Posted by Dr. Sara Barber on July 14 2009 08:51
Why is lighting important?
- Increased milk production
- Improved heifer growth
- Better working conditions and safety
Increased milk production
- Increased lighting in the fall and winter months increase milk production 5-16%
- Typical response is 5 lb/cow/day
- Increased feed consumption by 6%
- Increased milk production occurs over several weeks
Improved heifer growth
- Increased weight gain
- Increased feed consumption
- Reduced body fat
- Improved mammary gland development
Why is increased light associated with increased growth and milk production?
- Light suppressed melatonin release
- When darkness falls melatonin secretion increases and this decreases hormone secretion
- These hormones promote milk production so increased hormones = increased milk
Improved working conditions
- Reduce occurrence of slips and falls
- Improve detection of animal injury or estrus
- Facilitate animal behavior monitoring
- Help machine operators avoid obstacles in the barn
- Increase labor quality and productivity
- Facilitate making and reading records
How long?
- 16-18 hours of light
- 6-8 hours of dark
- Darkness period is very important or the positive effects of the lighting will be nullified
- If lighing is needed during the "dark period" then use low wattage red lights
Tie Stall Barns
- 10 foot candles over the manger (minimum)
- 15 FC 3 feet from the floor is recommended
- Fluorescent light fixtures
- Not incandescent (poor energy efficiency and short bulb life)
Freestall barns
- 20 foot candles over the stalls
- Feeding area: 20 foot candles
- Metal halide or high-pressure sodium lamps
How much is 20 foot candles?
- Well-lit office: 35-50 FC
- Cloudy day: 500-800 FC
- Sunny day: 5000 FC
Costs
- Fixtures
- Bulbs
- Wiring
- Timers
- Increased electrical use
- Greater feed intake
- Vary depending on types of fixture chosen
Light Requirements
- Fixtures resistant to corrosion
- Lights powerful enough to provide enough light to stimulate milk production
- Light should be energy efficient
- Include a timer and photosensor for optimum efficiency
Lamp Type
- High pressure sodium
- Most efficient with high bulb life
- Metal halide
- Incandescent
- Poor efficiency and short bulb life
Dry Cows
- Short photoperiod is needed
- Cows with short photoperiod over dry period, milked 7 lb/day more than cows with long day lighting while dry
- Studies show improved immune function after calving if dry cows on short photoperiod
- Practicalities
- Do not house dry cows with lactating cows with long day lighting
- Prefer less than 12 hours of light/day when cows are dry (or natural lighting)
Summary
- Long day lighting will increase milk production
- Minimum of 10 FC
- Need to have a 6 hour dark period
- Dry cows need short day lighting