This time the article about Light. Author:

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1 This is a series of 7 articles about CowSignals to improve health production and welfare of your cows. Content 7 articles: feed, water, light, air, rest, space and health. This time the article about Light. Author: Joep Driessen is a Dutch dairy vet with 15 years experience in advising dairy farmers in 45 countries. His Vetvice team is active in CowSignals trainings, Barn Design and Dairy management. The CowSignals Diamond: what is the weakest spot in your dairy? Look, Think, Act, do something to make your cows and yourself happy! Light Light, long days, short nights Water, light and air are the cheapest feed Daylight in the building is cheaper than electric light. However you will always need extra electric light to reach the optimum. We advice16 (-18) hours light (>200 lux) and 8 hours dark (< 50 lux). 200 lux will be reached with for example 70 neon tubes per 100 cows. 50 lux is what you have with full moon on a clear night. The cow recognizes this as night. During a nice winter day in Holland we reach around 200 lux in barns with large open roof rims and very open sides (4-6 metre high open) from about 11 till 16 o`clock. This is only 5 hours per day. In Finland it will be less because of the low sun and the too closed buildings

2 Why do we need light? We need enough light to do a good observation of the cowsignals and the situation in the barn. Can you easily detect slime and discharge? More light makes you feel happier! So turn on the light to see more and have more working pleasure. Why do cows need light? Cows like daylight, it makes them feel happy, just like farmers More light also means more feed intake. In several research we see that cows produce more milk because the dry mater intake goes up due to extra light. Some tests tell us that even with the same amount of dry matter intake cows will still improve their milk yield due to more light. It seems that the light exposure on the eye has a direct effect on natural hormone production and milk yield. With more light cows show better heat signs. They are more active and therefore easier to detect. Some farmers place a timer on the lights that lightens the barn a half an hour before they arrive in the morning. Cows are then already in their normal day activity, and it is possible to score the cows for any heat signs. Some farmers will react on some slight ear twisting and chin resting of an expected cow, as the only visible signs from last nights heat. Some farmers turn on the lights for 24 hours per day. This is a waste of money! We find a little more feed intake, but a lot less fertility. Cows need the change of day and night to let the eggs grow and release from the ovaries. With 16 hours light per day we find the optimum feed intake and still a good day-night rhythm for max fertility. Dry Cow Signals You can only check the cowsignals with enough light. To manage a cow herd is constantly full of compromises. Lactating cows need a lot of light, dry cows a lot of darkness. In nature cows used to calve in the spring, after a dark winter. This had a very good effect on feed intake while grazing. What we do nowadays in our barns is change the season for the cows: long summers and short winters. Dry cows are best off in an artificial winter according to light. This maximizes the light-shower effect after calving. We can keep them in a dark building or dark corner for 6-8 weeks. That means that we should only turn the lights on in this group during daily inspection and cleaning. However, we like to keep our precalving cows close to the lactating herd for the last 2-3 weeks before calving because of feeding and stress prevention. So we advise to keep this group next to the herd or make a separate light switch for them..

3 Practical light programme Best option is a light programme in winter with a timer and a sensor. For example: timer on at 6 am, sensor to switch it off when we reach 200 lux by daylight, sensor on when light intensity drops under 200 lux, timer to turn it off around 22 pm. A little light at night does not harm the cows and is good for the farmer, so you can easily leave one neon tube on at night. Or in milk-robot-barns, leave one light on in the robot. Cows don t need light to find the food or the robot, but a little light won t harm them either. Too much light? Too much sunlight is a risk of heat stress. However we like to have a nice light-rim on the middle of the roof, because this gives a lot of daylight for free. To keep the heat out you can choose to put a double layer plastic light cap. We also advise to insulate the roof, especially if you plan to keep your cows in all year around. Light plates on a south facing roof are tricky. In these barns we advice to make skylights(light plates) only on the north facing roof, because there the sun is not so intensive. You can put solar cells on the south roof. Top end triangles in the north can be made of light plates as well. Top ends on the south also, but there is a risk of heat stress there. I would make this south window a bit smaller. The lower 4 6 metres of the top ends of the barn we design with flexible roll up curtain walls for maximum air and light in the summer. What light do you prefer? White or yellow? Colour of light is not so important. It is your own choice. As long as you have enough intensity, that means enough bulbs, tubes or mirror lights. Cows don t mind to much. They say that cows are slightly more quiet with yellow or orange light. A disadvantage of yellow light is that urine, blood, discharge and milk all look the same colour. It is very difficult to see the difference. Therefore we prefer at least some white light in the calving area. White metal halide mirror lights are very good and have an excellent spread over the barn. A disadvantage can be that they are blinding for the farmer in a low building. There is not much price difference if you calculate prices of lights and costs of electricity over a long period together. Tubes are more easy to change by a farmer. He will wait until there are more of them broken, but you still will have reasonable light in the building. If you wait until 3 of your 10 yellow sodium lamps are broken, then the barn is already quite dark.

4 Mirror lights from the flower industry (more info: agrilight.com) have good spread and are a lot better than old round lights which only make a strict circle of light on the floor with a few metres diameter. Milkparlour Make sure you provide good light in your work place! In offices they provide more than 400 lux for working people. In a 2 x 12 parlour we put 12 neonlights just above the milker. In the parlour you can see many interesting CowSignals, so use your time as well as efficiency by scoring cow behaviour, udders & teat ends, claw dirtiness, walking, standing, tap-dancing, position of claws. The best parlour has a big roll up garage door (with glass) in the front, which is completely open for 9 months per year, so that you and the cows can have excellent day light and fresh air. And the cows will walk quicker in the parlour as well. Open front milk parlour, roll up door, with maximum daylight in summer and good artificial light in winter Where do you place your lights? Check your cows behaviour. Cows don t like to go into a dark hole or corner. So also provide light in and around concentrate feeders, feeding table, drinkers and the exit lane of the parlour. Cows don t like shattering light or reflection of light on metal plates, wet floors, food baths etc. Check this when cows don t like to come in your parlour. They can also be scared of sudden changes or weird things that are on the floor that were not there yesterday. The sensor of light is the cows eye. Therefore light has to be everywhere in the barn. Not only above the feeding table because the cow is only there for 6 hours per day. So also the bedding area need light because the cow is there for 9-14 hours per day. How many lights do you need? Per 100 cows you can choose: 50 neon tubes = 150 lux by 1 neon tube per 2 cows 70 neon tubes = 200 lux 12 metalhelide lights= 200 lux 16 natrium lights (orange/yellow light)= 200 lux The cheapest advice is turn on the lights, and clean the light tubes twice every winter. And explain to Granddad that light brings money, and not only costs money otherwise he will turn the lights off every time.. Lux meters are very cheap to buy and very good to convince you to put more light tubes in your buildings. So ask your Raisio or Proagria advisor to score the light intensity in your barn at the next visit.

5 And remember: If you do what you always did, you get what you always got! So do yourself a favour and: Look, Think and ACT! And let there be Light! Next article AIR!