Screening of Bovine Mastitis in Lactating Dairy Cows in and around Debra Tsige Town, North Ethiopia

of Bovine Mastitis in Lactating Dairy Mastitis an inflammation of the mammary gland caused by pathogenic microorganism, occurs in all mammalian species, particularly in dairy cattle. A cross sectional study design was conducted from June 2017 to December 2017 to screening bovine mastitis in randomly selected dairy farms in and around Debre Tsige. 384(119 cross, 214Exotic, 51 local breed) of lactating cows were included in the study. Prevalence of the clinical mastitis was determined through examination of abnormalities of milk and udder. The overall prevalence of clinical mastitis was 6.5% and 1.82% at cow and quarter level, respectively. Individual quarter milk samples from those which were normal in clinical mastitis were tested by California Mastitis Test (CMT) to diagnose sub - clinical mastitis. Of the 1536 quarters examined, prevalence of clinical mastitis, sub clinical mastitis and blind quarters (nonfunctional teats) were found to be 6.5%, 30.2% and 0.97%, respectively. On cow basis, out of 384 lactating cows, 143(36.7%) cows had abnormalities in their udder, teats, and milk as evidence of clinical mastitis. The prevalence of mastitis at cow level was higher in exotic breeds101 (26.30%) and in cows those which were found in late lactation stage63 (16.40%), which was found to be statistically significant (P < 0.05). The present study revealed that parity number was also found to have significant association with the prevalence of mastitis (P<0.05). In the present study, there was high prevalence of sub clinical mastitis that result losing of milk production and cause economic lose to the dairy farm. In view of this, the routine test of dairy cows, and preventive and control measures are recommended to reduce the prevalence of clinical and sub clinical mastitis in dairy farms in and around Debre Tsige.


Screening of Bovine Mastitis in Lactating Dairy Cows in and around Debra Tsige Town, North Ethiopia Introduction
The majority of the third world countries are located in tropic and livestock production is very important to their economy.
Dairying is a component of livestock production is an important economic activity in sub Saharan Africa. Ethiopia is the nations that possess the largest livestock population among African continent with an estimated 30-33 million cattle [1,2]. Moreover, the quality and quantity of milk in the country deteriorates because of various causes. Mastitis is an inflammation of the parenchyma of mammary gland and commonly associated with intra mammary bacterial infection. It is considered as one of the most important disease among diseases of the dairy animals; it is characterized by physical, chemical, bacteriological changes in milk, and pathological changes in glandular tissues [3]. Bovine mastitis (mast = breast; itis = inflammation), a major disease affecting dairy cattle worldwide, results from the inflammation of the mammary gland. The severity of the inflammation can be classified into sub-clinical, clinical, and chronic forms, and its degree is dependent on the nature of the causative pathogen and on the age, breed, immunological health, and lactation state of the animal. Sub-clinical mastitis is difficult to detect due to the absence of any visible indications, and it has major cost implications chronic mastitis is a rare form of the disease but results in persistent inflammation of the mammary gland currently, milk quality payments are based on somatic cell counts (SCCs), and elevated levels result in reduced payments. This, in addition to reduction in milk volume and treatment costs, significantly affects farm incomes [4].
Mastitis is a difficult problem to comprehend because, it is a disease caused by many factors, both in large and in small-scale herds. Micro-organisms are responsible for the infection, but for them to enter the mammary gland and establish themselves to the point that they cause an infection, a multitude of factors may be involved. There are many factors acting simultaneously, and the disease generally involves interplay between management practice and infectious agents but with other factors, such as genetics, udder shape or climate [5,6]. The occurrence of disease is an outcome of interplay between three major factors: infectious agents, host, and environmental factors [7]. Mastitis is a global problem as it adversely affects animal health, quality of milk and the economics of milk production, affecting every country, including developed ones and causes huge financial losses [8]. Mastitis could be classified as clinical or sub clinical. Clinical mastitis refers to inflammation of mammary gland with grossly visible changes on the udder and milk. It is characterized by abnormalities such as discoloration of milk, redness, increased temperature, pain, and disturbance of function of the udder [9]. Sub clinical mastitis on the other hand refers to inflammation of mammary gland in the absence of visible changes in the udder but presence of pathogenic organisms in the milk and can only be diagnosed with indirect screening tests or laboratory culturing [10].
Due to the heavy financial implications involved and inevitable existence of latent infection, it is obvious that mastitis is an important factor limiting dairy production. The disease is worth

Study Area
This study was conducted in and around DebreTsige town in North Showa zone of Oromia, Ethiopia. DebreTsige town is located 9o 48N and 38o 44E at about 89 km north of Addis Ababa. The altitude of the district is between 1500-2700m a.s.l, its minimum and maximum temperature varies from 19oC to 23oC.
It gets bimodal rain fall that ranges from 800-1200mm and the predominant soil type are black soil (56%) and red soil (38%). Two

Study Population
The study populations were selected from different farms which were large, medium, and small-scale dairy farms. An expected prevalence of the selected area is 0.5 so; this was used to increase the degree of precision and considering a 5% absolute precision and at 95% confidence level was give us 384 sample sizes [12].

Study Methodology
A total of 384 lactating cows; 214 exotic, 119 cross and51 local breeds were sampled from the randomly selected dairy farms.
Individual animals were selected using simple random sampling method from dairy farms. Milk samples were collected from individual quarters of apparently healthy lactating cows according to the procedures recommended by National Mastitis Council, [13]. The washing should be started sufficiently in advance of milking to allow the udders to drain dry before collection of the samples. After the udders, especially teats were cleaned and dried; the first 3-4 streams of milk were discarded. California mastitis test was carried out according to the method described by [14]. After withdrawing of the first two or three streams of milk about 2ml of the foremilk was collected from each quarter and mixed thoroughly in a plastic container. Two ml of composite milk was placed in a cup if the paddle to which an equal amount of CMT reagent was added. Then, the paddle was rotated gently in a circular pattern for 10 seconds so that the milk and reagent mixed well. Immediately the reactions were scored and the paddle was rinsed and shaken of excess moisture, The CMT reactions were scored and interpreted according to [15]. Both 0 (negative) and T (Trace) scored and interpreted absence of intra mammary infection, while CMT scores 1, 2 and 3 was considered as positive indicators of the infection [16].

Data Management and Analysis
The data were entered and managed in Microsoft Excel.

Discussion
Mastitis is an economically important disease of dairy cattle Prevalence of subclinical mastitis (30.2%) is higher than that of clinical mastitis (6.5%)in the present study which is in the agreement with several earlier reports from different parts of Ethiopia [24][25][26][27][28][29][30] and elsewhere in Africa [31]. Since, environmental factors play significant role, the prevalence of subclinical mastitis varies in dairy farms [32][33][34][35]. Additional agreement to other reports; clinical mastitis is far lower than subclinical mastitis [36][37][38][39][40]. This could be attributed to little attention given to subclinical stage. The finding of this study indicated that high prevalence was recorded in parity of greater than 6 parity 11.19% followed by 1-3 (7.55%) and 4-6 parity (17.96%). The findings those were obtained in this study agreed with previous findings of Lamma and Tibeb.
Their studies showed that older cows especially after 4 calves were more susceptible to bovine mastitis than the others; exotic breeds were more susceptible than others. Similar results are showed by Richard.

Conclusion
Mastitis especially subclinical mastitis is a problem, which threatens dairy farm owners usually by decreasing milk yield irrespective of adequate feed provision and deworming practices.