Red and Blue LED Light on Milk Yield in Dairy Cows
Ruminant nutritionists formulate rations balanced according to the nutritional needs for the ruminant at a specific production level. The assumption being that the cows will eat everything they offered. However, cattle can select their feed, as they put together feed using their tongue and lips. Sorting has been studied most in cows al mixed ration (TMR) since it is often is oftenibitum, allowing cows to pick the feed particles they prefer and still reach the total dry matter (DM) they want. The TMR reports show that the most likely sorting is in favor of the short particles (mostly concentrate) and against the long particles (forages). Therefore, the feeding behavior of the cow modulates the amount of feed she eats, the nutrients she gets, rumen health, and ultimately her milk production.
Several methods have been used to try and reduce feed sorting in dairy cows. Recently, a long day photoperiod has been reported that could lower feed sorting against long particles. Today, Kaiyan provides advanced LED light equipment that is available for commercial use. The LED wavelength can be adjusted to the desired output.
Blue and red wavelength light has attracted interest in dairy barns. The cow eye is not sensitive to a red light, and therefore red light has been suggested as an option for illumination when people need to work with the animals during a time of the day when the cows have night. In humans, blue light is known to cause a carryover effect with increased activity after the light is turned off. If cows respond similarly to blue light, it may be interesting to include blue light in the dairy barns in the late afternoon or evening to stimulate activity during the night. This is of particular interest for automatic milking systems since they require cow activity around the clock. Solutions for dairy barns that include periods of the day with more red or blue LED light are already available on the market, as we now have fixtures of white LED light.
Eating Behavior of Dairy Cows
Encouraging DMI to promote milk production is one of the primary objectives for dairy farmers. The daily eating time, selection, number of meals per day, duration, and number of eating occasions per day are important aspects of feeding behavior.
Factors that Influence Eating Behavior
The environment, age of cattle, teeth condition, feed composition, and processing influence eating behavior. Just like grazing cattle, group-housed cows synchronize their behavior, including eating when kept indoors. The eating behavior of cows is controlled by social interactions, management practices, the environment, and health. Long ago, dairy cows were thought to be crepuscular eaters, motivated by sunrise and sunset timing to go for grazing. However, studies reported that fresh feed delivery timing had more influence on the feeding behavior of dairy cows kept indoors than the time of day. Also, studies found that daily eating time distribution changed following an increase in feed delivery frequency in group-housed dairy cows. The first hour and a half after fresh feed delivery is the period of peak eating activity. Little effect on cow behavior was observed when feed push-ups were done while still some feed in the trough. The feed trough design also affects feeding behavior as cows prefer eating from a feed trough that allows their head to be in a natural grazing position than having their head in an elevated position.
Types of Lights Used in Dairy and the Newly Available Light Sources
Common light sources used in dairy facilities are fluorescent and metal halide lights. During the last few years, LED lights have also become available for animal housing. This is not a new technology; LED light has been used in plant growth research since the mid-1980s but has been costly; hence limited to research only. However, 19 the Haitz’ Law as projected by Steigerwald et al., has come to action, that every decade their cost will decrease by 10 whereas their performance advances by a factor of 20. Now they have become affordable and advanced white LED lights thereby increasing their potential use in animal houses commercially
Advantages of LED Lights
It is possible to adjust the light intensity and spectral composition of LED lights mimicking that of natural day sunrise and sunset, making it possible to control color combinations, e.g., green, blue, and red. A LED light's lifespan is longer than that of fluorescent lights, around 100 000h compared to 8000 h. Furthermore, LEDs thermal output is low, saving energy, containing no mercury, efficient photoelectric conversion, and easy-to-contact to digital control systems making photoperiod management easy, for example, in dairy barns. Due to their long life span, they can decrease production costs as they do not need regular replacement and cuts off labor costs and the often-high risk work task of replacing lights since most barns have very high ceilings. The white LEDs produce light in the wavelength that cows can detect better, with peaks of emission around 460nm and 550.
In one study, ten multiparous pregnant Swedish Red cows in post-peak lactation were used. Cows were housed in a tie-stall barn. They were subjected to a 33-day red or blue LED light treatment during a long day photoperiod with 16 hours day and 8 hours night. Cows were fed silage and concentrate separately. Silage was fed three times a day, ensuring ad libitum intake with 5–10% orts. The concentrate was fed four times per day. Samples of silage were collected thrice a day, and individual orts were collected at the end of the day and the night. Data for eating behavior and milk yield were collected five days before and five days after the treatment period. Eating behavior was determined using the difference in the distribution of fractions of different straw lengths in the silage fed and orts during daytime and night time. A 2-screen Penn State Particle Separator (PSPS) (19mm and 8mm) with a solid bottom pan was used to determine the distribution of large, medium, and short silage fractions. Treatments did not affect total DMI. Overall, cows sorted for the large fractions against the medium and short fractions. During the LED period, there was a difference (P<0.001) in sorting between Red and Blue cows during the daytime. Cows on the Red LED light are sorted for the short fractions during the daytime. Blue cows showed different sorting (P<0.05) during day and night. Their sorting for the large fractions was more pronounced during daytime than night. Milk yield did not change during the trial and did not differ between the Red and Blue groups. In conclusion, sorting activity was greater during the daytime in the LED period, which could have been influenced by the LED light. Interestingly cows seem to have better vision in red than blue LED light. Furthermore, it also possible that the LED light maintains milk yield since no change was observed during the four-week trial in post-peak lactation.