|
KMID : 1025520040460050707
|
|
Journal of Animal Science and Technology
2004 Volume.46 No. 5 p.707 ~ p.718
|
|
|
A Study on Estimating Daily Yield from Morning or Afternoon Milking Records with Unequal Milking Intervals
|
|
Cho Yong-Min
Park Byoung-Ho
Ahn Byeong-Seog
|
|
|
Abstract
|
|
|
|
This study was conducted to evaluate the adequacy of an alternative a.m.-p.m. testing scheme for milk yield in comparison with the official test method based on weighing two milkings within 24 h. A total of 8,309 p.m. milking weights and 6,767 a.m. milking weights from 72 Holstein cows raised at N.L.R.I. were collected between October 2000 and November 2001. Seven statistical models were fitted to the data to derive formulas for estimating daily milk yields from morning or evening yields. In general, use of evening milkings less accurately estimated than did use morning milkings. Although the models do not differ much in the correlations between estimated and true daily milk yields, systematic under- and overestimation of daily milk yields were observed in all models with the exception of model 7, which accounted for heterogeneous variances by parity class, milking interval class, and lactation stage by fitting separate regression formulas within each combination of three factors.
|
|
|
KEYWORD
|
|
|
Daily milk yield, a.m. p.m. Milking interval
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
|
|