Presence Of Cathelicidin-1 In Milk As An Indicator Of The Severity Of Mammary Infection In Ewes

Aims: The importance of cathelicidin-1 as an indicator of the severity of mammary infection in ewes.Background: Mastitis is an important disease of sheep, affecting their health and welfare.Objective: The association of the presence of cathelicidin-1 in milk samples from ewes with mastitis with the severity of the infection.Methods: Ewes were intramammarily inoculated with Mannheimia haemolytica or Staphylococcus chromogenes. Conventional (clinical, bacteriological and cytological examinations; milk yield measurements) and proteomics evaluation (2-DE, MALDI-TOF MS) to record cathelicidin-1 spot optical densities in milk samples were recorded.Results: Ewes challenged with M. haemolytica developed clinical and ewes challenged with S. chromogenes subclinical mastitis (P=0.05). The challenged organism was isolated from milk samples from inoculated mammary glands; increased somatic cell counts were also recorded. Cathelicidin-1 was detected in milk samples from the inoculated side of udders of all ewes. Mean spot density of cathelicidin-1 from samples from inoculated glands of ewes challenged with M. haemolytica was higher than from ewes challenged with S. chromogenes: 2896 +/- 973 versus 1312 +/- 361 (P=0.034). There were significant correlations between the presence of clinical mastitis / somatic cell counts with the spot density of cathelicidin-1 on 2-DE gels (P=0.043 and P=0.023, respectively). There was also a significant inverse correlation between the mean spot densities of cathelicidin-1 in milk samples and the milk yield of respective ewes on D10 (P=0.031).Conclusion: Potentially, cathelicidin-1 could be used as a marker to indicate the severity of damage to the mammary parenchyma.