As we move into the dog days of summer, the hot and dry weather often creates the perfect conditions for problems to arise. Weeds start to crop up and stagnant stock ponds can lead to decreased water quality; both of these issues are a threat to your herd health this summer. Here’s what you need to know about toxicity in weeds and water.

Which weeds are toxic to cattle?

In an article for the Ohio State University Extension Beef Newsletter, Extension Educator Cliff Little discusses how dry weather conditions can lead animals to consume plants, often toxic weeds, that they would otherwise avoid.

Little writes, “There are recognizable circumstances like drought, overgrazing, nitrogen fertilization and summer storms that all have the potential to contribute to livestock poisoning.”

He lists the potential culprits that could be poisonous to cattle including: buttercup, horsenettle, ground cherry, black and bittersweet nightshade, dogbane, milkweed, jimson weed, black locust tree, yew, and taxis evergreen shrub.

He adds, “As we move into dryer conditions, be aware of your forage availability and identify plants which may be of concern. We have only mentioned a few plants and there are many you should know. Watch your livestock closely, daily observing for signs of distress. Contact your veterinarian immediately if you suspect plant poisoning.”

Learn more about which plants are a big concern to livestock in the summer by clicking here.

What are the implications of poor water quality on herd health?

In addition to weed concerns, water quality during the hot, dry months of summer can also lead to health problems in the cow herd. Robin Salverson, South Dakota State University (SDSU) Extension cow-calf field specialist, recently wrote an article for SDSU’s iGrow that addresses this issue.

Salverson explains how little to no runoff from snow or spring rain along with hot, dry, windy conditions can lead to poor water quality and high levels of total salts. She said that high levels of sulfates in the water have already caused polioencephalomalacia (“polio”) in some herds in South Dakota.

READ: 5 summer water quality tips

She writes, "It is critical that producers be proactive and test their water sources prior to turning livestock into pastures. It is well documented that water from wells, dams, dugouts and creeks are often high in total salts and especially sulfates regardless of whether the water source is small or large; or has a lot of water or a little. Water sources that are often assumed to be safe, such as spring-fed reservoirs and clear-appearing water, can still be high in salts/sulfates. The visual appearance of water should not be used to determine if the water is good or bad. The only way to know if water is suitable for livestock is through testing.”

Poor water quality can lead to weight loss, decreased milk production, lower fertility, polio, and nutritional deficiencies due to improper mineral absorption.

Salverson writes, “Research conducted at the South Dakota Agricultural Experiment Station Cottonwood Range and Livestock Field Station near Philip, S.D., has evaluated the effect of high sulfate on both cow-calf pairs and yearling steers grazing pastures. Both classes of livestock were negatively impacted. Cows consuming high sulfate water (2608 ppm) lost 36 pounds, while cows on low sulfate water (388 ppm) gained 15 pounds during the treatment period (June 3 to August 26). Yearling steers grazing pastures with high-sulfate water had a decreased average daily gain and a few cases of polio at levels of 3900 ppm and 4600 ppm.”

For testing information and complete research details on this subject, click here.

Monitor your herds closely for other issues such as foot rot, pink eye, mastitis and flies to make sure your pairs stay healthy during the grazing months.

The opinions of Amanda Radke are not necessarily those of beefmagazine.com or Penton Agriculture.

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