Melatonin concentration in cow’s milk and sources of its variation

Abstract

The effects of weather/season (winter and summer), milk production (high and low), and milking time (night and day) on melatonin levels were evaluated. The melatonin in the milk from 30 individual cows, the bulk tank milk (BTM) from 16 farms, and ultra-high temperature (UHT) processed milk of 12 brands over two seasons were also assessed. The melatonin average concentration was 6.98 pg/mL in the cows' milk, 4.71 pg/mL in the BTM, and 5.62 pg/mL in the UHT milk. In the night milk, the melatonin concentration averaged 14.87 pg/mL, whereas it was 6.98 pg/mL in the total daily milk. In winter, the milk melatonin concentration was, on average, 74.7% higher than in the summer (13.89 vs. 7.95 pg/mL). The night milk from the low production group in winter also had a higher concentration of melatonin (41.94 pg/mL). The variables related to illuminance, such as the time of milking and season of the year, had considerable effects on the melatonin concentration in milk. Collecting and marketing melatonin-rich milk could benefit populations and agribusiness. ARTICLE HISTORY

Effects of photoperiod and light intensity on milk production and milk composition of dairy cows in automatic milking system

“…The level of blood melatonin was lower in T2 (17.44 pg/mL) and T3 (17.03 pg/mL) than in Control (25.55 pg/mL) and T1 (23.72 pg/mL) ( p < 0.05). Melatonin is a relationship between blood and milk concentrations [ 41 ], since melatonin is amphiphilic, so it can freely diffuse through biological membranes into the circulatory system and from the bloodstream into the milk [ 43 ]. Kollmann et al [ 44 ] found about 40% of the blood melatonin concentration in the milk of cows producing approximately 32 kg/milk/day.…”

Melatonin ve önemi

“…Sütteki melatonin düzeyine mevsimlerin, gündüz akşam sağılmasının etkisini inceleyen çalışmalarında [37] melatonin ortalama konsantrasyonu inek sütünde 6.98 pg /mL, bulk tank sütünde 4.71 pg / mL ve UHT sütünde 5.62 pg / mL olarak belirlemişlerdir. Gece sütünde melatonin konsantrasyonu ortalama 14.87 pg / mL, günlük sütte 6.98 pg / mL tespit edilmiş ve kış sütünün melatonin konsantrasyonu, yaz mevsimine göre ortalama %74,7 daha yüksek olduğu sunucuna ulaşılmıştır.…”

“…Daha yüksek melatonin konsantrasyonları, gece süresinin daha uzun olduğu kış aylarında gece sağımında elde edilmiştir. Süpermarketlerde satışa sunulan UHT ve işlenmiş sütün melatonin konsantrasyonu ile çiğ sütün melatonin düzeyleri birbirine benzer bulunmuştur [37].…”

Effects of the circadian rhythm on milk composition in dairy cows: Does day milk differ from night milk?

“…Melatonin is a key hormone that shows circadian variations, with high levels during the scotoperiod and low levels during the photoperiod (Castro et al, 2011). It was reported that the MLT concentration of night milk averaged 14.87 pg/mL; however, it was 6.98 pg/ mL in the total daily milk (Romanini et al, 2019). In Effects of the circadian rhythm on milk composition in dairy cows: Does day milk differ from night milk?…”

“…Sun, 1 L. Q. Han, 1 L. Y. Zhang, 1 and T. Y. Gao 1 * summer, the milk MLT concentration was lower than in the winter. These variables may relate to illuminance (Romanini et al, 2019). Moreover, night milk exhibits superior quality, as its SCC values are generally lower .…”