Variability in Holstein heifer heart-girth measurements and comparison of prediction equations for live weight

A. J. Heinrichs, H. N. Erb, G. W. Rogers, J. B. Cooper, C. M. Jones

Research output: Contribution to journalArticle

35 Scopus citations

Abstract

Measurement of heart-girth (chest circumference) is commonly used to estimate dairy heifer body weight from previously derived equations or tables. In this experiment, variability of heart-girth measurements as they are taken in the field was analyzed to determine the standard deviation within a group of 26 Holstein heifers of various ages weighing 42-590 kg. Standard deviations were 2.19 cm among 26 observers and 2.74 cm within any one observer. Repeatability between two heart-girth measurements by an individual observer on the same animal using a blind heart-girth tape was >0.99. Correlation coefficients between two measurements by different observers using blind measuring tapes on the same animal also were >0.99, with 99% of total differences due to observer and heifer, indicating very little random variation. A second part of this study was the validation of the most recently derived equation to calculate body weight from heart-girth. The equation was validated with data sets from universities across the United States and field data collected specifically for this study. Experimental and field data comprised of heart-girth and body weight measurements upheld the previously derived equation and support its continued use. These results allow more precise interpretation of heart-girth data collected from field studies with Holstein dairy heifers and provide more complete validation of existing body weight-prediction equations.

Original languageEnglish (US)
Pages (from-to)333-338
Number of pages6
JournalPreventive Veterinary Medicine
Volume78
Issue number3-4
DOIs
StatePublished - Mar 17 2007

All Science Journal Classification (ASJC) codes

  • Food Animals
  • Animal Science and Zoology

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