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Oregon State University Agricultural Research updates.

'Swim' Test Reveals the Best Breeders

A new test identifies superior roosters and tom turkeys and promises to make significant changes in the way male poultry are managed in commercial breeders' flocks.

The test, or "assay" in research terminology, measures how well sperm swim.

Illustrationof a chicken wearing goggles while swimming a lap in a pool.

Illustration: Tom Weeks

"Sperm mobility is essential if the sperm cell is to function as a self-propelled DNA delivery vehicle," says David Froman, Oregon State University poultry scientist.

"In the past, semen evaluation identified the losers. Our new assay picks the winners. So now instead of throwing out the losers--and there are a lot of them--breeders can pick out a relatively small number of highly fertile males. This is especially important in artificial insemination, because only a few males are needed to fertilize hundreds of females."

In less fertile roosters, sperm aren't mobile enough to get to sperm storage tubules in the hen's lower oviduct. If they don't swim that far, they'll never get to the site of fertilization, which is the uppermost part of the oviduct. "Those sperm don't even die trying; they're toast," Froman says.

OSU Agricultural Experiment Station scientists "stumbled onto the assay" as they were trying to find out why a particular line of roosters is sub-fertile. What the researchers found is that these roosters' sperm are notoriously poor swimmers.

Froman, doctoral student Derek McLean, and research associate Allen Feltman screened 100 roosters and compared the birds' sperm mobility. The hatchability of eggs from hens inseminated with highly mobile sperm was 10 percent greater than hatchability of eggs inseminated with sperm having average mobility.

Farmers Could Cut Water to Some Crops

Many farmers in dry areas would be better off if they under-irrigated some crops to save water for additional acreage, says an Oregon State University Agricultural Experiment Station scientist.

"By under-irrigating, you can make more money, save water and help protect the environment by reducing the amount of chemicals leached into water supplies," says Marshall English, an OSU professor of bioresource engineering.

English studied under-irrigation in Oregon several years ago and more recently in other countries, in cooperation with a graduate student researcher.

Irrigation sprinkler forming a rainbow above the crops.

Irrigating crops, like this eastern Oregon alfalfa, is expensive. Photo: Bob Rost

The OSU scientist explained that most irrigation systems in the western United States are designed to fully irrigate about 90 percent of a field. The remaining 10 percent is almost fully irrigated, but a small deficit is permitted. The percentage of the field that is fully irrigated is called the "irrigation adequacy."

In areas short of water, such as in India and South Africa, many farmers use a 50 percent adequacy guideline.

"In some of the cases we have studied, going from 90 percent to 50 percent adequacy would only lose 1 or 2 percent of yield-and you'd save a bunch on water and irrigation costs," English says. "The reason is that irrigation efficiency is much higher at 50 percent adequacy."

But he offers this note of caution: "Certain crops should not be under-irrigated. With potatoes, for example, the quality of the product can be greatly affected by water stress."

English's graduate student, Syed Navaid Raja, analyzed irrigated wheat in Oregon, cotton in California and maize (corn) in Zimbabwe.

"Our results suggest irrigation deficits between 15 and 59 percent below the normal irrigation amount would be the most profitable for those three cases," says English.

"For wheat on the water-short farms of eastern Oregon, a 20 to 30 percent reduction of water (from full irrigation) seems most optimum for farms where the water supply is not sufficient for full irrigation of all crops. Many farmers figured this out long ago," he adds.

In their Oregon wheat trials, English and Syed saw the best yields on fields irrigated every other week, but they had the best yield per unit of water when they irrigated just once a month-provided the water was applied at the optimum time."

Timing is critical, notes English. For wheat, irrigation between the plant's jointing and early grain-filling stages is essential.

Wheat is a fairly tolerant crop when it comes to needing water, but corn is much more sensitive, he adds. But the deficit irrigation strategy also worked well for maize in Zimbabwe.

Farmers there and in the United States have learned to "let crops grow thirsty sometimes," English says. "It won't hurt them."

When farmers pour too much water on crops, he explains, much of the excess is lost in drainage beyond the root zone and by excess evaporation.

Enzyme May Be a Key To Cow Disease

An enzyme found in a cow's liver and fat could lead to early detection of ketosis-a sickness that knocks milk production for a loop.

Oregon State University scientists are looking at ketosis-affected cows to see what happens to the enzyme PEPCK. A cow deficient in the enzyme will be deficient in glucose, and that can contribute to the development of ketosis.

"Our aim with the PEPCK study is to find a simple tissue indicator of the disease, which will aid dairy producers in prevention and treatment," says OSU animal scientist Diane Carroll. She and colleagues C.Y. Hu and Jennifer Duncan are testing PEPCK in fat and liver tissues.

Each year, more than 10 percent of the nation's highest producing dairy cows are struck by some form of ketosis. The ailment will cause a cow to go off feed and drop in milk production for weeks.

"When a cow has a glucose deficiency (low blood sugar), she mobilizes fat to make up for the deficiency. When she overcompensates, she gets ketosis," Carroll says.

The farm-gate value of Oregon dairy products, plus dairy cattle and calves, is about $338 million, according to Lorinda Moholt of the Oregon Dairy Products Commission. "Processing, packaging, transportation, distribution and retailing add another $600 million to the state economy," she says.

Hop Practice Helps the Environment

Oregon is second in U.S. hop production behind Washington and grows about 5 percent of the world's hops-about 13 million pounds on roughly 8,600 acres last year. That's enough to make a lot of beer.

But such a high-value, low-acreage crop, worth about $26 million in 1995, puts a premium on land management decision making. So about six years ago Oregon State University researchers began working with government agencies and hop growers concerned about sustaining the industry economically and environmentally.

Two men wearing ear protection while working on a large machine in a field.

OSU soil scientist Neil Christensen, standing, and Linn County extension agent Mark Mellbye drill a soil sample near Junction City. Photo: Bob Rost

The work is starting to pay off with more efficient, less costly fertilization that protects the environment.

"We found that many growers could reduce the amount of nitrogen fertilizer they used without reducing their yields," says Neil Christensen, a soil scientist with OSU's Agricultural Experiment Station.

This sounds simple, he explains, but it is a hard sell to producers because fertilizing is relatively inexpensive. At about 30 cents a pound, nitrogen fertilizer is cheap insurance for hop growers worried about keeping yields high.

"To their credit, though, most of the growers we worked with are aware that there are other considerations besides maximum yield. Too much nitrate-nitrogen remaining in the soil at harvest is a potential environmental pollutant if it ends up in the groundwater or surface water," says Christensen.

"Ideally," he adds, "you want to end the growing season with only small amounts of nitrate-nitrogen left in the soil. Excess nitrate is not only an economic waste, but Oregon's rainy winters tend to move it down into the groundwater system."

OSU researchers closely monitored nitrogen levels and hop yields and suggested adjustments that would reduce or eliminate excess nitrogen.

"We found that many growers could reduce nitrogen about 50 pounds per acre without reducing yields," says Christensen. "Another suggestion was using cover crops (grasses planted before or after harvest and disced under in the spring) to keep excess nitrogen from leaching during the winter.

"This is the kind of applied research we'd like to do more of," he says. "It has been truly a cooperative effort with the OSU Agricultural Experiment Station, the Oregon Hop Commission, the Oregon Department of Environmental Quality, the Oregon Department of Agriculture and the growers.

"The growers are concerned about doing things more efficiently," he adds. "In this case, doing things more efficiently is good for the environment.

"The private sector is now using soil and plant testing techniques we found useful in determining nitrogen needs of hops," says Christensen. "We hope they can confirm our results and refine the management practices."

Are You Eating the Best Vitamin B-6?

Some people who eat a vegetarian diet may be shortchanging themselves on vitamin B-6 by eating foods that contain a less usable form, Oregon State University Agricultural Experiment Station researchers warn.

Women are more likely than men to have a B-6 deficiency, which can weaken the immune system and make them more susceptible to heart disease.

The OSU researchers have found that some plant foods, like beans, contain as much as a third of their B-6 in the glycosylated form-a form not readily used by the body.

In a recent issue of the Journal of Nutrition, OSU foods and nutrition professors Jim Leklem and Lorraine Miller, and graduate student Christine Hansen, reported that the glycosylated form has a glucose molecule attached to it and is not absorbed and used efficiently.

Animal products such as beef, pork, turkey, chicken, tuna and salmon contain more digestible forms of vitamin B-6, according to the scientists.

But "don't go to extremes and eat all-animal food sources. You'll miss out on other good things you need in your diet," says Leklem.

He says good plant-food sources of usable vitamin B-6 include bananas ("the riper the better"), avocados and nuts--especially filberts, cashews, peanuts, walnuts and pecans.

Potatoes are a moderately good source of B-6, but part of it is glycosylated, says Leklem. As much as a third of the B-6 in legumes, such as soybeans, pinto, garbanzo and navy beans, is glycosylated, he adds.

Sunflower seeds are especially high in B-6. But again, about a third is glycosylated.

"That doesn't mean you should stop eating those foods," says Leklem. "After all, they contain protein, fiber and other important B vitamins."

Oregon Farmers Foil Potato Famine Disease

During the recently completed potato growing season, better detection devices, early intervention and more favorable weather headed off substantial losses from a disease called late blight that has caused problems in recent years in the Treasure Valley and the Columbia Basin.

"We beat late blight on both ends of the economic scale this year," says Clint Shock, superintendent of Oregon State University's Malheur Experiment Station at Ontario.

"There were fewer losses and less money was spent on spraying to prevent late blight," adds Shock. "It looks like fungicide treatment for prevention costs about $40 per acre this year compared to about $150 per acre last year."

A large bin of potatoes.

Potato harvest in eastern Oregon. Photo: Bob Rost

Until recent years late blight, the disease responsible for the Irish Potato Famine in the 1840s, was not thought to be a problem in the arid climates of the American West.

However, more virulent strains developed and weather conditions aided its spread. The disease was first detected in Oregon around Hermiston in 1993 (see "The Potato Eaters," Oregon's Agricultural Progress, Fall/Summer 1994, pp. 30­34). This year the OSU branch experiment station in Malheur County kept close track of weather conditions.

"The environmental conditions most conducive for late blight growth are temperatures below 78 degrees, with humidity higher than 90 percent," explains Shock.

"Though these conditions might sound unusual for this part of the country, 90 percent humidity often occurs down near the ground among the potato leaves," he says.

A Malheur experiment station cooperative program helped potato growers attack the disease. Others members of the team included Lynn Jensen, an OSU extension agent in Malheur County, and University of Idaho researchers Mike Thornton and Krishna Mohan.

"We put a lot of technology to use tracking (growing) conditions," says Shock. "We had eight remote sensing stations and dozens of cooperating field scouts and growers observing the crops. We ran automated weather data through a computer program called 'Blightcast' twice a week that gave growers a risk severity number."

For example, a severity number of 15 meant late blight could be expected to show up in 7­14 days, Shock explained. Growers could then head off the disease by applying protective fungicides.

Technology also was important in getting forecasts to growers.

"We had an 800 number, a Web page and faxes. There were about 4,000 calls to the hot line and about 2,000 visits to the Web page," said Shock.

Hermiston-area potato growers also seem to have minimized losses from late blight, according to Jeffrey McMorran, an OSU extension agent and agronomist in Umatilla County.

"We used a slightly different computer model for our area, but we also relied heavily on field scouting reports and getting the information out to growers quickly through an 800 number and electronic mail," says McMorran.

Light Can Tell Disease Story

A research team from four western universities has figured out how to use light to detect early warnings of disease and pest damage to plants--or of injury from freeze damage, drought stress or herbicide spray exposure.

A leaf shown in flurorescent lighting of reds, yellows, greens and blues.

OSU researchers analyzed fluorescent light from this leaf. The blue dots are where a fungus retarded normal function. Photo: Bob Rost

They study images on the leaves of trees and shrubs. Analysis of these images, which are invisible to the naked eye, will also make it possible to identify the type of disease or insect attacking the plant, the researchers say.

The team, led by OSU horticulture professor Larry Daley and graduate student Li Ning, has designed and built a better spectrofluorometer, a machine that is able to record very subtle changes in the fluorescent light given off by leaf tissue that has just been exposed to sunlight.

Once recorded, the different intensities of fluorescent light are translated by the instrument and rendered on a computer screen as colors visible to the human eye.

"The advantage of this technology is that it reads light from individual leaves," Daley says. "Other photo technologies used in horticulture, such as infra-red photography, are sensitive only to large planted areas such as sections of crop fields."

Eventually, Daley believes, an instrument similar to the spectrofluorometer could be deployed by a satellite in orbit around the earth. Then the information it records would be used to warn crop producers of pest insect or disease problems invading their fields.

"Down-to-earth application of this technology will make it possible to pinpoint a problem in a crop field when it is still very localized, perhaps even to a single plant," he says.

"Producers who have this kind of early warning system available to them," he adds, "will be able to limit pesticide treatments to a few plants rather than having to spray a whole field to make sure they covered the affected area."

Daley noted that the spectrofluorometer is a product of "very effective collaboration" with James Callis, a University of Washington analytical chemist; Gerry Edwards, a Washington State University plant physiologist; and Garry Strobel, a plant pathologist at Montana State University.

Bites and Bytes Steer Observers to Grasses

Researchers who monitored every bite have determined that steers at the Eastern Oregon Agricultural Research Center at Burns like the crested wheatgrasses Hycrest II and Nordan the best of eight grass varieties tested.

In fact, the steers preferred the two varieties by such a big margin that the researchers suggest Hycrest II and Nordan as "excellent candidates for pasture reclamation or establishment in beef production programs" in similar arid grasslands.

Oregon State University and and the U.S. Department of Agriculture's Agricultural Research Service operate the research center. David Ganskopp, a USDA scientist, led the project, which compared the two crested wheats and the grasses Goldar, Bannock, Secar, Bozoisky, Magnar and Trailhead.

"All the varieties provided suitable forage for cattle through the growing season and into early dormancy," Ganskopp says.

But, he adds, Hycrest II and Nordan are the best choices because of their proven ease of establishment, competitive ability, nutritional value, grazing tolerance and palatability.

Steers like them better, too. This was determined by how often steers "visited" and bit into those varieties compared to the others.

To track steer preference, each grazing steer was accompanied by an observer with a backpack-mounted platform and a lap-top computer. The observer tallied each bite.

"When grasses were green, Hycrest II was clearly the most preferred forage, with 31 percent of total bites," Ganskopp says. Next, in order, were Nordan, Goldar, Bannock and Secar.

When grasses were "cured" (mature and no longer growing), steers were less selective. Five varieties were acceptable: Hycrest II, Nordan, Bannock, Goldar and Bozoisky. Magnar and Trailhead were avoided by the steers and accounted for less than 5 percent of the total bites.

Will the Mystery Bird Come Back?

Oregon State University biologists are unraveling some of the mysteries of the band-tailed pigeon, a little-known native bird that has declined in numbers since the 1950s but may be staging a comeback.

The population of the band-tailed pigeon in Oregon is thought to be between 500,000 and 2.5 million. Its primary territory is along the coast. But the bird once was much more common in western Oregon, explains Bob Jarvis, an OSU professor of wildlife ecology.

"They are now at their lowest levels since monitoring began in the early 1950s," says Jarvis.

A pigeon sits in a fir tree.

A band-tailed pigeon nesting in Oregon's Coast Range mountains. Photo: Bob Jarvis

He and his graduate students started studying the bird in the early 1970s. Over the years, Jarvis and his students have discovered:

  • The western Oregon population of band-tails feeds almost exclusively on elderberries and cascara berries while nesting. Therefore, optimal nesting success pretty much overlaps the season when these berries are available, June through October.
  • While elderberries and cascara berries are nutritious, they contain little calcium, essential for reproduction and growth. To fill their need for calcium, Pacific Northwest band-tailed pigeons need calcium springs or seeps in their nesting habitat.

Locating, then studying more than 150 nests in the Oregon Coast Range, Jarvis and student Jerome Leonard found that band-tailed pigeons use a wide variety of nesting habitats. They range from saplings and tree farms to mature forests, from 10 to 150 feet high, and from Douglas fir to vine maple in mature timber.

"Their nest is a platform of sticks-nothing very fancy," says Jarvis. "We found out they like to nest in thick areas with lots of small branches-areas where the canopy has lots of depth. This might discourage hawk or owl predators."

Other findings:

  • Most band-tails nest twice per season. They lay one egg at a time, which hatches after about 20 days of incubation. Young are ready to leave the nest in another 25 days. "We found that later nesters were more successful than early nesters. We think that corresponds to the abundance of berries."
  • Both the male and female pigeons incubate the nest. The birds return to the same area to nest year after year.

More studies are underway.

"We want to find out the relative importance of nesting, feeding and mineral springs habitats to these birds," explains Jarvis, who is working with doctoral student Todd Sanders. "Are nesting habitats more important to the bird than mineral springs? Than feeding habitat? And how much of each do they need? How close together do the three habitats need to be?

"We want to know so we might be able to explain why the populations are declining and how future landscape changes might affect this bird. Forest environments will change in the future and we would like to be able to predict how band-tails will respond to those changes.

"There is some evidence from recent Oregon Department of Fish and Wildlife counts at mineral sites," notes Jarvis, "that they may be starting to make a comeback. But it's too early to jump to conclusions. We need 10 years' data."