Perennial ryegrass | Livestock metabolizes feed more efficiently if sugar content is higher, increasing milk production and weight gain
Sugar is the latest dietary devil as nutritionists constantly warn adults and children about the dangers of cola, candy and ketchup.
Livestock, however, may actually need more sugar in their diet, says Clayton Robins, who farms near Rivers, Man.
Robins, a Nuffield scholar, said there is a direct connection between sugar content and livestock performance because animals process high sugar forage more efficiently.
“We tend not to look at sugars in (this) country,” said Robins, who has traveled to Wales, Scandinavia, Spain and the United States in the last year to study dense energy forages.
“Most of our forage analyses, they look at fibre and sometimes digestibility and those sorts of things, but not actually sugar. In every country I was in so far, except the States, they look at sugars in every feed test.”
Robins’ research and travels are part of his Nuffield award for 2013, an agricultural scholarship presented to three Canadians a year.
He was a beef research assistant at the Agriculture Canada centre in Brandon before taking his current job as executive director of the Manitoba 4-H Council.
While at Agriculture Canada, Robins and his colleagues tried to enhance cattle performance on a forage-only diet but with limited success.
“The consistency was a big problem. Not only consistency of forage quality, but the consistency of carcass quality and even the ability to finish those cattle,” he said.
“We were missing something, but we didn’t know what it was.”
Robins discovered the missing piece of the puzzle in the late 2000s at a conference in Argentina. He saw a chart depicting the rate of gain of livestock and the sugar content of forage.
“I never believed in epiphanies until I saw (that) slide, but (it) changed my life,” he said. “There was (a) directly correlated relationship between plant sugars and average daily gain… I knew that was it…. I knew we were looking at plants the wrong way. That’s what’s driven me to pursue this whole study topic.”
Robins is studying the potential of dense energy forages, with a particular focus on high sugar forage.
He said most Canadian legumes and grasses have a sugar content of eight to 12 percent, but livestock can metabolize the feed more efficiently if the sugar content is higher. Studies indicate the additional sugar accelerates the fermentation of fibre in livestock’s rumen.
“You start seeing the true gain in animal performance when you get past 18 (percent). That’s what I was told,” Robins said.
“Then you get those big meta-biological performance gains.”
Research from the Institute of Biological Environmental and Rural Sciences (IBERS) at Aberystwyth University in Wales has demonstrated that high-sugar forages are more digestible. IBERS scientists have developed a high sugar perennial ryegrass that can improve the rate of gain and milk production by 24 percent in lambs and reduce greenhouse gas emissions from livestock by 20 percent.
Livestock producers in the U.K., New Zealand and Australia are now using the ryegrass. Two major U.K grocery chains, Sainsbury’s and Asda, are promoting the use of the high sugar forage within their supply chains, claiming it cuts greenhouse gas emissions and makes beef production more sustainable.
Robins visited the IBERS research centre last year.
“They’re one of the few places in the world that (is) capable of getting to these really high levels of sugar (in forage),” he said.
“I was chewing on plants in their greenhouses that had 36 percent sugar. You could tell. It was sweeter and had less fibre.”
Robert Berthiuame, a forage expert with Valacta, a dairy research centre in Quebec, has also spent time with IBERS scientists in Wales.
He said high sugar forages have potential in Canada, but perennial ryegrass isn’t a great fit for the climate.
“All of this classical work on high sugar grasses has been done on mostly one species, which is perennial ryegrass,” he said from his office in Sainte-Anne-de-Bellevue.
“(It) is not grown or almost not grown in Quebec, and very little is grown in Eastern Canada.”
Perennial ryegrass is grown in Manitoba as seed for the turf industry.
“In most areas of (Canada) it is an annual. Here it doesn’t last very long.”
Nonetheless, there are other opportunities to boost the sugar content of Canadian forage crops, Berthiaume said.
Quebec scientists are looking at the potential of high sugar alfalfa.
“We used a variety sold in Canada, called AC Caribou, and we took within that variety specific genotypes … that were high in sugars,” he said.
“We’ve shown we can increase by a significant amount the amount of sugars.”
Forage growers can also maximize the sugar percentage in a grass or legume by cutting the crop in the afternoon, Berthiaume said.
“This is true for alfalfa, it is true for red clover, timothy and a number of the grasses we grow here,” he said.
“If we have sunny conditions … the plant will make more sugars than she has time to bring them down into her roots or burn them through respiration. So she will accumulate sugars in the aerial part of the plant.”
To preserve the sugars in forage, producers need to cut the hay in a wide swath that “covers 80 percent of the cutting width,” Berthiaume said.
Tests from Quebec suggest that feeding dairy cattle silage from high sugar forage increases milk production by five to 10 percent.
“I cannot say it works all the time because of some of those uncertainties related … to the bacterial population on the crop (and how that affects silage),” Berthiaume said.
Robins said high sugar forages aren’t going to revolutionize livestock production in Canada, but they do represent an opportunity because they can significantly reduce methane and nitrous oxide emissions.
“Feedlots … are very well run. We can’t do without them. We’ve got winter here in Canada, we need them,” he said. “(But) is the system to supply feedlots a sustainable system? (Can we have) a forage production model that is much more attractive, in terms of greenhouse gas, than what we currently accept? That’s where I think the benefit is.”
Robins will report on his research this fall at the Nuffield Canada conference.