Additional WNV Positive Tests from Sentinel Chickens

September 30, 2014 in Uncategorized

The Delaware Department of Agriculture State Veterinarian Dr. Heather Hirst, DVM has announced that 4 additional sentinel chickens have tested positive for West Nile Virus (WNV).  Blood samples from the affected birds were obtained for testing purposes on September 21, 2014.  The sentinel birds were located in Cool Springs, Delaware Park, Cherry Island and Colonial Heights.  Horse owners and caretakers should be sure that equine vaccinations are current.  For more information on WNV and strategies for prevention, please visit a previous blog post http://extension.udel.edu/equine/2013/08/23/protect-your-horses-from-west-nile-virus/

Renovating or Planting New Pasture or Hay Field? Part 6: Managing Pasture and Hay Fields for Long-term Health

September 22, 2014 in Advice and Tips, Ask the Expert, Uncategorized

Part 6: How Do I Manage My Stand So It Stays Healthy and Productive?

In Part IV, I discussed the advantages of planting into moist soil during the ideal planting window for the selected forage species. I then discussed the planting options such as conventional seedbed preparation and no-till seeding. Along with these options, I discussed the need for calibration of the planter or drill to ensure the use of the proper number of pure live seed (PLS) per acre. Let us assume that the new planting has emerged from the soil so it is time to think about how to properly manage the new seeding to ensure a successful establishment and long-term productivity.

Usually even before the seed germinates, grazers want to know when they can return animal to the pasture to graze it. Hay producers have an easier time deciding when to begin using a new field especially for fall planted fields since cool-season grasses will signal their successful establishment by flowering in late spring or early summer the year following seeding.

For new pastures, the key to long-term health of the pasture is to wait about 12 to 18 months before grazing a new field. This means that the new pasture will need to be hayed at least once and possibly several times in the year following fall seeding. From a practical viewpoint, few grazers will wait 12+ months since it means not grazing the field until the second spring following fall seeding. At a minimum, a new fall-seeded pasture should be hayed in late spring or early summer the year following seeding and then allowed to regrow to a height of 8 to 12 inches before grazing is begun. It is possible to plant in the fall and begin grazing first thing the following spring but you will be sacrificing stand health and longevity with this practice.

Nutrient management plans call for a new soil test once every three years but a yearly sample will help the grazer manage the pasture better. This is very important if nitrogen (N) fertilizer inputs are used to stimulate the productivity of a pasture. Even without N fertilizer applications, the natural deposition of urine and feces in a pasture creates small areas where the process of nitrification produces acidity that can significantly lower soil pH in the small area. Higher stocking rates and intensive pasture rotations will result in more uniform spreading of the urine and feces (especially for ruminant animals); and therefore, a greater proportion of the pasture will be impacted by lower pH (more acid soil conditions). Since it can take a year for lime to move an inch down through the soil, yearly soil testing will allow the grazer to begin neutralizing soil acidity as it is produced by the soil N-cycle.

Another aspect of soil fertility to consider is the use of fall applied N to improve the rooting of pasture plants as well as help stimulate growth the following spring for early grazing. Although the practice has long been used in the turfgrass industry, those of us in forage management are just realizing the potential benefits to pastures of fall N applications. Small amounts of fall N (about 30 lbs N/acre) should be applied in mid-October and mid-November since at these times topgrowth has ceased but the deep soil layers are still relatively warm. The N stimulates further root growth creating pasture plants with deeper and larger root systems as they enter the winter period. Some of the N is stored in the plant and available to stimulate topgrowth the following spring as the hours of daylight increase and air temperatures warm. This type of fertilization makes for a stronger plant going into the summer months (greater rooting depth and therefore greater available soil water to draw on) and can improve the competitiveness of the pasture grasses against weeds.

Probably the number one key to maintaining the health and competitiveness of a pasture is to use rotational grazing where plants are allowed to fully recover from the prior grazing period (grow to a height of 8 to 12 inches or more) and the grazing interval is kept short enough that the same plants are not grazed over and over again during a rotation cycle. Generally, this means rotating livestock out of a paddock or grazing cell within three days of moving the animals into the paddock. This time can be stretched to as much as a week but the more rapidly the animals are moved among paddocks in the rotational grazing scheme the healthier the pasture. Another aspect to using rotational grazing is to not put animals on pasture when soil conditions are too wet when the presence of animals can lead to compaction issues. Not grazing when plants are under drought stress is also a key consideration. Use the extra forage produced during the spring and fall to make hay that can support animals on a heavy use pad during periods of wet weather, drought, or other conditions leading to poor pasture growth.

Another method used to maintain healthy and vigorous pastures is to periodically overseed pastures in the fall with grasses and/or legumes. Some producers do this every year while others do it every couple of years. In most cases, the new seedlings must compete against the established plants in the pasture so that there is often limited ‘take’ from the germinating seed. However in the weaker areas of the pasture stand, there will be more light, water, nutrients, and space for the seedlings so establishment will be better in these areas. The weak areas would be where weeds could become established but by overseeding the pastures weed encroachment is limited or prevented.

The species to use for overseeding should be those species that can grow rapidly especially in the cool conditions of late summer and early fall. This would include such species as the ryegrasses, festulolium, ladino white clover, and red clover. Although just broadcasting the seed over the surface and then using a chain harrow or other implement to slightly cover the seed has been used, the best seeding method is to use a no-till drill and drill the seed into the soil. Seeding rates typically used are about one-quarter that of a normal new pasture seeding rate since most of the seed will be planted where established plant competition will not allow the new seedlings to establish successfully.

Finally, the producer can manage the balance of legumes and grasses in the pasture by his/her fertilization practices. Potassium and phosphorus applications along with 1 to 2 lbs of boron per acre per year and maintaining a near neutral soil pH (6.5-7.0) will encourage legume growth. If the percentage of legume is too high and the risk of bloat is too great, N application to encourage grass growth can be used to lower the percentage of legume in a pasture. Grasses with their fibrous root system are much more competitive for applied N than are the tap-rooted legumes. The available N will stimulate the grass and help it shade the legumes as well as change the proportion of legume to grass biomass.

This article was submitted by Dr. Richard Taylor, Extension Agronomist, University of Delaware.  Dr. Taylor can be reached at rtaylor@udel.edu

 

Free Webinar: Disaster Preparedness for Horse Owners September 16th

September 12, 2014 in Advice and Tips, Educational Programs, Uncategorized

EXtension logoSeptember 16th- 7:00 pm EDT

When disaster strikes, a horse’s instinct and its owner’s preparation is the horse’s best chance for survival. Disaster preparation includes training your horse to load in a trailer under stressful circumstances, having an animal evacuation plan, and ensuring your horse can be identified with proper paper work. Join My Horse University and eXtension Horses FREE webinar on Tuesday, September 16th at 7 PM EDT to learn about Giving Your Horse the Best Chance During Disasters. Register for the webcast. You must register by September 15th.  A link to the meeting will be emailed to you once you register.  Presenters: Karen Waite, Michigan State University and Scott Cotton, University of Wyoming.

 

Karen WaiteDr. Karen Waite, PhD | Michigan State University

Dr. Karen Waite is an Equine Extension Specialist in Michigan and teaches and advises Equine students in the MSU Department of Animal Science. In her Extension roles she coordinates the Adult Equine Extension program, the Michigan Equine Survey, and is the Director of Leadership Development for My Horse University. In addition, she oversees the Youth Equine Extension program and is active with eXtension Horse Quest.

 

Scott CottonDr. Scott Cotton | Extension Disaster Education Network

Scott cotton is a University of Wyoming Area Agriculture Educator and Extension Disaster Education Delegate. His experience of working over two decades with three various land grant universities is combined with his previous experience as a Deputy Sheriff, Firefighter and EMT to lead him to an active role in managing animal and agriculture disaster response efforts on a number of regional and national wildfires, floods, and severe winter storms. With a family background of raising horses since the mid- 1880’s, his perspective blends research-based principles with actual field experience helping horses and livestock survive disasters.

Presentation Summary: Participants in this webcast will learn practical things a horse owner should know, and can do, that will reduce risks to horses during fires, floods and storms.

This webcast is presented by My Horse University and the Extension Disaster Education Network (EDEN).

Is it Time to Think About Planting a New Pasture of Hayfield? Part 5: Planting the Crop

September 11, 2014 in Advice and Tips, Ask the Expert, Uncategorized

Part 5:  When Do I Plant and How Much Seed Do I Use?

In the earlier posts in this series, I discussed some of the decisions and planning that need to be taken ahead of planting hay and pasture fields.  For this article, we have entered the ideal planting time for forage grasses and legumes.  However although we are in the ideal window for planting, there will be areas that have received enough rainfall to recharge the topsoil with moisture as well as areas that have not received enough rainfall for a successful seeding.  For those areas that remain dry until mid- to late-October, the best decision is likely to postpone planting until next year.

Some species have specific requirements that limit how late in the fall you can plant.  For example, reed canarygrass requires at least six weeks between planting and the average date of the first frost; otherwise, the crop could be winterkilled or severely weakened over the winter leaving the crop unable to compete with the usual spring flush of weeds.  Other species, such as Kentucky bluegrass, just take a very long time (21 to 28 days) to germinate and should not be planted late in the fall.  Before deciding to plant a species or mixture, be sure to study the species in question to avoid missing the ideal planting window.

In areas that have received enough rainfall to replace soil moisture reserves, planting can begin.  Early planting can lead to well established forage seedlings that are able to survive winter temperature extremes and get off to an early vigorous start next spring.  Early planted stands are better at competing against weeds next spring and often produce higher yields as well.  Work by Dr. Marvin Hall at the Pennsylvania State University showed significant yield decreases for all forage species tested as the date of fall planting was delayed with higher losses occurring the further north the site was located.

If planting into a prepared or tilled seedbed, be sure that all weeds have been killed during soil preparation and that a good smooth (clod-free), firm (your shoe should not sink deeper than the sole level) seedbed is prepared for planting.  Seed is then broadcast on the seedbed and firmed or pressed into the soil with any number of devices.  Seed of small seeded forages should not be buried more than 1/8 to ¼ inch deep.  Covering the seed is ideal since seed in contact with moist soil readily absorbs water but is not quickly dried again by the heat from the sun.  Seed can also be planted using a Brillion seeder followed by a cultipacker or roller or seed can be placed in the soil using a drill with packing wheels that firm soil over the seed.

Since drills (no-till and conventional drills) place the seed in rows from 4 to 8 inches apart, depending on the drill, I generally recommend that you drill at half the recommended seeding rate and run the drill twice over the field at about a 45 degree angle.  This will help new seedlings to cover the soil surface more quickly and reduce the chances for weed seed to germinate and compete with the new forage crop.

Another method of seeding is to use a no-till drill following an herbicide burn-down program.  This is especially useful when perennial weeds with underground rhizome systems are present.  Examples of these weeds are hemp dogbane, Canada thistle, and horsenettle.  Often several herbicide applications will be needed to get these weeds under control so plan a weed control program well ahead of seeding.  One of the best times to apply a translocated herbicide is in fall when weeds are sending carbohydrates (sugars) down to underground storage organs (rhizomes).  If a systemic herbicide that can move inside the plant is used, it will be taken with the sugars down to the rhizomes and help kill the meristem buds that are next year’s growing sites for the weed.  Read the herbicide label for the exact interval between treatment and seeding.  Generally for Roundup® or glyphosate you should wait several weeks after herbicide application before planting.  Since the herbicides used for control of these perennial broadleaf weeds will kill legumes that often are included as a component of pasture mixtures, it is best to work on controlling these weeds a year or two before spending the money to establish a new seeding or to renovate an existing stand.

In all cases I’ve talked about, be certain to calibrate your seeding equipment and make sure the drills and other equipment are clean and functional before entering the field.  These days forage seed is quite expensive so make the most of the money you spend by accurately calibrating your equipment.  This involves the following procedure:  weigh out some seed to add to the planting equipment, determine the width of area covered with seed by the equipment (in feet), run it for a certain number of feet (the length—say 50 or 100 feet); multiplying the two numbers together to get the number of square feet covered by the seed; divide that number by 43,560 (number of square feet in one acre); and finally weigh the amount of seed remaining in the equipment.  Subtract the final weight from initial weight and divide that number by the number of acres you covered (usually this will be a number such as 0.15 or even 0.015 or other very small number).  If your seed weights were in pounds of seed then the number you calculate at the end will be in pounds per acre or if you had access to an egg scale or something that measures in grams then divide the number of grams of seed used by 454 (grams per pound) to obtain pounds of seed and then divide that number by the number of acres planted in the calibration test.  If all else fails, email me or give me a call and I’ll help you do the calculations.

In summary, I’ll list some of the key points to keep in mind.

  • Make adjustments to soil fertility well in advance of seeding or renovating.
  • Have all perennial weeds under control before establishing a new seeding or conducting a major renovation in a field.
  • Monitor soil moisture levels to be sure an adequate reserve of soil water is available to establish the crop.
  • Understand the requirements for the forage specie or species chosen especially as it relates to fall planting date.
  • Start with a weed-free seedbed whether for conventional tillage or no-till.
  • Unless the site is known to be very low in available soil nitrogen (N), allow the new seedlings to develop 2 to 3 leaves before applying N in the fall.
  • Don’t delay planting; try to hit the optimum planting window.
  • Ideally, cover the seed with just a little soil but at the very least press the seed into the soil to ensure good soil to seed contact.
  • Most seeding rates really refer to the numbers of pure live seed (viable potential seedlings) that should be planted per acre so do the proper calculations to plant the correct amount especially when using coated seed.
  • If using preinoculated, lime-coated legume seed as a component of the pasture/hay mix, you should check to be certain the seed has been stored away from heat and high humidity and is not more than a year old, otherwise fresh legume inoculant should be applied to the seed just prior to planting.
  • Many small seeded species now come with a range of coatings (lime, moisture control compounds, etc.) that can halve the weight of pure live seed in the container so you should be sure to account for this when calculating the correct seeding rate.

In the last installment of this series, I’ll discuss how to manage new pasture and hay fields for long-term healthy stands.

This article was submitted by Dr. Richard Taylor, Extension Agronomist, University of Delaware.  Dr. Taylor can be reached at rtaylor@udel.edu

First WNV Positive Sentinel Chickens for 2014 Identified in Delaware

September 8, 2014 in Uncategorized

West Nile virus (WNV) has been detected in Delaware in blood samples taken from DNREC’s sentinel chickens that are monitored for mosquito-borne diseases. The samples are collected as part of a statewide surveillance program conducted by DNREC’s Mosquito Control Section. No cases of West Nile virus have been found in horses or humans so far in Delaware this year, with two cases found in wild birds in August.

The virus-positive chicken results were reported to DNREC by the Delaware Division of Public Health Laboratory. The chicken was sampled at a monitoring station along the Delaware River in southeast Wilmington on Aug. 25, according to Mosquito Control Section Administrator Dr. William Meredith of the Division of Fish and Wildlife. Based upon these positive virus findings, Mosquito Control will increase its mosquito population monitoring activities in this area and take appropriate mosquito control actions.

Mosquito Control operates 20 monitoring stations with caged chickens statewide. The sentinel chickens are humanely kept and tended in the field. Sentinel chickens bitten by mosquitoes carrying WNV or eastern equine encephalitis (EEE) – both of which can affect humans and horses – develop antibodies that enable them to survive. Their blood is tested every two weeks for these antibodies, which indicate exposure to these viruses.

The first indications of mosquito-borne viruses in Delaware for 2014 occurred earlier this summer in wild birds, involving two WNV-positive crows collected in August, one from north Wilmington and the other from the Hartly area in northwestern Kent County.

“So far in 2014, mosquito populations and occurrence of mosquito-borne illnesses have been a bit below normal, probably due to a relatively cool and dry summer,” Dr. Meredith said, noting Delaware’s numbers are similar to what’s happening across the country. Nationwide through Aug. 26, 2014 the federal Centers for Disease Control (CDC) has reported 297 WNV human cases with 12 deaths, with California, Louisiana, Texas and Arizona having the most cases, he said. In the mid-Atlantic region this year, two WNV human cases each have been reported in New York, New Jersey and Pennsylvania, with one death, plus one WNV human case in the District of Columbia, and no human cases in Virginia.  Maryland reported its first WNV human case last week.

The worst year on record for WNV was in 2003, with 9,862 human cases and 264 deaths nationwide. That year, the worst West Nile outbreak in Delaware also occurred, with 17 confirmed human cases and two fatalities, plus six equine cases. In 2012, there was a resurgence nationwide of WNV involving 5,674 human cases and 286 deaths, with nine WNV human cases in Delaware and one death, but no horse cases due to equine vaccinations. Last year, nationwide numbers declined to 2,469 human cases.

Dr. Heather Hirst, State Veterinarian with the Delaware Department of Agriculture, said effective equine vaccines exist to protect horses from WNV and EEE. “I am urging horse owners to assist with prevention efforts by making sure their horses are vaccinated against both WNV and EEE,” Dr. Hirst said. “Initially, two doses of the vaccine are necessary for immunization. After the initial two vaccinations, a yearly booster is needed. Horse owners should consult their local veterinarian for advice on vaccination protocols. If horses have not been vaccinated or have only recently been vaccinated, owners should keep horses inside during peak mosquito times, i.e., dawn, dusk, and throughout the night.”

There are no approved WNV or EEE vaccines for humans. The majority of humans infected with WNV typically have symptoms similar to a mild flu, if they show any symptoms at all; 20 percent develop a mild illness which includes fever, body and muscle aches, headache, nausea, vomiting and rash. A very small percentage of patients, usually the elderly, develop severe neurological disease resulting in meningitis or encephalitis (inflammation of the brain), or acute flaccid paralysis, and sometimes death. Symptoms may include sudden onset of severe headache, high fever, stiff neck, confusion and muscle weakness. Individuals with these symptoms should see their physician immediately.

“Most people bitten by an infected mosquito won’t get sick,” said Dr. Karyl Rattay, Division of Public Health Director. “Others are not as lucky. The risk of severe disease, such as meningitis and encephalitis, increases with age resulting in the elderly being at higher risk for complications.”

“This finding of West Nile virus in Delaware serves as a good reminder for people to take common-sense precautions against mosquito bites,” Meredith said. These include wearing long-sleeved shirts and long pants when outdoors in mosquito-prone areas, applying insect repellent containing 10-30 percent DEET in accordance with all label instructions, and avoiding mosquito-infested areas or times of peak mosquito activity around dusk, dawn or throughout the night.

“We know that insect bites are not only annoying and sometimes painful, but can be dangerous as well,” Dr. Rattay said. “It’s better medicine to prevent insects from biting you at all. Use insect repellant whenever outdoors.”

To reduce mosquito-breeding, Meredith said people should drain or remove items that collect water, such as discarded buckets or containers, uncovered trash cans, stagnant birdbaths, unprotected rain barrels or cisterns, old tires, upright wheelbarrows, flowerpot liners, depressions in tarps covering boats, clogged rain gutters, downspout extenders, and unused swimming pools.

“The possibility of mosquito-borne disease transmissions won’t subside until cooler autumn temperatures set in, usually in mid-October and sometimes even later,” Meredith added.

To help determine when and where control services are needed, Mosquito Control encourages residents to report intolerable numbers of biting mosquitoes by calling the numbers below. Staff answers phones between 8 a.m. and 4 p.m. Monday through Friday. Callers after business hours or during weekends or holidays should leave their name, phone number, address and a brief message.

  • Glasgow Office, serving New Castle County and northern Kent County (including the Dover area): 302-836-2555
  • Milford Office, serving Sussex and southern Kent Counties: 302-422-1512

Source: September4, 2014 News Release from the Delaware Department of Natural Resources and Environmental Control

For more information on WNV in horses, please visit our previous post http://extension.udel.edu/equine/2013/08/23/protect-your-horses-from-west-nile-virus/