Rounding Dairy Herd Improvement Milk Weights to the Nearest Pound

Supervisors in the Northeast United States currently report milk weights on test day to the tenth of a pound on only 39.9% of the cows tested. Of the remaining cows, 25.4% are reported to the fourth pound, 24.8% to the half pound, and 9.9% to the full pound. Corresponding for cows on owner sampler t...

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Bibliographic Details
Published in:Journal of dairy science 1972-10, Vol.55 (10), p.1517-1520
Main Authors: Everett, R.W., Wadell, L.H., Ainslie, H.R.
Format: Article
Language:English
Subjects:
animal husbandry
animal science
livestock
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Summary:Supervisors in the Northeast United States currently report milk weights on test day to the tenth of a pound on only 39.9% of the cows tested. Of the remaining cows, 25.4% are reported to the fourth pound, 24.8% to the half pound, and 9.9% to the full pound. Corresponding for cows on owner sampler test are 45.7, 9.0, 24.3, and 21.0%. Reporting Dairy Herd Improvement milk weights to full pounds rather than tenths of pounds increases the standard deviation of the difference of estimated and actual 305-day milk production by 1.7% for twice-a-day collection schemes and 2.6% for once-a-day collection schemes. A bias of approximately +18kg would occur for twice and once-a-day collection schemes regardless of the number of test days in a lactation. The maximum bias that could occur due to rounding to the nearest full pound would be 138kg in a 305-day lactation.
ISSN:0022-0302
1525-3198
DOI:10.3168/jds.S0022-0302(72)85708-4