Body weight change during lactaction in Holstein x Zebu and Holstein x Sahiwal dual-purpose cows in Mexico

摘要

Theobjectiveofthisstudywastoanalyzethebodyweightofaherdof#190;Holsteinx#188;commercialZebu(CZ)and#189;Holsteinx#189;Sahiwal(F2HS)cowsinadual-purposesysteminthehumidtropicsofMexico.Cowswereweighedatcalvingandeveryfifteendaysuntilthedrying.Thedataanalyzedincluded1520observationsfrom44cowsand113lactations,fromthefirsttothefourthcalving,duringtheyears1993to2001.Datawereanalyzedusingmixedmodelprocedures,includingthefixedeffectoftimeofmeasurementandtherandomeffectsofcowandtheresidual.TheliveweightoftheHCcowsshowedaslightbutpermanentincreaseinthefirsttwolactationsandatrendtoremainconstantinthethirdandfourthlactations.TheF2HScows,oflowbodyweightatcalvingmaintainedtheirbodyweightinthefirst,secondandfourthlactationsalthoughshowedaslightincreaseattheendofthelactation.Thebodyweightatcalvingandtheaverageofallweightsduringlactationincreasedwithparityofthecow.ThematurebodyweightoftheanimalswasreachedatthesecondlactationfortheF2HScowsandforthethirdlactationfortheHCcows.