1 4 6 Feb r u a ry2 0 0 5 Pneumoni a in Calves - Angus · PDF filePneumonia can affect calves...
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Pneumonia can affect calves of any age, from birth through weaning time and after. Most pathogens that cause lung infection are always present in the calf’s environment. They become a problem only when the calf’s immune defenses are compromised by stress. Stress may be due to bad weather, extreme changes in temperature, a long truck haul, overcrowding in a dirty environment or deficiencies of an important mineral, like copper (Cu) or selenium (Se). A newborn calf in a drafty or humid barn with saturated bedding and ammonia fumes that irritate lungs and airways may be a candidate for pneumonia. Viral or bacte rial ? “Most pneumonia cases are caused by pasteurella bacteria, but there are some viral pneumonias,” Salmon, Idaho, veterinarian Robert Cope says. Viral pneumonias may be caused by bovine respiratory syncytial virus (BRSV), infectious bovine rhinotracheitis (IBR) or bovine viral diarrhea (BVD). “These can set a calf up for a more serious bacterial infection. Death from pneumonia doesn’t always have to be bacterial, however,” Cope says. “BRSV can cause enough problems … without any bacteria being involved. This type of viral infection can cause serious lung damage or kill the calf.” A primary viral pneumonia may be mild, but secondary bacterial invaders can move in after the lung tissues are damaged by the virus. Bacterial pneumonia is generally more apt to kill the calf. Viral pneumonia may be insignificant and run its course without treatment — unless a secondary infection, such as pasteurella, turns it into an outbreak that may go through a group of calves with serious economic consequences. Young calves between 2 and 6 weeks of age may be most susceptible to pneumonia. This is the age when temporary immunity provided by antibodies from the dams’ colostrum is starting to wane. Calves that do not get colostrum, don’t get enough colostrum or don’t get it soon enough have less defense against pathogens in their environment. Calves stressed by a hard birth or calves that become chilled immediately after birth may not get up and nurse soon enough, or may not be able to absorb enough maternal antibodies due to stress and hastened thickening of the gut lining. Calves of any age, up through yearlings and older, may develop pneumonia when weather conditions are stressful. Particularly dangerous are extremes of temperature in fall or spring, with hot days and cold nights. Cope says these cases are almost always due to pasteurella. “What seems to be the key is a temperature differential of 40 to 50 degrees Fahrenheit or more,” he says. Fall days with 80°-95° afternoons, dropping to 40° at night, or spring days with 60° afternoons, dropping to 20° at night, can encourage the onset of pneumonia. “With these conditions you will get primary pasteurella infections, and you don’t need a virus to set them off. A virus vaccine won’t protect calves in this instance, but a pasteurella vaccine will,” he explains. Signs of ill n ess A calf with pneumonia usually goes off feed, acts dull and depressed, and may spend a lot of time laying down. It may stand hunched up. The calf’s ears may droop, it may have a snotty or crusty nose, and its respiration may be fast or labored. The calf will move slowly because it is in pain. It may have a cough or noisy breathing. In severe cases the calf may have difficulty breathing and might even breathe with its mouth open or with a grunting sound as the air is forced out of impaired lungs. A thermometer can give a clue as to the seriousness of the problem. If you can confine the calf, take its temperature. “As a general rule, if a calf has a temperature of 106 or higher, it’s usually viral,” Cope says. “If the temperature is 104 or lower, it’s usually bacterial. If it’s up around 106 to 107, it’s usually BRSV, which can be quite serious.” T h e re are a number of pathogens that can cause respiratory disease. What we used to call “shipping fever” is now called bovine respiratory disease (BRD). There are more than 20 bacteria and viruses that can be involved in lung infections, he says. Early treatment cr u cial T h e re are several good drugs available now for treating pneumonia, including Baytril ® , Nuflor ® and Micotil ® , that are all more effective for bacterial infections than the old standard penicillins or oxytetracyclines and sulfas, Cope says, but the key to successful treatment is catching them quickly, and that’s not always easy. “Often by the time a calf is obviously sick, there’s already permanent lung damage,” he says. “The main thing, with pasteurella pneumonias especially, is treating the calf before lung damage can become permanent. There have been studies that indicate the damage can become permanent within less than 8 hours. At that point you will have some scarring, even if you clear up the infection,” Cope says. Whether the calf can make it to adulthood then depends on how much scarring there is. “Once the permanent damage exceeds 20% to 25% of the lung tissue, the calf won’t do well, even if he survives the pneumonia. Those are often the ‘chronics’ that never grow, don’t do well and die about a week before you were going to haul your calves to market,” he says. The calf, even if it seems to be doing OK, will eventually outgrow its lung supply, he says. Either the calf will not grow well, which is fairly common, or it outgrows its lung supply and then suddenly dies. When treating a sick calf, if there is any congestion in the lungs, Cope recommends giving the calf dimethyl sulfoxide (DMSO) intravenously. DMSO helps reduce swelling and inflammation and reduces the fluid in the lungs. When it is difficult to find a vein in a young calf, DMSO can be injected under the skin or administered orally (squirted into the back of the mouth February2005 146 Pneumonia in Calves Bruce Anderson, ve terinarian at the Unive rsity of Idaho Caine Vete r i na ry Tea ching Center, Ca ld we ll, Idaho, says t ha t antibiotics may not always pull a calf t h rough because you may not rea l i ze how sick the ca l f is un t il it’s too la te. “Studies at the Unive rsity of N eb ras ka’s G reat Pla i ns Vete r i na ry Ed u cation Center, w h e regroups of ca l ves we re foll owed from bi rth through feedlot and slaughter showe d the ca l ves t ha t did not ge t good passi ve tra nsfer (from col ostrum) 18 months la ter per- formed less we ll in the feedlot,” he says. “These ca l ves had less functional l ung tissue t han normal ca l ves, proba bly because they had respira to ry infections and pneumonia early in life. It is rea lly the subclinical pneumonias that h u rt you, because you never know t h ese ca l ves we re rea ll y sick,” he ex plains. These are calves that may have been a little dull or off feed, but they never get treated because they don’t appear sick — or you can’t catch them if you do try to treat them. They end up with compromised lungs, however, and do not perform as we ll as the rest of the herd, Anderson says. “At slaughter we find that some of t h ese cattle have 10% to 15% dead lung, or some old ad h esi o ns, and we know that they had a respirato ry problem as a calf.” Permanent damage A calf with pneumonia usu a lly go es off feed, acts dull and depressed, and may spend a lot of time layi ng down. It may a lso stand hunched up. [PHOTO BY CORINNE PATTERSON] Treatment and preve ntion are key to preventing calf loss. S t o ry by HEATHER SMITH T H O M A S
Transcript of 1 4 6 Feb r u a ry2 0 0 5 Pneumoni a in Calves - Angus · PDF filePneumonia can affect calves...
Pneumonia can affect calves ofany age, from birth through weaningtime and after. Most pathogens thatcause lung infection are alwaysp resent in the calf’s enviro n m e n t .They become a problem only whenthe calf’s immune defenses arec o m p romised by stress.
S t ress may be due to bad weather,e x t reme changes in temperature, along truck haul, overc rowding in ad i rty environment or deficiencies ofan important mineral, like copper(Cu) or selenium (Se). A newborncalf in a drafty or humid barn withsaturated bedding and ammoniafumes that irritate lungs and airw a y smay be a candidate for pneumonia.
Vi ral or ba c te rial ?“Most pneumonia cases are
caused by pasteurella bacteria, butt h e re are some viral pneumonias,”Salmon, Idaho, veterinarian RobertCope says. Viral pneumonias may becaused by bovine re s p i r a t o rysyncytial virus (BRSV), infectious
bovine rhinotracheitis (IBR) orbovine viral diarrhea (BVD).
“These can set a calf up for am o re serious bacterial infection.Death from pneumonia doesn’talways have to be bacterial,h o w e v e r,” Cope says. “BRSV cancause enough problems … withoutany bacteria being involved. Thistype of viral infection can causeserious lung damage or kill the calf.”
A primary viral pneumonia maybe mild, but secondary bacterialinvaders can move in after the lungtissues are damaged by the viru s .Bacterial pneumonia is generallym o re apt to kill the calf. Vi r a lpneumonia may be insignificant andrun its course without treatment —unless a secondary infection, such asp a s t e u rella, turns it into an outbre a kthat may go through a group ofcalves with serious economicc o n s e q u e n c e s .
Young calves between 2 and 6weeks of age may be most susceptibleto pneumonia. This is the age whent e m p o r a ry immunity provided byantibodies from the dams’ colostru mis starting to wane. Calves that do
not get colostrum, don’t get enoughc o l o s t rum or don’t get it soonenough have less defense againstpathogens in their enviro n m e n t .Calves stressed by a hard birth orcalves that become chilledimmediately after birth may not getup and nurse soon enough, or maynot be able to absorb enoughm a t e rnal antibodies due to stress andhastened thickening of the gut lining.
Calves of any age, up thro u g hyearlings and older, may developpneumonia when weatherconditions are stressful. Part i c u l a r l yd a n g e rous are extremes oft e m p e r a t u re in fall or spring, withhot days and cold nights. Cope saysthese cases are almost always due top a s t e u rella.
“What seems to be the key is at e m p e r a t u re diff e rential of 40 to 50d e g rees Fahrenheit or more,” hesays. Fall days with 80°-95°a f t e rnoons, dropping to 40° at night,or spring days with 60° aftern o o n s ,d ropping to 20° at night, canencourage the onset of pneumonia.“ With these conditions you will getp r i m a ry pasteurella infections, andyou don’t need a virus to set themo ff. A virus vaccine won’t pro t e c tcalves in this instance, but ap a s t e u rella vaccine will,” he explains.
S ig ns o f ill n essA calf with pneumonia usually
goes off feed, acts dull andd e p ressed, and may spend a lot oftime laying down. It may standhunched up. The calf’s ears mayd roop, it may have a snotty or cru s t ynose, and its respiration may be fastor labored. The calf will moveslowly because it is in pain. It mayhave a cough or noisy breathing. Ins e v e re cases the calf may haved i fficulty breathing and might evenb reathe with its mouth open or witha grunting sound as the air is forc e dout of impaired lungs.
A thermometer can give a clue asto the seriousness of the problem. Ifyou can confine the calf, take itst e m p e r a t u re. “As a general rule, if acalf has a temperature of 106 orh i g h e r, it’s usually viral,” Cope says.“If the temperature is 104 or lower,i t ’s usually bacterial. If it’s up aro u n d106 to 107, it’s usually BRSV, whichcan be quite serious.”
T h e re are a number of pathogensthat can cause re s p i r a t o ry disease.What we used to call “shippingfever” is now called bovinere s p i r a t o ry disease (BRD). There arem o re than 20 bacteria and viru s e sthat can be involved in lunginfections, he says.
Ea r l y t rea t m e n t cr u cialT h e re are several good dru g s
available now for tre a t i n gpneumonia, including Baytril®,N u f l o r® and Micotil®, that are allm o re effective for bacterialinfections than the old standardpenicillins or oxytetracyclines andsulfas, Cope says, but the key tosuccessful treatment is catchingthem quickly, and that’s not alwayse a s y. “Often by the time a calf isobviously sick, there ’s alre a d yp e rmanent lung damage,” he says.
“The main thing, withp a s t e u rella pneumonias especially, ist reating the calf before lung damagecan become permanent. There havebeen studies that indicate thedamage can become perm a n e n twithin less than 8 hours. At thatpoint you will have some scarr i n g ,even if you clear up the infection,”Cope says.
Whether the calf can make it toadulthood then depends on howmuch scarring there is. “Once thep e rmanent damage exceeds 20% to25% of the lung tissue, the calf won’tdo well, even if he survives thepneumonia. Those are often the‘ c h ronics’ that never gro w, don’t dowell and die about a week before youw e re going to haul your calves tomarket,” he says.
The calf, even if it seems to bedoing OK, will eventually outgro wits lung supply, he says. Either thecalf will not grow well, which isfairly common, or it outgrows itslung supply and then suddenly dies.
When treating a sick calf, if thereis any congestion in the lungs, Coperecommends giving the calfdimethyl sulfoxide (DMSO)i n t r a v e n o u s l y. DMSO helps re d u c eswelling and inflammation andreduces the fluid in the lungs. Whenit is difficult to find a vein in a youngcalf, DMSO can be injected underthe skin or administered orally( s q u i rted into the back of the mouth
Feb r u a ry2 0 0 51 4 6
Pneumoni ain Calves
B r u ce Anderson, ve te r i na r ian at the Unive rsi t y o f I daho Caine Ve te r i na ryTea ch i ng Ce n te r, Ca ld we ll, Ida h o, says t ha t a n t i bi o t i cs may n o t a l ways pull a ca l ft h rough beca use you may n o t rea l i ze how si ck the ca l f is un t il i t ’ s too la te .
“ S tu d i es a t the Unive rsi t y o f N eb ras ka ’ s G rea t P la i ns Ve te r i na ry Ed u cation Ce n te r,w h e re gro u ps o f ca l ves we re foll owed from bi rth through fe e d l o t and sla u g h ter showe dthe ca l ves t ha t did not ge t good passi ve tra ns fer (from col ostrum) 18 months la ter per-formed less we ll in the feedlot,” he says. “These ca l ves had less fun c t i o na l l ung tissu et han norma l ca l ves, proba bl y b e ca use they had resp i ra to ry i n fe c t i o ns and pneumoniaea r l y in life. It is rea ll y the su b cl i n i ca l p n e u m o n ias t ha t h u rtyou, beca use you never knowt h ese ca l ves we re rea ll y si ck,” he ex pla i ns .
T h ese are ca l ves t ha t may ha ve been a little dull or off feed, bu t t h e y n e ver ge t t rea te db e ca use they d o n ’ t a pp ear si ck — or you ca n ’ t ca tch them if you do try to trea t them. T h e yend up with co m p ro m ised lungs, howe ve r, and do not p e rform as we ll as the rest o f t h eh e rd, Anderson says. “At sla u g h ter we find tha t some of t h ese ca t t le ha ve 10% to 15% deadl ung, or some old ad h esi o ns, and we know tha t t h e y had a resp i ra to ry p roblem as a ca l f. ”
Permanent damage
A ca l f with pneumonia usu a ll y go es o f f feed, acts d ull and depressed, and may spend al o t o f time layi ng down. It may a lso stand hun ched up. [ P H OTO BY CO R I N N E PATT E R S O N ]
Trea t m e nt a nd preve ntion are key t op reve nt i ng calf loss .
S t o ry byH E ATHER SMITH T H O M A S
1 4 7Feb r u a ry2 0 0 5
by syringe). DMSO is readily absorbedby the body tissues and will be takeninto the lungs by the bloodstream; youcan smell it on the calf’s breath almosti m m e d i a t e l y.
S u p p o rtive care is very import a n t .Make sure the calf is warm, dry andp rotected from bad weather. If the calf isnot eating or drinking, you may need tof o rce-feed fluids, or give fluids withnutrients (milk to a preweaning age calf).Anything you can do to help a calf willenable it to fight the battle mores u c c e s s f u l l y.
If a calf has a high fever and does notfeel like eating or drinking, anti-i n f l a m m a t o ry drugs like Banamine® c a nlower the fever and make it feel better— often enough that the calf will starteating and drinking again. Do not giveBanamine to a dehydrated calf, becauset h e re is risk for kidney damage. Using itin conjunction with fluid therapy,h o w e v e r, can be helpful.
Antibiotics are usually given, even ifthe pneumonia may be viral, sinces e c o n d a ry bacterial infection may occurand is usually deadly. Be diligent witht reatment and don’t quit too soon. Evenif the calf is feeling better, bre a t h i n gb e t t e r, eating, drinking and its fever isdown, keep antibiotic levels high for atleast two full days after all symptoms aregone, or the calf may relapse and bemuch harder to save the second timea round.
P re vention is p re fe ra bleT h e re are some good vaccines
available for helping prevent re s p i r a t o rydisease in calves, Cope says, adding hehas had good luck giving Pre s p o n s e® o rO n e - S h o t® at branding time, or atabout a month of age.
“One vaccination at branding timew o n ’t carry them all the way thro u g hthe next winter,” he cautions. “It worksbest to give these calves another shotjust before weaning.”
If you only give one shot during ac a l f’s early life, it’s usually best to give itp reweaning, Cope says, a couple weeksb e f o re you take calves off the cows.Most of the pneumonia vaccines aredesigned for weaning-age calves, hes a y s .
“ We have also used this type ofvaccine in the face of an outbre a k , ”Cope says. “In our experience we usuallyfind that calves are protected at sevendays postvaccination. We’ve had weanedcalves getting sick and have given themall a vaccination, and this pretty wellshuts down new cases within a week.”
The best prevention in earlycalfhood is to make sure each calf getsadequate colostrum soon enough, hesays. “There is no substitute for goodc o l o s t rum. If a calf doesn’t get it, he isvulnerable to every t h i n g .
“This protection is probably waningby the time most calves are 3 weeks old,h o w e v e r, and many cows’ immunity top a s t e u rella isn’t that great,” hecontinues. “If you have cases of springand summer pneumonia in calves, itmay pay to vaccinate calves at around amonth of age. It’s also important to see ift h e re are any underlying problems on
h e rd health. The cows may need a highernutrition level. Energ y, protein and traceminerals are things you should check ifcalves are getting pneumonia. A cow that’snot in good shape herself will not havegood colostru m . ”
If the cow herself does not have ap roperly functioning immune system dueto being low on selenium, energ y, pro t e i n ,etc. — or you have cattle that are
persistently infected (PI) with BVD — thecalf will not get good colostrum. So, if youa re having a problem in the calves, youneed to look hard at the cows. If you aregetting pneumonia in calves less than 3weeks old, it is generally less the calf’s faultthan the cow’s, Cope says.
Most calves that have good colostru mand nutrition can handle quite a bit ofweather stress without becoming sick, he
says, especially if they have some shelter.T h e re are more effective drugs fort reating pneumonia than there used to be,but prevention is still preferable. A goodtotal herd health program will go a longway toward preventing pneumonia, andthat involves a lot more than justv a c c i n a t i o n s .
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