ABSTRACT
Mastitis continues to be one of the economically most important diseases in dairy farming. Forty-six licensed dairy farms in the central region of Fars province were randomly selected in order to participate in a seasonal prevalence study. A cross-sectional study was designed to determine prevalence at cow and quarter level based on clinical signs for clinical mastitis and indirect tests for subclinical mastitis. 6180 quarters from 1545 dairy cows were tested by clinical examination and California mastitis test [CMT]. Milk samples from both clinical and subclinical quarters were collected for bacteriological culture. 4714 [76.28%] quarters were healthy, 1335 [21.6%] quarters were positive by results of CMT [as indicated to subclinical mastitis], 44 [0.71%] quarters showed clinical mastitis signs and 87 [1.41%] quarters were blind. The clinical and subclinical mastitis prevalence at cow level was 2.2 and 42.5%, respectively. There was no significant difference in the prevalence of mastitis between different quarters, seasons and cities. The most prevalent isolated bacteria were coagulase positive staphylococci followed by Streptococci, Escherichia coli and coagulase negative staphylococci. Insufficient control measures such as pre and post milking hygiene and dry cow therapy in dairy farms and limited knowledge of farmers on the importance, identification and control of mastitis, especially subclinical forms, can be the main causes for the high prevalence of mastitis in Fars province
ABSTRACT
To evaluate seasonal variation in sexual behavior of Fars Grey rams. Six healthy Fars Grey rams [3-4 years old]. Procedure: All rams were exposed fortnightly to ewes and the following indices were evaluated: 1] number of mounting 2] number of mating without ejaculate 3] number of ejaculation 4] reaction time. The test was carried out by exposing two rams to two ewes in a 20 minute period. Ram efficiency was calculated by dividing the number of ejaculation by the sum of number of mating with and without ejaculation. Blood samples were also collected immediately after each sexual behavior test to determine plasma testosterone concentrations. A commercial ELISA hormone assay kit was used to measure plasma testosterone concentrations. Chi-square test and GLM procedure in ANOVAofSAS.estosterone concentrations varied between 3.6 ng/ml in autumn to 10.3 ng/ml in summer [P<0.05]. A significant [P<0.05] seasonal effects was observed in the number of ejaculation in summer [0.9] and in winter [2.2]. Rams showed a significant individual variation in the number of ejaculations [P<0.05]. The highest number of mating without ejaculation was recorded in winter [7] whereas rams showed the lowest corresponding value in autumn [2.5]. Ram efficiency was varied among rams [P<0.05] and further a significant seasonal variation was observed in the ram efficiency [P<0.05]. There was a significant increase in the mean plasma testosterone concentrations in summer, particularly in late summer. The ram efficiency reached to the highest level in autumn, shortly after a decrease in plasma testosterone concentrations. Therefore, it can be concluded that the rise in ram efficiency is a delayed effect of the increase in mean plasma testosterone concentration. The results of this study also emphasize the need of evaluation of breeding rams for their sexual behavior prior to mating season. This is due to the individual variation that is observed among Fars Grey rams. An scoring system in the sexual behavior of breeding rams needs to be developed to make the test a useful tool in ram selection