Intake consistency a critical factor in reducing feed costs per litre

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Length: 1214 words; 5-6 minutes

TMR mixing

Plenty of effort goes into ration planning and design, carefully balancing the needs of the cow with performance targets, feed availability and costs. There’s also often considerable investment made in nutrition advice and the feeding equipment needed to deliver these ‘theoretical’ rations to the cow,

But according to KW nutritionist Dr Anna Sutcliffe, much less attention is paid to how consistently that system is actually supplying feed and nutrients to the cow. And when inconsistencies creep in, the negative impact on returns can be substantial.

“Rumen microbes are sensitive to change, so ration inconsistency can seriously undermine fermentation efficiency, cow performance and herd profitability,” she states. “Even if the ration isn’t quite right, the rumen can adapt if it’s consistent, and ultimately make the best use of the feeds available.

“The knock-on effects for…efficiency…and feed costs per litre are significant.”

“However, that adaptation typically takes around two weeks, so any day-to-day variation is hugely disruptive. The knock-on effects for overall feed conversion efficiency (FCE) and feed costs per litre are significant.”

Ongoing financial impact

With total feed costs typically ranging between 10-13ppl on most farms, even a 5% reduction in FCE means those costs are as much as 0.65ppl higher than they need to be, claims Dr Sutcliffe. For a 200-cow herd averaging 30 litres/cow, that’s worth £1,170/month.

“And the impact isn’t restricted to FCE,” she adds. “Variations in milk quality can affect milk price, whilst any production lost during the first 100 days in milk will directly affect total lactation yield.

“In addition, cows forced to regularly dip into body reserves due to inconsistent energy supply are more likely to suffer from poor fertility, with fertility further affected by excess nitrogen if energy and protein supply are too often out of balance.”

In-clamp forage variability

One of the biggest sources of variation is forage, and since silages typically account for 40-50% of dry matter intake (DMI), even relatively small changes can have a sizable effect.

“Measurements made across a single clamp face using the NIR4 Farm hand-held analyser have shown that grass silage DM can vary by as much as 10% from top to bottom, and up to 8% from the middle to the sides (figure 1),” Dr Sutcliffe continues.

Grass silage quality variation
Figure 1 – Grass silage dry matter % variation (figures in blue) across the clamp face (Source: NIR4 Farm, 2014) – click to enlarge

“To put that into context, just a 2.5% reduction in silage dry matter from one day to the next can alter nutrient supply enough to cut daily yields in a herd averaging 30 litre/day by 1.75 litres/cow!”

Similar results were reported following a 2013 study by Trouw Nutrition, which also found variations in NDF (10%), energy density (1.6MJ ME/kg DM) and crude protein (3%). With even greater variation possible when moving back through the clamp or between clamps, regular monitoring of forage quality – whether done using on-farm NIR testing or laboratory analysis – is essential.

“If you know there are differences in forage feed value, then you can adjust how and where you take silage from the clamp each day to produce a consistent mix, and update ration formulations if needed” advises Dr Sutcliffe. “Maintaining that forage quality through good clamp management is also important, particularly in warm weather or if there’s poor consolidation.”

Maize silage stability

Maize silage poses additional challenges to ration consistency as it continues to ferment through much of the winter (figure 2). As a result, Dr Sutcliffe suggests holding off opening clamps until after Christmas if possible, so that starch degradability and subsequent feed value are maximised.

Maize starch degradability graph
Figure 2 – Improvement in maize silage starch degradability over time (Source: Trouw Nutrition, 2016) – click to enlarge

“And for all silages, always aim to achieve the best possible quality – it’ll vary less in the clamp and from year-to-year,” she adds. “Good quality wholecrop cereal silage nearly every year is far better than maize silage that’s good only two years out of five!”

Consistent forage quality will also improve forward planning of rations and feed buying, allowing preferred feeds to be secured early if availability is tightening and so reduce feed ingredient changes during the winter. Plus, fewer changes make it easier to keep everyone on the team up to date with the current feeding plan, an area where significant errors can occur.

Reducing mixing errors

“Staff have a big impact on the ration, and the better they’re kept informed, the more they’ll care,” Dr Sutcliffe states. “Differences in accuracy, mixing times and attitudes towards excluding mouldy or spoiled feeds, for example, all have an effect on ration consistency.

“And it’s a particular challenge when more than one staff member is responsible for day-to-day feeding, or when others have to cover during weekends and holidays.”

A simple list outlining key feed mixing protocols kept in the tractor or loader cab can help. But time pressures, equipment limitations and inconsistent staffing can result in those protocols not being followed.

“One of the biggest changes we’ve seen in recent years is the replacement of straights with a single custom blend that contains all the concentrate ingredients,” adds Dr Sutcliffe. “It might seem counterintuitive, but the improvement in accuracy and consistency, plus reduced losses, mean overall feed costs per litre are actually lower.

Course blend image
A KW custom blend can be tailored to match nutrient requirements.

“Anecdotal reports suggest TMR mixing errors of 5% or more are common, which can add up across multiple ingredients – up to a dozen on some farms – to produce serious ration errors. If everything’s in one blend, that error is massively reduced.”

Fewer feeds stored and the elimination of cross-contamination also cuts spoilage and produces a more consistent overall concentrate quality, whilst light density – often expensive! – ingredients are less likely be lost in the wind between bucket and mixer wagon.

“…it’s easy to see why so many are making the switch.”

“When you consider that blends can include both pelleted and ground ingredients, plus liquid feeds to bind ingredients together, and can be formulated to flow out of bins, it’s easy to see why so many are making the switch. The reduction in ration preparation times also helps, because there’s simply less time pressure.

“However, full ingredient declaration and a commitment from the supplier to only change the formulation if agreed beforehand are essential to retaining control over both ration and nutrient supply consistency, as is the flexibility to adjust blend specification as forage quality changes.”

Consistent cow consumption

The final piece of the jigsaw is to ensure that what the cow eats is also consistent. Clearing away refusals at least daily and feeding twice rather than once a day if possible will minimise post-feeding ration deterioration, for example, and improve intake consistency.

“Make sure feeding areas have sufficient space to allow heifers and timid cows access to the full fresh ration not just leftovers,” highlights Dr Sutcliffe. “Reduce sorting by keeping fibre length below 50mm, and add a liquid like Molale or moist feed such as draff or Traffordgold to bind smaller particles to the forage.

“One idea that’s taken off in Denmark in a big way is compact feeding, where very short-chopped forage is combined with a low DM mash of concentrate ingredients to produce an overall ration of between 36-39% DM. The reduced opportunity for sorting means rations are eaten more quickly and consistently, which also leaves additional lying time for rumination, and it’ll be interesting to see whether this approach improves productivity in the UK.”

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