Normal pasture dwellers become mass murderers | TSLN.com

Normal pasture dwellers become mass murderers

Dave Barz, DVM

For the June 20, 2009 edition of Tri-State Livestock News.

Summer is almost here. The late spring rains have been just what we needed for our crops and pastures. It isn’t much fun to try and put up hay but let’s not complain! My story today is about a normally noxious pasture inhabitant becoming a mass murderer! Hopefully this sensationalized headline will stimulate your interest in the article.

Several weeks ago we went to a river bottom pasture near Mitchell, SD. The mama cows and their babies had been happily grazing for several weeks. The James River flowed through the edge of that pasture, but was flooded this spring. Because of the flooding only 35 pairs, about half the normal carrying capacity, were hauled to grass.

That fateful Saturday morning the owner noted several dead cows, a dead calf and three more sick cows. We began posting the cows after ruling out Anthrax. The cows had hemorrhage in various areas of the body, but all showed liver involvement. Samples were taken and sent to SDSU’s diagnostic lab.

We moved across the pasture to attempt to treat several affected animals. They were initially down and depressed. As I approached to take a temperature, the cow got up and began to give chase. My technician has a great video of me running for my life, lots of exercise for little fat boy. The cow actually rammed the grill guard as we continued to video tape.

After I caught my breath we decided to remove the cows from the pasture and take them back home while we searched for the cause of their deaths. We also collected water samples from a creak, a spring and the river. Then we searched the pasture for toxic plants. Over the next few days all the affected cows died bringing the total to five cows and one calf from 35 pairs, a mass murder.

The water samples were checked for normal toxins and none were found. One sample from the creek did have some blue-green algae present, but numbers were few and water was flowing. Most algae toxicosis I have seen had been in warmer temperatures and in pools of standing water. The liver destruction found on the pathology slides forced us to search further for the toxin.

Recommended Stories For You

When we went back to the creek to resample the creek water we found the area covered with cockleburs. Evidently the cows were eating them as fast as they could come up even though the pasture was loaded with great prairie grasses. Every fall at roundup the cocklebur plants are about six feet high, but the only problem is when you grab a cows’ tail or she slaps you in face with it, you get pain from sharp spines on the burrs.

Could this plant which is a normal inhabitant of the river bottom, as well as other pasture, be the cause of this problem? Literary research revealed young cocklebur plants can be extremely toxic. The burr itself contains a toxin, carboxyatractyloside, but what self respecting cow would eat these spiny burrs and we found no evidence in the cows posted. The sprouting plant in its two leaf emergence form is also very toxic.

When we went back to the pasture we found that the flooded river had created the ‘perfect storm” for this intoxication. The flowing river floated burrs from many miles upstream out onto the flats of this pasture. As the water began to slowly recede, these wet burrs germinated in the debris on the shore and when the cows went to drink they ate the young plants. These small plants appear to be much more palatable than the mature plants. Sadly this problem will persist in this pasture until the river drops to normal levels and the burrs quit germinating.

Once clinical signs begin the disease is untreatable and results in death. Sudden death occurs in younger animals and mature animals which consume large amounts of the toxin. All other animals exhibiting signs died within 2-3 days. We have no idea if other cows consuming smaller amounts of toxin have some liver damage but they are showing no signs.

It is hard to believe that something as common in our area as a cocklebur can cause this problem; after all the cocklebur was responsible for the invention of Velcro by a Swiss scientist. If you have any unexplained pasture deaths contact your veterinarian immediately. They will help you pinpoint the source and eliminate your problem. Hopefully you won’t have normal pasture dwellers becoming mass murderers.

Summer is almost here. The late spring rains have been just what we needed for our crops and pastures. It isn’t much fun to try and put up hay but let’s not complain! My story today is about a normally noxious pasture inhabitant becoming a mass murderer! Hopefully this sensationalized headline will stimulate your interest in the article.

Several weeks ago we went to a river bottom pasture near Mitchell, SD. The mama cows and their babies had been happily grazing for several weeks. The James River flowed through the edge of that pasture, but was flooded this spring. Because of the flooding only 35 pairs, about half the normal carrying capacity, were hauled to grass.

That fateful Saturday morning the owner noted several dead cows, a dead calf and three more sick cows. We began posting the cows after ruling out Anthrax. The cows had hemorrhage in various areas of the body, but all showed liver involvement. Samples were taken and sent to SDSU’s diagnostic lab.

We moved across the pasture to attempt to treat several affected animals. They were initially down and depressed. As I approached to take a temperature, the cow got up and began to give chase. My technician has a great video of me running for my life, lots of exercise for little fat boy. The cow actually rammed the grill guard as we continued to video tape.

After I caught my breath we decided to remove the cows from the pasture and take them back home while we searched for the cause of their deaths. We also collected water samples from a creak, a spring and the river. Then we searched the pasture for toxic plants. Over the next few days all the affected cows died bringing the total to five cows and one calf from 35 pairs, a mass murder.

The water samples were checked for normal toxins and none were found. One sample from the creek did have some blue-green algae present, but numbers were few and water was flowing. Most algae toxicosis I have seen had been in warmer temperatures and in pools of standing water. The liver destruction found on the pathology slides forced us to search further for the toxin.

When we went back to the creek to resample the creek water we found the area covered with cockleburs. Evidently the cows were eating them as fast as they could come up even though the pasture was loaded with great prairie grasses. Every fall at roundup the cocklebur plants are about six feet high, but the only problem is when you grab a cows’ tail or she slaps you in face with it, you get pain from sharp spines on the burrs.

Could this plant which is a normal inhabitant of the river bottom, as well as other pasture, be the cause of this problem? Literary research revealed young cocklebur plants can be extremely toxic. The burr itself contains a toxin, carboxyatractyloside, but what self respecting cow would eat these spiny burrs and we found no evidence in the cows posted. The sprouting plant in its two leaf emergence form is also very toxic.

When we went back to the pasture we found that the flooded river had created the ‘perfect storm” for this intoxication. The flowing river floated burrs from many miles upstream out onto the flats of this pasture. As the water began to slowly recede, these wet burrs germinated in the debris on the shore and when the cows went to drink they ate the young plants. These small plants appear to be much more palatable than the mature plants. Sadly this problem will persist in this pasture until the river drops to normal levels and the burrs quit germinating.

Once clinical signs begin the disease is untreatable and results in death. Sudden death occurs in younger animals and mature animals which consume large amounts of the toxin. All other animals exhibiting signs died within 2-3 days. We have no idea if other cows consuming smaller amounts of toxin have some liver damage but they are showing no signs.

It is hard to believe that something as common in our area as a cocklebur can cause this problem; after all the cocklebur was responsible for the invention of Velcro by a Swiss scientist. If you have any unexplained pasture deaths contact your veterinarian immediately. They will help you pinpoint the source and eliminate your problem. Hopefully you won’t have normal pasture dwellers becoming mass murderers.