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Flat rate feeding is a feeding strategy where all cows are fed the same level of concentrates during the whole, or part, of the lactation period. The concentrates are restricted to a certain level while roughage is fed ad libitum.
The cow’s energy and nutrient demands vary depending on the stage of the lactation. Because of the fixed concentrates ratio, flat rate feeding relies on fat mobilisation.
The surplus of nutrients in mid and late lactation is stored as body fat. The cow uses the surplus when demand is high, namely in early lactation. Fat mobilisation in early lactation can cause ketosis in high yielding cows. Cows are usually underfed during early lactation and overfed during late lactation.
Flat rate feeding is common in countries with extensive milk production and large areas of pasture, such as New Zealand, Argentina, Ireland and Australia.
While flat rate relies on fat mobilisation, challenge feeding/feeding to yield aims to supply the cow with the nutrients that are needed for the actual lactation stage.
Challenge feeding/feeding to yield is common in countries with intensive milk production.The advantages are that cows can be kept in proper body condition, and that each cow is given a fair chance to show her production potential. The incentives for this are considerable. Every extra litre in peak lactation can result in a higher total yield of up to 200 litres of milk per lactation (Michael F. Hutjens).
With challenge feeding/feeding to yield, feeding is adjusted to match milk yield.
The strategy is divided into two phases related to the different lactation stages.
I. Challenge feeding takes place in the early lactation period (marked 1 in picture above). It involves every cow, regardless of yield, being given a maximum ration of concentrates 4.6 weeks after calving. This procedure gives all cows the possibility to show their production potential. Underestimated cows can therefore be discovered. As mentioned before, every extra litre in peak lactation can give 200 litres more milk over the whole lactation period.
II. The second phase, feeding to yield (marked 2 in picture above), takes place approximately 100 days after calving. The cow is fed to match her measured milk yield. This strategy means feeding each cow individually. Feed is saved and the risk of fat cows is reduced. In large herds, the strategy requires advanced equipment to make work and management processes easier.
Phase feeding
Phase feeding is a type of challenge feeding/feeding to yield. Different feedstuffs are fed in different phases during lactation. For example, this means that feed 1 is fed in early lactation, while feed 2 is fed later on, etc.
In early lactation, high quality concentrates are fed. Later on in lactation, these high quality concentrates can be replaced by less expensive concentrates containing more roughage of poorer quality (see picture below).
Phase feeding can improve rumen health because better quality feeds are fed in early lactation.
Phase feeding, where the feed for high yielders fed in early lactation is gradually replaced with poorer quality concentrates and roughage.
Ad libitum feeding simply means that the animals are allowed to eat as much feed as they want. Roughage is often fed ad libitum.
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The dominant feeding systems for dairy herds are:
1. Separate Concentrate Feeding (SCF);
2. Total Mixed Ration (TMR); and
3. Partly Mixed Ration (PMR).
In a SCF system, the roughage and concentrates are fed separately. The system makes individual feeding of both roughage and concentrates possible, but roughage is usually fed ad libitum and concentrates are fed restrictively.
SCF in loose housing
In loose housing barns, the roughage is fed ad libitum in the feed bunk, while the concentrates are provided in feeding stations or in-parlour feeders.
The suitable feeding strategy for SCF with in-parlour feeders depends on the way in which the farmer can control the feeders. In some systems, it is possible to feed cows individually; in others, all cows must be fed the same amounts in the parlour. Feeding in parlour can improve cow traffic. The disadvantage is that only a small concentrates ratio can be fed. Ratios that are too large cause eating times that are too long and unhealthy for the rumen.
When the stations are placed out of the parlour, challenge feeding/feeding to yield can be used as the feeding strategy. The amounts of different feedstuffs are registered in a computer. When the cow enters the feeding station, she is identified and the correct amount of feed is dispensed.
A summary of advantages and disadvantages of the positioning of feeders is shown below:
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Advantages
Faster milking
Easier cow traffic |
Disadvantages
Concentrates can only be fed as many times as the cow is being milked (often twice/day).
The amount of concentrate is limited.
Restless cows during milking
Cows dung while they eat.
Risk of manure in the pit. |
Advantages and disadvantages of feeding in parlour.
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Advantages
Larger amounts of concentrates can be fed due to smaller rations and more frequent feeding.
Improved rumen health. |
Disadvantages
Less efficient cow traffic.
Problems with access to feeders during the grazing season. |
Advantages and disadvantages of feeding out of parlour.
SCF in stanchion barns
Separate feeding is the normal feeding system in stanchion barns. Concentrates are often fed individually, while roughage is fed ad libitum. Some farms, especially those that use phase feeding, also feed the roughage individually.
The common strategy in stanchion barns is some form of challenge feeding/feeding to yield.
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In the TMR feeding system, concentrates and roughage are mixed in a mixer wagon. The mix is often dispensed to the cow directly from the mixer wagon, but can also be distributed with conveyors or with feed wagons.
The TMR system is most common in large loose-housing barns, but can also be used in stanchion barns. The TMR is often fed ad libitum, although it can also be fed restricted.
TMR single ration
In single ration systems, only one mix is made and dispensed. The mix is composed so as to suit high yielding cows, while lower yielding cows will eat less. The balance of the ration is very important to avoid fat cows. The system works best with high yielding herds and breeds like Holstein and Jersey. If the cows are grouped, and the high yielders are fed ad libitum, it is possible to feed only one mix, and the next group are given a percentage of the mix and ad libitum straw or hay. Dry cows may be fed a small quantity of the mix in addition to straw or hay. One of the biggest advantages in using a single TMR is that cows do not have to change feed.
TMR several rations
There are many ways to divide cows into groups. They can be grouped according to yield, body condition score, stage of lactation, first calf heifers and fresh cows. The feed ration can be tailored to suit the needs of each specific group. Precision improves as the number of different groups increases. At the same time, the rationality of the system is lost. Much time has to be spent on moving the cows from one group to another as production changes. Several mixes have to be made and dispensed to the cows to suit each group.
Partly Mixed Ration (PMR) is a feeding regime that combines TMR and SCF. It involves a mixer wagon mixing roughage and some of the concentrates. The concentrates level is suited to low yielders. High yielders get extra concentrates in feeding stations, in-parlour feeders or from a feed wagon.
When feeding more than one roughage and by-products, PMR is a very smooth way of feeding if the farmer wants to feed concentrates individually. When some of the concentrates are mixed with the roughage, feed intake increases and the risk of rumen acidosis is reduced.
Situations where one or the other system is preferable:
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Separate feeding
- only one or two roughages
- roughage
- roughage in tower silos
- only dry feeds
- home produced grain
- small farms
(less than 30 cows)
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TMR / PMR
- several roughages
- roughage in clamp silos
- roughage in tower silos (with certain adaptations)
- high moisture products
- straights
- home produced grains
- bigger farms
(more than 50 cows). |
Comparison between the suitability of Separate and TMR/PMR feeding.
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