“Feed efficiency is an important aspect of rearing beef cattle and lambs, but it is also difficult to measure on farm,” explains Kevin Doyle, Technical Sales Manager at Phileo UK & Ireland. “Because of this, inefficient feed utilisation is often a hidden loss of revenue.”
“While nutrition is a key element to get right, a holistic approach to farm management is also needed as poor housing, illness and other stressors will limit any effect that improved nutrition can have. By getting these environmental and health factors right, we can remove those bottlenecks and begin to fully optimise feed efficiency through the diet.”
It starts and ends with the rumen microbes
When it comes to feed efficiency in sheep and cattle, it’s essential to focus on the rumen and the microbes within it, who are responsible for digesting feed and forage. Through the process of fermentation these bacteria and other micro-organisms break down fibre and nutrients, providing the majority of energy requirements in the form of volatile fatty acids, or VFAs.
If the rumen environment is optimised, they will convert lactic acid – which causes digestive upset and acidosis if left to accumulate in the rumen – into propionate, a highly efficient form of energy. Once they have done their jobs, the microbes then wash into the intestines where they are digested, providing the majority of the animal’s protein requirements.
“As we learn more about the rumen microbes, their impact on animal performance and health is being better understood,” says Kevin. “They also play an essential role in stimulating the immune response – protecting against pathogens, neutralising toxins and regulating the growth of gut tissue – which helps prevent setbacks in performance.”
The makeup of these micro-organisms varies dramatically between individual animals, and certain bacterial species have been found consistently in particularly feed efficient animals, which indicates their importance in feed utilisation.
“A 2018 study in the USA found that the microbes Eubacterium ruminantium, Fibrobacter succinogens and Megaspheara elsdenii were present in beef cattle that needed 5kg lower DMI for the same live weight gain as less efficient animals,” he adds. “In other words, animals that had these bacteria in their rumen required less feed than others in order to achieve the same amount of growth. This is really exciting data as it can help us focus on stimulating the growth and activity of these beneficial microbes to enhance rumen fermentation and feed efficiency with diet formulations and targeted feed additives.”
Optimising beef and lamb diets for feed efficiency
The cornerstone of every ruminant diet is forage, and this is especially true when considering feed efficiency and weight gain of lambs and beef cattle. The more digestible it is, the easier it is for the rumen microbes to break it down, which increases the efficiency at which nutrients can be utilised. After a forage analysis is completed, any nutrient deficiencies can be balanced with complementary concentrate feed.
Sheep and cattle require nutrients firstly to maintain themselves, for example to power the immune system, digestion, maintenance of body temperature etc., and secondly for growth. More detailed information on beef and lamb nutrition can be found in Phileo’s technical handbooks, available at the links below:
Other key factors for optimised fermentation in the rumen are diet consistency, correct pH, having balanced energy and protein sources, adequate water supply and animal genetics.
The most important pinch point for cattle and lambs is the transition onto finishing rations. This should ideally be done gradually over 14-21 days to allow time for the rumen to adapt. Diet changes that occur too quickly can cause long term damage to the rumen wall and result in poor rumen function and acidosis, which can lead to stalls in growth, or even death.
“Always change diets slowly, building up every three days as long as there are no signs of digestive disturbance,” adds Kevin. “For animals being finished indoors after being on grass, it can be beneficial to introduce the finishing ration whilst still grazing. Careful diet transitions are especially important with lambs as this is when Clostridial diseases like pulpy kidney are most commonly seen.”
The diet must also include balanced energy sources, such as digestible fibre in the form of beet pulp/soya hulls, as well as starches and sugars like those from forages, cereals and by-products. As with all ruminants, always ensure that there is a clean, palatable supply of water available - finishing cattle can require as much as 80 litres of water per day and lambs up to 8 litres.
Genetics, sex and age also play a major role in the feed efficiency potential of animals, and the diet should reflect this. With feed efficiency decreasing with age, it pays to maximise high feed efficiency early in life and consider the length of time an animal remains economically efficient on the farm.
“Maintenance is largely a function of weight, so a heavier animal requires more feed to maintain itself. So for a fixed rate of liveweight gain, the feed energy required to achieve this gain is higher for heavier animals,” he adds.
Optimising feed efficiency with Actisaf:
Feeding Actisaf live yeast to beef cattle and lambs has been repeatedly proven to aid in diet transitions, support the bugs that stabilise rumen pH, reduce build-up of lactic acid and digest fibre. In turn, this prevents digestive upset, acidosis and loss of performance, as well as increases VFA (energy) release from feed, the key driver of live weight gain. Good rumen function supported by Actisaf promotes efficient digestion, unlocking more from your forages and supporting high levels of performance.
Research carried out in France in 2013 shows that supplementation with Actisaf increases the population of rumen microbes identified in efficient animals, such as Megasphaera elsdenii, which converts lactic acid into propionate to drive weight gain, and Fibrobacter succinogens, a key microbe involved in fibre digestion.
Actisaf has been found in several trials to improve feed efficiency in ruminants by stimulating the growth and activity of rumen microbes, with no increase in feed intakes.
In lambs, trial results have shown that Actisaf improves average daily weight gain by 10pc, feed conversion rate by 11pc and increases carcass weight by up to 1.2 kg per lamb over a typical finishing period.
In beef cattle, EU registration trials show that Actisaf increases growth rates by up to 9pc and improves carcass classification – resulting in an average net return of €41 per animal.
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