Calf Scours (NCD)

Wangaratta Chronicle - North East Regional Extra - - News - Dr Meagan Lee BVSc (Hons), VET­ERI­NAR­IAN

NEONA­TAL Calf Di­ar­rhoea (NCD) is one of the most com­mon and frus­trat­ing dis­eases of cat­tle, mainly in calves less than six weeks of age.

Out­breaks of NCD can be costly for pro­duc­ers as treat­ment is time con­sum­ing and neona­tal death rep­re­sents a sub­stan­tial loss of profit from the cow. Sur­vivors have sub­se­quent re­duced growth rate, wean­ing weight and dif­fi­culty at­tain­ing an ad­e­quate join­ing weight.

NCD usu­ally re­sults from a com­bi­na­tion of three fac­tors: ad­verse en­vi­ron­ment, poor host im­mu­nity and a high chal­lenge from the in­fec­tious agents, al­though se­ri­ous im­pair­ment of any one of these fac­tors can re­sult in a NCD out­break.

“Ad­verse en­vi­ron­ment” re­lates to the con­di­tions the neonate is be­ing raised in.

Stress from weather, lack of shel­ter, high stock­ing rates with gross fae­cal con­tam­i­na­tion and heavy pick up of in­fec­tious agents all con­trib­ute to NCD out­breaks.

Healthy calves can be sub­clin­i­cally in­fected and am­plify en­vi­ron­men­tal con­tam­i­na­tion.

All ma­jor gas­troin­testi­nal pathogens are com­monly car­ried by asymp­to­matic adult cows and fae­cal shed­ding of these pathogens tends to in­crease around par­tu­ri­tion.

Many other an­i­mals, birds and flies are po­ten­tial vec­tors of cryp­tosporid­ium and sal­mo­nella.

Feral an­i­mals and do­mes­tic pets are po­ten­tial reser­voirs of Ro­tavuirus.

“Poor host im­mu­nity” re­lates pre­dom­i­nately to fail­ure of colostral (ini­tial ma­ter­nal milk) trans­fer from the cow to the calf within the first 12 hours of birth and the im­mune sta­tus of the cow.

A neona­tal calf should re­ceive at least four litres of colostrum in this 12 hour pe­riod.

“The de­gree of chal­lenge” is the po­ten­tial ex­po­sure, in­take and dose of the pathogen in­volved.

In a dis­ease out­break there is an am­pli­fy­ing effect with each new, in­fected an­i­mal in­cu­bat­ing and then shed­ding the in­fec­tious agent in in­creas­ing num­bers.

The in­fec­tious cause of NCD can be quite var­ied. The most com­mon pathogens as­so­ci­ated with NCD in suck­ling beef cat­tle in south­east­ern Vic­to­ria are Ro­tavirus and Cryp­tosporidia (pro­to­zoa).

Other ma­jor causes of NCD in ju­ve­nile bovines in both beef and dairy herds in­clude: Coron­avirus, Coc­cidia and Giar­dia pro­to­zoa, E.coli, Sal­mo­nella, Clostridial and Yersinia bac­te­ria.

Treat­ment should be di­rected at the most com­mon de­range­ments seen in NCD; de­hy­dra­tion, aci­do­sis, sep­sis and hy­po­gly­caemia.

Con­tact your vet for in­for­ma­tion if you sus­pect NCD in your calves.

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