵羊中采集牛奶样本，进行细菌培养和体细胞计数（SCC）测量。在此期间，每天使用连接到挤奶机每个半乳房组的电子奶量计测量产奶量。SCC通过以2为底的对数转换转换为SCS。一个SCS相当于25,000个细胞/毫升的SCC，SCS每增加1，SCC就会翻倍。IMI由从牛奶样本中分离出的五个或更多形态相似的菌落（≥500 cfu/ml）来定义。使用广义估计方程（GEE）评估IMI对SCS和产奶量的影响。

结果

在2828份牛奶样本中，有1186个半乳房存在IMI，患病率为41.9%。1186份培养阳性样本中的细菌种类分布包括476份（40.1%）表皮葡萄球菌、172份（14.5%）产色葡萄球菌、38份（3.2%）山羊葡萄球菌、134份（11.3%）模仿葡萄球菌、114份（9.6%）乳房链球菌、123份（10.4%）停乳链球菌和129份（10.9%）马链球菌兽疫亚种。存在IMI的半乳房的SCS（平均7.71；标准差0.82）高于无IMI的半乳房（平均5.53；标准差1.02）（p<0.01）。链球菌属引起的IMI与更高的SCS（平均8.24；标准差0.62）相关，高于葡萄球菌属引起的IMI（平均7.48；标准差0.79）（p<0.01）。存在IMI的半乳房的产奶量（平均439（标准差162）毫升/半乳房/天）低于无IMI的半乳房（平均602（标准差170）毫升/半乳房/天）（p<0.01）。葡萄球菌属引起的IMI与低于链球菌属引起的IMI的产奶量（平均399（标准差167）毫升/半乳房/天）相关（平均427（标准差156）毫升/半乳房/天）（p<0.01）。