About the project

• Background

  Det er vel kjent at belysningen kan påvirke produksjon og fruktbarhet hos våre

  It is well known that lighting can affect production and fertility in our production animals. A long day (16 hours of light) with sufficient light intensity is favourable for the production of dairy cows compared to shorter days (12 hours of light). This effect is partly due to increased feed intake with more daylight hours, and partly due to the stimulation of hormone secretion due to increased light duration.

  Melatonin is often referred to as a sleep hormone and plays an important role in the biological rhythm. The secretion of melatonin is controlled by light; when light hits the eye, the secretion of melatonin decreases, while the secretion increases in the absence of light. Since melatonin is associated with sleepiness, it is recommended that humans avoid blue light in the evening before going to sleep and instead ensure low light levels. Sleep in cows is spread throughout the day, but maintaining a natural production of melatonin is still important as the hormone affects the cows' biological rhythm and has an effect on other hormones. In addition to the direct effect, melatonin stimulates the growth hormone IGF-1 (Insulin-like growth factor 1), which has a direct stimulating effect on milk production. In other words, this hormone is one of the reasons for increased milk production on long days.

  I en tidligere studie gjennomført av oss testet vi høy lysintensitet på både dag og In a previous study conducted by us, we tested high light intensity in both day and night, and saw that the concentrations of IGF-1 were lower for cows that had constant high light intensity. This may be a sign that constant light can be unfavourable for milk production. In Norway, the law stipulates that cows should have sufficient light during the day, and that orientation light can be used at night. It is also stipulated that cattle should be allowed to rest from artificial light during the day, although it is legal to have low lighting at night as well. A Norwegian study found that light intensity during the day varied between 4 and 160 lux in Norwegian cubicle barns, where 4 lux is clearly inadequate daytime lighting, while 160 lux is the recommended level.

  In loose housing barns with automatic milking systems (AMS), it is desirable to have light around the clock to keep activity levels high and distribute the cows' time budget so that, for example, the milking robot is loaded evenly throughout the day. For many, it is therefore attractive to have a relatively high light intensity even at night. A study in Swedish loose housing barns found that light intensity was often at a level that would also inhibit the hormone melatonin at night, and would therefore not allow a normal biological circadian rhythm.

• Objectives

  The aim of the project is to investigate how low light intensity affects the secretion of hormones that are central to milk production in Norwegian red cattle. ‘We also want to investigate the impact of diurnal shifts on the biological rhythm of the cows.

• News

  Project partner Emma Ternman participated in Fjøsystemer's podcast about lighting for cattle.
  
  Hør episoden her: https://shows.acast.com/5f96e2da0a79d550d5d50fae/64774b3f2cb92f001275658b

Participants

External participants

Nord Universitet: Emma Ternman (https://www.nord.no/en/about/employees/emma-matilda-ternman)

TINE: Stine Grønmo Kischel

Swedish University of Agricultural Sciences (SLU): Sigrid Agenäs, Sofia Lindkvist og Björn Ekesten