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Extension > Agriculture > Dairy Extension > Calves and heifers > Is there enough light in the calf house?

Is there enough light in the calf house?

Neil Broadwater, Extension Educator-Dairy

September 13, 2008

There have been numerous scientific studies that have shown exposing lactating dairy cows to a long-day photoperiod (LDPP -- 16-18 hours of light and 6-8 hours of dark) in a 24-hour period improves milk production and reproduction performance, that this response persists through an entire lactation, perhaps increasing milk yield as much as 8-10%. This management practice, called photoperiod manipulation, uses a designed lighting system to artificially extend the duration of light that a lactating cow is exposed to especially during the fall, winter and spring seasons of the year.

Photoperiod studies have also been conducted on dry cows. A study by dairy scientists from Vermont, Illinois and Clemson as well as a study at the University of Maryland found that exposure to a short-day photoperiod (SDPP -- 8 hours of light and 16 hours of dark) during the 60-day dry period was a management practice that increased milk yield of cows in the subsequent lactation.

What about photoperiod manipulation in raising dairy calves and heifers? Several studies have been conducted in recent years that show some promise to consider this management practice at least up through puberty.


If photoperiod manipulation is being considered, it is recommended that lighting have a color rendition index (CRI) of >80. Light intensity of at least 100 lux (9.3 footcandles) seems to be necessary. Note: Light is measured as footcandles (lumens/square meter) or lux (lumens/square foot). There are 10.76 lux (lx) in 1 footcandle (ftc). For calves, use incandescent, halogen, fluorescent and metal halide lamps. Avoid high pressure sodium and mercury vapor lamps. See Table for light source characteristics.

Characteristics of light sources (adapted from Kammel and Holmes, 2003).
Lamp Type
Lamp Size, Watt

Color
Rendition
Index CRI)

Efficiency, Lumens/Watt
Lamp Hours

Incandescent

60-200

100

15-20

750-1,000

Halogen

50-150

100

18-25

2,000-3,000

Fluorescent

32-95

70-95

81-98

15,000-20,000

Mercury Vapor

50-250

20-60

40-50

16,000-24,000

Metal Halide

100-250

60-80

80-92

7,500-10,000

High-Pressure Sodium

100-250

20-80

90-110

15,000-24,000

In summary:

Would photoperiod manipulation be beneficial to you in raising dairy calves and heifers? First, do you have a calf raising facility where the photoperiod can be manipulated? It may be hard to accomplish if using outside hutches and pens. Secondly, the economic benefit needs to be determined weighing the investment in more and better lighting, if that is the case, additional cost for energy and any other costs against any of the benefits of growth desired. Thirdly, Hugh Chester-Jones, Animal Scientist at the Southern Research and Outreach Center in Waseca, cautions that we need to recognize that many other variables including calf comfort, nutrition and environmental interactions will affect the magnitude of the photoperiod response as well, so one needs to understand what photoperiod manipulation would do for your dairy replacement enterprise.

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