Comparison of Two Regimens of Nigella Sativa Extract for Treatment of Subclinical Mastitis Caused by Staphylococcus Aureus (Report‪)‬

INTRODUCTION Clinical and subclinical mastitis are the 2 major forms of the diseases. Clinical mastitis results in alterations in milk composition and appearance, decreased milk production, elevated body temperature and swelling, redness, or heat in infected mammary quarters. It is readily apparent and easily detected. However, detection of mammary quarters with subclinical mastitis is more difficult because signs are not readily apparent (Radostits et al., 2000). Consequently, subclinical mastitis, which is the most prevalent form of the disease, often goes undetected. Many subclinical Intramamal Infection (IMI) tend to persist, resulting in elevated milk SCC and decreased milk production, which may lead to development of clinical mastitis and the opportunity for certain mastitis pathogens to spread from infected mammary quarters to uninfected mammary quarters. Acceptance and application of mastitis control programs implemented in the 1960s, including teat disinfection, antibiotic therapy and culling of chronically infected cows, has led to considerable progress in controlling contagious mastitis pathogens. Staphylococcus aureus is one of the most common causes of contagious bovine mastitis and subclinical mastitis in dairy cattle worldwide and 50-100% of herds may be infected with this pathogen (Radostits et al., 2000; Morgan, 2008)