TY - JOUR

T1 - Different reticuloruminal pH metrics of high-yielding dairy cattle during the transition period in relation to metabolic health, activity, and feed intake

AU - Heirbaut, S.

AU - Børge Jensen, D.

AU - Jing, X. P.

AU - Stefańska, B.

AU - Lutakome, P.

AU - Vandaele, L.

AU - Fievez, V.

N1 - Publisher Copyright: © 2022 American Dairy Science Association

PY - 2022

Y1 - 2022

N2 - The measurement of pH in the reticulorumen in combination with a time–pH threshold has been widely applied in research to diagnose subacute ruminal acidosis. However, other pH metrics also have biological value. In this study, 44 animals were monitored during the transition period using reticuloruminal pH boluses. Traditional and more complex pH characteristics were calculated to characterize the reticuloruminal pH profile: time pH <6, slope of a logistic cumulative pH curve (β0), and deviations [squared error (SqEr)] from pH predictions based on a harmonic static model. In this study, we aimed to examine the associations between those pH metrics and metabolic health parameters, feed intake, and activity. Finally, to describe the reticuloruminal pH dynamically, we also constructed a dynamic linear model. The results of this model were studied in relation to feed intake. All pH parameters were mutually correlated (particularly β0 and SqEr; mean Pearson correlation of −0.52). pH patterns, rather than time pH <6, were associated with metabolic health and feed intake: high variation in daily pH (β0 parameter) was reflected in higher blood concentrations of nonesterified fatty acids. Moreover, pH deviations of the harmonic model were negatively associated with feed intake and rumination behavior. This research confirms the biological importance of pH metrics focusing on pH variation and pH deviations and provides deeper insight into its associations with metabolic health status, feed intake, and activity during early lactation.

AB - The measurement of pH in the reticulorumen in combination with a time–pH threshold has been widely applied in research to diagnose subacute ruminal acidosis. However, other pH metrics also have biological value. In this study, 44 animals were monitored during the transition period using reticuloruminal pH boluses. Traditional and more complex pH characteristics were calculated to characterize the reticuloruminal pH profile: time pH <6, slope of a logistic cumulative pH curve (β0), and deviations [squared error (SqEr)] from pH predictions based on a harmonic static model. In this study, we aimed to examine the associations between those pH metrics and metabolic health parameters, feed intake, and activity. Finally, to describe the reticuloruminal pH dynamically, we also constructed a dynamic linear model. The results of this model were studied in relation to feed intake. All pH parameters were mutually correlated (particularly β0 and SqEr; mean Pearson correlation of −0.52). pH patterns, rather than time pH <6, were associated with metabolic health and feed intake: high variation in daily pH (β0 parameter) was reflected in higher blood concentrations of nonesterified fatty acids. Moreover, pH deviations of the harmonic model were negatively associated with feed intake and rumination behavior. This research confirms the biological importance of pH metrics focusing on pH variation and pH deviations and provides deeper insight into its associations with metabolic health status, feed intake, and activity during early lactation.

KW - diurnal pH patterns

KW - metabolic health status

KW - reticuloruminal pH bolus

KW - subacute ruminal acidosis

U2 - 10.3168/jds.2021-21751

DO - 10.3168/jds.2021-21751

M3 - Journal article

C2 - 35773031

AN - SCOPUS:85133165052

VL - 105

SP - 6880

EP - 6894

JO - Journal of Dairy Science

JF - Journal of Dairy Science

SN - 0022-0302

IS - 8

ER -