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Free traffic vs. directed-cow traffic in robotic milking barns

Jan Hulsen Published on 10 June 2013
Robotic milking
Despite the fact that free-cow traffic is the norm on robotic milking farms (in the Netherlands around 90 percent of farmers choose this option), we often get questions from farmers about directed-cow traffic.

“What does Vetvice think about directed-cow traffic?” they ask us.

Or, in a more challenging vein: “Why do you never talk about directed-cow traffic – that works well too, doesn’t it?” And they often go on to cite one or more farms as examples.

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Our answer
We firmly believe that free-cow traffic is the preferred choice, so the cows can do their own thing without being made to wait. The animals can improvise continuously and make decisions based on the options available to them: visit the robot, go to eat or go lie down.

Directed-cow or forced-cow traffic has no substantial advantage over free-cow traffic, but it does put pressure on the cows’ use of time and entails higher initial costs for the farmer.

Where do we get this knowledge from?
Very little – too little – scientific research has been done into cow behaviour in milking robot barns and time use. We have conducted a number of surveys, including a study of “cross use” of milking robots and a recent comparison of cow behaviour on farms with free-cow traffic and farms with directed-cow traffic.

Our opinion is also based on our knowledge of cows and our experience on hundreds of farms we have visited, and still visit, for a variety of reasons.

In our eyes, DeLaval merits a favourable mention for the support they provided to us in our comparison of free-cow traffic and directed-cow traffic.

Why is there still interest in directed-cow traffic?
We wonder that sometimes ourselves … First of all, it is our everyday observation that farmers who have no experience of milking robots and want to change over to a robotic system have a number of unnecessary uncertainties.

As a result, their decisions are influenced by arguments that are actually irrelevant …

Provocative statement
Directed-cow traffic holds out a spurious solution for farmers afraid of losing control over their herd.

The insecure, inexperienced farmer
The inexperienced farmer wonders, first of all, if the cows will indeed visit the robot. The answer is: Yes, they do. If a cow and her hooves are healthy and a reward awaits in the robot, she will visit the robot four times a day on average.

After three weeks, almost all cows will “get it,” provided the farmer doesn’t do anything silly, such as urge them on too much.

Farmers also worry about cows that have to be fetched, but in a properly organized barn, fetching a cow is a piece of cake. So seek good advice when designing your barn.

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And if more than 5 percent of cows have to be fetched each time (you are fetching cows twice a day), there is something wrong with the hoof health or nutrition of the cows. And for this, directed-cow traffic is not a solution: You need to tackle the problem itself.

To be perfectly clear: Farms with directed-cow traffic also have cows that need to be fetched. The next question is: What are those cows doing all that time? The answer is: They have spent hours unable to eat or lie down …

The salesmen
Milking robot salesmen sometimes strongly recommend opting for directed-cow traffic. Besides “not having to fetch cows,” their arguments are more regular milking intervals, so better udder health and better use of the milking robot.

They may be relevant, but these are not strong arguments. Milking intervals are indeed slightly shorter, mainly because there are fewer cows with longer milking intervals. But it’s not all honey and roses.

The biggest gains are to be achieved with cows in early lactation, cows you want to be milked four times a day. If these animals are healthy and eating a correct ration, they visit the robot spontaneously four times a day.

If they don’t do so, it is highly likely there is something wrong with them. Do you want those animals to be locked up in a part of the barn?

And every farmer with a high-yielding cow that is not visiting the robot readily wants to identify and examine that animal at an early stage. In a barn with free-cow traffic, you stand a greater chance of stepping in early. And after examining the cow, you can drive her to the robot or the treatment box, as you see fit.

In addition, in directed-cow traffic the selection gate should have a counter that stops too many cows entering the holding area at the same time.

Too many cows in the holding area causes a lot of stress among low-ranking cows, which also take a dislike to the robot as a result. Therefore, at peak times cows wanting to be milked are not directed to the robot and not milked until later. So these animals don’t have a regular milking interval.

In addition, it is debatable whether the slightly longer milking intervals for – take note – part of the herd actually make a difference …

The better use of the milking robot may not be all it appears to be. In directed-cow traffic, only cows that actually want to be milked enter the robot.

You save 1.5 refusals per robot. A refusal takes what … 15 seconds? So you save 23 seconds per cow per day. With 60 cows, this is a difference of 23 minutes per day or 1.7 percent of the robot’s capacity.

This is the time taken to milk one cow, but it is only relevant if the milking robot is 100 percent occupied ... Otherwise, the robot still has reserve capacity. And with a 100 percent occupied milking robot, the maximum number of cows needs to pass through all the selection gates and holding areas, with all the attendant congestion and stress.

Background: the cow
In a good barn with good feed management, cows eat 10 to 14 meals a day on average, ruminate for eight to nine hours (six to seven of these lying down) and spend 12 to 14 hours lying down. Limited access to feed increases the risk of metabolic problems and acidosis. As if that wasn’t enough, limited access to lying areas increases the risk of hoof problems.

The price paid by cows and farmer
 The costs of directed-cow traffic are twofold:

1. Directed cow traffic requires a lot of selection gates and barriers that are otherwise unnecessary. And that can break or fail. They cost money and pose a health and safety risk.

2. Cows are forced to wait longer or to spend time in a part of the barn where they don’t actually want to be. This comes either at the expense of number of meals and feed intake or at the expense of resting time.

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It won’t lead directly to an increase in cases of disease, or a sharp decline in milk yield, but it does put the herd under pressure. Low-ranking and weaker cows are hardest hit. So the farmer has to take greater pains to keep his herd healthy and/or accept a higher replacement rate.

In directed-cow traffic, therefore, there is a shift in the balance of work from fetching cows to caring for weaker and low-ranking cows because these are under greater pressure than on farms with free-cow traffic.

But some directed-cow traffic farms run very well
Perhaps this very same comment was on the tip of your own tongue? This is true. Those are farms where the farmer is very good at what he does.

Without directed-cow traffic, they would run just as well or even better and probably with less effort (i.e. if the barn with free-cow traffic is organized properly).

Let’s make it clear: Directed-cow traffic can work well provided the cows rarely have to wait at selection gates and provided the animals are able to eat and lie down enough.

This means no more than one robot per group or separating the robots so that each one has its own selection gate and holding area.

And no four-row barns. In four-row barns, there is much too little feeding space available for the cows. (Four-row barn: Four rows of cubicles to one feed barrier.)

To summarize
Farmers wishing to change over to a milking robot need to take the time to familiarize themselves with the work and management practices on a robotic milking farm. Otherwise they risk making bad decisions and missing out on opportunities for building an efficient, safe and animal-friendly barn.

So seek proper advice about your choice of milking system, barn layout and organization of the work from an independent adviser. And aim high in terms of labour efficiency, ease of work and cow comfort.  PD

—Excerpts from Vetvice website


Q.
In what situations would you recommend directed-cow traffic over free-flow traffic for a robotic milking dairy?

LELY
A.
At Lely, we do not believe in directed-cow traffic. This is because, when done properly, free-cow traffic helps better ensure cows stay healthy and happy, while at the same time reach optimum milk quality and production.

Of the thousands of robotic milkers installed worldwide, most farmers opt for free-cow traffic and the choice for unlimited access to feed, water and rest. Free-cow traffic allows the cow to discover her own daily routine, i.e., showing up for milkings at the same time, eating as often as she likes and resting as needed.

Cows also tend to eat smaller portions of feed more frequently and spend more time chewing their cud, which results in a constant rumen pH, healthier cows and higher solid levels in the milk.

Farmers who have transitioned from guided-cow traffic to free-cow traffic saw 80 percent of the cows eat, drink or rest in the freestall, versus just 44 percent in guided systems.

This is especially important for lower-ranking cows which would otherwise not have enough rest to produce milk because they are blocked by dominant cows – and therefore have to stand and wait for an opportunity to go through passages and gates.

We have to think from the perspective of the timid cow and what is good for her, rather than from the perspective of “what is easy to understand for the farmer.”

Free-cow traffic matches the cow’s natural biorhythm better; she can do what she wants, when she wants it.

— Ben Smink, farm management support technician, Lely

DELAVAL
A.
With our system, cows decide when they want to be milked. I advise owners to choose a cow traffic system that strikes the right balance between cow motivation and herd management variables. There are pros and cons with both directed-cow and free-flow traffic operations.

Free-flow traffic is the most popular system requiring the least initial investment and allowing cows to move freely in the barn. The system works with PMR (partial mixed ration) feeding strategies, but capacity and labour efficiency are the lowest of all cow traffic scenarios – cow fetch rates are typically higher. For farms with eight or more robots, I do not recommend this traffic system.

In our barns, producers have two options for directed-cow traffic: feed-first or milk-first pre-selection. Both are designed to increase robot capacity and labour efficiency using our selection gates to guide and pre-select cows for milking.

Software determines whether or not a cow has permission to milk based on her expected yield, hours since last milking, lactation number and stage of lactation.

Feed-first is a great option for forage-based diets where no grain is fed at the feedbunk. Milk-first offers greater flexibility with minimal grain needed to be delivered through the robot. The PMR she gets at the feedbunk is her main motivator.

— Francisco Rodriguez, dairy management adviser, DeLaval Inc.

GEA
A.
We recommend directed-cow traffic or what we refer to as a milk-first, feed-second concept. This allows the dairy to feed much less purchased feed than a free-flow system. After milking, cows are sorted through the post-selection gate into their proper feeding zone.

Some of our robotic barns in North America are utilizing up to five feeding zones for optimum feeding practices. Utilization of zone feeding is a key attribute to the milk-first, feed-second concept.

Zone feeding allows producers to mix their TMR with the proper proportions of dry matter, energy and protein requirements for a very high level of milking frequency. The highest level of milking frequency allows for optimum milk production and milk components per cow.

The fact is that today’s producers face continuing pressure to be as efficient as possible. With the milk-first, feed-second concept our customers will have less purchased feed and labour costs associated with operating the dairy compared to a free-flow system.

We believe dairies shouldn’t have to make compromises on their operation when they choose to milk robotically. Our focus is on total cow management and husbandry practices in a multi-box application, incorporating intelligent barn designs.

—Greg Larson, MIone milking systems expert, GEA Farm Technologies

Jan Hulsen

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