Development of a subacute ruminal acidosis risk score and its prediction using milk mid-infrared spectra in early-lactation cows

A routine monitoring for subacute ruminal acidosis (SARA) on the individual level could support minimization of economic losses and ensuring animal welfare in dairy cows. The objectives this study were (1) to develop a SARA risk score (SRS) by combining information from different data acquisition systems generate an integrative indicator trait, (2) investigation associations SRS with feed analysis data, blood characteristics, performance milk composition, including fatty acid (FA) profile, (3) development mid-infrared (MIR) spectra-based prediction equation novel reference trait SRS, (4) its application external set consisting MIR test day records investigate association between MIR-based predictions FA profile. primary set, which was used (3), consisted collected 10 commercial farms total 100 Holstein cows early lactation. comprised barn climate parameters, pH temperature logging intrareticular measurement boluses, as well jaw movement locomotion behavior recordings noseband-sensor halters pedometers. Further sampling collection included samples, performance, whereof latter get spectra estimate main components, lactoferrin content. Because all measurements characterized temporal resolutions, preparation aggregation into values daily basis merging it one set. For 7 traits selected, derived reticulum, chewing behavior, yield. After adjustment fixed effects standardization, these combined using linear combination directional weights based current knowledge literature studies. secondary objective entire herds, MIR-predicted FA. At farm level, be shown that diets higher proportions concentrated resulted both lower mean values. On increased associated modified profile (e.g., levels short- medium-chain FA, C17:0, odd- branched-chain FA). Furthermore, partial least squares regression model moderate predictability established SRS. This work provides demonstrates high potential composition-based assessment health status lactating