Off-campus UNL users: To download campus access dissertations, please use the following link to log into our proxy server with your NU ID and password. When you are done browsing please remember to return to this page and log out.
Non-UNL users: Please talk to your librarian about requesting this dissertation through interlibrary loan.
Reproductive hormones in pigs selected for reproductive traits
Abstract
The objective in experiments 1 and 2 was to determine if boars with large testis (TS) had altered concentrations of FSH as compared to boars with smaller testis (C) when they were intact, 14 d after castration and after treatment with 17$\beta$-estradiol or during anesthesia. Concentrations of FSH were similar (P $>$.05) in males from TS and C lines at all bleeding periods. In experiments 3, 4 and 5 the effect of selection on an index for ovulation rate and embryo survival (I) on concentrations of FSH, LH, testosterone (T) and 17$\beta$-estradiol (E) during neonatal and pubertal development and in mature boars was studied. Concentrations of E were greater in pigs from the C line than those from I line during pubertal development. Concentrations of FSH were greater in mature boars from the I line. In experiment 6, mature boars from a RL line (cross of Relax Selected and Litter Size lines both selected for high ovulation rate) and boars from a control line (C) were used. Concentrations of T were greater (P $<$.05) in boars from the C than those from the RL line. The objective of the final experiment was to examine concentrations of FSH, LH, progesterone (P) and E in sows from a line selected on an index of ovulation rate and embryo survival and from a control line. Sows of each line were ranked in a group according to their estimated number of ovulations per one estrous cycle. Mean concentrations of all hormones that were evaluated over the entire estrous cycle were not different (P $>$.05) either between the lines or when comparisons were made based on ovulation rate. Selection for testes size did not influence concentrations of FSH in adult boars. Selection for ovulation rate and embryo survival did not affect secretion of FSH, LH, P and E in sows, but may have altered pattern of secretion of E prior to puberty and changed concentrations of FSH in mature boars.
Subject Area
Anatomy & physiology|Animals|Genetics|Livestock
Recommended Citation
Mariscal Aguayo, Dolores Valentina, "Reproductive hormones in pigs selected for reproductive traits" (1994). ETD collection for University of Nebraska-Lincoln. AAI9500599.
https://digitalcommons.unl.edu/dissertations/AAI9500599