8/2/2019 Acidosis in Feedlot Cattle Practical Observations

1/4

A C I D O S I S I N F E E D L O T C A T T L E : P R A C T I C A L O B S E R V A T I O N S 1C . J . E l a m

Agricultural Tecbnology, Inc., Santa Ynez, California 93 46 0S U M M A R Y

A c i d o s i s i n c a t t l e i s c a u s e d b y e x c e s s i v ei n g e s t i o n o f f e e d s w h i c h a r e r i c h in r e a d i l ya v a i l a b l e c a r b o h y d r a t e s . T h u s , f a c t o r s w h i c hc o n t r i b u t e t o e x c e s s i v e i n g e s t i o n o f h i g h e n e r g yd i e t s a r e p r e d i s p o s i n g t o a c i d o s i s. M a n y o f t h ec o n d i t i o n s w h i c h p r e v a i l i n c a t t l e f e e d l o t sc o n t r i b u t e t o v a r i ab l e f e e d i n t a k e b y c a t t le a n ds u b s e q u e n t l y t o a c id o s i s.A m u l t i t u d e o f m a n a g e m e n t f a c t o r s a r ei n v o l v e d i n s u c c e s s f u l l y f e e d i n g l a r g e n u m b e r so f c a t t l e u n d e r t y p i c a l f e e d l o t c o n d i t i o n s .M a n a g e m e n t is m o s t c r i t ic a l d u r in g t h e f o l l o w -i n g p e r i o d s : 1 ) s t a r t i n g c a t t l e o n f e e d , 2 )g r a d u a t i n g c a t t l e t o h i g h e r c o n c e n t r a t e r a t i o n s ,3 ) d u r i n g c h a n g e s i n w e a t h e r , 4 ) d u r i n g l o n gp e r i o d s o n a f i n i s h i n g d i e t , a n d 5 ) w h e n c a t t l ea r e e x t r e m e l y h u n g r y d u e t o f e e d i n g p r o b l e m so r e r r o r s .

T h e r e a p p e a r t o h e s o m e b r e e d d i f fe r e n c e s int h e d e v e l o p m e n t o f a c id o s i s.( K e y W o r d s : A c i d o s i s , C a tt l e , F e e d l o t C a t t l e. )

I N T R O D U C T I O NI n r e c e n t y e a r s i t h a s b e c o m e a r o u t i n e

p r a c t i c e i n f e e d l o t s t o r a p i d l y i n c r e a s e t h ec o n c e n t r a t e p o r t i o n o f t h e d i e t b e i n g fe d t oc a t t l e i n o r d e r t o h a v e t h e m o n a h i g h - c o n c e n -t r a t e o r e v e n a n a l l - c o n c e n t r a t e d i e t a s s o o n a sp o s s i b l e . I n g e n e r a l , t h e e c o n o m i c s i n v o l v e dh a v e u s u a l l y f a v o r e d t h i s p r a c t i c e w h e n f i n i s h -i n g c a t t l e f o r m a r k e t . T h i s s y s t e m o f f e e d i n gc a t t l e ha s re s u l t e d i n t h e f r e q u e n t o c c u r r e n c e o fa p r o b l e m c o m m o n l y c a l l e d " a c i d o s i s " . A c i d o -s is r ef e r s t o t h e s y n d r o m e i n r u m i n a n t s w h i c h i sb r o u g h t a b o u t b y e x c e s si v e i n g e s ti o n o f f e e d sw h i c h a r e r ic h i n r e a d i l y a v a i l a b le c a r b o h y -d r a t e s , s u c h a s s t a r c h a n d s u g a r .

~Presented a t the Sy mpo sium on Acidosis inFeedlot Ca t t le a t the 67th Annua l Meet ing of theAmerican Society of Animal Science, Fort Collins,July 28 t o 30, 1975. Co-sponsored by the AmericanSoc ie ty of Animal Sc ience and the Commit tee onAnimal N utr i t ion , N at iona l Research Counc il .

S i n ce i t h a d b e e n s h o w n t h a t t h e r e is ab u i l d u p o f D - l a ct i c a c i d in t h e r u m e n a n d b l o o do f a n i m a l s d u r i n g a c id o s i s, D u n l o p a n d H a m -m o n d ( 1 9 6 5 ) s u g g e s te d t h e n a m e D - l ac t ic a c i-d o s is f o r t h is m a l a d y . I t is c o m m o n l y s h o r t e n e dt o a c i d o si s . S o m e o t h e r c o m m o n n a m e s f o r t h es a m e c o n d i t i o n a r e: o v e r e a t i n g , a c u t e i m p a c -t i o n , g r a i n e n g o r g e m e n t , f o u n d e r , a n d o v e r l o a d -i n g . O f c o u r s e , s o m e o f t h e s e c o m m o n n a m e sd o n o t a c c u r a t e l y r e f le c t t h e p r o b l e m o f a c i d o -sis.Signs of Acidosis. F o l l o w i n g th e i n g e s t io n o fa n e x c e s s iv e a m o u n t o f r e a d i l y a v a i l a b le c a rb o -h y d r a t e f e ed s , s o m e o f t h e o u t w a r d s ig n s o fa c i d o s i s a r e a n o r e x i a , d i a r r h e a , m u c o u s i n f e c es ,d e h y d r a t i o n , i n c o o r d i n a t i o n a n d , s o m e t i m e s ,d e a t h .

W h e n a c i d o s i s d e v e l o p s i n t h e a n i m a l t h ef o l l o w i n g p h y s i o l o g i c a l c h a n g e s h a v e b e e n o b -s e r v e d :

1 . I n c r e a s e d l e v e l o f l a c t i c a c i d i n t h e t u r e e na n d b l o o d .2 . R e d u c t i o n i n r u m e n p H a n d b l o o d p H .3 . I n c r e a s e d o s m o t i c p r e s s u r e i n t h e r u m e n .4 . D e s t r u c t i o n o f g r a m n e g a t i v e b a c t e r i a a n d

p r o l i f e r a t io n o f g r a m p o s i t i v e b a c t e ri a i nt h e r u m e n .

5 . R e d u c t i o n i n r u m e n p r o t o z o a l c o u n t .6 . R u m e n i t i s a n d s l o u g h in g o f r u m e n e p i t h e -

l i u m .7 . R u m e n s ta s i s.8 . R e d u c e d u r i n e p H .9 . D e h y d r a t i o n a n d h e m o c o n c e n t r a t io n .Experimental Acidosis. A c i d o s i s h a s b e e n

p r o d u c e d e x p e r i m e n t a l l y b y m a n u a l l y e n g o rg -i n g r u m e n - f i s t u l a t e d a n i m a l s w i t h g r a i n o r b yv o l u n t a r y e n g o r g e m e n t o f " s t a r v e d " a n i m a l s.

U h a r t a n d C a r r o l l (1 9 6 7 ) w e r e a b l e t op r o d u c e a c i d o s i s i n s t e e r s b y i m m e d i a t e l yc h a n g i n g t h e m f r o m a r a t i o n o f a l f al f a h a y t oo n e c o n t a i n i n g 90% g r a i n . S t e e r s r e p o r t e d l yw e n t " o f f - f e e d " w i t h i n 2 t o 3 d a y s . O t h e rc h a n g es t h e y n o t e d i n c l u d e d a m a r k e d i n c re a s ei n r u m e n l a c t ic a c i d le v e l a n d d e c r e a s e s i nr u m e n p H a n d u r i n e p H .

8 9 8JOU RNA L OF A NIMAL SCIENCE, Vol . 43 , No. 4 (1976)

8/2/2019 Acidosis in Feedlot Cattle Practical Observations

2/4

AC I DOSI S I N F EEDLO T C ATTLE 899C h a n g es t o t h e r u m e n e p i t h e l i u m w e r e r e -

p o r t e d b y A h r e n s ( 1 9 6 7 ) . T h e s e c h an g e s i n -c l u d e d t h e l o ss o f k e r a t in a n d v a c u o l a t i o n o fc y t o p l a s m , r u p t u r e o f c e il s , m i c r o v e s ic l e f o r m a -t i o n , a n d n e u t r o p h i l i c i n f i l t r a t i o n . T h e a ss o c i a -t i o n o f l a c t ic a c id o s i s w i t h r u m e n i t i s w a s s h o w nb y t h e f a c t t h a t e p i t h e l i a l c h a n g e s w e r e o b -s e rv e d u p o n t h e a d d i t i o n o f i s o t o n i c l a ct i c a c i ds o l u t i o n t o t h e r u m e n .

P r e d i s p o s i n g F e e d l o t F a c t o r s . O u r f i r m i sr e t a i n e d b y c a t t l e f e e d i n g o p e r a t i o n s i n j u s ta b o u t a l l a r e a s o f t h e U . S . a n d s e v e r a l f o r e i g nc o u n t r ie s . A s a r e s u l t, w e h a v e t h e o p p o r t u n i t yt o f r e q u e n t l y o b s e r v e c a tt l e b ei n g f e d a w i d ev a r i e t y o f f e e d s a n d u n d e r a w id e ra n g e o fc o n d i t i o n s . I n t h i s p r e s e n t a t i o n i t is m y p u r p o s et o p o i n t o u t s o m e o f t h e o b s e r v a ti o n s w h i c hh a v e b e e n m a d e b y p e o p l e i n t h e c a t t le f e e d i n gi n d u s t r y w i t h r e g a r d t o l a c t i c a c i d o s i s i n c a t t l e .N a t u r a l l y , t h e s e o b s e r v a t i o n s o r a s s o c ia t i o n sh a v e n o t b e e n m a d e u n d e r c o n t r o l l e d c o n d i -t i o n s , b u t , o n t h e o t h e r h a n d , h a v e b e e n s e eno f t e n e n o u g h t o j u s t i f y p o i n t i n g o u t a s p r ac t i c a lc o n s i d e r a t i o n s .

C a t t l e f e e d e r s a r e i n b u s i n e s s w i t h t h eo b j e c t i v e o f m a k i n g a p r o f i t a n d a s a r e s u l tu s u a l l y " p u s h " c a t t l e to g a in at t h e i r m a x i m u mp o t e n t i a l r a t e . T h i s u s u a l l y i n v o l v e s g e t t i n gc a t t l e o n t o f u l l - f e e d o f a h i g h - c o n c e n t r a t e d i e tv e r y r a p i d l y . I n a d d i t i o n , th e c o m m e r c i a l c a t t l ef e e d i n g b u s i n e s s i s s u c h t h a t v o l u m e is h e l p f u li n o r d e r t o b e e ff i c i e n t a n d c o m p e t i t i v e a n d ,t h e r e f o re , i n d i v i d u a l f e e d l o t s o f t e n c o n t a i n1 0 , 0 0 0 t o 4 0 , 0 0 0 h e a d o f c a t tl e , a n d s o m e e v e nm o r e .

E c o n o m i c s a l s o f a v o r p r o c e s s i n g th e g r a i np o r t i o n o f t h e r a ti o n b y o n e o f s e v er a l m e t h o d sa v a i l ab l e w h i c h w i l l i n c r e a s e t h e s t a r c h a v a i l a b i l-i t y . T h e s e p r o c e s s e s , e .g . , s t e a m f l a k i n g , e x p l o d -i n g , e t c . , u s u a l l y r e s u l t i n i n c r e a s e d a v a i l a b i l i t yo f s t a r c h ( T r e i et al . , 1 9 7 0 ) a n d t h u s i n c r e a s e i tsr a t e o f d e g r a d a t i o n i n t h e r u m e n . T h u s , t h es t a g e i s s e t f o r a c i d o s i s .

T h e r e a r e m a n y b a r r ie r s t h a t c a n i n t e r f e rew i t h t h e p r o p e r f e e d i n g o f l a r g e n u m b e r s o fc a t t l e c o n c e n t r a t e d i n p e n s w i t h i n a f e e d l o t .N a t u r a l l y , t h e l a r g e r t h e f e e d l o t t h e m o r ep e o p l e a n d m a c h i n e r y n e c e s s a ry to c o n d u c t t h ej o b o f f e e d i n g . I t t a k e s s e v e r a l c a p a b l e p e o p l ew i t h g o o d s u p e r v i s i o n t o o p e r a t e t h e f e e dt r u c k s a n d d o a g o o d j o b o f f e e d in g t h e c a t t lei n a la r g e f e e d l o t . F r e q u e n t l y , o n e f e e d e r m i g h tb e r e s p o n s ib l e fo r f e e d in g 8 , 0 0 0 t o 1 0 , 0 0 0 h e a do f c a t t l e .

C a t t le m a y b e p e n n e d i n p e n s o f v ar i o u s

s i ze s a n d s h a p e s . P e n c a p a c i t i e s c o m m o n l yr a n g e f r o m 5 0 t o 3 0 0 h e a d . S o m e f e e d l o t s a l s oh a v e l a rg e r p e n s t h a t m a y h o l d u p t o 1 , 0 0 0h e a d . O f t e n p e n s o f t h e s a m e si z e m a y n o tc o n t a i n t h e s a m e n u m b e r o f c at t l e. L a r g er p e n sw i ll o f t e n h a v e c a t t l e a d d e d p e r i o d i c a l l y f o r aw e e k o r m o r e b e f o r e th e n u m b e r r e m a i n sr e l at i v e ly c o n s t a n t f o r t h e m a j o r p o r t i o n o f t h ef e e d i n g p e r i o d . L i k e w i s e , c a t t l e a r e o f t e n s o l da n d s h i p p e d o u t i n a s i m i l ar m a n n e r s o t h a t t h ec a t t l e i n a p e n a r e s h i p p e d a t i n t e r v a l s , a n d t h ep e n c o u n t w i l l b e r e d u c e d s e v e r a l t i m e s b e f o r et h e p e n i s f i n a l ly e m p t y . A l l o f t h e s e f a c t o r si n c re a s e t h e d i f f i c u l t y o f p r o p e r l y fe e d i n gc a t t l e .

P e r h a p s m o r e s e r i o u s a r e t h e p e r s o n n e lp r o b l e m s w h i c h s e e m t o b e c o m m o n i n t h ef e e d l o t i n d u s t r y . R e l a t i v e l y ra p i d tu r n o v e r o fc o w b o y s a n d f e e d t r u c k d r i v es i s c o m m o n l ye x p e r i e n c e d a n d m a k e s i t v e ry d if f i c u lt t o k e e pt r a i n e d p e o p l e o n t h e s e i m p o r t a n t j o b s . T h ed a m a g e r e s u l t i n g t o a p e n o f c a t t l e t h a t i s f e d b ye r r o r a fi n i s h i n g d i e t w h e n t h e y s h o u l d h a v eb e e n f e d a s t a r t i n g d i e t c a n b e d i f f i c u l t t oo v e r c o m e . N e w l y a r r i v e d c a tt l e c a n s o m e t i m e sd e v e l o p a c i d o s i s f r o m e a t i n g a h o t r a t i o n l e f t i nt h e b u n k f r o m p r e v i o u s c a t t l e . C o n t r i b u t i n g t ot h i s t y p e o f p r o b l e m a r e t h e d a y s o f f a n dh o l i d a y s t h a t a r e a l l o w e d . I t is c o m m o n p r a c -t i ce f o r " s k e l t o n c r e w s " t o o p e r a t e o n S u n d a y sa n d h o l i d a y s a n d c a t t l e a r e o f te n f e d h e a v i lyt h e d a y b e f o r e s o t h a t o n l y a s m a l l a m o u n t o ff e e d i n g w i l l b e n e c e s s a r y b y t h i s c r e w . U s u a l l y ,t h e r e a r e m o r e p e n s o u t o f f e e d o n M o n d a ym o r n i n g t h a n a n y o t h e r d a y o f t h e w e e k .

Cri t ica l Per iods . N u m e r o u s f a c t o r s a r e p r e -d i s p o s i n g t o a n i m a l s c o n s u m i n g a n e x c e s s iv eq u a n t i t y o f h i g h - e n e r g y f e ed s . F r o m a p r a c t i c a ls t a n d p o i n t i n t h e f e e d l o t , a c i d o si s p r o b l e m s a reu s u a l l y e n c o u n t e r e d : 1 ) w h e n s t a r ti n g c a tt l e o nf e e d , 2 ) w h e n g r a d u a t i n g c a t t l e t o h i g h e rc o n c e n t r a t e r a t i o n s , 3 ) w h i l e f e e d i n g c a t t l e o n ah i g h - e n e r g y f i n i s h i n g d i e t f o r l o n g p e r i o d s , 4 )a f t e r w e a t h e r c h a n g e s , a n d 5 ) a f t e r p e r i o d s i nw h i c h s o m e p r o b l e m , su c h a s a m i l l b r e a k d o w n ,h a s r e s u l te d i n t h e c a t t l e b e i n g o u t o f fe e d a n dh u n g r y . M a n a g e m e n t p r a c t i c e s a r e v e r y c r i t i c a ld u r i n g t h e s e p e r i o d s .

S t a r t i n g C a t t l e in t h e F e e d l o t . I n o r d e r t os t a r t c a t t l e o n f e e d w i t h o u t c a u s in g r u m e nd a m a g e d u e t o a c i d o s i s , i t i s h e l p f u l t o k n o wt h e p r e v i o u s h i s t o r y o r b a c k g r o u n d o f th ec a t t le . T h a t i s, t h e u s u a l p r o b l e m w i t h n e wc a t t le t h a t h a v e n ' t r e c e i v e d m i x e d f e e d b e f o r e iso n e o f g e t t in g t h e m t o e a t e n o u g h f e e d r a t h e r

8/2/2019 Acidosis in Feedlot Cattle Practical Observations

3/4

900 ELAMthan eating too much feed. On the other hand,cattle that have previously had mixed feed orthat have eaten out of feed bunk s usually starton feed rapidly and will sometim es eat tooheavily and bring about digestive disturbanceseven when fed relatively low-concentrate ra-tions. Thus, for starting hungry cattle that areknown to have been fed mixed feed previouslyit is important that they be fed a low-concen-trate, high-roughage level for several days be-fore they are graduated to higher levels ofconcentrate.

A program often suggested for starting cattleon feed involves feeding a starting diet made upof 40 to 60% roughage, cont aini ng approxi-mately 40 Meal NEg, plus feeding long hay adl ib i t um for the first few days. Once cattle arefilled and are eating the diet, the hay isdisc ontin ued. The starting diet is then con-tinued until most of the cattle appear to beeating to near capacity before a ration change ismade.

Cbanging Diets. When raising the caloricdensity of the diet, or when increasing theconcentrate portion of the diet, it is impo rtan tto make increases gradua lly. A safe rule is toincrease the level of net energy about 10% at atime. For example, if cattle are started on a dietcon tainin g 40 Mcal NEg per 45.5 kg, the y arethen moved up to 44 Mcal and then on to a 48Mcal diet, et cetera.

Another precaution is never to make a dietchange when cattle are hungry due to lack offeed. In additi on, if cattle fed a finishing diethave been out of feed for a sufficie nt time tobecome extremely hungry, they should be fedone feeding of a lower energy diet in order tofill them before resumi ng the finishing diet. Theobjective is to feed cattle a low energy diet at atime when they are likely to eat a large amount.Then return them to the regular diet at the nextfeeding, when they are less hungry.

Feed ing H igh -Energy D ie t s , In general, high-energy diets are syn on ym ous with high concen-trate diets which in turn usually contain highlevels of grain and low levels of roughage, It isdifficult to feed a diet containing a high levelof grain and low roughage without eventuallyexperiencing some acidosis, founder or bloat.Naturally, the longer cattle are fed this type ofdiet the greater the chance for acidosis tooccur.

If some of the grain in a high-energy diet isreplaced isocalorically with roughage and fatthere is usually less acidosis experienced. In

addition replacement of grain with other highenergy ingredients, such as molasses dried beetpulp, will tend to redu ce acidosis problems.

While high-grain diets are p redisposing toacidosis, some grains are worse than others.Wheat is generally considered the worst grain asfar as development of acidosis is concerned.Milo and corn diets are also highly conduciv e tothe occurrence of acidosis, while barley isobserved to be the least predisposing to acido-sis.

Weatber and Seasonal Factors . The highestincidence of acidosis and similar problems isobserved in feedlots during the warmer seasonsand is especially high during the summermonths. The reason for this is unkno wn, but isprobably related to fluctuations in feed intake.Livestock and other animals are known to besensitive to changes in barometric pressure andhave been observed to reflect weather changeswith marked changes in their eating and otherbehavioral patterns. Acidosis in feedlot cattle isoften associated with weather changes and theresultant disruption of feed consumption pat-terns. In additi on, when rain is involved andfeed becomes wet and possibly even moldy,feed intake usually drops. When fresh dry feedis offered again there can be a marked increasein feed intake which results in some cattledeveloping acidosis.

Breed D i f f e rences . Some breed differencesappear to exist regarding the development ofacidosis. Brahman cattle are observed in feed-lots to develop founder more frequently thancattle of the English beef breeds. Researchresults in Florida (llentges, 1970) confirmedthis observation and revealed that followingengorgement with a high concentrate diet bloodlactate levels increased more rapidly in Brah-mans than in Herefords or Angus. Holsteinsappear to be more resistant to acidosis, andfounder is uncommon in Holsteins that arefinished for beef.

L I T E R A T U R E C I T E DAhrens, F. A. 1967. Histamine, lactic acid, andhypertonicity as factors in the development o frumenitis in cattle. Amer. J. Vet. Res. 28:1335.Dunlop, R. H. and P. B. Hammond. 1965. D-lacticacidosis of ruminants Ann. N.Y . Acad. Sci.

1 1 : 1 1 0 9 .Hentges, Jr., J. F. 1970. Problems in formulatingrations to avoid digestive disorders in full-fedBrahmans as compared to cattle of British breedorigin. Mim. ser. no. AN70-8, Florida, Agr. Exp.Sta.Trei, J., W. H. Hale and B. Theurer. 1970. Effect o f

8/2/2019 Acidosis in Feedlot Cattle Practical Observations

4/4

A C I D O S IS I N F E E D L O T C A T T L E 9 0 1

g r a i n p r o c e s s i n g o n in vitro g a s p r o d u c t i o n . J . U h a r t , B . A . a n d F . D . C a r ro l l. 1 9 6 7 . A c i d o s i s i n b e e fA n i t a . S e i. 3 0 : 8 2 5 . s t e e r s . J . A n i m . S e i. 2 9 : 1 1 9 5 .