# UVB Light as a Source of Vitamin D for Indoor-Housed Gestating Sows

## TL;DR

Exposing indoor-housed pregnant sows to UVB light improved their and their offspring's vitamin D levels, but more efficient lighting is needed to achieve optimal benefits.

## Contribution

This study introduces UVB lighting in electronic sow feeders as a novel method to enhance vitamin D status in indoor-housed gestating sows.

## Key findings

- UVB-exposed sows and their offspring had significantly higher vitamin D levels than the control group.
- No significant differences in litter weight or piglet numbers were observed between groups.
- The UVB lamps used were insufficient to reach the vitamin D levels seen in outdoor-housed sows.

## Abstract

A randomized parallel study on UVB light exposure was conducted in a Danish herd. The aim was to improve the vitamin D status in gestating sows and their offspring by exposure to UVB light during visits to electronic sow feeders. A total of 386 sows were included in the study and divided into a group of 197 sows receiving a daily dose of UVB light and a control group of 189 sows under standard indoor production conditions. Both groups received standard vitamin D supplementation in their feed. Serum levels of vitamin D were significantly higher for UVB-exposed sows and their offspring compared to the control group. However, the vitamin D levels in UVB-exposed sows were lower than those previously reported in studies of outdoor-housed sows. No statistically significant difference in litter weight at birth, number of liveborn piglets, or number of stillborn piglets was observed between groups. The study showed that the vitamin D status of gestating sows was improved through UVB exposure using lamps installed in electronic sow feeders. Further studies using more efficient lamps are needed to investigate whether a further increase in levels of UVB-derived vitamin D can improve the birth weight of piglets and litter size in sows.

Vitamin D has been shown to influence growth in both fetuses and piglets. Pigs housed indoors rely solely on their feed as a source of vitamin D since they are never exposed to natural sunlight. UVB light is effective in improving the vitamin D status in sows and piglets housed indoors. This study aimed to investigate an innovative method for UVB lighting to enhance the vitamin D status of gestating sows to a level that could positively impact the growth of both fetuses and suckling piglets. A total of 386 sows were included at the time of insemination. Of these, 197 were exposed to a daily dose of UVB light, and 189 sows served as a control group. Both sows and piglets in the UVB group had significantly higher vitamin D levels in serum samples at the time of farrowing than sows and piglets from the control group. No statistically significant differences in litter weight or the number of liveborn or stillborn piglets were observed between groups. UVB light installed in an electronic sow feeder was successful, but, unfortunately, the lamp used in the study was unable to induce the production of vitamin D to the desired level in the sows. Further studies are needed to investigate the effect of higher doses of UVB light.