332 Buletin USAMV Veterinary Medicine, 65(2)/2008 pISSN 1843-5270; eISSN 1843-5378 SYSTEMIC IMMUNE PROTECTIVE CAPACITY IN RELATION TO THE BACTERIAL LOAD OF THE UDDER IN BOVINE MASTITIS Spînu Marina, Carmen Dana andru, Gh.F.Brudacă, S. Karolyi, Mihaela Niculae, Rodica Popescu University of Agricultural Sciences and Veterinary Medicine, Cluj-Napoca, Romania, Str. Manastur, No.3-5, email: marina.spinu@gmail.com Keywords: bovine mastitis, systemic immunity, Staphylococcus, bacterial load Abstract. Mastitis is one of the most important bovine diseases causing economic losses to dairy producers and it is a consequence of the activity of various internal factors that cooperate to destroy the invading microorganisms. The local immune response during the bacterial infection is fundamental in effectively designing therapies and control measures to help eradicate bovine mastitis (Oviedo-Boyso et all., 2007). Many studies have examined the intramammary neutrophil, lymphocyte, and monocyte function by in vitro “testing”, but a gap still persists in relating the local, innate and adaptive immune function to the systemic process of immune defense of the mastitic animals. The study aimed to establish a connection between non-specific (phagocytosis, total Ig, circulating immune complexes) and specific (lymphocytes) effectors involved in the overall immune protection of the intensively farmed animals, diagnosed with various degrees of clinical mastitis, and the species of bacteria involved in inducing the disease, as well as to investigate the therapeutic potential of several vegetal extracts. The microbiological results indicated a dominance of staphylococci, but did not exclude Gram-negative bacteria, suggesting the endemic chatacter of the mastitis in the investigated unit. Clinical disease influenced the humoral immune effectors in a differentiated manner, significantly increasing the total Ig levels, but diminishing the CIC concentrations. Both phagocytosis and blast transformation capacity of mononuclear cells were diminished in diseased animals, indicating a poor cellular defence at systemic level, possibly due to the circulating staphylococcal enterotoxin. Only the Thymus vulgaris extract showed restoring capabilities in the blast transformation test, suggesting possibilities for its potential therapeutic use. INTRODUCTION Mastitis is one of the most important bovine diseases causing economic losses to dairy producers and it is a consequence of aggressiveness of the “invader” the activity of various internal factors that cooperate to destroy the invading microorganisms. In spite of the efforts deployed to control it, the incidence of mastitis continues to be one of the highest of all the cattle diseases and its prevalence in dairy herds remains at the forefront on the international scale, as a result of the most common, subclinical form of the disease (Rainard and Riollet, 2006). Disorders such as mastitis, associated with an animal’s inability to cope with the demands of high production also have an economic impact, leading to early culling, especially in intensively raised animals (Goff, 2006). The major losses are produced through reduction in milk yield and waste of milk unfit for consumption due to mainly massive antibiotic use (Rainard and Riollet, 2006). The prevention and treatment of mastitis represent a serious burden to producers and are primary concerns of the dairy industry. The factors involved in the inflammatory response recorded during mastitis differ depending on the infectious agent. The local immune response during the bacterial infection is fundamental in effectively designing therapies and control measures to help eradicate bovine mastitis (Oviedo-Boyso et all., 2007). Local and mobilized innate defense mechanisms are bound by the inflammatory processes, so that when resident defenses are not sufficient to