Predicting body weight from heart girth, height at withers and body condition score in Bos indicus cattle bulls of Uganda

摘要

Heartgirth(HG),heightatwithers(HW)andbodyconditionscore(BCS)wereusedtopredictthelivebodyweight(BW)ofBosindicuscattlebullsinUgandausing24Ankoleand24Ngandagrowingbulls.Thebullsweresubjectedtothreefeedingregimesforaperiodof392days(56weeks).ThedataobtainedonthethreebodymeasurementswerefittedtosimpleandmultiplelinearregressionequationstopredictBW.Testsforhomogeneityofslopesandinterceptsshowednodifferencesbetweenthetwobreedsandacrossthethreefeedingregimes.Linearregressionsindicatedthatallthethreebodymeasurementscanbeusefulinpredictingbodyweight;however,HGwasthemostaccuratepredictorasasingleexplanatoryvariable(R2=0.86)comparedtoHW(R2=0.76)andBCS(R2=0.55).TheR2valueimprovedto0.85afterHWandBCSwerecombinedinthesameequation.QuadraticandcubiceffectsofthethreebodymeasurementsonBWwerenotsignificant.ItisconcludedthatlivebodyweightofBosindicuscattlebullscanbeaccuratelypredictedfrombodymeasurementsregardlessofbreedtypeandfeedingregime.