Abstract
The goat udder infection at dry period in relation to mammary gland infection at lactation,and persistence of infection as well as incidence of goat mastitis and the pathogens responsible for that were studied in the goat herd related to Borg-Elarab research farm. A total of 38 Udder secretion samples, and 12 teat skin swabs were collected from animals in dry period, 28 milk samples were taken Around parturition ( 3 days before, during and 3 days after parturition), 22 milk samples collected 3 weeks after parturition, and 20 milk samples collected 6 weeks after parturition. Bacterial species isolated from dry period secretion samples were Coagulase positive staphylococci (CPS),Coagulase negative staphylococci(CNS), Streptococcus .uberis, (S. ueberis), Escherichia coli (E. colil) and Pseudomonas species and its approximate incidence at dry period sampling (about 1 moth) were (7.9%), (7.9%),(7.9%), (5.3%), (7.9%),without obvious clinical signs. Pseudomonas species was the only species isolated from teat skin swabs (41.7%)at dry period.Subclinical mastitis incidence in Borg Elarab farm during the study period (4 months) was (43.9%) approximately. All bacterial species isolated during the dry period were represented by varying incidences during the first 6 weeks of lactation. CPS dominated in milk samples around parturition (approximate incidence 25%), Pseudomonas dominated in milk samples 3 weeks after parturition (approximate incidence 22.7%),and E.coli dominated in milk samples 6 weeks after parturition (approximate incidence 25%) while S. uberis is represented only in milk samples 3 weeks after parturition (approximate incidence 4.5%). CNS species was lower than expected and its` incidence during the study (4 months )was (7.1%). Incidence of clinical mastitis in the farm was (2.5%). Four bacterial isolates from farm clinical mastitis 2 (50%)were CPS, 1 (25%)was E. coli and 1 (25%) was S. dysagalactia.
It could be concluded that subclinical mastitis is very common in dairy goats and dry goats , and coagulase positive staphylococci are the predominant pathogens. Intramammary infection with S. aureus in dry period persist over the lactation.

Key words: Goat mastitis, skin flora, dry period infection, persistent infection