Robotic milking demands focus on forage quality
|By Mike Brouk|
The author is a professor and extension dairy specialist with Kansas State University.
As robotic milking continues to grow in the U.S., we are gaining knowledge and understanding of the interactions between nutrition, cow comfort, animal behavior, and facility design. Robotic milking systems require a greater per-cow investment in milking equipment as compared to conventional milking systems. This generally results in greater expectations in per-cow milk production to help offset this higher investment.|
The robotic system is only capable of harvesting the milk produced by the herd. The system does not produce milk. Thus, the focus really needs to be on comfort and nutrition to allow the cattle to express a higher level of milk production associated with the genetic capabilities of the animals.
Forages will generally comprise 50 to 60 percent of the ration dry matter and represent the greatest amount of variability in the dairy ration. The first critical factor is harvesting at the correct maturity to ensure the forage is of high quality and will allow for adequate rates of passage. As crops mature, the fiber content rises and the fiber itself becomes more indigestible. This results in longer residence time in the rumen and less digestible fiber.
The next effect on the cow is a slower passage rate and lower dry matter intake. In early lactation, dairy cattle intake is limited primarily by the distention of the rumen and how quickly (rate of passage) the feedstuffs move through the rumen, encouraging the animal to return to the feedbunk for an additional meal.
In early lactation, dairy cows can convert a pound of dry matter into 2.5 to 3 pounds of milk. A higher rate of passage will generally result in greater amounts of digestible nutrients being available to the cattle. Forages represent the portion of the diet with the longest residence time in the rumen, and as forage digestibility (mature forages) declines, residence time lengthens.
Once the goals for plant maturity at harvest are set, the next task is to set the goals and plans for harvesting. Try to ensure that there is always adequate moisture available in the plant mass
Robotics make a difference
Forage quality in robotic milking systems is even more critical than in conventional milking systems. In robotic milking systems, cattle independently present to the milking system. In conventional milking systems, cattle are taken to the milking parlor two or three times per day. This creates movement in the pen and encourages the cattle to consume feed following milking. However, in most robotic milking systems, cattle present to the milking system or feedbunk independently.
The main driver to encourage them to move from their stall to the milking system or feedbunk is hunger. Hunger is driven by the level of milk production and the rate of passage of the diet they are consuming. In early lactation, total intake is related to physical capacity and how often the capacity can be refilled. Feeding lower quality forages in a robotic milking system will result in lower milk production per cow, reduced intake, more time spent fetching (humans moving cattle to the milking system), and fewer daily milkings. The general effect is less milk income and higher labor costs associated with fetching.
When selecting forages for use in dairies with robotic milking equipment, always consider the amount and rate of fiber digestion in the rumen. Typically, the level of neutral detergent fiber (NDF) and the rate at which NDF ferments in the rumen is utilized to determine the quality of forage. In the laboratory, we routinely measure the NDF content and usually determine the NDF digestibility (NDFD) at either 30, 120, or 240 hours of exposure.
A newer procedure, TTNDFD (total tract NDF digestibility) is superior in determining the value of the forage in the dairy cow. It predicts the rate and extent of forage NDF digestion. This is highly correlated with milk production and is a better predictor of forage value than simply looking at NDF content and a single NDFD time point. In general, TTNDFD results of 50 or greater indicate superior forages and levels of 35 or less generally result in lower milk production and reduced total intake.
Improved cow movement
For robotically milked herds, cow flow is very important and forage quality is a key factor when addressing the needs of improving milk production and reducing fetching efforts. In early lactation, the level of milk production drives intake. Cows producing greater quantities of milk have higher intakes and as production climbs, intake does the same. High-quality forage is necessary for higher levels of milk production in early lactation, which encourages cattle to eat more often and improves animal traffic in the facility.
Getting animals to move independently in early lactation is greatly influenced by forage quality. Using poor-quality forages in conventional milking systems will not reduce cow movement as much as in a robotic facility. This is due to the fact that cattle are fetched to the milking parlor two or three times each day, resulting in more activity at the feedbunk following milking.
Adoption of robotic milking equipment is occurring at a rapid rate in the U.S., and it will enhance the opportunity to produce and sell greater quantities of high-quality forages. With grasses and legume forages, the focus will be on rate and extent of NDF digestibility. Dairy producers and forage growers need to focus on these key issues when harvesting and selecting forages for robotic milking centers.
This article appeared in the April/May 2019 issue of Hay & Forage Grower on pages 8 and 9.
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