Barry Whitworth, DVM | Area Food/Animal Quality and Health Specialist for Eastern Oklahoma 

*Article originally printed in the October 2022 issue of Oklahoma Farm & Ranch.

Since most of Oklahoma experienced drought conditions and with fall fast approaching, producers with fescue pastures should closely observe their livestock for any signs of fescue toxicity. According to Mike Trammel, Pottawatomie County Ag Educator and Muti-County Agronomist, fescue toxins (ergot alkaloids) tend to increase in Kentucky-31 tall fescue pastures in the fall. Some reports indicate more problems with fescue toxins following a summer drought and limited fall rains. All of this may put Oklahoma cattle at a greater risk of fescue toxicity.

One issue that cattle experience with fescue toxins is fescue foot. Fescue foot is thought to be caused by ergot alkaloids such as ergovaline. These alkaloids are produced by endophyte fungus (Epichloë coenophiala) which is in tall fescue. Ergovaline has been proven to be a vasoconstrictor which might be responsible for fescue foot and heat intolerance also known as summer slump in cattle. Other issues that may be seen with the ergot fescue toxins are reduced milk production and reproductive issues.

Clinical signs of fescue foot appear within a few days of cattle being turned on to tall fescue pastures or it may take weeks if toxins in the pasture are low. Producers will initially observe cattle with arched back, rough hair coats, and sore feet. These symptoms are more noticeable early in the morning and with cold weather. This is followed by reddening and swelling in the area between the dewclaws and hooves. The lameness usually becomes more severe with time. If no action is taken, gangrene will result in loss of tissues distal to the coronary band and declaws. If the weather remains mild, other signs such as increase respiration rate, increase heart rate, and higher body temperature are more common.

Other causes of lameness in cattle must be differentiated from fescue foot. One simple method that will help differentiate fescue foot from footrot is to check the temperature of the foot. If the foot is cold, this is an indication that the problem is more likely fescue foot.

Since there is not a specific treatment for fescue foot, the condition must be managed. Cattle need to be observed daily for any signs of lameness or stiffness during the first few weeks on fescue pastures. This should be done early in the morning before cattle walk off the stiffness. Producers should pay close attention during cold weather, especially when rain, snow, or ice are present. Any animal showing clinical signs of fescue foot should be removed from the pasture and placed in a clean environment. The animal should be fed a ration with no fescue toxins.  

The best but most costly solution to reduce fescue toxicity is to renovate old pastures with new endophyte friendly varieties. If this option is not possible, producers might try interseeding fescue pastures with clovers or other grasses. This should dilute fescue toxins. Nitrogen fertilization may increase ergot alkaloids, so producers should avoid fertilizing fescue pastures with high amounts of nitrogen. Researchers have demonstrated that feeding a supplement while grazing fescue pastures reduces clinical symptoms. Some studies indicate a difference in susceptibility to fescue toxicity in some cattle. Selecting cattle based on genetic tolerance of fescue toxins is an option. (For more information go to www.agbotanica.com/t-snip.aspx)

With large areas in Oklahoma covered with Kentucky-31 fescue pastures, fescue foot as well as other fescue toxicities are not going away any time soon. Livestock producers will need to watch their livestock closely for any signs of fescue toxicity and manage their pastures to keep toxins as low as possible. If producers would like more information on fescue foot, they should consult their veterinarian and/or visit their local Oklahoma State University Cooperative County Extension Agriculture Educator.  

Barry Whitworth, DVM – Area Food/Animal Quality and Health – Specialist for Eastern Oklahoma

A ranch in Australia experienced an abnormally high number of stillbirths and weak born calves in 2004-2005. An investigation revealed that the usual infectious causes were not the problem. After additional testing, veterinarians diagnosed low levels of vitamin A as the cause.

According to Dr. Greg Hanzlicek, with the Kansas State Veterinary Diagnostic Laboratory (KSVDL), Kansas had an unusually high number of stillbirth cases and weak born calves in the spring of 2019. After many laboratory tests, it was concluded that the problem stimmed from a lack of energy, protein, Vitamin A, or combinations of all of these.

Both of the above examples demonstrate the importance of vitamin A in reproductive efficiency. Research has shown that low vitamin A levels during pregnancy are associated with abortions, stillbirths, and weak born calves. In addition to playing an important role in reproductive efficiency, vitamin A is essential for vision, bone growth, and maintaining epithelial tissue such as skin and hooves.

Animals obtain vitamin A from consuming green forage and/or the addition of vitamin A supplements to the diet. Lush green pastures contain high amounts of vitamin A. As plants mature and during times of drought, the amount of vitamin A decreases. The ranch in Australia experienced below average rainfall in the previous two years prior to the calving season. During the calving season, rainfall was below average with very dry conditions and little green forage was available.

In general, animals obtain adequate amounts of vitamin A by grazing green forage. Animals grazing green pastures will build a healthy store of vitamin A in the liver. When vitamin A is in short supply, the stores in the liver prevent deficiencies. According to Dr. Lalman, Extension Beef Cattle Specialist Oklahoma State University, the stores should last 2 to 4 months during times of deficiency. During times when green forage is not available, vitamin A supplements need to be added to the diet to prevent deficiencies.

When vitamin A levels are deficient, night blindness is one of the earliest clinical signs. Other eye issues include clouding of the cornea, ocular discharges, and possible ulcerations. Skin issues found when levels of vitamin A are deficient include a dry rough coat, scales on the skin, and dry cracked hooves. Other neurological signs include incoordination or gait problems. Seizures may occur due to the increase cerebrospinal fluid pressure. Birth defects have also been attributed to low vitamin A levels.

Animals displaying vitamin A deficiency should be treated immediately with vitamin A injections. If treated early, response is usually rapid and complete. However, delaying treatment may result in irreversible damage. Even with treatment, cattle with vision impairment due to vitamin A deficiency may not regain their sight.

Preventing Vitamin A deficiency depends on producers being attentive to the environmental conditions that favor low vitamin A levels in forage. During these times, producers need to supplement the diet with vitamin A. Producers need to be aware that Vitamin A supplements degrade rapidly, so vitamin A supplements should not be stored for long periods of time. In addition to vitamin A supplementation, research indicates that diets low in protein result in poor absorption of vitamin A. It is important that producers ensure that the rations have sufficient protein levels. Lastly, since colostrum contains high levels of vitamin A, producers need to ensure that newborns obtain adequate amounts of colostrum at birth.

Similar to the Australian example, most of Oklahoma had below average rainfall for the year of 2022. This resulted in pasture quality decreasing earlier than normal. Due to this year’s lack of green forage, liver stores of vitamin A may be inadequate for the animal’s needs. Producers need to ensure that the diets of their cattle have adequate amounts of vitamin A, energy, and protein. For more information about Vitamin A, producers should contact their veterinarian and/or visit with their Oklahoma State University County Ag Educator.

References

Hanzlicek, G. (2019, May). Difficult Calving Season Findings:2019. Diagnostic Insights. www.ksudl.org/resources/news/diagnostic_insights/may2019/difficult-calving-season2019.html.

Hill, B., Holroyd, R., & Sullivan, M. (2009). Clinical and pathological findings associated with congenital hypovitaminosis A in extensively grazed beef cattle. Australian Veterinary Journal, 87(3), 94–98.

Parker, E. M., Gardiner, C. P., Kessell, A. E., & Parker, A. J. (2017). Hypovitaminosis A in extensively grazed beef cattle. Australian veterinary journal, 95(3), 80–84.

Many ranchers across North Texas have discovered an easy, natural way to keep water troughs cleaner: add a few fish. It might sound like something from a backyard pond hobby, but keeping hardy fish such as goldfish or small koi in livestock troughs can help reduce algae, control insects, and even provide a little entertainment during daily chores.

The main benefit of adding fish is algae control. When sunlight hits the water and nutrients from dust, hay, or manure accumulate, algae blooms can appear quickly, especially in warm weather. Fish feed on the small organisms that make up the base of that algae growth. Goldfish, minnows, and koi are particularly effective at grazing on microscopic material and keeping buildup manageable.

Another advantage is mosquito control. In summer, stagnant water attracts mosquitoes, which lay eggs along the edges of the trough. A few small fish will eat the larvae before they hatch, breaking the cycle before it starts.

There’s also an element of simple enjoyment. Watching fish dart around beneath the water adds a bit of life to the barnyard, and they’re surprisingly hardy if cared for properly. Many livestock owners say once they’ve added fish, they never go back to fishless troughs.

Despite the practical benefits, there are some important considerations before stocking your trough. The success of fish in small water containers depends on size, sunlight, and maintenance.

Smaller troughs heat and cool quickly, so temperature swings can stress fish. Metal troughs exposed to full sun get hotter than shaded plastic or concrete ones. When possible, locate the trough where it gets partial shade and is deep enough for fish to retreat from temperature extremes.

Choosing and Caring for Fish

Goldfish are the most common choice because they tolerate temperature changes, low oxygen levels, and variable water conditions better than most species. They’re inexpensive, easy to find, and don’t require a filtration system if the water is changed regularly.

A few general guidelines make the difference between a thriving setup and a short-lived one:

Begin with only two or three fish per 100 gallons of water. Overcrowding leads to oxygen depletion, which is the main reason fish die in troughs.

Feed stores and local pet shops often sell small feeder goldfish or minnows at low cost. Avoid releasing fish from ornamental ponds or unknown sources, since they may introduce disease or parasites.

Fish should adjust slowly to temperature differences between the water they came in and the trough. Float the transport bag in the trough for 15–20 minutes, then add small amounts of trough water before releasing them.

Most fish will find enough to eat naturally — algae, insects, and organic debris. Supplementing food isn’t necessary and can actually foul the water.

While fish help limit algae, they don’t eliminate it. Every few weeks, scrub the sides of the trough lightly and refill it completely to maintain water quality. When cleaning, move the fish temporarily to a bucket with some of their old water to minimize stress.

If you use bleach, copper sulfate, or any algaecide in your tanks, the fish will not survive. Once fish are introduced, rely on natural cleaning and partial water changes instead of additives.

Most animals quickly get used to fish in their tanks and don’t bother them. If a horse or cow tends to stir the water excessively or dump feed in the trough, install a section of wire mesh or a large rock area for the fish to hide under.

Winter Care and Cold-Weather Survival

A common question is what to do when temperatures drop. In most of North Texas, you can leave the fish in the trough all winter. They tolerate cold far better than people expect.

When the water temperature falls, fish become sluggish and sink to the bottom where the water remains slightly warmer. Even when ice forms on top, they usually survive without issue as long as the trough isn’t completely frozen solid.

If your tanks regularly freeze over, here are a few tips:

Keep a small opening in the ice to allow oxygen exchange. You can gently pour a small pot of warm (not boiling) water on one spot or set in a floating object so the ice forms around it and leaves a gap.

Avoid breaking thick ice with force. The shock and vibration can stress or kill fish.

Don’t move the fish indoors unless the tank will freeze solid. Sudden temperature changes are more harmful than cold water itself.

Fish can overwinter outside just fine if there’s some depth — at least 18 to 24 inches — and no complete freeze-through. In fact, many people report their fish living for several years in the same trough, even through occasional hard freezes.

If you use a stock tank heater for livestock, that’s perfectly fine for the fish too, as long as it doesn’t raise the water temperature dramatically. They’ll appreciate the small patch of open water and the stable oxygen exchange.

During cold months, fish won’t need food. Their metabolism slows, and uneaten feed can decay and foul the water. Once temperatures climb again in spring, they’ll become more active.

Even with the best care, fish sometimes die suddenly due to poor water quality or low oxygen. Murky water, slimy buildup, or a sulfur-like smell are warning signs. Dumping and refilling the tank usually fixes the problem. If losses are frequent, check for contamination from feed, manure, or chemicals.

It’s also worth knowing that goldfish reproduce quickly. If your trough has a gravel bottom or lots of algae, you might end up with more fish than you started with by midsummer. A few extra can be rehomed in a garden pond or given away, but be careful not to release them into creeks or natural ponds — that can harm native species.

Adding fish to water troughs isn’t new, but more landowners are rediscovering its usefulness. It’s a low-maintenance, inexpensive, and surprisingly effective way to help keep tanks clearer, reduce insects, and add a little charm to daily chores.

For the most part, the system takes care of itself. A handful of goldfish or minnows, a little common sense, and routine cleaning are all it takes. Come winter, just leave them be — odds are they’ll be waiting under the ice when spring rolls around, ready to start another season of quiet work in your stock tank.

References

Texas A&M AgriLife Extension – Managing Water Quality for Livestock and Wildlife.

Oklahoma State University Extension – Farm Pond Ecology and Fish Care Basics.

Texas Parks & Wildlife Department – Small Pond and Trough Fish Management Guidelines.

North Central Texas Council of Governments – Water Conservation for Rural Landowners.

Oklahoma Department of Agriculture, Food & Forestry – Livestock Water Tank Maintenance Resources.