Heifer Mastitis: Prevalence, Risk Factors and Pathogenesis

The importance of heifer mastitis is not completely understood by veterinary surgeons and breeders in our country and world. In contras to the idea of mammary infections can not in heifers, intramammary infections could be detected even in the six-month old heifers. The prevalence of intramammary infection can be as high as 90% in precalving period, and 45% in post calving period. However, the rate of intramammary infections and types of pathogens causing these infections may show variations in each herd. The most frequently isolated microorganisms are Staphylococcus chromogenes, Staphylococcus hyicus, Staphylococcus aureus and Streptococcus uberis from heifer mammary quarters in subclinical and clinical mastitis. The somatic cell count was reported to be 20x106 and 3.5x106 cell/ml in the mammary secrets collected from infected heifers and healthy heifers, respectively. Risk factors for heifer mastitis are calving in summer, feeding calves with mastitic milks, suckling among calves, contact with adult cows, absence of fly control, and poor housing conditions. The aim of this review was to evaluate with respect to prevalence, risk factors, and pathogenesis.