HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Jordan, R. M. Articles by Croom, H. G. Search for Related Content PubMed Articles by Jordan, R. M. Articles by Croom, H. G.

The Effect of Various Hormone Implants on Fattening Lambs¹

University of Minnesota²

Abstract

In a trial conducted during the early spring with feeder lambs, increased rate of gain and feed efficiency occurred in all lambs treated with various combinations of hormone implants. However, without exception, carcass grade and yield were lower in the treated groups than in the control groups. At the levels used in this experiment, neither progesterone nor testosterone protected the lambs from the adverse side effects of estradiol. However, when used in combination with estradiol progesterone reduced the increased rate of gain to a greater degree than the testosterone estradiol combination.

Lambs treated during the summer months with combinations of estradiol and testosterone, and estradiol and progesterone responded to a very slight degree as measured by rate of gain and feed efficiency. Carcass grade, however, was decidedly lower in all groups except one (200 mg. progesterone and 5 mg. estradiol). As was the case in the spring trial, progesterone reduced growth stimulation from estradiol to a greater extent than did testosterone. The inconsistent effects of estrogen implants on secondary sex glands and particularly carcass grade and yield limits their use and suggests the need for additional research.

¹ Paper No. 3549, Scientific Journal Series, St. Paul.

² This project was supported in part by Grants-In-Aid from Chemical Specialities Company, Inc., New York City.