In dairy cows, ACM can range from a mild disease of short duration to a severe, peracute, life-threatening condition. Severity of an episode of ACM is associated with degree of production loss and clinical outcome.1 Therefore, evaluating the severity of episodes of ACM in dairy cows is important in determining appropriate treatment and making sound management decisions.
Various factors have been used as measures of the severity of clinical mastitis in affected cows, including milk production changes, inflammatory changes in the gland, changes in milk composition and appearance, extent and degree of systemic signs of disease, and hematologic changes, and various scoring systems for severity of clinical mastitis have been developed.2-5 For most of these scoring systems, severity is determined on the basis of whether physical characteristics of the mammary gland and milk are normal or abnormal and whether systemic signs of disease are present or absent.6 Typically, the highest score is assigned to cows with any systemic signs of disease, regardless of the extent or degree of systemic disease involvement, even though systemic disease severity has been shown to have a significant impact on milk production and clinical outcome. Importantly, none of the studies that used these scoring systems have detected important differences in outcome among cows with clinical mastitis grouped on the basis of severity scores.
Recently, we reported on a rapid, simple severity classification system for ACM that was based on systemic disease signs.7 When cows were grouped according to this classification system, significant differences in hematologic findings, number of bacteria in secretions from the affected mammary gland, death rate, culling rate, and occurrence of bacteremia were identified among severity groups. The purpose of the study reported here was to compare results of use of 4 severity scoring systems to predict outcome (survived vs died or culled) and the presence of bacteremia (yes vs no) in dairy cows with ACM. Severity scoring systems that were used included an SSS system7 and 3 scoring systems primarily based on local inflammatory changes of the affected mammary gland that included systemic disease signs to various degrees. The ideal scoring system would group most cows needing special treatment or management into a single group (ie, it would be sensitive) while placing few cows that did not need special treatment or management in that group (ie, it would be specific). In this way, critical management decisions could be made in an efficient and cost-effective manner.
Acute coliform mastitis
Systemic severity score
Local severity score
Local-systemic score 1
Local-systemic score 2
J-5 Bacterin, Pharmacia & Upjohn Animal Health, Kalamazoo, Mich.
SAS/STAT software release, version 9.0, SAS Institute Inc, Cary, NC.
Lohuis JACM, Schukken YH & Verheijeden JHM, et al. Effect of severity of systemic signs during the acute phase of experimentally induced Escherichia coli mastitis on milk production losses. J Dairy Sci 1990;73:333–341.
Hoblet K, Schnitkey G & Arbaugh D, et al. Costs associated with selected preventive practices and with episodes of clinical mastitis in nine herds with low somatic cell counts. J Am Vet Med Assoc 1991;199:190–196.
Morin DE, Shanks RD, McCoy GC. Comparison of antibiotic administration in conjunction with supportive measures versus supportive measures alone for treatment of dairy cows with clinical mastitis. J Am Vet Med Assoc 1998;213:676–684.
Sischo W, Moore D, Fedon J. Use of physiologic variables to predict milk yield after clinical mastitis in dairy cattle. J Am Vet Med Assoc 1997;211:470–475.
Erskine RJ, Bartlett PC & VanLente JL, et al. Efficacy of systemic ceftiofur as a therapy for severe clinical mastitis in dairy cattle. J Dairy Sci 2002;85:2571–2575.
Wenz JR, Barrington GM & Garry FB, et al. Use of systemic disease signs to assess disease severity in dairy cows with acute coliform mastitis. J Am Vet Med Assoc 2001;218:567–572.
Wenz JR, Barrington GM & Garry FB, et al. Bacteremia associated with naturally occurring acute coliform mastitis in dairy cows. J Am Vet Med Assoc 2001;219:976–981.
System for classifying severity of ACM in dairy cows on the basis of systemic disease signs.7
|Rectal temperature (°C [°F])|
|37.8 (100)–39.27 (102.7)||0|
|39.33 (102.8)–39.8 (103.7)||1|
|> 39.8 (103.7) or < 37.8 (100)||2|
|Hydration status (degree of enophthalmos)|
|Rumen contraction rate (contractions/min)|
|Attitude (signs of depression)|
Cows with total score of 0 to 2 were classified as having mild disease, cows with total score of 3 to 5 were classified as having moderate disease, and cows with total score of 6 to 9 were classified as having severe disease. Reproduced with permission.
System for classifying severity of ACM in dairy cows on the basis of local disease signs.
|Signs of quarter pain|
|Thin with clots or flakes||1|
|Serum-like with clots or flakes||2|
Cows with total score of 0 to 2 were classified as having mild disease, cows with total score of 3 or 4 were classified as having moderate disease, and cows with total score of 5 to 7 were classified as having severe disease.