Effects of UV-B light exposure during automatic milking on vitamin D levels in Holstein Friesian cows

Hodnik, Jaka Jakob (author), Jankovec, Marko (author), Ježek, Jožica (author), Krušič, Žiga (author), Mitterhofer, Stefan (author), Starič, Jože (author)

Vitamin D is essential for cattle and can be synthesized in the skin under ultraviolet irradiation. This study investigated the effects of narrow-band UV-B irradiation during automatic milking on blood vitamin D concentration and the influence of hair and black skin areas on cutaneous vitamin D synthesis in Holstein Friesian cows. Fifty-one cows were stratified by milk yield, days after calving, and percentage of black skin, then divided into three groups: shaved and irradiated (80 J/m2), unshaved and irradiated (129–305 J/m2), and a control group. A custom UV-B light (peak radiation at 295 nm) was installed in the milking robot. Blood 25-hydroxyvitamin D (25(OH)D) levels were measured at baseline, and 7, 30, and 60 days postexposure using an enzyme-linked fluorescent assay. UV-B exposure significantly (p < 0.001) increased 25(OH)D levels in shaved (13.4 ng/mL), unshaved (10 ng/mL), and control groups (5.1 ng/mL). Despite receiving less than half the UV-B dose, the shaved group had superior 25(OH)D synthesis compared to the unshaved group (p < 0.05), highlighting hair’s role in reducing UV-B absorption. Cutaneous synthesis correlated with black skin area in shaved cows but not in unshaved cows. UV-B irradiation also increased daily milk production by 2.2 kg (shaved) and 2.9 kg (unshaved) compared to controls (p < 0.001). UV-B exposure during automatic milking offers a novel, non-disruptive method for enhancing vitamin D levels in dairy cows.

• Language: English
• Keywords: ultraviolet-B light, cattle, 25-hydroxyvitamin D, milk yield skin, skin, hair, color, blood
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: VF - Veterinary Faculty
• Publication status: Published
• Publication version: Version of Record
• Publication date: 01.01.2025
• Year: 2025
• Number of pages: 8 str.
• Numbering: Vol. 11, [article no.] 1433230
• PID: 20.500.12556/RUL-166711
• UDC: 636.2.09:616
• ISSN on article: 2297-1769
• DOI: 10.3389/fvets.2024.1433230
• COBISS.SI-ID: 223240707
• Publication date in RUL: 22.01.2025

Record is a part of a journal

• Title: Frontiers in veterinary science
• Shortened title: Front. vet. sci.
• Publisher: Frontiers Media S.A.
• ISSN: 2297-1769
• COBISS.SI-ID: 3969402

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Funding programme: P4-0092
• Project number: P4-0092
• Name: Zdravje živali, okolje in varna hrana