PREVENTING WIN­TER RESPIRATORY DIS­EASE

Broiler-house man­age­ment and vac­ci­na­tion es­sen­tial

The Poultry Bulletin - - FRONT PAGE - This is an edited ex­tract of an ar­ti­cle au­thored by Tak Ni­ino of Zoetis Inc

Respiratory dis­ease in broil­ers can oc­cur any time of year. Dur­ing win­ter, how­ever, it is par­tic­u­larly prob­lem­atic when air and en­vi­ron­men­tal con­di­tions could be com­pro­mised as pro­duc­ers try

keep costs un­der con­trol.

Main­tain­ing good air qual­ity is es­sen­tial and is heav­ily in­flu­enced by ven­ti­la­tion tech­niques. When a house is un­der ven­ti­lated, am­mo­nia lev­els and lit­ter mois­ture can rise to the point where it is detri­men­tal to the birds’ health and pre­dis­poses them to respiratory dis­ease.

El­e­vated am­mo­nia lev­els dam­age the cilia, those brush­like struc­tures re­spon­si­ble for clear­ing de­bris out of the tra­chea. When the cilia are dam­aged or de­stroyed, birds may suc­cumb to vi­ral in­fec­tions such as In­fec­tious Bron­chi­tis (IB), In­fec­tious Laryn­go­tra­cheitis (ILT) or New­cas­tle Dis­ease (ND). These vi­ral pathogens can also cause cil­iosta­sis, which can re­sult in chick­ens dis­play­ing signs

of lethargy, de­pres­sion or cough­ing and snick­ing.

Poor lit­ter qual­ity due to in­ad­e­quate ven­ti­la­tion is fa­vor­able for bac­te­rial growth. That’s why it’s not un­com­mon for birds that have a respiratory virus to de­velop a se­condary bac­te­rial in­fec­tion - usu­ally Escherichia coli - which can lead to se­vere pol­y­serosi­tis, sep­ticemia and even death.

Ev­i­dence of respiratory dis­ease can show up at the pro­cess­ing plant as well as in the poul­try house. Con­dem­na­tion due to air­sac­culi­tis, of­ten due to an un­der­ly­ing respiratory dis­ease, may trend up­ward dur­ing cooler months, when main­tain­ing an op­ti­mal en­vi­ron­ment be­comes a chal­lenge. An in­creased num­ber of birds with air­sac­culi­tis can af­fect the ef­fi­ciency of the pro­cess­ing plant. More birds will have to be rerouted and sal­vaged for parts, which can slow the line speed, and that’s costly.

Big­ger houses

One trend that may in­flu­ence ven­ti­la­tion prac­tice is vari­a­tion in house sizes. To­day, many poul­try grow­ers are choos­ing to build larger houses to raise more birds more ef­fi­ciently. How­ever, meth­ods tra­di­tion­ally used to ven­ti­late smaller houses may not yield the same re­sults in larger ones. Care must be taken to en­sure that longer and wider poul­try houses have the proper equip­ment and ven­ti­la­tion set­tings nec­es­sary to ad­e­quately move and ex­change air. Air has to travel fur­ther, and if air­flow is un­even, birds at one end of the house might have fresh air while birds at the other don’t.

Age­ing equip­ment

Poorly main­tained equip­ment can lead to dif­fi­culty in heat­ing and ven­ti­lat­ing the house. Old and un­main­tained fans might still run, but that is no guar­an­tee that the cu­bic feet of air moved per minute is the same as it was when the fans were first in­stalled. A fan may not move the re­quired amount of air if shut­ters are dirty and belts need re­plac­ing. Air flow can be eas­ily mon­i­tored us­ing an air flow me­ter. Proper and→

reg­u­lar main­te­nance is crit­i­cal to make sure the sys­tems are work­ing prop­erly.

Mon­i­tor au­to­ma­tion

Com­put­erised, au­to­mated sys­tems with pre­set pro­grams are handy and can work well if used ap­pro­pri­ately. Ad­vance­ments in farm equip­ment make it easy for grow­ers to mon­i­tor the house con­di­tion and ven­ti­la­tion set­tings with­out hav­ing to en­ter the house. How­ever, never as­sume birds are com­fort­able just be­cause the com­puter in­di­cates ev­ery­thing is run­ning smoothly. There is no one-size-fits-all set­ting since the con­di­tions for keep­ing birds com­fort­able and healthy can vary flock to flock. Be­cause of this, it’s im­por­tant to look at the birds reg­u­larly to make sure they are com­fort­able. Visu­ally check­ing birds is a fail-proof way to con­firm that house con­di­tions, in­clud­ing ven­ti­la­tion and lit­ter qual­ity, are ap­pro­pri­ate. Check am­mo­nia Peo­ple who spend a lot of time in poul­try houses can eas­ily be­come de­sen­si­tized to the smell of am­mo­nia and may not re­al­ize these lev­els are too high for bird health. A highly sen­si­tive hu­man nose is ca­pa­ble of de­tect­ing am­mo­nia at a con­cen­tra­tion as low as 1 ppm. For poul­try, it’s im­per­a­tive to keep lev­els be­low 25 ppm to pre­vent a loss in per­for­mance and in­crease in dis­ease - and to pro­tect the safety of work­ers.

Am­mo­nia lev­els should be mon­i­tored rou­tinely through­out the life of the flock, and if they’re too high, ven­ti­la­tion set­tings must be ad­justed to re­duce am­mo­nia con­cen­tra­tion. There are sev­eral dif­fer­ent tools avail­able for eval­u­at­ing am­mo­nia lev­els; just en­sure that the tool cho­sen yields con­sis­tently ac­cu­rate re­sults.

Vac­ci­na­tion

Avac­cine pro­gram tai­lored to help pro­tect against respiratory dis­ease risks is es­sen­tial and should be in­di­vid­u­alised, tak­ing into ac­count risks on the farm and in the ge­o­graphic area.

In­fec­tious bron­chi­tis virus (IBV), for ex­am­ple, is al­ways a con­cern for broiler flocks, and the key to pro­tec­tion is iden­ti­fi­ca­tion of the IBV strain that’s cir­cu­lat­ing. Di­ag­nos­tic meth­ods such as serol­ogy, hemag­glu­ti­na­tion in­hi­bi­tion and poly­merase chain re­ac­tion anal­y­sis can de­ter­mine the most preva­lent IBV serotypes in a flock.

Some­times a het­erol­o­gous pro­gram (us­ing vac­cines with dif­fer­ent serotypes) may help pro­vide cross pro­tec­tion in the field. Proper vac­ci­na­tion pro­grams play a ma­jor role in help­ing to pro­vide pro­tec­tion against these dis­eases.

Con­clu­sion

In sum­mary, vac­ci­na­tion along with man­ag­ing the en­vi­ron­ment is cru­cial for main­tain­ing bird health. For many grow­ers, de­sir­able ven­ti­la­tion can be chal­leng­ing in cooler months, es­pe­cially due to high en­ergy costs. How­ever, in­ad­e­quate ven­ti­la­tion puts birds at risk for respiratory dis­eases that can lead to high rates of mor­bid­ity and con­dem­na­tion. Ini­ti­at­ing good man­age­ment and a solid vac­ci­na­tion plan are of­ten more cost ef­fec­tive in the long run.¡

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