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 Hulet, C. V. Search for Related Content PubMed PubMed Citation Articles by Hulet, C. V.

Determining Fetal Numbers in Pregnant Ewes

U. S. Department of Agriculture, Dubois, Idaho 83423 and Ruakura Agricultural Research Centre, Hamilton, New Zealand

Abstract

Twenty-nine ewes were laparotomized about 30 days postbreeding, CL counted and uteri palpated for amnionic vesicles. These same ewes were palpated about 40 days later using a bimanual rectal-abdominal palpation technique made possible by the aid of a hollow plastic palpation rod, 1.6 cm x 50 cm with a bullet shaped tip. The ewes are held flat on their backs during examination. Using number of CL, amnionic vesicles and solid uterine masses as indicator of whether a ewe would give birth to single or multiple lambs, accuracy of prediction was 86, 89 and 89%, respectively. The possibility of using two ultrasonic Doppler instruments simultaneously to distinguish independent fetal arterial circulations or fetal hearts was investigated. The equipment currently available was not satisfactory for differentiating independent fetal circulations. Although a systematic search for fetal hearts can lead to accurate observations this technique is extremely slow and tedious. Sixty-three ewes in two flocks were used to study the effects of stage of gestation and operator differences on accuracy of prediction using rectal-abdominal palpation. Although neither stage of gestation, between 62 and 107 days, nor operator had a significant effect on accuracy, consistency and accuracy appeared to be poorer at the two earliest observations (days 62 and 69 in flock 1). Ability to detect twins appeared to improve slightly with experience. Approximately 30 sec. per ewe was required for determining number of lambs. The technique appears to offer distinct advantages of simplicity, economy and speed over other techniques of comparable accuracy.

¹ Animal Science Research Division, Sheep and Fur Animal Research Branch, U. S. Sheep Experiment Station, Dubois, Idaho 83423.

² Research conducted at and in co-operation with the Ruakura Animal Research Station, Private Bag, Hamilton, New Zealand with the aid of a Fulbright-Hays Grant.

³ The author gratefully acknowledges the assistance and encouragement of Mr. John Ackerley, Dr. Robert Welch and administrators and staff of the Ruakura Animal Research Station.