Some endocrinological studies into periparturient reproduction in the cow

Munro, Colin David (1976) Some endocrinological studies into periparturient reproduction in the cow. PhD thesis, University of Glasgow.

Abstract

This thesis describes a study of some hormonal, behavioural and gonadal changes during the peri- and post-parturient period of a group of suckled cows. The investigation was commenced just prior to calving, continued through the post-partum anoestrus period, and terminated when pregnancy was established. To enable ovarian functional changes to be monitored radioimmunoassays were developed for progesterone, oestrogens and androgens. Validation of these assays for measurement of the steroids in peripheral plasma samples was by recognised reliability criteria. In addition, by applying the methods to samples from cows during the oestrous cycle comparison of the results with ovarian structural changes, and with the levels reported by other workers was possible. At calving observations on the inter-relationship of progesterone, oestrogens, androgens and cortisol revealed alterations in the peripheral plasma levels of these hormones which gave information on possible sources of secretion, and suggested functional roles for these steroids in the process of birth. Post-partum the peripheral plasma levels of progesterone, oestrogens, and androgens were related to the presence of follicles and corpora lutea in the ovaries, to the size and degree of turgidity of the uterine horns, and to behavioural changes typifying prooestrus and oestrus. Subdivision of the anoestrus period on the basis of endocrinological and gonadal structure changes, and comparison of silent, overt and false heats during the period of study elucidated some aspects of the aetiology of this period of altered reproductive function. In animals in which pregnancy was established luteal function was compared to that observed earlier in the post-partura period and to dioestrus progesterone levels in cycling cows. The clinical significance of cystic ovarian structures recorded mainly during early pregnancy was studied. The results of the thesis raised the question of the value of some of the accepted parameters to determine if oestrous cycles were occurring in cows. In addition the accuracy of endocrinological, behavioural and structural changes in the reproductive tract as a means of assessing the stage of the oestrous cycle were discussed.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: William Weipers
• Keywords: Animal sciences, Endocrinology
• Date of Award: 1976
• Depositing User: Enlighten Team
• Unique ID: glathesis:1976-73417
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 14 Jun 2019 08:56
• Last Modified: 14 Jun 2019 08:56
• URI: https://theses.gla.ac.uk/id/eprint/73417