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Social rank and feed intake important for pregnant sows in group housing

Published September 25, 2017
Janeen Johnson

URBANA, Ill. – Eleven states and several large pork producers are moving away from gestation crates for sows, but the effects of alternative housing designs on the sows’ reproductive performance are unclear. In a new article, an animal welfare expert from the University of Illinois takes a closer look at group housing.

“Reproductive performance has always been a metric that people have been concerned about with housing,” says Janeen Salak-Johnson, an associate professor in the Department of Animal Sciences at U of I.

Most previous research suggests reproductive performance is approximately equal in group housing versus individual stalls, but in real-word scenarios, many producers notice compromised reproduction in group pens. Most sows are put into group housing after pregnancy is confirmed, so the effects of the transition usually manifest in low birthweight piglets or fewer piglets, rather than an impaired ability to become pregnant or stay pregnant.

“That’s one of the big reasons people don’t see effects of group housing on reproductive success – the sows are already pregnant. But that doesn’t mean there aren’t potential effects on the litter during the course of the pregnancy,” Johnson says.

Differences in design, size, feeding system, and number of animals in group pens may have a huge impact on stress levels – and therefore reproductive performance – but no one has successfully identified the factors that have the biggest impact. 

“You can’t just look at individual versus ‘group housing,’ because group housing means something different to every producer. There is no one set standard,” Johnson says. “And nobody has done direct comparisons between things like floor space or group size to determine the best designs.”

In her article, Johnson examines the effects of group housing on reproductive success for pregnant sows in the context of stress, touching on competitive versus non-competitive feeding systems, group size, floor space, and social rank.

The relationships between group housing variables are complex, but Johnson says maintaining reproductive performance boils down to social rank and feed intake.

Aggression is strongest when animals are first mixed into groups and during feeding, especially if competitive feeding systems such as floor feeding are used. However, if too much emphasis is placed on protecting submissive sows during feeding, for example by using long feeding stalls, dominant sows can experience negative reproductive outcomes.

“If dominant sows are not able to assert their dominance during feeding by displacing submissive individuals, they get frustrated,” Johnson says. “That can lead to low birthweight piglets. Short feeding stalls offer some level of protection, but also allow dominant sows to exhibit normal behavior.”

Johnson’s article concludes that the wide variation in group housing designs makes it difficult to provide research-backed recommendations for producers, but she does have some ideas.

“Maybe we start grouping them by body weight, parity, or speed of feed intake. Heavier sows eat much faster. Maybe put them all together,” Johnson says. “You’re still going to have a dominant sow and a submissive sow, but if you bring your composite groups closer together, I think you have an opportunity to do a better job in reducing this variation that occurs in group housing.”

The article, “Social status and housing factors affect reproductive performance of pregnant sows in groups,” is published in Molecular Reproduction and Development. The work was supported by the National Pork Board, grant no. 12-200.

Corn prices unlikely to find support from Sept. 1 Stocks Report

Published September 25, 2017

URBANA, Ill. – Corn prices continue to reflect the presence of a large, old-crop ending stock and higher-than-expected corn production. The USDA will release the Quarterly Grain Stocks report on Sept. 29. The report will provide an indication of corn use during the fourth quarter of the 2016-17 marketing year. According to University of Illinois agricultural economist Todd Hubbs, corn prices are unlikely to find any support with the release of the report on Friday.

Hubbs says an estimate of corn exports for the fourth quarter is based on the cumulative weekly export inspections estimate available for the entire quarter. Cumulative marketing-year export inspections through August totaled approximately 2,240 million bushels. During the first 11 months of the marketing year, total Census Bureau corn exports were greater than cumulative export inspections by 49 million bushels.

“Assuming the margin is maintained through August, corn exports through the marketing year equaled 2,290 million bushels,” Hubbs says. “Because exports in the first three quarters of the marketing year totaled 1,771 million bushels, the estimate for third quarter corn exports equals 519 million bushels.”

The Grain Crushing and Co-Products Production report released on Sept. 1 estimated corn used for ethanol and co-product production during June and July of 2017 at 889 million bushels.  Weekly estimates of ethanol production provided by the Energy Information Administration indicates ethanol production increased by 2.7 percent in August 2017 from the preceding year. 

“By calculating the amount of corn used to produce ethanol from these August numbers, corn used for ethanol production in August was approximately 470 million bushels,” Hubbs says. “Total use for the quarter is estimated at 1,360 million bushels.”

Corn used to produce other food and industrial products during the 2016-17 marketing year is estimated at 1,435 million bushels by the USDA.

“Using historical corn use data, typically around 25 percent of the final marketing year, food and industrial products use occurs in the last quarter of the marketing year,” Hubbs says. “If this historical pattern holds and the USDA projection is correct, corn use for the fourth quarter of the marketing year totaled 359 million bushels.” 

The current USDA projection for feed and residual use sits at 5,425 million bushels. Hubbs says the projection for feed and residual use declined by 250 million bushels during the current marketing year. Use during the first three quarters of the marketing year totaled 4,780 million bushels. To reach the projection for the year, fourth quarter feed and residual use must equal 645 million bushels.  The historical pattern of feed and residual use in corn may provide some indication of the fourth quarter use.

“For the five previous marketing years, use during the fourth quarter of the marketing year ranged from 5.7 to 12.5 percent of the marketing-year total, with an average of 8.4 percent,” Hubbs says. “Due to expansion in the livestock sector, an increase of corn used in feed is expected during this quarter. For this analysis, a percentage in the higher end of the range during the previous five marketing years is used to calculate expected feed and residual use during the fourth quarter. Feed and residual use during the fourth quarter of the 2016-17 marketing year is calculated at 653 million bushels.” 

The supply of corn available on June 1 of the 2016-17 marketing year is the base for estimating Sept. 1 stocks, Hubbs says. Corn stocks at the beginning of the quarter were estimated at 5,225 million bushels in the June Grain Stocks report. Currently, the Census Bureau estimates for corn imports are only available through July. In the first three quarters of the marketing year, corn imports totaled 39.4 million bushels.

“Imports for the fourth quarter might have been around 11 million bushels,” Hubbs says. “By combining imports with the beginning stocks, total available supply for the fourth quarter comes in at 5,236 million bushels.”

By adding the estimates for exports and domestic uses, the total use of corn during the fourth quarter is estimated at 2,891 million bushels. The total use estimate for the fourth quarter places Sept. 1 corn stocks at 2,345 million bushels. At this level, Sept.1 stocks come in 5 million bushels smaller than the projected Sept.1 corn stocks.

“A Sept. 1 corn stocks estimate that supports the USDA projection of 5,425 million bushels of feed and residual use during the 2016-17 marketing year is considered neutral for corn prices,” Hubbs says. “This analysis indicates a Sept. 1 corn stocks estimate near 2,345 million bushels should not change expectations that feed and residual use is on track to meet the marketing-year projection and provides support for the current 2016-17 corn ending stock produced by USDA. For corn prices to find strength, either a change in current corn production forecasts or a new source of demand must occur to change the fundamentals associated with current corn prices in the near term.”







Illinois corn and soybean harvest considerations

Published September 20, 2017

URBANA, Ill. – The USDA’s September predictions for Illinois corn and soybean yield are 189 and 58 bushels per acre, respectively. According to University of Illinois agronomist Emerson Nafziger, these are good yields after the challenges of the 2017 season. As we head into harvest, Nafziger provides considerations for farmers looking to minimize last-minute yield losses.

“While we don’t expect as many yields in the 80-90 bushel range as we had in 2016, pod numbers in many fields are higher than expected after the dry weather in August and September,” Nafziger says. One reason is the cooler temperatures in recent weeks; with water use lower under cooler temperatures, plants avoided the premature leaf drop that sometimes signals an early end to seed filling. Rain might help boost yields a bit, but only in fields planted late or with late-maturing varieties where plants are still green.

With high temperatures predicted for the rest of the week, seeds and pods of maturing soybeans will dry within hours, rather than days. “We need to be alert and ready to harvest as soon as plants can be cut and seed moisture drops to 13 percent,” Nafziger says. “If moisture drops to 10 percent or less during harvest, it might be worth stopping until pods and seeds take on some moisture in the evening or overnight.”

Breeding and the use of improved combine headers have reduced pod shatter at harvest, but soybean seeds with less than 10 percent moisture can crack, lowering grain and seed quality.

“Harvest is getting underway at about the same time for both corn and soybean this year, but there might need to be frequent switching between the two crops as harvest progresses in order to maximize quality and minimize losses,” Nafziger says. 

Nafziger notes that the corn crop in many fields is looking better than expected. As of Sept. 17, five percent of the state’s corn crop had been harvested, mostly in the southern half of the state. So far, reported yields have been highly variable, reflecting differences in planting (or replanting) time, soil water-holding capacity, and precipitation during critical times throughout the season.

When lack of water lowers photosynthetic rates, sugars are pulled out of the stalk into the ear to fill the grain, leaving stalks more susceptible to stalk-rotting fungi and lodging. Nafziger recommends that farmers should check fields for stalk strength, especially where leaves dried earlier than expected. However, good growing conditions in July likely increased the deposition of stalk-strengthening lignin, making stalks less likely to break. “As long as winds stay relatively calm, lodging is not expected to be much of a threat, especially in those parts of the state that received more rainfall in July and August,” he says.

Most of central and northern Illinois are approximately 150 growing degree days (GDD) behind normal since May 1. According to Nafziger, below-normal temperatures in recent weeks have slowed grain-filling rates and delayed maturity of the corn crop. But the cooler temperatures probably have been positive for yields by extending the water supply into mid-September. “With GDD accumulation rates above normal now, a lot of fields will reach physiological maturity quickly, and grain will start to dry down. High temperatures mean rapid grain moisture loss.  We’ve seen corn grain lose moisture as much as one percentage point of moisture per day under high temperatures, especially if it's breezy,” he says.

Dry conditions over the past month have limited the spread of ear rots. “Most kernels have the bright yellow color of healthy grain, and if the grain can be harvested without an extended period of wet weather, we expect grain quality to be good. Harvesting at high moisture, drying at high temperatures, or storing grain without proper care can all compromise quality, however,” Nafziger says. “While we like to finish harvest early, the threat of loss in yield or quality from delaying harvest to October is low. But waiting too long isn’t good, either; delaying harvest until grain moisture drops below 16 or 17 percent can increase loss due to shelling of kernels onto the ground as ears go into the combine.”

Nafziger notes that test weight is an issue that comes up every year during corn harvest. He says test weights lower than the standard of 56 pounds per bushel have many people thinking that something went wrong during grain fill. Likewise, above-normal test weights are often taken as a sign that kernels filled extraordinarily well, and that yield was maximized. “Neither of these is very accurate – high yields often have test weights less than 56 pounds, and grain from lower-yielding fields can have high test weights,” he says.

Test weight is bulk density – it measures the weight of grain in 1.24 cubic feet, which is the volume of a bushel. Kernel density is the weight of a kernel divided by its volume, not including air the way bulk density does. Kernel density is a more useful measure of kernel soundness and quality than is test weight – it’s often used by the food corn processing industry – but it is harder to measure than test weight.

“A typical kernel density might be 90 pounds per ‘bushel’ (1.24 cubic feet) of actual kernel volume,” Nafziger explains. “So, a 56-pound bushel of corn grain is about 62 percent kernel weight and 38 percent air. Kernels with higher density tend to produce higher test weights, but only if they fit together without a lot of air space. For example, popcorn has small, high-density kernels that fit together well, and its test weight is typically 65 pounds per bushel.”

Hybrid genetics, growing conditions, and grain moisture at the time it is weighed can all affect test weight. If kernels appear to be well-filled without a shrunken base, which can signal that grain fill ended prematurely, it’s likely that yield was not compromised even if test weight is less than 56 pounds per bushel.

“For reasons that go back to an earlier time, though, corn test weight needs to be at least 54 pounds per bushel in order to be sold as U.S. No. 2 corn, which is the most common market class. Corn with a test weight of 52 or 53 might not be docked in price if it can be blended with higher test weight grain to reach the minimum. That’s much easier to do in a year when test weights are generally good. We expect 2017 to be such a year,” Nafziger says.

For more on the 2017 harvest, read Nafziger’s recent post on The Bulletin.

Infection in pregnant pigs leads to antisocial piglets

Published September 19, 2017
Adrienne Antonson and Rod Johnson
Adrienne Antonson and Rod Johnson

URBANA, Ill. – When a pregnant woman gets a bad case of the flu, her immune system may react in a way that affects her baby’s developing brain, which could lead to behavioral disorders like autism in the child or schizophrenia in the young adult. The link is well established in humans, which is one reason it’s standard practice to get a flu shot during pregnancy. But until now, the majority of studies testing the underlying causes have been done with rodents, including two that were released just last week.  

Some scientists think that immune cells called microglia are affected in the fetal brain when the mother’s body starts fighting an infection. Microglia play an important role in normal fetal brain development, but if their activity is altered, they could attack healthy synapses or prevent new neurons from forming. And that could increase the risk of learning or behavioral disorders after birth.

“This hypothesis has been supported by research in rodents, but brain development and morphology in rodents are quite different than in humans. The goal in our study was to test this hypothesis in domestic pigs because their brains develop similarly to humans,” says Rodney Johnson, professor of integrative immunology and behavior in the Department of Animal Sciences at the University of Illinois.

Adrienne Antonson, a doctoral student working with Johnson, and lead author of the new study, gave pregnant pigs a virus that causes flu-like symptoms and then compared piglets from those mothers with piglets from mothers that were not infected during pregnancy. “We wanted to understand how the mother’s immune response impacted the piglets’ behavior and their own immune responses to later infections,” she says.

The researchers looked at the piglets’ immune response to E. coli lipopolysaccharide (LPS) – a molecule given to mimic a bacterial infection. They expected piglets from infected mothers to have an exaggerated immune response to LPS, but that’s not what happened. Their immune systems functioned normally. But that was only the first surprise.

Because people with autism and schizophrenia often struggle with learning difficulties and social scenarios, the researchers wanted to assess those abilities in the piglets as well. In a spatial learning task, piglets had to find their way to a chocolate milk reward using visual cues – in this case, SpongeBob SquarePants and Mario Kart posters placed in different spots around a simple maze.

“They learn to locate their reward whether it’s next to the SpongeBob poster or Mario Kart. Instead of learning to come out of their start box and just turn left, we alternate what side the reward is on. So they have to learn instead of going left every time, they have to turn according to SpongeBob and Mario,” Antonson says.

Again, the researchers were surprised to find that the piglets completed the task just fine whether or not their mothers had been infected during pregnancy. The result suggested that the hippocampus, the brain region responsible for spatial learning, was largely unaffected in piglets from infected mothers. But Johnson says more research is needed to confirm their suspicion.   

Like humans, pigs are highly social animals that usually prefer the company of others to isolation. Individuals with autism and schizophrenia, on the other hand, tend to isolate in social situations. So, in the last test, researchers gave piglets the choice of meeting a stranger or spending time alone.

Piglets were placed in an arena with two crates separated by an empty space. When a stranger piglet was placed in one of the crates, the researchers watched to see if the study piglets chose to visit the stranger or not. After about 10 minutes, another stranger was added to the second crate. If the piglet spent significantly more time with the new stranger, it would have been showing a preference for “social novelty,” a common behavior in social species.

In this test, an important effect of maternal immune activation was revealed. Unlike piglets from healthy mothers, piglets whose mothers had infections during pregnancy stayed away from the strangers.

Following the behavioral tests, the researchers examined microglial cells to see if there were differences between piglets whose mothers had an infection during pregnancy and those that came from healthy mothers.

“I think the most important finding is that the antisocial behavior caused by maternal immune activation was not accompanied by a change in microglial cell activity after birth,” Johnson says. “If microglial cells are contributing to antisocial behavior, those changes are likely happening in utero. It’s possible microglia become activated during maternal immune activation, alter fetal brain development, and then return to normal before birth.” 

Antonson’s next project is to look at what’s happening in the brains of fetal pigs during the maternal infection, to try to pinpoint changes in real time.

The researchers are quick to point out that getting an infection during pregnancy does not guarantee the occurrence of neurodevelopmental problems in children. Instead, it’s all about levels of risk.

“We all know we’re supposed to wear seat belts,” Johnson says. “If I don’t put on my seat belt when I go home tonight, does that guarantee I’m going to die in a crash? Of course not. It just increases the likelihood, should an entire sequence of unfortunate events occur. It’s not a guarantee. It just adds risk.”

Antonson adds, “You have to mount a pretty significant immune response to see something like this. If it’s a less severe infection, it’s likely not going to trigger the same responses.”

The article, “Maternal viral infection during pregnancy elicits anti-social behavior in neonatal piglet offspring independent of postnatal microglial cell activation,” is published in Brain, Behavior, and Immunity. Additional authors of the study include Emily Radlowski, Marcus Lawson, and Jennifer Rytych, all from U of I. The project was supported by a “Dual Purpose with Dual Benefit” grant program administered through the National Institutes of Health and the U.S. Department of Agriculture.

Corn gluten meal needs a name change. Where’s the gluten?

Published September 18, 2017
corn stalks

URBANA, Ill. – One coproduct from wet milling corn is corn gluten meal—a high-protein ingredient used in many pet foods and livestock feed. By the name of the coproduct, one would think that corn gluten meal contains gluten, when in fact, it contains 60 to 70 percent protein and is 100 percent gluten free. It’s a misnomer. There is no gluten in corn gluten meal.

According to University of Illinois food engineer Kent Rausch, it’s clear. “This is a textbook fact. Wheat contains gluten. Corn does not. There has never been any reason why corn gluten meal and another wet milling coproduct, corn gluten feed, should contain the word gluten. Gluten is found in wheat, barley, and rye—not in corn or corn coproducts.”

Rausch says because corn wet mills exclusively process corn grain only—no wheat, and therefore no gluten—there isn’t even a concern about the possibility of cross contamination present to cause contamination of corn gluten meal or corn gluten feed.

So, how did the word creep in? Rausch says the story goes that one of the early corn processors hired someone from a wheat gluten processing facility. “He just called everything that had protein in it ‘gluten.’ But I’ve never seen anything in writing to verify the story.”

Some animal food processors would like to see the name officially changed to something more accurate and to avoid any confusion on the part of consumers. Rausch says pet and livestock owners see corn gluten meal in the list of ingredients on feed labels and have questioned it, assuming that it’s the same as the gluten linked to celiac disease in humans.

When you think about the texture of yeast breads that contain gluten, it’s obvious that corn doesn’t have it. That’s why cornbread has the consistency it does—no gluten equals drier and more crumbly—compared to wheat bread with gluten that’s stretchy.

“It’s ironic that corn protein is a great source of gluten-free protein but everything in the wet milling process has the term ‘gluten’ attached to it. If the name could be changed, it would be a lot less confusing,” Rausch says. “Every year during our wet milling workshop at the U of I, we have representatives attending who are confused by the names and whether gluten is in corn.  These are people that actually work in the wet mills.”

Rausch says it’s up to the Association of American Feed Control Officials to change the name. AAFCO is responsible for creating ingredient definitions for animal food products.

With gluten allergies in the health spotlight and more and more gluten-free products being produced, now would be a good time to clarify the term and confirm the absence of gluten in corn and corn products. “It would certainly stave off the confusion,” Rausch says.

Kent Rausch is an associate professor in the Department of Agricultural and Biological Engineering in the College of Agricultural, Consumer and Environmental Sciences at U of I.  


Corn and soybean production outlook in 2017-18

Published September 18, 2017

URBANA, Ill. – Given the price reaction, the market remains uncertain about the USDA’s September forecast of 2017 corn and soybean production. November 2017 soybean futures closed at $9.68 on Sept.15, down 7 cents on the day but up from the $9.61 close of a week ago.  Despite the increase in corn yield, December corn futures prices stayed in a tight range between $3.53 and $3.55 to close out the week.

USDA’s September soybean production forecast for 2017 came in at 4,431 million bushels, up 50 million bushels over the August forecast. Yield per harvested acre increased to 49.9 from the August forecast of 49.4. Compared to the August forecast, yield prospects for the top ten states in soybean acreage increased in Indiana, Iowa, Kansas, North Dakota, South Dakota, and Ohio.  Yield prospects declined in Minnesota and Nebraska, although they remained the same for Illinois and Missouri. 

Despite the increased production forecast, total supply for the 2017-18 marketing year increased only 24 million bushels to 4.801 billion bushels. According to University of Illinois agricultural economist Todd Hubbs, the smaller supply increase was due to lower beginning stocks for the marketing year. Soybean crush and export estimates for the 2016-17 marketing year increased and lowered ending stocks by 25 million bushels to 345 million bushels.

The USDA increased to 2017-18 soybean export forecast by 25 million bushels to 2,250 million bushels. This left the 2017-18 ending stocks forecast at 475 million bushels, the same as the August projection.

“The seasonal average price for soybeans projected by the USDA is down 10 cents with a range of $8.35 - $10.05,” Hubbs says. “If production issues do not materialize, the rate of consumption for this large crop will be paramount. The ample supply of soybeans places an increased emphasis on the ability to export soybeans throughout the marketing year and brings South American production prospects in focus.”

South American production for the 2017-18 marketing year is forecast to be 6,570 million bushels, down 4.7 percent from last year’s estimate, Hubbs says. The projected size of the Brazilian soybean crop decreased by 257 million bushels to a production level of 3,931 million bushels.

“Current reports out of Brazil indicate dry weather is delaying the start of the planting season in many areas,” Hubbs says. “A weather outlook for Brazil indicates continued dryness, which may delay planting even longer and have implications for second crop corn planting in the region.” 

The soybean production forecast for Argentina decreased 1.4 percent from last year’s estimate to 2,094 million bushels. Wet weather appears to be influencing Argentine soybean planting. 

The Rosario Grain Exchange set soybean production within the country at 2,002 million bushels, down almost 5 percent from last year on tight margins for Argentine producers. World soybean production for 2017-18 marketing year came in at 12,803 million bushels, down 0.9 percent from last year. World ending-stocks [QLD1] projections decreased 9 million bushels from August projections to 3,584 million bushels, but are up 58 million bushels from the 2016-17 marketing year estimate. 

For corn, Hubbs reports that USDA’s September production forecast for 2017 came in at 14,184 million bushels, up 31 million bushels over the August forecast. Yield per harvested acre increased to 169.9 from the August forecast of 169.5. Compared to the August forecast, yield prospects for the top 10 states in corn acreage increased in Illinois, Ohio, Missouri, North Dakota, and South Dakota. Yield prospects declined in Indiana, Iowa, Minnesota, and Nebraska and remained the same for Kansas. 

According to Hubbs, total supply for corn during the 2017-18 marketing year was forecast to increase 12 million bushels to 16.585 billion bushels. The ending stocks estimate for the 2016-17 marketing year decreased by 20 million bushels to 2,350 on stronger exports and ethanol use. The USDA increased to 2017-18 feed and residual use forecast by 25 million bushels to 5,475 million bushels. Food, seed, and industrial consumption was lowered 75 million bushels on lower ethanol and industrial use. This left the 2017-18 ending stocks forecast at 2,335 million bushels, up from the August projection of 2,273 million bushels. USDA’s forecast for the seasonal average corn price also decreased 10 cents in a range of $2.80 -$3.60.

“Production issues or sharp demand increases will need to materialize to exceed this range during the current marketing year,” Hubbs says.

World production projections for 2017-18 decreased 3.6 percent from last year’s estimates to 40.65 billion bushels. The September world ending-stocks projection increased slightly to 7,971 million bushels for the 2017-18 marketing year and is down 964 million bushels from the 2016-17 marketing year estimate. The projected size of the Brazilian corn crop remained at 3,740 million bushels, down 3.5 percent from last year. Corn production projections for Argentina during the 2017-18 marketing year currently sit at 1,653 million bushels, up 5 percent from August projections and 2.4 percent from this year’s estimates. Chinese production is forecast at 8,464 million bushels, down 2.1 percent from last year’s estimate.

“The reduction in production combined with a projected decrease in ending stocks in China by 787 million bushels encapsulates a majority of the ending-stocks decrease forecast for the world,” Hubbs says.

The current weather outlook for the next 8-14 days projects warmer temperatures and more precipitation over many areas of the Corn Belt. “The drought monitor released on Sept. 12 indicated abnormally dry to drought conditions over large areas of Kansas, Iowa, Illinois, North Dakota, and Missouri,” Hubbs says. “Recent dryness may limit yield potential for soybeans and late-finishing corn in these key production regions. The market now anticipates the October production forecast. Barring a significant decrease in production, both corn and soybean prices will be dependent on strong consumption throughout the marketing year.”