The Effect of Exposing High Yielding Dairy Cows To Short Wavelength LED Illumination During The Night On Fatty Acid Profile

Abstract

Fatty acid levels vary between day and night milking. Many dairy cows are kept under whole light at night (LAN) illumination using a white light-emitting diode (W-LED) suspected of disrupting circadian rhythms. We investigated the effect of W-LED LAN and same lux level red LED (R-LED) LAN, which is known not to disrupt circadian rhythms in other mammals, on milk yield and circadian composition, compared to a natural light-dark (LD)-cycle of 10-11 h light. Cows under the natural LD-cycle showed circadian variation in milk-fat composition, characterized by higher health-promoting monounsaturated fatty acid (MUFA) and lower saturated fatty acid (SFA) levels in 13:30-h (day milk, DM) than 03:30-h (night milk, NM). W-LED did not affect milk and milk-fat yields, yet abolished the circadian pattern of milk-fat composition towards a less healthy fatty acid profile by lowering MUFA levels of DM. Switching W-LED to R-LED reversed these circadian disruptions. Therefore, R-LED and W-LED have no commercial advantage over the tested LD-cycle, while W-LED is disadvantageous, showing a circadian disruption. Accordingly, if the illumination is indispensable, the R-LED regime is preferable over W-LED for cow’s wellbeing and for preserving the natural milk-fat profile; while differentiating DM from NM from a commercial-health-promoting perspective.

Effect of Illumination on Milk Yield

“…При сравнении ахроматического и хроматического искусственное освещения выявлено, что разный спектр света по-разному влияет на качественные и количественные показатели продуктивности КРС [5]. Также установлено, что при использовании светоди-одных ламп [6], белый свет не повлиял на выход молока и молочного жира, но привел к изменению циркадных ритмов и жирнокислотного профиля молока. При естественном цикле освещения влияние циркадных изменений на жирномолочность характеризовалось более высоким содержанием полезных для здоровья мононенасыщенных жирных кислот и пониженным уровнем насыщенных жирных кислот.…”