In this research, effects of vitamin A (Retinol) and vitamin E (alphatocopherol) on subclinical mastitis and on bactericidal ability of neutrophils were investigated. In addition, teats which is the most important factor in mastitis were investigated morphologically.
Forty dairy cattle kept in a good feeding and management farm were monthly examined on milk yield and quality, mastitis tests, blood analysis, serum vitamin A and E level for one year. Electronic conductivity and somatic cell counts in milk were found to have a relatively well correlation to milk yield and quality. Serum vitamin E levels was found to have some relation to these test results.
Effect of retinol and alpha-tocopherol was investigated in vitro on the bactericidal ability of neutrophils obtained from 20 lactating cows. Nitroblue tetrazolium (NBT) reduction test was employed. After the isolation of neutrophils from blood, NBT reduction test was conducted under the condition of intact, retinol and alpha-tocopherol a
ddition. The most high NBT reduction ability was obtained at 100 IU/dl of retinol and at 200 mug/dl of alpha-tocopherol, respectivily. Ethanol, retinol or alpha-tocopherol were added to the medium of neutrophil's culture. Though NBT reduction ability decreased to about half level in control, it was well preserved in retinol or alpha-tocopherol addition. As a result, it was suggested that the bactericidal ability of neutrophils from lactating cows was influenced in vitro by the level of retinol or alpha-tocopherol, and was well preserved under the presence of retinol or alpha-tocopherol.
Several parts of the teats were measured and its results were compared to milk quality and bacteria. It was found that the teat with bigger teat gradient or teat canal diameter is liable to mastitis. Then, the teats were examined by ultrasonography, macroscopically and histopathologically. Abnormal findings were diagnosed by ultrasonography as follows, obstraction of teat sinus, hypertrophy of intima, abscess, polyp, diverticulum, stenosis and malformation. They were confirmed by morphological examination. Less