JDS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Journal of Dairy Science Vol. 41 No. 2 255-260
© 1958 by American Dairy Science Association ®
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Wilcox, C. J.
Right arrow Articles by Bartlett, J. W.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Wilcox, C. J.
Right arrow Articles by Bartlett, J. W.

Change's in Type Classification Ratings of Immature Holstein Females. I. The over-all Ratings1

C. J. Wilcox, K. O. Pfau, R. E. Mather and J. W. Bartlett

New Jersey Agricultural Experiment Station, Sussex

ABSTRACT

Semiannual type ratings by official inspectors from 1945 to 1956 were analyzed to show some changes occurring in Holstein females of the New Jersey Agricultural Experiment Station from 6 mo. of age to the end of the first lactation. Ratings of 94 animals were grouped according to age, 6 to 18 mo. (yearlings), 18 mo. to freshening (2-yr.-olds), first lactation (first-calf heifers), and 6 mo. to freshening (nonadult) with each animal having two or more ratings in each period. Means of ratings decreased significantly with age from yearlings to 2-yr.-olds and from 2-yr.-olds to first-calf heifers. The correlation (0.16) between yearlings and first-calf heifers was not significant. Although significant, correlations between 2-yr. old and first-calf heifer ratings (0.41), and nonadult and first-calf heifer ratings (0.27), were also low. Eandom and confounded effects difficult to measure combined to account for from 45 to 54% of the total variation. Under the present rating systems, it does not seem practical to select for type at early ages.

FOOTNOTES

1 Paper of the Journal Series, New Jersey Agricultural Experiment Station, Rutgers University, the State University of New Jersey, Department of Dairy Industry, New Brunswick. This study was part of a joint project between the Holstein-Friesian Association of America and the New Jersey Agricultural Experiment Station.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1958 by the American Dairy Science Association ®.