Maternal liver retinol stores do not ensure adequate calf vitamin A under restricted late-gestation vitamin A intake

Authors: SPEER, HANNAH - University Of Nebraska; FREETLY, HARVEY - Retired ARS Employee; DREWNOSKI, MARY - University Of Nebraska

Submitted to: Animal Science Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/12/2026
Publication Date: 4/10/2026
Citation: Speer, H.F., Freetly, H.C., Drewnoski, M.E. 2026. Maternal liver retinol stores do not ensure adequate calf vitamin A under restricted late-gestation vitamin A intake. Animal Science Journal. 97. Article e70175. https://doi.org/10.1111/asj.70175.
DOI: https://doi.org/10.1111/asj.70175

Interpretive Summary: Vitamin A is essential for calf health, but calves are born with very little stored in their liver and depend almost entirely on what they receive from their dam before and shortly after birth. This study evaluated whether beef cows with adequate liver vitamin A levels at calving can reliably provide enough vitamin A to their calves when dietary vitamin A intake is low. Cows in this study began late gestation with high liver vitamin A stores, but received low dietary vitamin A for 128 days prior to calving and 32 days post calving. At one month post calving, most cows still had liver concentrations considered adequate by current reference guidelines. However, their calves had uniformly low liver vitamin A concentrations at one month of age. These findings show that adequate maternal liver stores alone are not sufficient to ensure adequate vitamin A transfer to the calf when dietary vitamin A intake during late gestation is limited. When compared with recent research in which high dietary vitamin A intake during gestation and early lactation improved both cow and calf vitamin A status, the evidence suggests that cows require both adequate liver reserves and sufficient dietary vitamin A intake to reliably support calf vitamin A needs.

Technical Abstract: Vitamin A is critical for immune function and epithelial integrity, yet the relationship between maternal and calf vitamin A sta­tus is not well defined. This study evaluated cow-calf vitamin A status under restricted maternal vitamin A intake during late gestation and early lactation. Beef cows (n = 114) were individually fed 14,000 or 29,000 IU/d of vitamin A (approximately 30% or 75% of recommendations) from 128 days pre-calving to 32 days post-calving. All cows began with high liver retinal concentrations (mean ± SD: 786 ± 252 µg/g DM) from prior grazing. Cow liver and plasma, and calf liver and plasma, were sampled 32 ± 7 days postpartum. Cow liver retinal declined to 483 ± 182 µg/g DM by 32 days postpartum. Calf liver retinal averaged 51 ± 27 µg/g DM and plasma retinal 190 ± 47 ng/mL, both below adequacy thresholds. Calf plasma retinal increased with calf liver retinal (p < 0.01; R2 = 0.22). Maternal post-calving liver retinal explained 9.5% of the variation in calf liver retinal. These results indicate that adequate maternal liver vitamin A stores at calving do not ensure adequate calf vitamin A status when maternal dietary vitamin A is restricted.