Maximise the efficiency of your herd this winter

Feed efficiency

Feed efficiency is a measure of the amount of energy corrected milk (ECM) that is produced from one kilogram of dry matter feed, expressed as a ratio. The higher the ratio, the better the rate of feed efficiency.

For example, if a herd is producing 30 litres of ECM and consuming 20 kg of dry matter to achieve this yield, the feed efficiency of the herd is 1.5 (30 ÷ 20 = 1.5). If milk yield increased to 31 litres and intake remained the same, then the feed efficiency would increase to 1.55.

Increasing milk output for the same amount of feed enhances a farm’s income over feed costs, as there is more milk produced from the same amount of feed consumed; diluting the maintenance cost of each cow and spreading feed costs over more litres of milk.

Figure one (below) outlines feed efficiency guidelines for dairy herds. Remember that first and second lactation cows will be less feed efficient as they are still directing energy towards growth. Similarly, mature cows past peak production will divert increasing amounts of energy towards bodyweight gain.

Adapted from: Penn State University (2011)

Feeding the rumen

Rumen microbes are responsible for fermenting feed and producing fatty acids and microbial protein. These energy sources fuel a cow’s maintenance, lactation and reproductive performance. To improve feed efficiency, it is, therefore, essential to optimise the performance of rumen microbes.

High milk yields present a challenge in modern, high performing herds and in order to promote the high feed intakes needed to achieve these yields, the feeding of relatively low fibre diets (usually in the range of <35% NDF), which also contain
 a large proportion of concentrates, is required. This results in very high rates of feed passing through the rumen, which can result in sub-optimal digestion by the rumen microbes. As a result, more feed can end up passing out in the dung rather than being digested and absorbed as
 an energy source in the rumen.

These high intakes can also promote sub-acute rumen acidosis (SARA), a mild form of acidosis, which results 
in digestive upset, reduced feed intakes and depressed milk yields.

Rumen microbes flourish on being fed a stable, well balanced diet, day in, day out. This ensures maximum feed digestion and the production of higher levels of microbial crude protein.

As such, diet changes should be made over a gradual period of time (usually over a two to three week period) to ensure that rumen microbes can adapt to changes in diet, with minimal impact on performance.

Feed management

As explained above, rumen microbes thrive on consistency, so it makes sense that cows will perform best if diets are stable, with as little content variation as possible. By keeping feed rations stable during the winter period, you can help maintain high feed intakes, minimise digestive upsets and improve milk yields.

Forages by their nature are inherently variable, and the variability they create in a cow’s diet on a day-to-day basis can negatively impact feed utilisation. Gaining a better understanding of the quality and makeup of forage stores can help you deliver as consistent a feed ration as possible.

While a silage core sample will usually be taken by a nutritionist at the start of the winter, it is important to analyse clamp faces at least once a month. This will enable you to identify any variation in forage quality and make necessary adjustments to feed rations to maintain consistency.

In particular, pay attention to the fermentation characteristics of forage analysis, as high readings of volatile fatty acids can be a sign of poor fermentation, which could adversely affect palatability.

When it comes to changing silage clamps, ensure that the new clamp is opened before the back wall of the other clamp is visible. An overnight switch from feeding from one clamp to another can negatively impact rumen digestion.

It is inevitable that there will be compositional changes in clamps of forage over the course of the winter. By measuring the quantity of silage in all clamps, on a dry matter basis, and drawing up a budget for the winter (based on the quantity and quality of forage that will be fed to each animal on a daily basis), nutritional deficits can be identified and alternative feeds secured if required.

If you are buying in moist by-products it is important that contracts secured at the start of the winter guarantee supply, as on/off supplies lead to changes in a cow’s diet and subsequent digestive upset.

Ration consistency and presentation

Just as minimising compositional variation of feed is important, managing feed delivery is also essential when trying to maximise feed utilisation. By properly presenting cows with well mixed feed, you can reduce levels of sorting and encourage higher feed intakes.

To ensure the optimum presentation of feed, do not overload feeder wagons and make sure that feed components are mixed in the correct order, with the smallest being loaded first and the largest added last.

It is also advised that the feeder wagon mixes for the same amount of time each day, at the same RPM, to ensure that the mix is as similar as possible every day.

Ensuring that structural fibre, such as straw, is adequately chopped (to the width of a cow’s muzzle) will also help reduce intestinal upsets and sorting. Using pre-chopped straw, either by a forage harvester or specialist straw chopper, is therefore strongly advised.

TMRs and PMRs must be distributed all the way along, and pushed up against, feed barrier spaces to reduce competition for access to feed. This will minimise the risk of bullying from cows and encourage higher intakes.

It is absolutely essential that cows are not left without feed, as this can promote gorging when food is reintroduced and result in cow’s suffering from acidosis.

To read how cow care and Actisaf supplementation can also help you to boost feed efficiency and minimise the impact of low milk prices this winter, please read part two of this article by clicking here.