Προστατευτικός ρόλος της θηλής και σημασία των παθήσεων της στην εκδήλωση μαστίτιδας από mannheimia haemolytica σε πρόβατα

Abstract

The objectives of the present thesis were: (i) the study of the dynamics of infection of bacteria in the teat of ewes, (ii) the elucidation of the role of the teat as a protective structure for the mammary gland of ewes and (iii) the evaluation of the importance of the disorders of the teats in predisposing ewes to mastitis.The thesis is divided into five chapters followed by the General Discussion.In the first Chapter, the relevant literature is reviewed. The Chapter is subdivided into four Parts. In Part A the literature on the anatomy and histology of the teat of ewes is briefly reviewed. In Part Β the literature on ovine mastitis is presented. In Part C the literature on the defence mechanisms of the mammary gland is cited and in Part D the literature on M.haemolytica is reviewed.In the second Chapter, after a brief introduction (Part A), a novel technique to obtain material from the teat duct of ewes is described and validated (Part B). Then, the bacteriological findings in the teat duct and the mammary gland of clinically healthy ewes, as well the effects of milking are presented (Part C). Finally, the histopathological findings in clinically healthy teats of ewes are presented (Part D).In Part B, a new technique that may be used for studying the bacterial flora of the teat duct in live ewes is described; furthermore, evidence regarding its accuracy, safety and repeatability is presented. A sterile, plastic, 20 G catheter is used for sampling. The catheter stylet is taken out and the plastic catheter cut with a sterile blade to a length of 2 mm. In order to ensure accurate and consistent cutting of the catheter at the desired length, a sterilized ruler is placed beside the catheter. The whole procedure is carried out under aseptic conditions, on sterilized surgical screens. Before sampling, a thorough disinfection with povidone iodine scrub solution of the teat apex and the lower (1 cm) part of the teat skin, is carried out. The investigator holds the catheter from the cannula hub; then, it is inserted into the teat, rolled around the internal teat wall, in order to sample the mucosa, and then withdrawn. Material collected on the tip of the catheter is plated onto bacteriological media. The sensitivity of the technique compared to a method that detects the bacterial flora of the teat after slaughter of the animals (scratching of the teat mucosa by means of a scalpel blade) was 99% for field samples and 100% for experimental samples; specificity of the technique was 91% and 100%, respectively; kappacoefficient between results of the two methods was 0.9045. The safety of the technique was 12Institutional Repository -Library & Information Centre -University of Thessaly 11/05/2018 11:26:29 assessed in an investigation, where ewes were repeatedly (eight times) sampled by means of this technique, throughout their lactation; in no case was clinical or subclinical mastitis recorded. Finally, the repeatability of the method was assessed in 37-paired samples, obtained 30 to 40 min. apart; a 100% match was r...

Μελέτη Του Ρόλου Της Θηλής Του Μαστού Στην Παθογένεια Της Μαστίτιδας Των Προβάτων

“…Οι Kraft, Bachmann, Bachmann, Buerki, Hess, Cottier και Stoner (1987) ανέφεραν ότι η λειτουργικότητα των δευτερογενών λεμφικών οργάνων μειώνεται με την πάροδο της ηλικίας. H αύξηση του ποσοστού προσβολής των προβατίνων από μαστίτιδα έχει συσχετιστεί με την πάροδο της ηλικίας και τον αριθμό της γαλακτικής περιόδου.Καθώς δεν έχει βρεθεί διαφορά στην πιθανότητα μόλυνσης της θηλής και του μαστικού αδένα μεταξύ πρωτοτόκων και πολυτόκων προβατίνων(Μαυρογιάννη 2006, μάλλον τα αίτια σχετίζονται με την αμυντική ικανότητα της θηλής και του μαστικού αδένα. Έτσι, πιθανόν αυτή η αύξηση οφείλεται σε ανεπάρκεια των αμυντικών κυτταρικών μηχανισμών της θηλής, ακριβώς λόγω της μειωμένης λειτουργικότητας αυτών των λεμφοειδών δομών με την πάροδο της ηλικίας των ζώων.…”