When it comes to more efficient feed conversion in calves before weaning, the sooner you develop a calf’s rumen, the better.
According to Gerard Roney, founder and managing director of Advantage Feeders in Australia, controlled creep feeding is a good way to develop a calf’s rumen, allowing for better uptake of energy and protein at an earlier age.
“We have a lot of control on how (the rumen) operates, and this is the most important thing we’ve got on our livestock farms,” Roney explained at the 2025 Ag in Motion farm show near Langham, Sask., as part of a learning session presented by Huber Ag Equipment.
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Roney discussed how producers can help control the length of the papillae on the rumen wall, which pulls volatile fatty acids out of the rumen to be used as energy. Feeding starch lengthens the papillae, and the longer the papillae, the more energy the rumen can extract.
“It’s helpful to start at the beginning of the calf’s life,” said Roney, sharing an image of the undeveloped rumen wall of a six-week-old calf, which was smooth and without long papillae.
He compared this to the developed rumen wall of a calf of the same age, which had a greater surface area to allow for more energy uptake.
“The difference is this rumen had grain from the (start), so it’s really showing us we can get that rumen developed where they can eat pasture and digest it really quickly.”
While unrestricted creep feeding can lead to unnecessary feed expenses, he said, the idea behind controlled creep feeding is to allow for rumen development as early as possible before moderating for better feed conversion.
“What controlled creep feeding is, is providing that feed ad lib until that rumen starts to get going roughly that 100 days of age, so we feed them as much as we can early on,” said Roney.
“Once that intake starts going more than two pounds a day, for instance, we start using the feeding system to restrict intake.”
At this point in the calf’s life, pastures are usually providing more of the energy and protein they require.
“We’re just giving them a small supplementation, keeping that papillae long and getting really good growth rates.”
As an example, Roney compared an unrestricted creep feeding situation — where calves consumed 370 kilograms of creep feed per head prior to weaning — to a controlled creep feeding situation that reduced intake to about 120 kg per head.
“If feed is $0.40 per kg, it’s a $100 per calf saving,” he said.
“The younger we feed animals, the higher the feed conversion, so that’s really the best time to supplement an animal.”
Getting the most from pastures
Controlled creep feeding can also be used as a method for maximizing your grazing land, Roney told the audience, in addition to supplementing to maintain growth rates.
He explained how feeding small amounts of feed throughout the day impacts the pH levels in the rumen — and in turn production — compared to feeding a large amount once a day.
“The component of the rumen that can really make a difference for our costs side of things is getting the rumen fluid pH to remain constant,” he said.
If the pH level in the rumen is between six and seven, the rumen microbes responsible for digesting forage are more efficient.
“But if the rumen becomes more acidic and the pH is dropping, all of a sudden we’re running into acidosis issues,” said Roney.
This can happen when animals are fed too much at once, as “those microbe populations explode, they start digesting more of the feed, creating more volatile fatty acids. So their production goes up a lot, and those acids drop that rumen pH into an area that’s really problematic,” he said.
When this happens, the animal will feel unwell and won’t consume much feed for a while, meaning they’re not getting as much nutrition as they could out of their grazing source.
“It takes about anywhere between half a day and a day to for that rumen pH to rise again. Our microbes really aren’t performing until that rises, so that’s a lost opportunity,” said Roney.
The idea, then, is to supplement animals in small amounts throughout the day so they get the nutrients they need without negatively impacting rumen pH levels.
Roney has been involved with several feed trials comparing little-and-often feeding to once-a-day feeding and has found that by creep feeding 0.5 per cent of the feeder calf’s body weight as pasture supplementation, “we’re achieving really good conversions of three to one of our feed, and a lot of that is because we get better pasture digestion,” he said.
“We can feed 45 per cent less feed and get the same growth results, just through treating the microbe problem.”
Managing excess protein
A third component of controlled creep feeding — using it to manage excess protein in pastures — is one that Roney has seen great value in using.
“I think it probably is the one of the biggest applications to increase our profits, and it’s the least commonly one done,” he noted.
While production requirements for protein are generally about 14 to 16 per cent, high-performing pastures can have up to 30 per cent protein content.
“What it’s really doing is causing the liver to work overtime with that pasture imbalance, so it can really restrict our growth rate opportunity by 20 per cent,” said Roney.
“When you have that high-protein pasture coming into the rumen, microbes are fermenting it, and through that fermentation process creates a lot of ammonia,” he continued. “The liver has to work overtime to convert that ammonia into urea, and it gets urinated out, so that whole process is very energy intensive.”
Extra ammonia can be managed by creep feeding small amounts of grain, he explained.
“That grain is converted into volatile fatty acids that combines with that ammonia, and that’s what grows microbes…. Those microbes can just flush out of the rumen naturally into the next stomach and get metabolized. So … we’re not having those production losses from the excess ammonia.”
To illustrate this concept in action, Roney referenced a feed trial conducted in New Zealand, with two groups of 60 steers weighing between 800 and 900 pounds on pasture. The control group steers were fed about four lb. of hay per head each day in addition to grazing pasture. The second group received the same amount of hay on pasture and was also fed 2.2 lb. of barley per head each day.
On average, the control group steers consumed nine kg of forage per head per day and gained one kg per day — a feed conversion ratio of 11 to one.
Steers in the second group, however, only consumed about six kg of forage per head per day but gained 1.5 kg per day for a six-to-one feed conversion ratio.
“Despite them eating a lot less than the control group overall, they grew 50 per cent faster at 1.5 kg a day. So that little bit of supplementation didn’t just make them grow faster, it actually reduced pasture intake,” said Roney.
“We’re getting increased growth rates, pasture is going further (and we are) increasing our stock numbers because we can carry more on limited pasture.”
