Consistency of dry matter intake in Holstein cows: heritability estimates and associations with feed efficiency

Authors: CAVANI, LIGIA - University Of Wisconsin; PARKER GADDIS, KRISTEN - Council On Dairy Cattle Breeding; Baldwin, Ransom - Randy; SANTOS, JOSE - University Of Florida; KOLTES, JAMES - Iowa State University; TEMPELMAN, ROBERT - Michigan State University; VANDEHAAR, MICHAEL - Michigan State University; WHITE, HEATHER - University Of Wisconsin; PENAGARICANO, FRANCISCO - University Of Wisconsin; WEIGEL, KENT - University Of Wisconsin

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/10/2023
Publication Date: 1/24/2024
Citation: Cavani, L., Parker Gaddis, K.L., Baldwin, R.L., Santos, J.E., Koltes, J.E., Tempelman, R.J., Vandehaar, M.J., White, H.M., Penagaricano, F., Weigel, K.A. 2024. Consistency of dry matter intake in Holstein cows: Heritability estimates and associations with feed efficiency. Journal of Dairy Science. 107(2):1054–1067. https://doi.org/10.3168/jds.2023-23774.
DOI: https://doi.org/10.3168/jds.2023-23774

Interpretive Summary: As we seek to enhance the sustainability of dairy farming, it will become more important to considerer the ability of dairy cows to perform under variable environmental and management conditions. Analyzing fluctuations in daily feed intake can be a promising tool for identifying cows that display resilience under challenging conditions. In this study, we proposed new phenotypes for DMI consistency and investigated their relationships with other traits. Our results demonstrate that DMI consistency is a heritable trait in Holstein cattle and suggest that cows with greater variation in daily DMI (less consistency) are less feed efficient and may be less resilient to challenges or perturbations.

Technical Abstract: Resilience can be defined as the capacity to maintain performance or bounce back to normal functioning after a perturbation, and studying fluctuations in daily feed intake may be an effective way to identify resilient dairy cows. Our goal was to develop new phenotypes based on daily DMI consistency in Holstein cows, estimate genetic parameters and genetic correlations with feed efficiency and milk yield consistency, and evaluate their relationships with production, longevity, health, and reproduction traits. Data consisted of 397,334 daily DMI records of 6,238 lactating Holstein cows collected from 2007 to 2022 at 6 research stations across the United States. Consistency phenotypes were calculated based on the deviations from expected daily DMI for individual cows during their respective feeding trials, which ranged from 27 to 151 d in duration. Expected values were derived from alternative models, including simple average, quadratic and cubic quantile regression with a 0.5 quantile, and LOESS regression with span parameters 0.5 and 0.7. We then calculated the log of variance (log-Var-DMI) of daily deviations for each model as the consistency phenotype. Consistency of milk yield was also calculated, as a reference, using the same methods (log-Var-Milk). Genetic parameters were estimated using an animal model, including lactation, days in milk and cohort as fixed effects, and animal as random effect. Relationships between log-Var-DMI and traits currently considered in the US national genetic evaluation were evaluated using Spearman's rank correlations between sires' breeding values. Heritability estimates for log-Var-DMI ranged from 0.11± 0.02 to 0.14 ± 0.02 across models. Alternative methods used to calculate log-Var-DMI yielded very similar results, with genetic correlations ranging from 0.94 to 0.99. Estimated genetic correlations between log-Var-DMI and log-Var-Milk ranged from 0.51 to 0.62. Estimated genetic correlations between log-Var-DMI and feed efficiency ranged from 0.55 to 0.60 with secreted milk energy, 0.59 to 0.63 with metabolic body weight, and 0.26 to 0.31 with residual feed intake. Relationships between log-Var-DMI and the traits in the national genetic evaluation were moderate and positive correlations with milk yield, moderate and negative correlations with female fertility, no significant correlations with health and longevity, and favorable correlations with feed efficiency. We concluded that DMI consistency is heritable and may be an indicator of resilience. Cows with lower variation in the difference between actual and expected daily DMI (more consistency) may be more effective in maintaining performance in the face of challenges or perturbations, whereas cows with greater variation in observed versus expected daily DMI (less consistency) are less feed efficient and may be less resilient.