Incidence of Mastitis in the Dairy Herd of the College of Agriculture, King Saud University, Riyadh, Saudi Arabia PDF

Keywords

Saudi Arabia, agriculture, dairy

Abstract

Milk samples from the dairy herd of the College of Agriculture, King Saud University, Riyadh, were subjected to bacteriological examination, somatic cell counts and qualitative milk tests, namely pH-determination, Whiteside and MBR tests. Coagulase- positive Staphylococcus aureus was the only major pathogen isolated. This organism was responsible for subclinical mastitis in 10% of the Friesian and 20% of the Jersey cows in the herd. The corresponding counts of viable bacteria in these two breeds were 6.69 x 10^2/ml and 5.7 x 10^3/ml, respectively. The same organism was isolated from all cases of clinical mastitis met with in these cows (10% and 16.7% incidence in Friesian and Jersey cows, respectively). More than 50% of the cows also excreted large numbers o micrococci in the milk (3.9 x 10^3 - 6.5 x 10^3/ml) but these are known to cause very mild infections and are often disregarded in mastitis surveys. Somatic cell counts averaged 1,622,000/ml in cows infected with Staph aureus, 272,000/ml in those infected with micrococci and 204,000 in non-infected cows. A good correlation was noted between Whiteside and MBR tests and between these tests and bacteriological findings. The pH of the milk was slightly alkaline