C4-Lancasttr Fanning, Saturday, Novambar 27, 1993 iuli Itry Penn State iSfejv | Poultry T\ j " Pointers 7 Agricultural & Biological Engineering Agricultural Economics STRAY VOLTAGE ON POULTRY FARMS Paul H. Patterson, Ph.D. Assistant Professor Poultry Science Poultry producers may be con cerned about stray voltage (or neutral-to earth-voltage) and how it may be affecting the health and production of their birds. Stray voltage is a small voltage (less than 10 volts) measured between two points that can be simultaneously touched by a bird. This could be between the floor of a laying cage and a nipple drinker, or the feed trough and slat floor in a breeder house. Birds really respond to the cur rent produced by a voltage and not to the voltage directly. More cases of stray voltage have been traced on dairy farms, but poultry farms are not immune to this problem. One of the early cases docu mented in Pennsylvania was a 43-week-old laying flock in Erie County. Feed consumption dropped from 23.3 pounds/100 birds to 15.6 pounds/100 birds and remained at this level for four days. Egg production dropped from 83 percent to 45 percent between 43 and 45 weeks and mor tality increased from a monthly rate of .7 percent to 1.7 percent for that four-week period. voltmeter readings taken between the cage and water in the cups showed .8-.9 volt Voltage potential between the cage and a ground line driven into the earth was 1.3-1.5 volts. Readings at the entrance box (secondary ground) indicated that the voltage was coming from the power company’s neutral. The power company took corrective action and reduced the voltage between the cage and water cup to .2-.3 volt. Installation of a water meter immediately thereafter showed normal water consumption and feed consump tion and egg production returned to normal. An investigation this summer of a suspect case of stray voltage in a breeder flock of Leghorn hens located in southcentral Pennsylva nia revealed from 0 to 2.0 neutral to ground volts at the service pole entering the farm. This was later corrected with a neutral isolator by the power company. Further inves tigation revealed an uninsulated electric fence around the feed hop pers secured to the wood slat floor that continued as a shock line above the water line. According to the producer, the flock had been experiencing some type of emotional distress, and were “rushing” back and forth within the pens. Mortality was ele vated and had been traced to egg yolk peritonitis. Prior to installing the neutral isolator, voltage readings taken from the water line to the damp slat floor read between .3-2.2 volts with the shock line turned off, and from 17-70 volts with it on! Feed trough to floor readings were .2-1.7 and 3-14 volts with the unit off, and on, respectively. Surprisingly, no drops in feed or water consumption, egg produc tion, fertility or hatchability could be documented by the producer or hatchery. To date, the flock remains nervous and rushes despite correction of the problem. Another case involving turkey poults was reported by University of Minnesota researchers in the journal, Avian Diseases. Three successive flocks of poults exper ienced cumulative mortality of from 10 to 26 percent through the fifth week of rearing. Stray voltage was suspected after no definitive laboratory diagnosis could be made, and no management defi ciencies were found. Alternating current voltages of .2-2.5 volts were detected between waterers and the floor and between the water line and gas line. When the water line was equipment grounded to the electrical service entrance, the subsequent flock had no mortality problem. According to the dairy litera ture, the voltage necessary to deliver currents that would elicit a response depends on the body impedance or resistance of the cow. This would include the con tact impedance between the cow and the conductive structure'and any impedance of the structure and .the impedance of the voltage source. For cattle, a very conservative estimate for a worst-case tot£l impedance is 500 ohms. A more realistic estimate of total circuit impedance is 1,000 ohms. Older recommendations for tolerable levels of cow contact voltages were .S-. 7 volts based on the low est values of perceived current and low values for body, contact, struc ture and source impedance’s. Recent research indicates that current levels below 6 milliamps have no direct effect on produc tion, reproduction, or animal health, although some behavioral changes are seen in cows exposed to currents between 3 and 6 mil liamps. Based on these estimates for impedance and current, the more realistic voltages that may elicit a response in cattle might be between 1.5-6.0 volts. Threshold voltages based on body, contact, and total circuit impedance for poultry have yet to be determined. Pennsylvania Power & Light Co. (PP&L) has summarized their research and experiences into some of the main causes of stray voltage. These include; • Short circuits in wiring and equipment. • Improperly grounded equipment • improper interconnection of ground'and neutral wires in equip ment wiring. • Fault currents through poor • Agricultural • Commercial • Residential • Retaining Walls • Bunker Silos • Manure Storage, Etc. LET OUR EXPERIENCE WORK FOR YOU ESTABLISHED SINCE 1979! WE ORIGINATED THE CONCRETE SYSTEM! Sizes And Layouts To Your Specifications We Work Hard For Customer Satisfaction! insulation or damp, dirty electrical equipment • Unbalance of load on 120-volt circuits on the farm system. • Induced voltages on equipment • Low voltages carried on the electric utility’s neutral. It is essential for producers who suspect they have a stray voltage problem to prompdy investigate and lake the necessary corrective actions. PP&L recommends the following five steps be taken: 1. Record signs of flock disorder. HUNTINGDON (Huntingdon Co.) Accountants, attorneys, and other professionals who pre pare tax returns for businesses and individuals will converge on Penn State’s University Park Campus the week of December 6. More than 300 tax professionals are expected to attend the 41st annual Tax Week at Penn State, 'which will be held at the Days Inn Penn State. The week-long prog ram features a combination of technical tax topics and special interest workshops to help tax pro fessionals better serve their clients. Topics to be discussed Monday and Tuesday of Tax Week include die new tax law. employment tax es, small business tax issues, and basic rules for preparing individu al income tax returns. The prog ram also covers Pennsylvania state income tax preparation and helping clients survive an audit. Daniel J. Pilla, a nationally known tax litigation consultant and author of five books about representing taxpayers before the Internal Revenue Service, will be the featured speaker on Tuesday, December 7. He will discuss how professional tax preparers can pro tect their clients’ interests. His address will be followed by a question-and-answer session. Wednesday will be devoted to tax rules that apply to organiza tions exempt from federal income * t&X** y* 4 Commodity Bins And Trench Silos Authorized Dealer For KEYSTONE CONCRETE PRODUCTS • Hog & • Trench Cattle Silo Slats Walls • H-Bunks • J-Bunks Tax Week At Penn State Dec. 6-10 INC. 430 Concrete Ave., Leola, PA 717-656-2016 2. Consider all other possible causes for these problems (your county cooperative extension agent, veterinarian, or other spe cialist could review ,your feeding and management programs with you). 3. Consult with specialists and examine the farm’s electrical system. 4. Have a qualified electrician correct all on-farm electrical problems. 5. Contact PP&L for any assis tance along the way. tax. including charities, educa tional groups, and service organi zations such as volunteer fire associations. Topics to be dis cussed include applications for tax-exempt status, filing forms required once an exempt status is attained, and special rules related to charitable fund raising. A two-day estate and Gift Tax workshop, to be conducted on Thursday and Friday, concludes Tax Week at Penn State. This program will detail the tax aspects of estate transfer, the rules for completing the estate and gift tax forms and techniques that may reduce estate or gift tax. Dr. William Kulsrud, associate professor of accountancy at India na University at Indianapolis, will teach the estate and gift tax work shop. His 250-page workbook about estate and gift taxes will be distributed to all participants in the workshop. Participants can register for the entire conference or for only those sessions of interest to them. Registration fees and the number of continuing professional educa tion (CPE) credits participants receive depend on the number of sessions attended. Additional information about Tax Week at Penn State and a registration packet are available from the Tax Week Coordinator, The Pennsylvania State Universi ty. 8 Armsby Building. University Park. PA 16802; (814) 863-4580.
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