Post by Joann on Oct 9, 2006 12:20:21 GMT -5
Yesterday under a post about feeding beet pulp Kelsey gave us some warnings and Heather provided an analysis on feeding beet pulp. I do not see this post today. Here is some further information on the subject.
The recent spinach recall caused by contamination with E. coli .0157:H7 has us all worried about this important issue. It is a relatively new problem, therefore new information will continue to emerge making it necessary for us to readjust our thinking from time to time. Some facts seem beyond challenge. Kelsey was almost correct yesterday in her statement posted under the heading Feeding Beet Pulp, that if no cattle were fed grain nobody would sicken or die of poisoning from this dangerous form of E. coli. I say “almost” because now that the genie is out of the bottle the organism can now be found in numerous other species. If nobody had ever fed grain to cattle at the levels current in feedlots the problem would not have developed. Studies have been consistent in showing that cows on pasture or hay do not harbor this dangerous organism and that as little as five days of forage feeding to infected cattle results in as much as a 1000 fold decrease in shedding of the organism.
E. coli is a bacterium which makes its home in the hindgut. Even when the rumen is deliberately inoculated it has been impossible to recover E. coli 0157:H7 from the rumen. We must never say never, because sometimes even benign E. coli will find its way into the rumen, usually due to pastured cows using a contaminated farm pond. The E. coli don’t like it there and kicks up a fuss and normal rumen activity is slowed down, but if the cows have no other water source they will have no choice but to swallow E. coli. As a general statement, it is safe to say that E. coli inhabits the hindgut, not the rumen.
In cattle fed a high starch(carbohydrate) diet it becomes impossible for the rumen to successfully buffer (neutralize) it all or to properly ferment it. It passes over into the true gut where much is absorbed and thence to the hindgut where it produces abnormally acid conditions. Normal old fashioned E. coli thrives in a medium closer to neutral. E. coli 0157:H7 has evolved to survive at this low (acidic) pH. Normal E. coli even if it finds its way into food is destroyed by acid shock in the human stomach. This is a survival mechanism which has stood humans and other monogastric (single stomach) species well for our entire existence. Life devoid of any challenge from E. coli has never been possible. Even if some bacteria make it past the stomach (levels of hydrochloric acid in the stomach can vary) illness is usually not too serious. E. coli 0157:H7 is an enterohemorrhoragic E. coli (EHEC) which upon reaching the colon can cause severe symptoms or death. One researcher states that “Results indicate that switching cattle from grain to forage could potentially reduce EHEC populations in cattle prior to slaughter; however the economic impact of this needs to be examined.” (see footnote).
In other words it would cost a lot of money to institute this switch in feedlots or confinement dairies. Those of us who feed hay know all about how much trouble it is to store, handle and feed out. Feedlot and confinement dairy cows do not get fed anything that cannot be sent through an auger.
This cost/benefit ratio between consumer safety and extra work (lower profitability) would appear to some degree to have suppressed the enthusiasm of departments of health in pursuing the source of EHCH outbreaks. Kelsey notes that unnecessary illness and deaths occur each year because of the presence of this avoidable pathogen. Probably many outbreaks go unreported. The three year old granddaughter of a woman I have known for 30 years was hospitalized for more than six weeks with it. She survived, but lay in a coma for two weeks and was so badly stricken that her parents took home a little girl who could no longer walk or talk. She had to learn everything all over again. She eventually made a full recovery, according to my sister who sees the family. But there was no big flap about it or story in the paper.
What is the answer for those of us for whom feeding our cows an all-forage diet is a practical impossibility? Here is my perspective. Bear in mind that the emergence of this pathogenic bacteria is recent. Feeding supplements to forage is not. All over the US and the world cattle are eating not only grass but vegetables, fruit, and any concentrated carbohydrate sources they can find. Cows grazing after seed heads have formed eat considerable grain. Spring grass is a high carbohydrate source. This has been going on for centuries. If concentrated carbohydrate sources do not reach levels which prevent maintenance of the forage raft in the rumen (and thus inhibit cudding) or exceed the ability of rumen microorganisms to buffer and ferment the feed, it is extremely unlikely that sufficient undigested carbohydrate will reach the hindgut (colon) to foster any pathogens.
As cow owners, it is our obligation to keep our cows in good condition. When conditions of freezing or drought make grazing impossible, we feed hay or in some cases silage, yet the cow may not get enough calories. Dairy cows respond to insufficient calories by either dropping in production or getting thin or both. Many dairy cows refuse to cut production and become shockingly thin unless supplemented with a dense calorie source. If your are concerned that your cow might be getting more grain than you think appropriate, then make sure to feed hay prior to feeding concentrates. Most of the grain will then become imbedded in the forage raft in the rumen and will come up for cudding. Your cow’s saliva will buffer it (neutralize it). This is always good practice because it enables your cow to extract more value from the grain.
Footnote:
Forage Feeding to Reduce Preharvest Escherichia coli Populations in Cattle, a Review
T. R. Callaway*, R. O. Elder*, J. E. Keen , R. C. Anderson* and D. J. Nisbet*,1
* Food and Feed Safety Research Unit, Southern Plains Agricultural Research Center, Agricultural Research Service, USDA, College Station, TX 77845, USA
Meat Animal Research Center, Clay Center, NE
Corresponding author:
T. R. Callaway; e-mail:
callaway@ffsru.tamu.edu.
Joann
The recent spinach recall caused by contamination with E. coli .0157:H7 has us all worried about this important issue. It is a relatively new problem, therefore new information will continue to emerge making it necessary for us to readjust our thinking from time to time. Some facts seem beyond challenge. Kelsey was almost correct yesterday in her statement posted under the heading Feeding Beet Pulp, that if no cattle were fed grain nobody would sicken or die of poisoning from this dangerous form of E. coli. I say “almost” because now that the genie is out of the bottle the organism can now be found in numerous other species. If nobody had ever fed grain to cattle at the levels current in feedlots the problem would not have developed. Studies have been consistent in showing that cows on pasture or hay do not harbor this dangerous organism and that as little as five days of forage feeding to infected cattle results in as much as a 1000 fold decrease in shedding of the organism.
E. coli is a bacterium which makes its home in the hindgut. Even when the rumen is deliberately inoculated it has been impossible to recover E. coli 0157:H7 from the rumen. We must never say never, because sometimes even benign E. coli will find its way into the rumen, usually due to pastured cows using a contaminated farm pond. The E. coli don’t like it there and kicks up a fuss and normal rumen activity is slowed down, but if the cows have no other water source they will have no choice but to swallow E. coli. As a general statement, it is safe to say that E. coli inhabits the hindgut, not the rumen.
In cattle fed a high starch(carbohydrate) diet it becomes impossible for the rumen to successfully buffer (neutralize) it all or to properly ferment it. It passes over into the true gut where much is absorbed and thence to the hindgut where it produces abnormally acid conditions. Normal old fashioned E. coli thrives in a medium closer to neutral. E. coli 0157:H7 has evolved to survive at this low (acidic) pH. Normal E. coli even if it finds its way into food is destroyed by acid shock in the human stomach. This is a survival mechanism which has stood humans and other monogastric (single stomach) species well for our entire existence. Life devoid of any challenge from E. coli has never been possible. Even if some bacteria make it past the stomach (levels of hydrochloric acid in the stomach can vary) illness is usually not too serious. E. coli 0157:H7 is an enterohemorrhoragic E. coli (EHEC) which upon reaching the colon can cause severe symptoms or death. One researcher states that “Results indicate that switching cattle from grain to forage could potentially reduce EHEC populations in cattle prior to slaughter; however the economic impact of this needs to be examined.” (see footnote).
In other words it would cost a lot of money to institute this switch in feedlots or confinement dairies. Those of us who feed hay know all about how much trouble it is to store, handle and feed out. Feedlot and confinement dairy cows do not get fed anything that cannot be sent through an auger.
This cost/benefit ratio between consumer safety and extra work (lower profitability) would appear to some degree to have suppressed the enthusiasm of departments of health in pursuing the source of EHCH outbreaks. Kelsey notes that unnecessary illness and deaths occur each year because of the presence of this avoidable pathogen. Probably many outbreaks go unreported. The three year old granddaughter of a woman I have known for 30 years was hospitalized for more than six weeks with it. She survived, but lay in a coma for two weeks and was so badly stricken that her parents took home a little girl who could no longer walk or talk. She had to learn everything all over again. She eventually made a full recovery, according to my sister who sees the family. But there was no big flap about it or story in the paper.
What is the answer for those of us for whom feeding our cows an all-forage diet is a practical impossibility? Here is my perspective. Bear in mind that the emergence of this pathogenic bacteria is recent. Feeding supplements to forage is not. All over the US and the world cattle are eating not only grass but vegetables, fruit, and any concentrated carbohydrate sources they can find. Cows grazing after seed heads have formed eat considerable grain. Spring grass is a high carbohydrate source. This has been going on for centuries. If concentrated carbohydrate sources do not reach levels which prevent maintenance of the forage raft in the rumen (and thus inhibit cudding) or exceed the ability of rumen microorganisms to buffer and ferment the feed, it is extremely unlikely that sufficient undigested carbohydrate will reach the hindgut (colon) to foster any pathogens.
As cow owners, it is our obligation to keep our cows in good condition. When conditions of freezing or drought make grazing impossible, we feed hay or in some cases silage, yet the cow may not get enough calories. Dairy cows respond to insufficient calories by either dropping in production or getting thin or both. Many dairy cows refuse to cut production and become shockingly thin unless supplemented with a dense calorie source. If your are concerned that your cow might be getting more grain than you think appropriate, then make sure to feed hay prior to feeding concentrates. Most of the grain will then become imbedded in the forage raft in the rumen and will come up for cudding. Your cow’s saliva will buffer it (neutralize it). This is always good practice because it enables your cow to extract more value from the grain.
Footnote:
Forage Feeding to Reduce Preharvest Escherichia coli Populations in Cattle, a Review
T. R. Callaway*, R. O. Elder*, J. E. Keen , R. C. Anderson* and D. J. Nisbet*,1
* Food and Feed Safety Research Unit, Southern Plains Agricultural Research Center, Agricultural Research Service, USDA, College Station, TX 77845, USA
Meat Animal Research Center, Clay Center, NE
Corresponding author:
T. R. Callaway; e-mail:
callaway@ffsru.tamu.edu.
Joann