Bovine mastitis is one of the diseases in dairy cattle industry that cause severe damage to the farmers. With the entry of bacteria into the mammary gland and production of various toxins, damage to the mammary gland leads to reduced milk production and inefficiency of the milk produced. Ideally, research related tobovine mastitis should lead to recommendations for better herd management, so that farmers can help reduce the incidence and preva‎lence of mastitis in a cost-effective manner. The aim of present study was to eva‎luate mastitis in dairy herd of Isfahan University of Technology and to provide alternative indicator traits to eva‎luate resistance to mastitis in Holstein cows. In this research, information and records of ten years (from 2009 to 2019) of Lavark dairy farm of Isfahan University of Technology were used and in addition to the SCC, other indicators traits such as mean of SCS in the early days (5-150) or late of lactiotion period (305-151) (SCS150 or SCS151-305), maximum SCS, the standard deviation of SCS, SCC excessive test day and SCC peak pattern were investigated. The preva‎lence of mastitis in the Holstein dairy cows located in the first lactation period of the investigaed herd during the 305 days postpartum period was about 6%, which is in the lower range of previous studies in the Isfahan province. The trend of test-day milk SCC of this herd during the years 2009 to 2019, has a downward trend that shows the level of management, health and resistance of livestock of this herd to this disease has increased. In addition, the results of the present study showed that the maximum time for animals to go to the clinic for mastitis is withinn 40 days postparum, and it seems that in animals that are not pregnant for any reason and their lactation period are longer than usual, due to weakness of immune system, the percentage of visits to the clinic for the treatment of mastitis also increases. In eva‎luation of other predictor traits for mastitis at the herd level, it was observed that the sick cows had a higher mean for SCS150, SCS151-305, SCSMAX and SCSSD, as well as a higher abundance for PK. PK was defined as a binary trait (0 = no peak, 1 = peak) based on whether or not the cow had at least one peak with the pattern low-high-low. Based on the results of this study, it can be argued that by using SCC alternative traits, it may be possible to better, more accurately identify, cull or select animals susceptible or resistant to mastitis. However, in order to use these criteria in the genetic eva‎luations as a better indicator trait for mastitis, it is necessary to eva‎luate the genetic relationship of each indicator traits to other production and functional traits at a wide level, such as the province.

عباس پاكدل

علي صادقي سفيد مزگي

سعيد انصاري مهياري، آقا فخر ميرلوحي