SEED AVAILABLE FOR NEW CATTLE OAT SO-1

The new low-lignin hull, high-oil (fat) groat oat variety, CDC SO-1, will be commercially available in limited quantities for the 2010 growing season.

Beef producers have been following the development of this new feed oat variety as feeding trials were carried out at the University of Saskatchewan using the prototype lines during the early stages of the breeding program.

This proof-of-concept, or try-as-you-go, approach of testing the merit of the variety as a feed grain in tandem with its development is new to plant breeding, explains Brian Rossnagel, an oat and barley breeder with the Crop Development Centre (CDC) at Saskatoon. It has a couple of advantages over the traditional method of developing a variety, then testing it after its release. Had CDC SO-1 not proven out with the animals, the breeding program could have been discontinued to save time and resources. Secondly, a lot is already known about how CDC SO-1 fits into cattle diets as the seed comes into commercial production.

The goal of the breeding program was to develop an oat variety with digestibility and energy value similar to that of barley, specifically for the ruminant feed market. CDC SO-1 is not suitable for milling because of its high fat content and relatively low milling yield.

SO-1’s parent lines are AC Assiniboia, which donated the low-lignin hull with twice the digestibility of regular oat hulls, and SA96121, a CDC high-fat breeding line.

Lignin is a complex compound that gives plant tissues their firmness and strength. John McKinnon, beef chair at the University of Saskatchewan, explains that as an oat plant matures, the lignin content of the hull increases. This results in a protective barrier that makes the hull of the seed difficult for cattle to digest. An oat with less lignin in the hull should be more digestible for animals.

The second important feature is the high oil content of the groat. The groat of CDC SO-1 is seven to eight per cent oil by weight, which is about two per cent higher than that of regular oat varieties. Unit for unit, fat has 2.2 per cent more energy than starch. Therefore, higher fat content equals higher energy in the total oat kernel, McKinnon explains.

Graduate students Grant Zalinko and Sushama Arya conducted the backgrounding and finishing trials using CDC SO-1 at the Beef Cattle Research Unit of the University of Saskatchewan with calves provided by Pound-Maker Agventures of Lanigan. The objectives were twofold: to find out if CDC SO-1 could replace barley in the diet, and to evaluate whether or not the improved digestibility would eliminate the need to roll the oat for feeding.

BACKGROUNDING TRIALS

“In the backgrounding trials, the cattle fed the diet with the new oat consumed slightly less dry matter, but gained at the same rate as those on the diets with corn or barley,” McKinnon reports. “Therefore, feed efficiency is improved on the new oat versus barley and also versus corn in a backgrounding diet.”

The first backgrounding trial involved 400 calves. The control diet was barley silage, grass hay, barley straw, a supplement, and rolled barley grain, which constituted 38 per cent of the dry matter weight of the diet. The test diet was the same, but with CDC SO-1 replacing the barley grain. The gain-to-feed ratio was 0.171 for CDC SO-1 and 0.159 for barley. This represents a 7.5 per cent increase in feed efficiency for cattle fed CDC SO-1 compared with those fed barley.

The second backgrounding trial with 240 calves was another direct comparison the grain portion of the rations, this time comparing CDC SO-1 against both barley and corn. Each diet contained 55 per cent of one of either rolled CDC SO-1, rolled barley or rolled corn on a dry-matter basis. Barley silage and a supplement completed the ration. The gain-to-feed ratio was 0.198 for CDC SO-1, 0.188 for barley, and 0.183 for corn. The feed efficiency of cattle fed CDC SO-1 was 5.3 per cent better than that for barley and 8.2 per cent above that for corn-fed cattle.

Another trial involving 124 calves at the Western Beef Development Centre (WBDC) was designed to compare whole CDC SO-1 with rolled CDC SO-1 in a backgrounding diet. The results showed no difference in how the cattle performed in terms of gain, intake, or feed efficiency, suggesting that the new oat could be fed whole in backgrounding diets, without any loss of performance.

This was an important finding because processing grain costs producers anywhere from $5 to $15 per tonne, McKinnon adds.

A followup trial with 105 calves at the WBDC pointed to the same conclusion. The diet was 63 per cent alfalfa-brome hay, two per cent supplement and 35 per cent grain on a dry-matter basis targeting 2.5 pounds of gain per day. The three grains compared were rolled barley, rolled CDC SO-1, and whole CDC SO-1. Average daily gain was similar for all three groups. Feed intake was highest for the calves fed the diet containing the rolled oat, and lowest for those fed the whole-oat diet, therefore, the whole-oat diet had the lowest feed-to-gain ratio again. Ultrasound backfat measurements taken at the end of the feed period

confirmed that all three rations met the objective of the backgrounding program, that being to promote muscle and frame development and minimize fat deposition.

FINISHING TRIAL

The advantage of CDC SO-1’s improved digestibility and high oil content disappears as the grain portion of the ration is increased to 88 per cent in finishing diets.

The 240 calves from the second backgrounding trial were stepped up into a finishing program. The diets remained the same with the grain portion (rolled CDC SO-1, rolled barley or rolled corn) gradually bumped up to achieve the targeted rate of gain.

“The reduction of dry matter intake continues, but it is now to the point that the average daily gain is reduced relative to the barley-fed cattle,” McKinnon explains. “Therefore, we saw more days on feed and the feed efficiency declines.”

Researchers are exploring why intake is further reduced when CDC SO-1 is fed at the higher levels. One theory is that the high level of fat in the diet may restrict digestion in the rumen. Another consideration is that the improved digestibility allows for rapid digestion of the starch, which could be causing subacute acidosis.

SO-1 is not being recommended for finishing programs until further research unravels the mystery and there is a better understanding of how CDC SO-1 could fit into finishing rations.

A fact sheet covering the details of the trial involving rolled oat, barley and whole oat is available on the WBDC website at www.wbdc.sk.caor by calling 306-682-3139. The findings from the backgrounding and finishing trials have been accepted for publication in the Canadian Journal of Animal Science and should be available as a fact sheet later in the year.

GROWING CDC SO-1

The story of firsts with CDC SO-1 carries through to the marketing of this unique oat variety. This past March, the Crop Development Centre awarded the pedigreed seed marketing rights to T & L Seeds, which is owned by two well-established seed growers located in two of the largest cattle regions of Saskatchewan — Tim Charabin of North Battleford in the northwest, and Les Trowell of Saltcoats, in the east-central region. CDC SO-1 is T & L Seeds’ first proprietary variety.

“Both of us had grown the variety in the past and recognized that it was a great fit for western Canadian beef producers. We wanted to help control its destiny and make sure it stayed here in Western Canada,” Charabin explains.

Though the timing didn’t allow seed growers much leeway to work CDC SO-1 into their plot plans for the 2009 growing season, T & L Seeds has some growers in Saskatchewan and one in Alberta, who indicate that they will have certified seed available for sale next year. The company hopes to have more growers involved next year.

Trowell adds that there was some 2007 pedigree production still in store due to uncertainties around marketing rights in 2008. The provincial seed guides only list the growers who grew the varieties in the previous growing season, therefore, the 2010 seed guides will only list the growers who grew CDC SO-1 in 2009. The best way to find out about its availablity nearest to you is to contact either Charabin or Trowell directly.

CDC SO-1 is suited to all oat-growing areas of the Prairies. Fertility management and weed control are no different from growing any other oat variety. It has a fairly good disease resistance package, with susceptibility to rust equal to other oat varieties if rust is present. Follow the control recommendations for your area.

Trowell is impressed with the straw strength of CDC SO-1, which in his growing area is slightly taller than CDC Dancer and similar to CDC Weaver. It grows to about chest height, yet resists lodging if fertility is a little on the high side. There’s lots of plant growth for greenfeed, silage and straw, he says. CDC SO-1’s suitability for swath grazing is being tested this year at the WBDC.

CDC SO-1 is an average-yielding oat with average maturity. The seeds are large and fairly plump, but thinner than those of CDC Dancer. The test weight and per cent groat are less than CDC Dancer, but greater than Morgan. The hull is tan in colour and the seed has a dorsal awn, which normally comes off with a bit more aggressive combining.

For more information, contact Charabin at 306-445-2939, or Trowell at 306-744-2618.

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