By Silvie Andrieu, European Technical Ruminant Manager, Alltech
(Reproduced by kind permission of Alltech (UK) Ltd)

Many dairy producers will look at lowering feed costs to improve financial performance, but few actually look at measuring and improving feed conversion efficiency (FCE) as a way to increase profitability.

"Yet in many cases greater gains can be made from improving FCE than can be achieved by cheapening the diet," says Alltech's European ruminant technical manager Sylvie Andrieu. "A 5% improvement in conversion efficiency resulting in an extra 1.5 litres of milk/cow/day from the same level of feed intake can be worth an additional 0.39 €/cow/day. Even if it takes another 0.11 €/cow/day to achieve this by altering the components of the diet, the net gain still equates to an extra 28 €/day for the average 100-cow herd.

"This may not look like a significant improvement, but over a typical 180-day winter this would deliver an extra 5040 € in margin over feed costs."

In the pig and poultry sectors feed conversion efficiency is monitored on a daily basis to ensure every gram of liveweight gain is achieved from their high cost rations. While she accepts that controlled environments and consistent rations mean it is relatively easy to get an accurate measurement of FCE in non ruminants, Mrs Andrieu argues that it is possible to get a handle on dairy cow feed efficiency especially on units using feeder wagons.

"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 nor necessary," she suggests. "My recommendation as a starting point would be to monitor total dry matter intake for the herd on a weekly basis, by subtracting any left over feed from what has been fed. It is then simply a matter of taking account 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."

Feed conversion efficiency does vary during lactation and is at its highest in the first few months after calving when it can be as high as two kilograms of milk for every kilogram of dry matter intake. Towards the end of lactation this value can be closer to 1.1 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 kilogram of dry matter intake," says Mrs Andrieu

"Feed conversion efficiency can be affected by a number of factors, and not least the genetic potential of the cow," she adds, "but influencing performance on a daily or weekly basis can be achieved by improving feed utilisation and helping the cow extract more nutrients from the fibre component of the ration in particular."

In a recently completed trial at Harper Adams University College cows were supplemented with Alltech's live yeast culture Yea-Sacc1026 and the impact on yield, liveweight and feed efficiency was monitored over a three-month period.

At the start of the study the cows were, on average, about eight weeks into lactation and achieving daily yields of 38.1 kg/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 in the TMR with Yea-Sacc1026 Farm Pak at a rate of 50g/head/day.

The supplemented group built up to a yield response of an extra litre/cow/day when compared with the control group. The supplemented group also achieved a significant increase (12%) 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.

The positive FCE response achieved by feeding the live yeast culture results from improved rumen function. Yea-Sacc works by stabilising the rumen environment and stimulating the activity of beneficial rumen bacteria, thereby improving fibre digestion (and feed conversion efficiency).

A more stable rumen pH is a fundamental part of this process, and particular the maintenance of a pH level at 6.0 or above, as this ensures the continuing activity of the fibre-digesting bacteria. Recent trial work carried out in Spain confirmed the effectiveness of Yea-Sacc in this context, and therefore underlined it 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 fibre-digesting bacteria would cease to function.

"By creating a more stable environment for key bacteria to multiply and get to work, the yeasts are improving the efficiency of digestion and at the same time speeding up the passage of the feed through the rumen, which encourages the cow to eat more often," explains Mrs Andrieu

"In the Harper Adams trials, and indeed in many typical farm situations, this increased efficiency translates into a sustained yield response of 1- 2 litres/cow/day once the rumen has had a short period of time for the processes to become established. To emphasise the real significance, this means more milk for each kilogram of feed intake, which has to be good news at any level," she says.

"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."