DE­TECT­ING DIS­EASE SOONER

The Poultry Bulletin - - FRONT PAGE - The ar­ti­cle above is an edited ex­tract from an orig­i­nal first pub­lished by Cana­dian Poul­try Con­sul­tants. Ref­er­ences are avail­able on re­quest.

Spot­ting dis­ease early key to pro­tect­ing your enterprise

An ef­fec­tive on-farm dis­ease con­trol pro­gram de­pends on spot­ting an ab­nor­mal­ity or a prob­lem early on. To do so, there are a num­ber of signs to look out for and ar­eas we should reg­u­larly watch. These in­clude eat­ing or drink­ing more or less, atyp­i­cal or ab­nor­mal be­hav­iour in the flock, and phys­i­cally check­ing and mon­i­tor­ing in­di­vid­ual birds. Lastly, to be ef­fec­tive, ac­cu­rate di­ag­no­sis and quick treat­ment of the prob­lem is es­sen­tial.

Quick ac­cu­rate di­ag­no­sis

If we are not ca­pa­ble of de­tect­ing an early dis­ease

process or chal­lenge, then the fi­nan­cial bur­den of bird mor­tal­ity and pro­duc­tion pa­ram­e­ter losses will in­crease. Not only is the early de­tec­tion of a dis­ease crit­i­cal for the im­me­di­ate flock, but also sur­round­ing flocks or suc­ces­sive flocks to fol­low. Dis­ease trans­mis­sion of an in­fec­tious or­gan­ism could cause se­vere reper­cus­sions for the op­er­a­tion and the in­dus­try.

As crit­i­cal to the early de­tec­tion of a dis­ease or prob­lems is a quick and ac­cu­rate di­ag­no­sis. This is hope­fully fol­lowed with im­me­di­ate pro­fes­sional sup­port for ther­a­peu­tic in­di­ca­tions and or man­age­rial ad­vice.

It is not only our re­spon­si­bil­ity to recog­nise the early stages of the dis­ease process but to pre­vent or treat the dis­ease as well. Know­ing what is nor­mal and how to

de­tect what is ab­nor­mal for the flock is cru­cial to good man­age­ment. It is your busi­ness; hence pro­tect it.

The fol­low­ing will pro­vide some in­put to spot­ting dis­ease early. To ac­com­plish this takes an ob­jec­tive thinker, a hard worker, and a clear un­der­stand­ing of nor­mal ver­sus ab­nor­mal. It also re­quires proper record­ing ca­pa­bil­i­ties and open com­mu­ni­ca­tion with pro­fes­sional sup­port groups. Although there are many facets to dis­ease recog­ni­tion, some of the on-farm dis­ease sur­veil­lance tech­niques are fea­si­ble to con­duct im­me­di­ately.

Wa­ter and feed in­take

Wa­ter is the most crit­i­cal in­put in poul­try pro­duc­tion yet can be taken com­pletely for granted. Wa­ter is by far the largest sin­gle com­po­nent of the bird’s body rep­re­sent­ing some 70% of the to­tal body weight in a ma­ture bird. Un­like other farm an­i­mals, chick­ens and tur­keys need a con­tin­u­ous wa­ter sup­ply.

They drink only small amounts at a time. The bird ob­tains its wa­ter by three routes - by drink­ing, by eat­ing, and by break­ing down its body tis­sues which is part of its growth and de­vel­op­ment. When a dis­ease or stress oc­curs, a de­crease in wa­ter con­sump­tion is usu­ally noted a day or two be­fore the de­crease in feed con­sump­tion. For this rea­son, grow­ers are ad­vised to in­stall wa­ter me­ters on all wa­ter lines and record con­sump­tion daily. Such records can give early warn­ing of po­ten­tial prob­lems with the flock. Hence, us­ing wa­ter me­ters and stay­ing with a reg­is­tered on-farm food safety pro­gram is crit­i­cal to early dis­ease de­tec­tion.

Feed me­ters or scales are also pro­vided as an on-farm man­age­ment tool. Scales not only pro­vide safety and pre­ci­sion in daily feed re­stric­tion pro­grams but they can also be an as­set and a valu­able tool for the daily con­sump­tion of feed. A re­duc­tion of feed in­take could mean a dis­ease process in pro­gres­sion or a me­chan­i­cal fail­ure in the feed line sys­tem. Other fac­tors that can in­flu­ence feed in­take in­clude the en­vi­ron­ment, tem­per­a­ture, palata­bil­ity, feeder space, wa­ter de­pri­va­tion, com­po­si­tion, pel­let qual­ity, en­ergy lev­els and pos­si­ble tox­i­c­i­ties. Me­chan­i­cal break­down not recorded can lead to a moult in lay­ers or un­due stress in broil­ers and breed­ers. Stress, a ma­jor fac­tor in im­muno­sup­pres­sion, can leave the birds open for a tar­geted mi­cro­bial in­sult.

Keep in mind that the feed:wa­ter ra­tio at 20oc is from 1:1.75 to 1:2. At higher en­vi­ron­men­tal tem­per­a­tures, birds will con­sume more; there­fore, al­low wa­ter for longer pe­ri­ods of time dur­ing the day. Dur­ing drink­ing hours it is im­por­tant to check that all drinkers are func­tional and filled with wa­ter. Wa­ter me­ters are used as a man­age­ment tool to record daily ac­tiv­i­ties in wa­ter con­sump­tion. As a rule, wa­ter and feed con­sump­tion must be mea­sured and recorded at the same time ev­ery day. Call on an ex­pert in wa­ter line me­chan­ics or call upon pro­fes­sional ad­vice and sup­port on a pos­si­ble dis­ease process. Once

again, mea­sure­ments can be af­fected by things other than dis­ease and should al­ways be con­sid­ered.

Be­havioural ab­nor­mal­i­ties

One should al­ways check to see if nor­mal bird be­hav­iour is oc­cur­ring on the pen floor. Nor­mal be­hav­iour can only be learned by walk­ing the barn daily or ob­serv­ing the birds from a sta­tion­ary stand. A sta­tion­ary stand, at rest, can be achieved by ob­serv­ing the birds through a pen win­dow or sit­ting on a seat amongst the birds. Daily be­hav­iour, even in in­tense farm­ing is char­ac­ter­is­tic and pre­dictable. Preen­ing, strut­ting, re­ac­tion to light, fight­ing, dust bathing, feed­ing and drink­ing, per­sonal space and dis­tance are all pat­terns of nor­mal ac­tiv­ity.

Un­for­tu­nately the abil­ity to ob­serve is not eas­ily ac­quired and is a gift. As men­tioned, this comes from ed­u­ca­tion and most im­por­tantly, ex­pe­ri­ence. Get­ting into the barn and ded­i­cat­ing time to ob­serve and record ob­ser­va­tions will even­tu­ally be re­warded, re­mem­ber­ing that ab­nor­mal be­hav­iour is a sign of en­vi­ron­men­tal im­bal­ance or a dis­ease process af­fect­ing the bird’s nor­mal ac­tiv­ity. The per­son who is highly ob­ser­vant is likely to make a good mem­ber of the farm staff.

When it comes to as­sess­ing a flock there are two crit­i­cal things that we can look at to see if pro­duc­tion is right or not. These are the bird’s en­vi­ron­ment and the flock records.

As far as the en­vi­ron­ment is con­cerned we need to use all our senses. Senses such as sight (ab­nor­mal drop­pings, lit­ter, feath­ers, hud­dling), smell (am­mo­nia, bird de­cay), touch (wet lit­ter, con­sis­tency un­der foot) and what we hear (snick­ing, sneez­ing) are tuned in to look at ab­nor­mal­i­ties from the nor­mal be­hav­iour process. Again the skill is to de­tect vari­a­tions from nor­mal, there­fore an ap­pre­ci­a­tion to just what nor­mal is.

When it comes to documenting a chal­lenge or prob­lem, record keep­ing (mon­i­tor­ing) is a valu­able tool. The on-farm food safety pro­gram is a ve­hi­cle to do just that. Food safety is­sues, dis­ease sur­veil­lance and good man­age­ment prac­tices all re­quire doc­u­men­ta­tion. Write down what you do, do what you write down and prove it, are the keys to flock health and prof­itabil­ity. Be­come an au­di­tor and not just an in­spec­tor of your birds.

Bird con­for­ma­tion

This sim­ply refers to a gross in­di­vid­ual ap­praisal of the bird. It is best to have a log­i­cal ap­proach. The best is to ran­domly se­lect birds or iden­tify chal­lenged birds and record ob­ser­va­tions start­ing at the head and pro­ceed to the toes, ex­am­in­ing ev­ery­thing as you pro­ceed. For each body part or com­po­nent as­cer­tain whether it is nor­mal or if ab­nor­mal­i­ties are present.

Colour- Is colour nor­mal, pale (anaemia), dark (de­hy­dra­tion, fever)?

Size - Is a com­po­nent larger than nor­mal such as the in­fra-orbital si­nus or a wing/ leg joint? Are the birds light/ skinny, de­pleted in mus­cle mass? Shape - Ab­nor­mal swelling as seen with the early stages of

as­cites.

Po­si­tion - Parts of the body ab­nor­mally po­si­tioned; droop­ing wings, twisted legs.

Heat - Ex­ces­sive heat to the touch such as hock joints, in­di­cat­ing a dis­ease process.

Soil­ing - Ex­ces­sive soil­ing of the feath­ers, which could in­di­cate an en­teric prob­lem or up­set. In­creased ac­cu­mu­la­tion of fae­cal ma­te­rial or urates around the vent or of caked lit­ter around the toes could re­veal a dis­ease process or man­age­rial over­sight.

Dis­charges - Healthy ori­fices such as the nos­trils, ears, eyes and oviduct do not have dis­charges. If dis­charges are present then look at the colour, con­sis­tency and smell of dis­charge. Eye dis­charge could be a dis­ease process (virus, bac­te­ria) or en­vi­ron­men­tal in­sult such as high am­mo­nia or dust.

Stance - A crouched or hud­dled po­si­tion or stance could re­veal gen­eral ill­ness, chill­ing or fever, some­thing is not right in­ter­nally. Lame­ness re­veals a stance favour­ing the good leg to al­le­vi­ate pres­sure from the af­fected leg.

Alert­ness - Birds are usu­ally very in­ter­ac­tive with their en­vi­ron­ment. A sick bird is de­pressed, lethar­gic, re­sponds slowly to changes. How do birds re­spond when you walk through the barn?

Vo­cal­i­sa­tion - What is the nor­mal level of noise in a pro­duc­tion barn i.e.; lay­ers when hun­gry? A vari­ance from the nor­mal oc­cur­ring day to day in­di­cates dis­com­fort, stress or sick­ness. Pres­ence of Le­sions Mu­cosal le­sions such as pox, skin scratches, pre­lim­i­nary in­sti­ga­tor of cel­luli­tis. If you keep a list from day

to day and eval­u­ate the ab­nor­mal and nor­mal birds as part of a rou­tine, one will be amazed at how much one will ac­tu­ally see or ob­serve. This is truly a start­ing point for an on-farm dis­ease de­tec­tion pro­gram. As time pro­gresses in the flock, as birds get older, stan­dards and ap­pear­ance change also. Keep these fac­tors in mind in pa­ram­e­ters such as feath­er­ing, colour, stance and po­si­tion. With the col­lec­tion and anal­y­sis of the bird data comes the easy tran­si­tion to the ap­pear­ance of the flock in gen­eral. Ob­ser­va­tions that be­come per­ti­nent here are the dis­tri­bu­tion of the birds when sit­ting, feed­ing, drink­ing and milling about, or in the case of breeder flocks the mat­ing ac­tiv­ity and be­hav­iour.

Look for non­in­fec­tious con­di­tions first

It is our re­spon­si­bil­ity to al­ways con­sider in­fec­tious causes of mor­bid­ity or mor­tal­ity in a flock that may be present. How­ever, do not for­get to in­ves­ti­gate man­age­ment er­rors im­me­di­ately. A high per­cent­age of bird sub­mis­sions to the lab­o­ra­tory, or ref­er­enced to a pro­fes­sional source, are in fact non-in­fec­tious con­di­tions re­lated to man­age­ment.

Such man­age­ment fac­tors to con­sider are; beak trim­ming er­rors, con­sump­tion of lit­ter or bed­ding, wa­ter and/ or feed de­pri­va­tion, chill­ing of chicks due to im­proper brood­ing fac­tors, rough han­dling, elec­tri­cal fail­ures (light­ing pro­grams), over­crowd­ing, poor spac­ing and po­si­tion of feed­ers and wa­ters, smoth­er­ing, in­ad­e­quate ven­ti­la­tion, low qual­ity feed in­gre­di­ents/vi­ta­mins and min­er­als, ro­dent and preda­tor at­tacks.

It be­comes clear that mon­i­tor­ing of the man­age­ment fac­tors is an­other im­por­tant step in eval­u­at­ing dis­ease-caus­ing or­gan­isms. Check­ing re­ports or records on these in­puts quickly de­ter­mines the need for pro­fes­sional sup­port or ref­er­ence to a lab­o­ra­tory for di­ag­no­sis.

Ac­cu­rate di­ag­no­sis and cor­rec­tive ac­tion

The goal of the di­ag­no­sis is to de­ter­mine the cause of im­paired per­for­mance, the signs recog­nised, or the mor­tal­ity col­lected. The ex­am­i­na­tion of the tis­sues and or­gans, and the pro­ce­dure→

to ob­tain the best spec­i­mens for vi­rol­ogy, mi­cro­bi­ol­ogy, serol­ogy and/or histopathol­ogy re­quire ex­per­tise. The di­ag­no­sis is en­hanced if the birds are sub­mit­ted with proper records, a flock his­tory and an open mind. A key to good poul­try di­ag­no­sis is the art of “see­ing the for­est as well as the trees”.

The pro­fes­sional sup­port team will try to iden­tify the most sig­nif­i­cant flock prob­lem(s), rather than be­com­ing en­grossed in in­di­vid­ual bird dis­or­ders. How­ever, their role and out­come is cru­cial on the sub­mis­sion and com­mu­ni­ca­tion. Spot dis­ease early and fol­low up with pro­fes­sional sup­port from the vet­eri­nary field. Your di­ag­nos­tic re­port and pro­fes­sional fol­low-up pro­vides you with the cor­rec­tive ac­tion that must fol­low. Man­age­rial al­ter­ations and/or ther­a­peu­tic regimes are war­ranted only if based on pro­fes­sional ad­vice.

Ac­count­abil­ity for ones ac­tions and pro­ce­dures must be doc­u­mented as we are faced with in­creas­ing de­mands to record what we do. Records also val­i­date treat­ment suc­cess and fail­ure, hence the abil­ity to make other cor­rec­tive ac­tion. We learn by our fail­ures as well as our suc­cesses.

When sub­mit­ting birds think of Pat­tern Recog­ni­tion. This sim­ply means sub­mit­ting enough birds so that the di­ag­nos­ti­cian (pathol­o­gist) has a rep­re­sen­ta­tive sam­ple size. It is best to sub­mit 10 to 12 birds if mor­tal­ity is present in the flock. Live birds rep­re­sent­ing the dis­ease process are also an ex­cel­lent ref­er­ence source as clin­i­cal signs can be ob­served and fresh blood sam­ples col­lected. Re­mem­ber that di­ag­nos­ti­cians are not ma­gi­cians; they need your sup­port and above all a rep­re­sen­ta­tive num­ber to eval­u­ate the prob­lem.

Con­clu­sion

When it comes to check­ing the flock there is a whole host of pa­ram­e­ters to look for. It is very im­por­tant that you and your staff are ca­pa­ble of de­tect­ing when some­thing is ab­nor­mal. If you can­not, then dis­ease could get out of hand. Do not fall into the cat­e­gory of ‘look but don’t see’ farm man­age­ment. If this is so, seek sup­port or re­place with knowl­edge­able staff. Try to as­sess your­self and/or staff reg­u­larly. This can be ac­com­plished by lit­er­ally sit­ting with the birds in the house for 30 min­utes at a time. Ask your­self or the staff mem­ber what was seen. If the an­swer is chick­ens then there is a prob­lem. How­ever, if you can give or they share with you a de­tailed de­scrip­tion of flock be­hav­iour or bird con­for­ma­tion then nur­ture this with fur­ther con­tin­u­ing ed­u­ca­tion and train­ing. Spot­ting dis­ease early could make or break the prof­itabil­ity of the busi­ness.¡

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