Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Animal Science


This study was conducted to determine if taillessness has any effect on production characters in the South Dakota Agricultural Experiment station’s No-Tail sheep flock. Taillessness in this flock is derived from six Siberian fat-rumped sheep brought to South Dakota in 1913. These sheep did not have a tail but had a large gob of fat on either side of the rump. They were crossed with common United States breeds to develop a breed of sheep with good mutton and wool qualities as well as being tailless. Initial crossbreeding from which the No-Tail flock was established was done in 1913. Records were kept each year, but prior to 1947 they were limited to pedigree, birth date, lamb tail length, and birth weight. The data used in this study include records of the No-tail flock for the years 1947 through 1960. A total of 763 lambs were used in characterizing the traits which were measured. There were 614 of these records that had complete data for tail length, birth weight, and 120-day weight. Means for the other factors were based on the maximum number of records for each of the traits measured. Means have been calculated for tail length, birth weight, 120-day weight, yearling fleece weight, and yearling staple length. For these characterizations, lambs were classified by tail length, type of birth, type of rearing, and sex. The results indicated that tail length has no effect on any of the characters studied in this thesis. There was an influence of sex on birth-weight of the 622 lambs. Sex had a significant influence on 120-day weight. The influence of sex on yearling fleece weight was very small and it did not influence yearling staple length.

Library of Congress Subject Headings

Sheep breeds


Includes bibliographical references



Number of Pages