Linking Animal Behavior to Useful Natural Repellents

A little monkey business is revealing a few clues about natural remedies that animals use to protect themselves against biting insects and arthropods. Certain species of animals, such as monkeys and birds, anoint themselves with citrus, other plants, and creatures like millipedes. To find out more about this behavior and to determine if any chemicals in the anointing substances effectively deter ticks and mosquitoes, scientists are examining responses to natural compounds. Scientists at the Agricultural Research Service Henry A. Wallace Beltsville [Maryland] Agricultural Research Center (BARC) and the Smithsonian Conservation Biology Institute (SCBI) at the National Zoological Park in Front Royal, Virginia, compared the effects of citrus compounds on lone star ticks and yellow fever mosquitoes. They also investigated compounds found in millipedes. Citing Citrus Effects “We tested a number of components known to be abundant in all citrus extracts, not just lemons, limes, and oranges, but all the fruits that are used in anointing— including citrus leaves,” says SCBI researcher Paul Weldon. Of the more than 20 citrus compounds they evaluated, the scientists found that 10 deterred ticks and/or mosquitoes, and 9 impaired basic tick behavior. Weldon used a feeding membrane module that he developed to test citrus compounds against mosquitoes. Some compounds were very effective. But the same compounds were not effective at all when mosquitoes were exposed to them in a wind tunnel module by chemist Ulrich “Uli” Bernier, in the Mosquito and Fly Unit at the ARS Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, Florida. “We viewed the results of the wind tunnel as being more authentic,” Weldon says. “The compounds didn’t affect mosquitoes that much, but mainly affected ticks. It was a step forward in pinpointing what we believe is the reason that animals anoint themselves with citrus substances.

Linking Animal Behavior to Useful Natural Repellents

A little monkey business is revealing a few clues about natural remedies that animals use to protect themselves against biting insects and arthropods. Certain species of animals, such as monkeys and birds, anoint themselves with citrus, other plants, and creatures like millipedes. To find out more about this behavior and to determine if any chemicals in the anointing substances effectively deter ticks and mosquitoes, scientists are examining responses to natural compounds. Scientists at the Agricultural Research Service Henry A. Wallace Beltsville [Maryland] Agricultural Research Center (BARC) and the Smithsonian Conservation Biology Institute (SCBI) at the National Zoological Park in Front Royal, Virginia, compared the effects of citrus compounds on lone star ticks and yellow fever mosquitoes. They also investigated compounds found in millipedes. Citing Citrus Effects “We tested a number of components known to be abundant in all citrus extracts, not just lemons, limes, and oranges, but all the fruits that are used in anointing— including citrus leaves,” says SCBI researcher Paul Weldon. Of the more than 20 citrus compounds they evaluated, the scientists found that 10 deterred ticks and/or mosquitoes, and 9 impaired basic tick behavior. Weldon used a feeding membrane module that he developed to test citrus compounds against mosquitoes. Some compounds were very effective. But the same compounds were not effective at all when mosquitoes were exposed to them in a wind tunnel module by chemist Ulrich “Uli” Bernier, in the Mosquito and Fly Unit at the ARS Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, Florida. “We viewed the results of the wind tunnel as being more authentic,” Weldon says. “The compounds didn’t affect mosquitoes that much, but mainly affected ticks. It was a step forward in pinpointing what we believe is the reason that animals anoint themselves with citrus substances.

A Dose of Selenium That Goes a Long Way

In western parts of the United States where some rugged ranges can only be reached by horseback, ranchers often find themselves saddling up weekly to deliver mineral supplements to livestock grazing in nutrient-deficient regions, especially areas scarce in selenium. The routine is not only time-consuming but also costly, and in some leased-land arrangements, such supplementation practices are prohibited. Selenium, a trace mineral and component of important selenoprotein antioxidants, is essential for good health in livestock and humans. If the body cannot form these important antioxidant proteins, it predisposes the animal to sickness and eventually death at a young age. Selenium deficiency in livestock affects more than 35 states and costs sheep, beef, and dairy producers an estimated $545 million in losses each year. Lack of adequate selenium in sheep reduces conception rates, increases neonatal mortality, and in some instances, causes white muscle disease—nutritional muscular dystrophy. Lambs that do survive suffer from increased disease, reduced weight gain, and impaired performance

Metagenomics Offers Insight into Poultry Diseases

Less than 10 years ago, the world marveled at the completion of the human genome project, which involved traditional technology to identify all the genes in a single organism—the human. Today, a more powerful technology is being used to detect thousands of organisms in an entire community. Unlike traditional gene sequencing, the new molecular technique—metagenomics— eliminates the need to cultivate and isolate individual microbial species. Scientists can apply genomic analysis to mixed communities of microbes instead of to just one organism. For example, researchers examining viral enteric (intestinal) diseases in poultry can take intestinal samples from different poultry flocks. The material can be processed to sequence all the viral nucleic acid—RNAand DNA—in the sample and then analyzed as a single genome

Recognizing the Threat of Leptospirosis

“The disease in humans can often be an acute infection,” says lead scientist Richard Zuerner, a former microbiologist with the Agricultural Research Service’s National Animal Disease Center (NADC) in Ames, Iowa. “In areas where it is endemic, like Brazil, it occurs on a periodic basis, and a portion of those infected will experience pulmonary hemorrhage, which can lead to a very rapid and painful death.” Leptospirosis in livestock can cause abortions, stillbirths, reduced milk production, and lower fertility, Zuerner says. In horses, it can also result in uveitis, a potential cause of blindness. Less is known about leptospirosis in wildlife, such as California sea lions, but scientists are finding out how the disease is spread in these mammals, exploring vaccines for cattle that carry the virus, and using hamsters as models to better understand leptospirosis

Temperament Plays Key Role in Cattle Health

Do you know someone who’s temperamental? What about an animal? Amazingly, cattle can be temperamental too, which influences how they should be handled, how they perform, and even how they react to viruses that cause diseases. For cattle, temperament is defined as the reactivity or fear response to humans or handling. Terms used to describe temperamental animals include “flighty,” “excitable,” and “high strung.” These animals can potentially injure themselves or their handlers. Beef cattle experience stressful events during routine management practices— weaning, transportation, social mixing, and vaccination. These practices have been shown to induce secretion of the stress-related hormones cortisol and epinephrine. Stress can negatively affect growth, reproduction, welfare, and immune function— predisposing cattle to infectious intestinal and respiratory diseases that cost U.S. cattle producers an estimated $500 million per year. Reducing adverse consequences of stressful incidents and identifying animals that may react differently to stressors may benefit cattle’s growth and health. A team of scientists in the Agricultural Research Service’s Livestock Issues Research Unit (LIRU) in Lubbock, Texas, Mississippi State University (MSU), and Texas AgriLife Research—a member of the Texas A&M University System—are studying interrelationships of stress and cattle temperament with transportation, immune challenges, and production traits. They have found that, depending on temperament, cattle respond differently. Testing Temperament Most studies were done shortly after weaning to emulate what happens in the industry, says Ron Randel, animal physiologist at the Texas AgriLife Research and Extension Center in Overton, Texas. One of the most stressful times for an animal is after it is weaned. The team was among the first in the United States to adopt and use the exit velocity system developed in Australia, Randel says. The system measures the rate at which an animal exits a squeeze chute or scale box where it’s been restrained or held after transport. A fast exit indicates the animal is showing fear and is stressed by handling and human activity. Scientists also used pen scoring, a subjective measurement in which small groups of cattle are scored based on their reactions to a human observer. Scores range from 1—calm, docile, and approachable, to 5—aggressive and volatile

Rooting Out a Novel Stress Syndrome in Pigs

Undergoing surgery, even a minor procedure, can be stressful for anyone. But for people who have malignant hyperthermia, a hereditary disease that’s triggered by certain drugs used for general anesthesia, it can also be dangerous. Research into this rare, life-threatening condition, which causes a fast rise in body temperature, severe muscle contractions, and sometimes death, was limited until the discovery of a similar disorder in pigs, referred to as “porcine stress syndrome.” The classical syndrome is associated with poor response to stressors like transport and with poor-quality pork. It has been eliminated from commercial herds in the United States, but stress-related issues, most often associated with transportation, continue to cause substantial losses—an estimated $50 million per year—to the U.S. swine industry. These issues indicate that there may be another stress-related syndrome affecting the health and well-being of pigs in the United States. In response to these concerns, scientists at the Agricultural Research Service’s Roman L. Hruska U.S. Meat Animal Research Center (USMARC) in Clay Center, Nebraska, have identified a previously undetected genetic stress syndrome that is most likely affecting the swine industry. They are mapping the defect in pigs to get to the root of the problem

New Discovery Makes Detecting Johne\u27s Disease Easier

Before a disease can be treated, it must first be identified. But that’s not always easy, especially in the case of Johne’s disease, which affects cattle, sheep, goats, deer, and other ruminants. Johne’s disease—also known as “paratuberculosis”— is a costly, contagious disease that causes diarrhea, reduced feed intake, weight loss, and sometimes death. Annual estimated losses to cattle producers range from $40 to$227 per infected animal. For the U.S. dairy industry alone, losses exceed $220 million each year. For years, scientists have been hampered by the fact that any antibody—a protein produced by the immune system to fight infections and foreign substances—used to detect the Johne’s disease bacterium also reacted to other environmental bacteria or maybe the pathogen responsible for bovine tuberculosis. This caused false-positive test results. “You may think cattle are infected, based on a positive antibody test result, but they may simply have been exposed to nonpathogenic mycobacteria that’s ubiquitously present in the environment,” says microbiologist John Bannantine at the Agricultural Research Service’s National Animal Disease Center (NADC) in Ames, Iowa. That problem, however, is now history. Bannantine and his colleagues at NADC have found an antibody that’s 100 percent specific in detecting Mycobacterium avium subspecies paratuberculosis (MAP)—the cause of Johne’s disease. “No one else in the world has been able to find such a specific antibody that binds only to MAP strains, until now,” says Bannantine, who’s in NADC’s Infectious Bacterial Diseases Research Unit

Early Weaning: A Good Bet for Beef Producers in Drought-Stricken Areas

At the beginning of 2013, cattle-ranchers in the Northern Plains were among U.S. agricultural producers still feeling the lingering effects of the sweltering 2012 drought, the worst in half a century. Beef cow numbers were at the lowest in 50 years as U.S. beef producers—severely affected by extended drought—tried to recover from some of the driest months on record. Across the Northern and Southern Plains, beef producers hit the hardest by drought are threatened by limited forage resources for cows, which restricts calf growth, resulting in lighter calf weaning weights. In addition, drought can decrease cow body weight and condition and weaken immune functions that may affect overall health and reproductive performance

House Fly Virus Stops

The house fly is often considered merely a nuisance. But these flies are capable of transmitting animal and human pathogens that can lead to foodborne diseases, including Escherichia coli, Salmonella, and Shigella bacteria. Insecticides are important for control, but house flies are particularly good at developing resistance, and their larvae tend to stay deep enough within their gooey food to avoid exposure to sprays. Scientists at the Agricultural Research Service’s Center for Medical, Agricultural, and Veterinary Entomology (CMAVE) in Gainesville, Florida, are looking at new methods that target adult flies. A promising biological control agent—salivary gland hypertrophy virus (SGHV)—was recently discovered. Once infected with the virus, female flies do not produce eggs, and male flies do not mate. Entomologist Chris Geden in the Mosquito and Fly Research Unit at CMAVE partnered with scientists at the University of Florida (UF) and Aarhus University in Denmark to study the distribution and host range of the virus as well as the effectiveness of different application methods