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 Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Neville, W. E. Articles by Neathery, M. W. Search for Related Content PubMed PubMed Citation Articles by Neville, W. E., Jr. Articles by Neathery, M. W.

Effect of Natural Differences in Atmospheric Temperature on the Incidence of First Estrus following Anestrus in Ewes¹

Georgia Station, Experiment and Georgia Mountain Experiment Station, Blairsville

Abstract

Two locations in Georgia, Experiment and Blairsville, which are 246 km apart and differ 5 C in summer atmosphere temperature, were utilized to study the effect of naturally occurring differences in atmospheric temperature on the incidence of first estrus following anestrus in ewes. A portion of the Experiment ewes (approximately one-half Hampshire and one-half southwestern whiteface) were moved to Blairsville in May. At the same time, a portion of the Blairsville ewes (Hampshire and first-cross Dorset x Hampshire) were moved to Experiment. Care was taken to maintain proportionality for age and genotype of ewes. The ewes were kept as a group on bermudagrass pasture during the summer and were returned to their original location in mid-September each year. This was done 3 yr. for a total of 520 ewe observations.

The mean date of first estrus was June 20 with yearly means ranging from June 16 to June 23. The mean date of esterus was significantly earlier each year ( 8,4 and 16 days for 1960, 1961 and 1962, respectively for ewes summered at blairsville compared with Experiment. Experiment ewes exihibited esterus significantly earlier each year (30, 8 and 4 days for the respective years) compared with Blairsville ewes. A significant interaction for summer location x genotype of ewe occurred each year. Date of first estrus was not significantly exhibited estrus significantly later than Dorset x Hampshire crosses.

¹ Journal Series Paper No. 556, University of Georgia, College of Agriculture Experiment Stations, Georgia Station, Experiment, and Georgia Mountain Experiment Station, Blairsville. Contribution to Southern Regional Project S–29, Genetic and Physiological Factors Affecting Reproduction of Sheep in the South.

² The authors gratefully acknowledge the assistance of Dr. E. P. Warren, Computer Center, University of Georgia, Athens, in conducting the statistical analysis.