GROWTH STANDARDS OF BODY WEIGHT AND MEASUREMENTS OF HOLSTEIN-FRIESIAN HEIFERS KEPT UNDER INTENSIVE MANAGEMENT

Abstract

Growth standards were developed for body weight (BW) and measurements (BMs) of wither height (WH) and chest girth (CG) of Holstein-Friesian (HF) heifers kept during a period of 1994 - 2002 at an intensive dairy breeding station (BS) in Banyumas district, Central Java. Data of repeatable measurements of individual body traits were mostly recorded bimonthly from non-contemporary heifers within an age range of 2 - 570 d. Specified values at any given ages of BW, WH and CG were predicted from individually best fitted growth-curve equations derived from initial records of heifers’ body traits. Growth standards of BW, WH and CG were developed by fitting up to the third terms of regression of means of the specified values of individual body traits on age. Similar regressions were fitted to the means i 1 SD to establish a range around the population estimate. Quadratic regression resulted in the best
fitted models in developing the growth standards of individual body traits and to produce their confidence ranges. This was due to the significances (P<0.0l) and the highest R2 values yielded from the quadratic expressions of means ofBW (R2 = 99.7 - 100), WH (R2 I 99.7 - 99.9) and CG (R2 = 99.9 - 100) on age. By developing the growth standards, recommendation of predicting values of BW, WH and CG at various ages, from 2 to 570d, of HF heifers can be determined. Growth rates of BW and BMs of HF heifers were lower to those of HF heifers kept in temperate regions and some tropical regions. Low growth potential, inferior feeding and management, disease incidence and tropical heat stress might be crucial factors in diminishing the growth rates of HF heifers in the current study.