Semen parameters, spermatogenesis and hormone concentrations in stallions subjected to long-term estrogen administration /

Eight pony stallions were paired by estimated daily sperm

Bibliographic Details
Main Author:	Lang, Anita Lynn
Format:	Thesis Book
Language:	English
Published:	[Place of publication not identified] : [publisher not identified] ; 1997.
Subjects:	Major animal science.
Online Access:	http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=736824261&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD

Description
Summary:	Eight pony stallions were paired by estimated daily sperm output (DSO) and randomly assigned to one of two treatments. Stallions received 44 []g/kg BW estradiol cypionate (ECP) or an equivalent volume of physiological saline solution on alternate days during the breeding season. Blood samples collected immediately preceding each injection were assayed for luteinizing hormone (LH), estradiol-17[] (E2) and testosterone (T). Semen collected at 3.5-d intervals was evaluated for spermatozoal motility, total number of sperm per ejaculate and seminal plasma E2 (SE2). Prior to and after four, eight and 12 wk on treatment, DSO was determined. Data were separated into nine 10-d periods for statistical analysis. As expected, E2 was higher (p<.05) in the ECP- treated group after 20 d (period 2) of treatment and for the remainder of the experiment. Although, E2 was higher (p<.05) in the C group prior to treatment, there was no difference between groups after 10 d of treatment. ECP stallions had higher (p<.05) DSO after 30 d on treatment. After 40 and 50 d (periods 4 and 5), ECP stallions demonstrated higher (p<.05) total sperm per period. This was preceded by higher (p<.05) LH concentrations for ECP stallions after periods 1 and 2. There were no differences (p>.05) in SE2 between groups after periods 1 and 2. Between 30 and 70 d, ECP stallions had higher SE2 concentrations. Elevated SE2 in ECP stallions was moderately correlated to total sperm per period (r =.53). No differences (p>.05) were seen between 30 and 60 d for LH, after 60 d for DSO or after 60, 70 or 80 d for total sperm per period. ECP stallions had higher (p<.05) DSO and total sperm per period after 90 d. Additionally, LH remained higher (p<.05) in the ECP group after 60 d. Seminal plasma E2 was higher (p<.05) in ECP stallions after 90 d. There were no differences between the two groups for testicular cell data. Elevated LH concentrations in ECP stallions demonstrated that estrogen treatment did not inhibit LH in this study. Treatment with ECP did not have a detrimental effect on potential DSP in this study.
Item Description:	Vita. "Major Subject: Animal Science".
Physical Description:	xi, 104 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc.
Bibliography:	Includes bibliographical references: pages 49-53.