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Volume 8, Number 7 - July 2002

This Month in Ag Connection

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Topics at the Midwest Meeting of the American Society of Animal Science


Below are very brief summaries of some presentations at the Midwest Section of the American Society of Animal Science. These are research updates, not necessarily the final answer.

(Author: Tim Safranski, State Swine Breeding Specialist)

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Infectious Bovine Keratoconjunctivitis: Pinkeye!

Pinkeye is a bacterial disease affecting the eye of cattle causing inflammation of the eyelid and eyeball. It causes pain, weight loss and possible blindness if the cornea becomes ulcerated. Table 1 shows the impact of pinkeye infection on weaning weight of beef calves.

Table 1
Effect of Pinkeye Infection on Beef Calf Weaning Weight
  Bull Calves Heifer Calves
% Pinkeye infection 56% 27%
Weight loss due to pinkeye 36 lbs. 40 lbs.
1975 Beef Cattle Research Report, Progress Report 218, Kentucky Ag. Experiment Station

The main cause of pinkeye is the bacteria Moraxella bovis (M. bovis) of which there are multiple strains, each of which can cause pinkeye. Cattle can become predisposed to pinkeye by a number of agents. Anything that can cause eye irritation such as seed heads and the feeding of face flies on eye secretions can set up an infection of M. bovis.

Cow head

Face flies are the major carrier of M. bovis, which, can remain viable on feet and wings of face flies for up to three or four days. Therefore, a face fly feeding on infected eye secretions of a calf can infect several other animals within a herd. In addition to M. Bovis being located in the eyes of cattle it can also be contained in nasal cavities. It is then possible for cattle to act as carriers for M. Bovis in their nasal cavities in excess of a year. During this time these animals can allow for the persistence of pinkeye at a particular site from year to year.

Presence of other organisms such as Chlamydia, Mycoplasma, Acholeplasma and the virus Infectious Bovine Rhinotracheitis (IBR) can add to the severity of pinkeye or predispose animals to an infection of M. Bovis. Other factors that can predispose animals to an infection of M. Bovis include: age (young animals are more susceptible than older animals), weaning stress, dusty conditions, pollen, and increased animal concentrations can all set animals up for an infection of M. Bovis.

Incubation period for pinkeye is normally two to three days but in experimental trials has ranged to as much as three weeks. Initially, watering and tearing of the eye will be the first symptoms noted, followed by squinting of the eye due to light sensitivity and pain. Infected animals may run a slight temperature. Approximately 2 days after initial symptoms, ulceration of the eye will begin.

Antibiotic treatment of pinkeye can be very effective if done early. M. Bovis can be treated with oxytetracycline, ceftiofur, penicillin, and sulfonamides. Consult with your veterinarian prior to treatment to determine the best treatment methods and products for your herd. Eye patches can also be an effective treatment as they will provide shading of the eye and prevent additional irritation of the eye.

Management is key to prevention of pinkeye in cattle.

Some producers have added chlortetracycline to mineral mixes to reduce the incidence of pinkeye in cattle. Research in Kentucky has shown good results from this practice, Table 2.

Table 2
Effect of Chlortetracycline in Mineral Supplement on Incidence of Pinkeye
  Control Chlortetracycline
Number of Calves 54 49
% Calves with pinkeye 16.7% 6.1%

Dealing with pinkeye is tough, there are no silver bullet solutions, only sound management and diligence.

(Author: James Rogers, Livestock Specialist)

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West Nile Virus


West Nile virus (WNV) is a mosquito carried encephalitis disease. Mosquitoes are infected when they feed on birds with high levels of WNV in their blood. Wild birds are the most common carriers of this disease and are considered a reservoir. Humans, horses and other animals are considered occasional hosts. WNV was first recorded on the east coast in the United States in 1999 and in Missouri in late 2001 in a wild bird. To date, no infected horses or humans have been diagnosed in Missouri. Across the U.S., mosquitoes, birds, horses and humans are being screened to detect WNV.

There is no evidence of animal to animal transmission without a mosquito carrier. However, people handling live or dead birds are encouraged to use protection like rubber gloves. Livestock other than horses and poultry do not commonly show symptoms of this illness.

Most humans infected with WNV do not exhibit symptoms. A small number of people develop mild symptoms that include fever, headache, body aches, skin rash and swollen lymph glands. Less than 1% of infected people develop more severe illness that includes meningitis (inflammation of the spinal cord) or encephalitis. The symptoms of these illnesses can include headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, and paralysis. Of the few people with encephalitis, a small proportion die. Death is estimated to occur in less than 1 out of 1000. The highest risk is among the elderly and those with weak immune systems. Children are not at a higher risk than adults.

Horses appear to react in much the same way to WNV as humans and most do not exhibit symptoms. Symptoms may be indistinguishable from those produced by other forms of equine encephalitis. The most common signs of WNV infection in U.S. horses have been ataxia, weakness of limbs, recumbency, muscle fasciculation, and death. Fever has been detected in less than one-quarter of all confirmed cases. One in three horses that exhibit symptoms of WNV will die or need to be euthanized.

Reducing exposure to mosquitoes is the best way to prevent infection. The primary way to limit exposure is to eliminate stagnant water sources where most mosquitoes breed. Most mosquitoes identified as carriers are active from dusk till dawn. Stabling horses in the evening, and limiting evening and night activities, may help.

People should take the typical precautions to prevent mosquito bites. Wear clothing that covers as much of the skin as practical when outside. Use a recommended insect repellant like DEET on clothing and exposed skin. Permanone should be used only on clothing allowed to dry before wearing and does not protect exposed skin. Be cautious during the first ever application of DEET to young children. Other repellants may be effective but the length effectiveness is less than DEET or permanone. Limit outside activity from dusk till dawn when mosquitoes are most active.

(Author: Jim Jarman, Agronomy Specialist)

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Taxation Tidbits: Charitable Contributions Are Not Always Deductible

Giving money

A gift to a charity is one of the deductions allowed as an itemized deduction on Schedule A. Taxpayers that have greater itemized deductions than the standard deduction may file Schedule A. Some taxpayers, due to their filing status, are not eligible to take the standard deduction and are required to file Schedule A. The deductibility of certain charitable gifts is a common question raised in calculating the itemized expenses.

Giving financial assistance to individuals who are needy or worthy, while the right and good thing to do, is not a deductible contribution for tax purposes. Camouflaging a charitable gift to specific individuals by routing the transfer through a qualifying charitable entity, such as a church, does not make the gift deductible.

Occasionally checks are made payable to the "XYZ Church" with a memo notation "for the John Doe family". The regulation dealing with this issue is a "no variance rule": all gifts to specific individuals, directly or indirectly, are not tax deductible. This non-deductibility even applies to gifts made to an individual who provides service to a qualifying charitable entity (i.e. clergy or missionary), if the gifts can be spent as the individual desires, such as for personal expenses.

The important lesson in this example is - the IRS always has the right to consider the beginning and ending tax consequence of a series of transactions - ignoring any superfluous intermediary transactions.

(Author: Parman R. Green, Ag Business Management Specialist)

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Staff Farewells

Moving truck

Two of our Central Missouri Agriculture Staff members are leaving us in the next few weeks. Tim Schnakenberg, Agronomy Specialist in Morgan County will be moving to Stone County in mid-July. James Rogers, Livestock Specialist in Benton County will be moving to Oklahoma to work as a Forage Specialist for the Noble Foundation.

Both Tim and James have been valuable members of the agriculture staff in Central Missouri. They have conducted excellent programs and have written many articles for Ag Connections. We will miss them and we wish them well as they move to their new positions.

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Advanced Reproductive Management Conference

On July 18-19 the University of Missouri will be holding an advanced reproductive management conference. For more information contact your local University Extension Center or click here to check out the program's website.

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Publishing Information

Ag Connection is published monthly for Central Missouri Region producers and is supported by University of Missouri Extension, the Commercial Agriculture program, the Missouri Agricultural Experiment Station and the MU College of Agriculture, Food and Natural Resources. Managing Editor: Kent Shannon.