Summer is coming to an end and I’m looking forward to cooler weather. We’ve had a long streak of hot days that stressed the livestock, and our pastures, as well. With little or no rain and a lot of heat, some plants become stressed and can be dangerous for cattle, goats and sheep.
One problem cattle operators can face with dry conditions is prussic acid poisoning.
Prussic acid, or hydrogen cyanide, is found in certain plants like Johnsongrass, Milo, and other forage sorghums. Drought can concentrate prussic acid in the leaves; when fed as chop, or when cattle heavily graze an area, as is the case in high stocking density grazing operations, animals can become affected and die very quickly.
The best bet for livestock producers is to reduce broadleaf weeds through herbicide application and stay away from sorghum green chop during these hot times.
Also, if you used 2,4-D Amine late in the spring to kill off problem weeds, any remaining Johnsongrass will have high concentrations of prussic acid. Signs of prussic acid poisoning include staggering, labored breathing, foaming at the mouth, and laying down and thrashing around. Call a vet if you see these signs.
High stocking density (HSD), or rotational grazing is a land management practice in which livestock herds are combined and moved through pastures in a rotational basis. This strategy allows most of the land to “rest” and not be grazed while a smaller percent of the management area is grazed more heavily. It is a good way to let the land replenish itself, especially during drought conditions.
There are multiple benefits to this approach, including increased trampling of the landscape to press organic material into the soil; grazing of less
desirable plants or areas of the landscape; and reducing parasite burdens to the livestock.
The downside is that there is an initial period that requires more labor and monetary investment in fencing and water for the smaller paddocks. This strategy also requires diligent attention to the animals and the land to make sure the pasture is not grazed too closely.
The land should never be grazed to dirt, unless total defoliation is the objective. If defoliation is the objective, then parasite control and vaccination for preventable respiratory diseases need to be aggressively implemented and supplemental feeding must be made available.
Drought can cause forages to produce less vitamin A. Low vitamin A can lead to problems with calves like weakness and blindness, so be sure to give a vitamin A and D shot about 30 days before calving if your cows are near the end of their gestation. Another shot to calves at birth is also recommended.
Surviving the Texas heat can be a challenge for both humans and livestock, but with a little extra caution, knowledge and planning, your herds can thrive here.
After graduating from Michigan State University College of Veterinary Medicine, Dr. Carlton served four years in the United States Army as a Veterinary Corps Officer. Stationed at Fort Hood, his patients included the Military Working Dogs of Air Force Security Forces, Army Military Police, Army Rangers, Special Forces, and the Marines. While serving as an Army veterinarian, he also was the vet for the horses of 1st Cavalry Division. He honed his clinical skill set working on these unique animal populations, and now brings that special knowledge to the community at Jarrell Animal Hospital. Dr. Carlton is a member of the American Association of Bovine Practitioners, American Association of Equine Practitioners, Texas Veterinary Medical Association, and he continues to serve in the United States Army Reserve.
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Dr. Carlton will share news and views for your pets and animal friends as a regular writer for City Insider. Send your questions to firstname.lastname@example.org