What are the benefits of fine tuning the rumen for a successful finishing period? With feed and forage representing 70% of the variable costs of finishing beef cattle, improving its utilisation can have a substantial impact on profitability.
Feed efficiency, or the amount of growth achieved on a decided amount of feed, is affected by several factors including age, genetics, environment, health status and nutrition.
“Feed efficiency is an important aspect of rearing beef cattle, but it is also difficult to measure on farm,” explained the technical manager at Phileo by Lesaffre UK and Ireland, Kevin Doyle.
“This means that 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, parasites, illness and other stressors will limit any effect that improved nutrition can have.
Kevin added: “By getting these environmental and health factors right, we can remove those bottlenecks and begin to fully optimise feed efficiency through the diet.”
Rumen microbes
As the engine room of cattle, the rumen is where bacteria and other microorganisms break down feed and forage through the process of fermentation, producing volatile fatty acids (VFAs) that meet most of the animal’s energy requirements.
Additionally, when the microbes eventually die off, they pass through the intestines where they are digested into microbial protein and absorbed.
This is the highest quality protein cattle can get, and it also covers a majority of their protein requirements.
Because of their important role in nutrition and feed efficiency, we need to focus first on the rumen and the microbes within it when rationing cattle.
If the rumen environment is optimised for a stable and balanced microbiome, cattle can extract more from their diet, primarily due to improved fibre digestion and optimal levels of key VFAs.
This is particularly important in finishing diets where higher starch levels lead to a higher production of lactic acid, which causes digestive upset and acidosis if left to accumulate in the rumen.
If this occurs, feed efficiency is reduced and the gut wall is damaged, leading to a reduced ability to absorb nutrients and reduced immune function.
However, when rumen function is optimised, specific bacterial species (such as M. elsdenii) are able convert this lactic acid into propionate – a highly efficient form of energy and key driver of lean tissue growth – while regulating the acidity in the rumen at the same time.
“As we learn more about the rumen microbes, their impact on animal performance and health is being better understood,” Kevin said.
“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 communities 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 presence of specific microbial species (e.g. Eubacterium ruminantium, Fibrobacter succinogenes, and Megasphaera elsdenii) in beef cattle correlated with 5kg lower DMI for the same live weight gain as less efficient animals,” he added.
“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 diets for feed efficiency
The cornerstone of every ruminant diet is forage, and this is especially true when considering feed efficiency and weight gain in finishing 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 and reduces the quantity of supplementary feed required.
After a forage analysis is completed, any nutrient deficiencies can be balanced with complementary concentrate feed by working with your nutritionist.
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 nutrition can be found in Phileo’s technical handbook on feeding finishing herds, available here.
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 beef cattle 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, illness 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.”
Successful finishing period
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.
Always ensure that there is a clean, palatable supply of water available – finishing cattle can require as much as 80L of water per day.
It is also important to remember the negative impact of pests and disease on performance and work with your vet to prevent or treat them quickly.
Parasites damage the gut wall and draw nutrients from diets to feed themselves, while sick animals will prioritise energy and nutrients to support their immune systems.
Both of these result in less growth, reduce feed efficiency and increase the cost of every unit of growth, making animal health just as important as getting nutrition right when it comes to a successful finishing period.
Feeding for genetics
Genetics will firstly determine cattle’s performance potential and plays a major role in the feed efficiency potential, alongside sex and age.
These factors will also influence the most appropriate diet to help them meet this potential. For example, continental bulls with high growth potential will require a very different diet when compared with Angus or Hereford heifers.
In addition, feed efficiency decreases with age, so it pays to maximise high feed efficiency early in life and consider the length of time an animal remains economically efficient on the farm.
Ensure that you work with a nutritionist to formulate the most appropriate diet to the stock classes you are feeding.
“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,” Kevin adds.
Optimising feed efficiency with Actisaf
Feeding Actisaf live yeast to beef cattle has been repeatedly proven to aid in diet transitions, support the bugs that stabilise rumen pH, reduce build-up of lactic acid and increase fibre digestion.
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 to support 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 beef cattle, EU registration trials show that Actisaf increases growth rates by up to 9% and improves carcass classification – resulting in an average net return of €40 per animal.
To add Actisaf to your herd’s rations, speak to your feed miller or nutritionist.
Alternatively, contact Phileo UK & Ireland for more information at +44 (0)2893 343900.
