Current Progressive Dairy digital edition

0708 PD: Feed efficiency focus: A route to higher margins

Kevin Tuck Published on 25 April 2008

It is in all milk producers’ interests to continually drive for greater efficiency in their businesses.

While many will look at lowering feed costs to improve financial performance, few actually look at measuring and improving feed conversion efficiency (FCE) as a way to increase profitability. Traditionally, the drive for extra milk production was all-important and increases in dry matter intake (DMI) were seen purely as the vehicle to achieving this goal. However, with the significant increase in feed and feed ingredient costs, this is no longer seen as a viable option, which in turn focuses the attention back on feed efficiency.



In many cases, greater gains can be made from improving FCE than can be achieved by low-cost feed. A 5 percent improvement in conversion efficiency resulting in an extra 3.3 pounds of milk per cow per day from the same level of feed intake can be worth an additional 65 cents per cow per day. Even if it takes another 10 cents per cow per day to achieve this by altering the components of the diet, the net gain still equates to an extra $55 per day for the average 100-cow herd. Another way of looking at this is that every ton of feed incorporating the live yeast culture technology is capable of producing an additional 325 pounds of milk.

This increase may not look like a significant improvement, but over a typical 200-day feeding period this would deliver an extra $11,000 in margin-over-feed costs. This indeed has become the center of focus for many producers and also for the industry involved in the feeding and nutrition of these animals.

In the pig and poultry sectors, feed conversion efficiency is monitored on a daily basis to ensure every pound of liveweight gain is achieved from their high-cost rations. While one can accept that controlled environments and consistent rations mean it is relatively easy to get an accurate measurement of FCE in non-ruminants, one could also argue that it is possible to get a handle on dairy cow feed efficiency, especially on units using feeder wagons. The compilation of data is quickly becoming a necessity on dairy units and is a practice that is not only being encouraged, but it is something being offered by the feed and nutritional services as a support to farmers using their inputs.

We need to be realistic about what is practical on a dairy farm, and highly accurate daily assessments of the situation may be neither feasible or necessary. My recommendation as a starting point would be to monitor total DMI for the herd on a weekly basis by subtracting any leftover feed from what has been fed. It is then simply a matter of taking inventory of the number of cows and the total volume of milk produced in order to be able to work out the FCE and monitor any upward or downward trends that will be relevant indicators of performance. This advice is something which is being taken up by dairy producers in many countries and it is predicted that the year 2008 will become the year of feed efficiency for the dairy industry.

FCE does vary during lactation and is at its highest in the first few months after calving, when it can be as high as 4.4 pounds of milk for every 2.2 pounds of dry matter intake. Towards the end of lactation this value can be closer to 2.42 pounds because the cow is diverting more energy towards building body reserves.


By taking a weekly whole-herd FCE snapshot you can keep track of the amount of milk you are actually getting out of every pound of DMI. The findings of these simple measurements can be quite staggering and account for some of the greatest waste occurring in our existing systems.

FCE can be affected by a number of factors, and not the least being the genetic potential of the cow. Influencing performance on a daily or weekly basis can be achieved by improving feed utilization and helping the cow extract more nutrients from the fiber component of the ration. Regardless of genetic make-up, one of the greatest wastages on any dairy unit is unrealized potential, and any technology or practice that can help extract more nutrients from existing feed programs is greatly appreciated.

In a recently completed trial at Harper Adams University College in the United Kingdom, cows were supplemented with a live yeast culture. The impact on yield, liveweight and feed efficiency was monitored over a three-month period. This work was critical in the evolving use of yeast cultures whereby milk yield per se was not the central factor of the research but rather investigating as to where the additional milk was coming from. This investigation into the evolving use of live yeast cultures was driven by the significant increases in the price of feed and feed ingredients and simply producing more milk from additional intakes was not what the producer required.

At the start of the study, the cows were, on average, eight weeks into lactation and achieving daily yields of 84 pounds of milk per cow. Both the trial and control group of 20 cows were fed a basic TMR comprising one-third grass and two-thirds maize silage along with caustic wheat, soya, rape, molasses and minerals. The trial group of the cows were also supplemented a live yeast culture at a rate of 2 ounces per head per day. This ration represented a very common feed formulation in today’s market place and would be a true reflection of the type of circumstances in which such products would be expected to work in the market place.

The supplemented group built up to a yield response of an extra 4.4 pounds per cow per day, when compared with the control group. The supplemented group also achieved a significant increase (12 percent) in feed efficiency during the first fours weeks of the trial and remained with a similar or higher FCE throughout the remaining weeks of the study. This was a significant breakthrough, as historically it had been considered that the use of yeast culture was purely to drive additional intake. This study was clearly showing that the benefits were actually coming from more efficient use of existing feedstuffs.

In addition to producing more milk, the supplemented cows also gained more weight than the control group, which suggests that FCE was actually higher than when calculated on yield alone. This bodyweight response in early lactation will obviously have a positive benefit on fertility, as cows that are losing weight are more difficult to get in calf. The added benefit of achieving greater feed efficiency is more valuable than the actual increase in additional milk production in some systems. By allowing the animal to take more nutrients from its existing feed, there were less requirements for her to give of her own body condition, the foundation stone of compromised fertility. Since then, three further studies across the European Union at the University of Hohnenheim, Germany; University of Tartu, Estonia; and more recently at University College, Dublin, Ireland; have all yielded similar responses in improved milk yield through greater feed efficiency and all have reported improvements in dairy fertility. By controlling excessive bodyweight loss through greater feed efficiency the dairy cow is allowed to more closely achieve her potential without compromising fertility in the process.


The positive FCE response achieved by feeding the live yeast culture results from improved rumen function. Live yeast cultures work by stabilizing the rumen environment and stimulating the activity of beneficial rumen bacteria, thereby improving fiber digestion (and feed conversion efficiency). These were all parameters that were studied and reported on numerous occasions over the previous years, but recent developments in ruminant nutrition research have allowed us to investigate even further in our attempts to understand why these changes in feed efficiency were coming about.

A more stable rumen pH is a fundamental part of this process. In particular, the maintenance of a pH level at 6.0 or above is important, as this ensures the continuing activity of the fiber-digesting bacteria.

Recent trial work carried out in Spain confirmed the effectiveness of live yeast in this context and therefore underlined its positive impact on FCE. In these trials, the animals receiving the live yeast culture maintained an average rumen pH of around 6.5, with reduced fluctuations compared with the control group. In contrast, the animals in the control group endured significant periods when rumen pH fell to less than 6.0, therefore creating an environment in which the fiber-digesting bacteria would cease to function. In summary, the longer the rumen pH remains above 6.0, the more prolonged period of efficient digestion can be achieved. This of course is the target of every feed consultant and nutritionist when formulating diets for dairy cows. Any technology products or management practices that can contribute towards achieving this higher more stable rumen pH is greatly valued.

By creating a more stable environment for key bacteria to multiply and get to work, the yeasts are improving the efficiency of digestion while at the same time speeding up the passage of the feed through the rumen. Simply put, this encourages the cow to eat more often.

In the Harper Adams trials, and indeed in many typical farm situations, this increased efficiency translates into a sustained yield response of 3.3 to 4.4 pounds per cow per day once the rumen has had a short period of time for the processes to become established. To emphasize the real significance, this means more milk for each pound of feed intake, which will show the dairyman bottom line results.

It is important to remember that this improvement in feed conversion efficiency is also beneficial in terms of improving fertility in early lactation and is not just about extra milk. PD

References omitted but are available upon request at

Kevin Tuck
Product Manager
for Alltech