Inoculation with rumen fluid in early life as a strategy to optimize the weaning process in intensive dairy goat systems

摘要

Ruminants are born with an undeveloped physical,metabolic, and microbial rumen. Rumen developmentis limited under artificial rearing systems whennewborn animals are separated from the dam, fed onmilk replacer, and weaned at an early age. This studyaims to evaluate the effects of early-life inoculation ofyoung ruminants with rumen fluid from adult animals.Eighty newborn goat kids were randomly allocated to1 of 4 experimental treatments and inoculated dailyfrom d 1 to wk 11 with autoclaved rumen fluid (AUT),fresh rumen fluid obtained from adult goats fed eithera forage diet (RFF) or concentrate-rich diet (RFC), orabsence of inoculation (CTL). Goat kids were artificiallyreared with ad libitum access to milk replacer,starter concentrate, and forage hay. Blood was sampledweekly and rumen microbial fermentation was monitoredat 5 (preweaning), 7 (weaning), and 9 wk of age(postweaning). Results indicated that inoculation withfresh rumen fluid accelerated the rumen microbial andfermentative development before weaning. As a result,RFC and RFF animals had higher solid feed intake(+73%), rumen concentrations of ammonia-N (+26%),total volatile fatty acids (+46%), butyrate (+50%),and plasma β-hydroxybutyrate (+48%), and lowermilk intake (−6%) than CTL and AUT animals atwk 5. Inoculation with fresh inoculum also promotedearly rumen colonization by a complex and abundantprotozoal community, whereas CTL animals remainedprotozoa free. Although all kids experienced moderategrowth retardation during 1 wk after weaning,inoculation with fresh rumen fluid favored the weaningprocess, leading to 2.2 times higher weight gain thanCTL and AUT animals during wk 8. Some of these advantageswere retained during the postweaning periodand RFF and RFC animals showed higher forage intake(up to +44%) than CTL and AUT animals with nodetrimental effects on feed digestibility or stress levels.The superior microbial load of RFC compared withRFF inoculum tended to provide further improvementsin terms of forage intake, plasma β-hydroxybutyrate,and rumen protozoa, whereas AUT inoculation providedminor (if any) advantages with respect to CTLanimals. Although no differences were noted on animalgrowth, this study suggests that early life inoculationof goat kids with rumen microbiota can represent aneffective strategy to accelerate the rumen development,facilitating a smooth transition from milk to solid feedand to the potential implementation of early weaningstrategies.