This paper is only available as a PDF. To read, Please Download here.
Abstract
Various time constraints and cow numbers were used to identify the minimum time per cow and the minimum number of cows needed to permit ranking of students for their skills in linear type evaluation. Three separate trials were conducted involving 23, 15, and 12 students from three universities who evaluated 15 traits on 30, 20, and 27 cows, respectively, using a 50-point scale. Time constraints included 1.5, 2, 3, and 4 min per cow as well as unlimited time per cow. The mean of the absolute difference between official and student scores was used to rank students. Lower means indicated greater student accuracy. Mean differences and (standard errors) across trials were 7.28 (0.24), 7.41 (0.11), 7.18 (0.11), and 7.41 (0.18) for 1.5, 2, 3, and 4 min of evaluation, respectively. The overall effect of time was not significant, and no pairs were significantly different. Rank correlations between student means suggested that 2 min of evaluation were adequate, and no advantage was found for evaluations of >3 min per cow. Rank correlations for student evaluation means based on 5 versus 10 cows were 0.85 to 0.90. Evaluation of <4 cows dropped rank correlations, but evaluation of >5 cows did not improve correlations greatly. Results suggested that use of 4 or 5 cows, evaluated at 2 to 3 min per cow, permitted accurate ranking of students for their ability to evaluate linear type traits.
Key words
References
- Linear Classification System.Holstein-Friesian Assoc. Am., Brattleboro, VT1994
SAS® User's Guide: Statistics, Version 6.04 Edition. 1990. SAS Inst., Inc., Cary, NC.
Article info
Publication history
Accepted:
February 26,
1996
Received:
September 18,
1995
Identification
Copyright
© 1996 American Dairy Science Association. Published by Elsevier Inc.
User license
Elsevier user license | How you can reuse 
Elsevier's open access license policy
Elsevier user license
Permitted
For non-commercial purposes:
- Read, print & download
- Text & data mine
- Translate the article
Not Permitted
- Reuse portions or extracts from the article in other works
- Redistribute or republish the final article
- Sell or re-use for commercial purposes
Elsevier's open access license policy
