Advice on using data to deliver consistent rations

Dairy farmers need to make efforts to use their farm data to manage nutrition, monitor the results, then train staff correctly.

This is because cows respond to consistency, says professor of veterinary science at Penn State University, Robert Van Saun.

“Feed quality, nutrients, timing and water quality – we need to eliminate sources of variation in the system to make the system more consistent,” he says.

However, the largest potential for diet variation comes from the mixing and delivery process.

See also: Tips for avoiding contamination and wastage of dairy rations

Robert says the transition cow is “the most important animal on the farm”, yet she is often compromised at feeding.

“We have high precision in the way we formulate diets, but they fall apart when you look at ingredient consistency, dry matter content, nutrient composition and accuracy of what the animal actually eats,” he explains.

Impact of inconsistency

Research has shown that variations in the delivered total mixed ration (TMR) can lead to three times as many aggressive cow behaviours and interactions at the feed fence.

Robert says what a cow actually eats is then affected either by excess feed delivery or what he terms “bare-bunk syndrome”, neither of which promotes good intakes.

“Mineral delivery can range from a 12-52% difference in what is formulated and what is actually fed.

“We pay a lot of money for bypass fat, but research on 26 Californian dairies showed there is a 15% variation in [its] nutrient content in a load of feed.”

Robert says that the key to business performance and profitability – considering that feed accounts for more than 50% of input costs – is to identify and fix the production bottlenecks that restrict these areas.

Common issues Robert sees on dairy farms include:

1. Feed ingredient variation

Forage dry matter (DM) varies in the clamp depending on consolidation and can lead to water ingress.

“But how often do you measure DM in the clamp? The university does it three times a week – more if we have a lot of rain.

“Water is not accounted for in the formulated diet, so you end up with inaccurate mixing of feeds,” says Robert.

In US clamp studies, he reports that lucerne silages ranged from 25-55% DM; neutral detergent fibre (NDF) consistency varied from 37.8% at the bottom of the clamp to 43.3% at the top, while haylage crude protein content measured 17-24% across the face.

“So which number do you use in a formulation?” he says.

2. Sampling accuracy

Testing a mixed pile of silage samples taken from across the face will reduce variation for nutritional analysis.

To counteract individual farm variations, multiple sampling in specific ingredients such as maize silage, or wet brewers’ grains is advised.

3. Mixer wagon size

The mixer wagon scale should be calibrated regularly, and the effect on the load of any farm expansion taken into consideration.

Whether the farm has more cows or another unit, the existing mixer wagon may not cope with more mouths to feed.

“You can’t overload them – they are made to very precise specification, so you either need to buy a bigger one, or another one,” he says, adding that he has seen feed spill over the side of wagons that has been outgrown by the scale of operation.

Conversely, feeding small groups of cows – such as transition animals – from a large wagon can lead to some ingredients sitting on top of the mixer, instead of being incorporated into the diet.

4. Staff training

Two people – preferably four, depending on farm size – should be trained to correctly feed a TMR and understand the consequences of poor weighing, mixing, or feeding, says Robert.

This will improve consistency and, therefore, cow performance – particularly over weekends and holidays.

Scale accuracy combines with operator skill in adding the correct amounts of ingredients.

“No one goes into the mixer to remove any excess they might have put in,” he points out.

5. Loading and mixing

Filling wagons in the middle and loading ingredients in the correct sequence are also important for thorough mixing.

Blunt blades will neither chop nor mix properly. Cows can sort out the long fibre in poorly mixed diets, which leads to digestive upsets.

6. Variation in delivery

To measure how different members of staff are effective at mixing and delivering the correct TMR, Robert suggests using a Penn State Separator to assess particle size.

7. Feeding frequency

Feeding once a day is labour efficient and cost-effective, however, Robert says that it allows feed sorting.

The result is 30-50% of fibre being left in the bunk because cows eat concentrates first. “You can reduce feed sorting 20% by feeding twice a day.

“Fresh feed is also better than push-ups to stimulate intakes. But feeding three or four times reduces cow lying time.

“The optimum for high-yielding groups is two or three feedings a day,” he says.

8. Trough construction

Positioning neck rails correctly to allow for the tall Holstein frame encourages cows to eat – Robert says they should be 129cm high to allow for a natural grazing position at the feed fence.

A 53.5cm barrier prevents a cow’s foot from getting in the trough or onto the feed, while a platform of 7.5cm to 15cm directly in front of the barrier also encourages a natural grazing position.

“Yokes give a defined space to individual cows for feeding, whereas you can get reduced feed time because of more cow displacements when you increase stocking density in post-and-rail systems,” he adds.

9. Finally, test the results

Having dealt with any issues, Robert advises using milk yield records, body condition scoring, manure scoring and metabolic profile measuring to test the resulting performance of a ration digested by the cow.

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Prof Robert Van Saun was speaking at the recent Hannah Dairy Research Foundation Next Generation Data-Led Dairying conference, Edinburgh.