Barry Whitworth, DVM
Senior Extension Specialist

Department of Animal & Food Sciences

According to the Mesonet, Oklahoma received some much-needed rain in late April. With the moderate temperatures and high humidity, the environment is perfect for the proliferation of gastrointestinal nematodes (GIN) which are commonly called “worms.” Cattle can be infected with a variety of GIN. Most do not cause issues unless husbandry practices are poor. However certain GIN have been associated with disease. The most pathological GIN in cattle is Ostertagia ostertagi. Cooperia species and Haemonchus species are two that have been implicated with production issues. Control of these parasites is constantly changing due to environment, anthelmintic (dewormer) resistance, and consumer preference. Cattle producers should develop a plan to manage these parasites. 

In order for GIN to complete their life cycle, certain environmental conditions must exist. The development stage begins with passing of the egg in the feces of the animal. If the egg is to hatch, the temperature must be warm and the humidity needs to be close to 100%. Ideal temperature ranges from 70⁰ to 80⁰ Fahrenheit (F), but any temperature above 45⁰ F will allow for development. Temperatures above 85⁰ F or below 45⁰ F will begin to hamper development. Humidity needs to be 80% or higher.

Once the egg hatches, the larva goes through a couple of molts to reach the infective stage which is the third stage larva (L3). L3 must have moisture to free itself from the fecal pat. Once free, it rides a wave of water on to a blade of forage. Once ingested, this begins the prepatent or pre-adult stage. Two molts take place during this stage (L3 to L4 and L4 to L5). If conditions are not favorable for survivability of offspring, L4 will go into an arrested development stage (hypobiosis) for a period of time. The patent or adult stage is the mature breeding adult.

Once inside the body, the parasite will migrate to certain locations in the digestive tract. For example, O. ostertagi develop in the gastric gland in the abomasum. H. placei and H. contortus will migrate to the abomasum. Cooperia species will live in the small intestine. A few like Trichuris (whipworms) are found in the large intestine.

Clinical signs of parasitism vary according to the species of parasite, burden, and site of attachment. Severe disease, which is referred to as parasitic gastroenteritis (PGE), with internal parasites is unusual with today’s control methods. Clinical signs of PGE are lack of appetite, weight loss, weakness, diarrhea, submandibular edema (bottle jaw), and death. However, most parasite infection are subclinical which means producers do not see clinical signs of disease. In subclinical infections, the parasite causes production issues such as poor weight gain in young cattle, reduced milk production, and lower pregnancy rates.  

Producers should be monitoring their herds for parasites throughout the year but especially in the spring when conditions are ideal for infection. A fecal egg count (FEC) is a good way of accessing parasite burdens. Livestock producers need to gather fecal samples from their herd periodically. The samples should be sent to their veterinarian or a veterinary diagnostic lab. Different techniques are used to access the number of eggs per gram of feces. Based on the counts, the producer will learn the parasite burden of the herd. Producers can use this information to develop a treatment plan.

 In the past, GIN control was simple. Cattle were routinely dewormed. Unfortunately, anthelmintic resistance has complicated parasite control. Now proper nutrition, grazing management, a general understanding of how weather influences parasites, biosecurity, refugia, anthelmintic efficiency, and the judicious use of anthelmintics are important in designing an effective parasite management program. All of these considerations need to be discussed in detail with a producer’s veterinarian when developing a plan for their operation.

Cattle producers need to understand that parasites cannot be eliminated. They must be managed with a variety of control methods. Designing a parasite management plan requires producers to gain a general understanding of life cycle of the parasite as well as the environmental needs of the parasite. Producers should use this information as well as consult with their veterinarian for a plan to manage GIN. For more information about GIN, producers should talk with their veterinarian and/or with their local Oklahoma State University Cooperative Extension Agriculture Educator.

References

Charlier, J., Höglund, J., Morgan, E. R., Geldhof, P., Vercruysse, J., & Claerebout, E. (2020). Biology and Epidemiology of Gastrointestinal Nematodes in Cattle. The Veterinary clinics of North America. Food animal practice, 36(1), 1–15.

Navarre C. B. (2020). Epidemiology and Control of Gastrointestinal Nematodes of Cattle in Southern Climates. The Veterinary clinics of North America. Food animal practice, 36(1), 45–57.

Urquhart, G. M., Armour, J., Duncan, J. L., Dunn, A. M., & Jennings, F. W. (1987). In G. M. Urquhart (Ed). Veterinary Helminthology. Veterinary Parasitology (1^st ed., pp 3-33). Longman Scientific & Technical.

Read more in the June 2023 issue of Oklahoma Farm & Ranch.

By Bryan Painter

What was the door opener?
What was the need or idea that led you through the door of your local Conservation District office for the first time?
There is a better than average chance several producers pushed that door open for the first time in 2022 to apply for Emergency Drought Cost-Share Funding. The Oklahoma Conservation Commission and the Districts are glad you did and hope to see you again soon under better circumstances than a weather disaster.
However, the odds are even greater that you or a neighbor had a good working relationship with your district before the bottom of your ponds took on the look of a 1,000-piece jigsaw puzzle. Afterall, Conservation Districts are not exactly newcomers to your Oklahoma community – in fact, 2023 is a historic year.
It has been 85 years since the McIntosh Soil Conservation District was the first district to be organized in January 1938. That same year, the Arkansas-Verdigris SCD, now the Tulsa County Conservation District, and the Garvin Murray SCD, now the Garvin Conservation District, made history as the first districts to begin program operations in November 1938.
If you have not been through the door of your local Conservation District or visited with them on the phone or at an event, we would like to share with you why now is the time to do so.
Oklahoma’s 84 state-appropriated Conservation Districts tirelessly strive to provide and administer programs to help people conserve, improve and sustain natural resources and the environment. This may be through consultations, renting equipment, Field Days, operation and maintenance of the nation-leading 2,107 upstream flood control dams or a host of other services. We thought we would narrow the focus and offer a snapshot of what you might find at your local district.
These examples come from efforts of the Oklahoma Association of Conservation District’s five Outstanding Area Conservation Districts in 2022. The overall Outstanding Conservation District will be recognized this month at the OACD State Meeting, scheduled for February 26-28, 2023, at the Embassy Suites in Oklahoma City.
Area I: Alfalfa County Conservation District
Who is your prescribed burn buddy? This Conservation District, based at Cherokee in northwest Oklahoma, fits the description of a prescribed burn buddy for the Alfalfa County Prescribed Burn Association. The district serves as the burn association’s headquarters and is a strong advocate for this practice.
“The Alfalfa County Conservation District is a huge supporter of this much needed service to our community. Annual dues are 25 dollars. If you plan to burn, this is the best decision you could ever make,” the District’s Annual Report stated. “There is a burn trailer available with the necessary equipment, along with the technical assistance needed to complete a successful and safe burn.”
Those wanting to rent the trailer must have a burn plan in place and be a member. Burn plans are kept on file in the office, and the Natural Resources Conservation Service can assist with burn plans. Prescribed burning is a key land management practice used to restore and maintain native plant communities to their former diversity and productivity for livestock production and wildlife habitat, along with reducing fuels and damage from wildfires.

Area II, Payne County Conservation District
Based in Stillwater, The Payne County Conservation District in 2022 proudly opened their Education Pavilion. The District, with the help of a grant from Friends of Blue Thumb and a grant from Xerces, was able to plant 130 pollinator plants and will be planting more seeds this fall. Jake Linneman prepped the bed, Ray Moranz, Jim Ellis and Anita Kaufman planted all of the plants and kept them watered.
“We are excited about adding this element to our outdoor classroom and look forward excitedly for all the plants to mature and feed pollinators for years to come,” Kaufman said. “We will also use this as a teaching area to show others what plants they can plant to get the best results.”

Area III, Wagoner County Conservation District
This northeastern Conservation District, based in Wagoner, has been a major supporter of the Conservation and Agricultural Reach Everyone Project, a collaborative effort being led by the Oklahoma Association of Conservation Districts with the Oklahoma Black Historical Research Project, and partners agencies/organizations in Texas. The CARE project places an emphasis on assisting socially disadvantaged and veteran farmers/ranchers, while working with this targeted group to expand their knowledge of innovative technology, soil health, and invasive species eradication that will assist them in sustaining their farms.
“We can’t stay in the past,” CARE Champion, Major T.J. Love said, in an OACD video. “I’m not saying we need to forget about the past by no means, we’re not acting like the past didn’t happen, but right now we’ve got to move forward. That’s what I want to do as a CARE Champion in Wagoner County. I want to help bridge that gap between minorities and what happened in the past … There are great opportunities out there. There are great programs out there to help any farmer be successful, but we just have to take that initial step and that step may be walking in and letting go of the past and having that mindset of well they won’t help me anyway. The initial step is letting that go. I want to empower, I want to motivate and I want to encourage.”

Area IV, North Fork of Red River Conservation District
As mentioned, Oklahoma leads the nation in upstream flood control dams, which protects lives, infrastructure and property. The North Fork of Red River Conservation District is responsible for the operation and maintenance of 42 watershed structures, of which eight are high hazard in Beckham County. The District Technician works to keep the dams operational and clear of growth and debris and performs yearly inspections. The rehabilitation of Upper Elk Creek 23D watershed started in June 2021, and the final inspection was performed April 20, 2022. District personnel visited the site several times during the rehab to check on progress and to work with the landowner. In September, a re-dedication involved the Oklahoma Association of Conservation Districts, the Oklahoma Conservation Commission, the Natural Resources Conservation Service, the National Association of Conservation Districts and others, with attendees including Congressman Frank Lucas and NRCS Chief Terry Cosby.

Area V, Johnston County Conservation District
The Johnston County Conservation District, based in Tishomingo in southeastern Oklahoma, purchased a hog trap with local funds to assist landowners in reducing the feral swine population. They have one trap and it is rented out continuously. The trap is available for a period of one month to landowners. It is a JAGER PRO system which operates from an app installed on the landowners’ cell phone. Because the board felt like it was a valuable tool to help landowners control the feral hog population in the area, they have graciously donated their time to deliver and install the trap. Feral hogs are a major problem for the agricultural community, as well as some urban communities, causing millions in damage to land and crops each year. Feral hogs pose disease risks to livestock, pets and humans.

Again, these efforts from the Oklahoma Association of Conservation District’s five Outstanding Area Conservation Districts in 2022 are a small sample of the great conservation work being led by local Conservation Districts throughout Oklahoma. Producers can contact their local Conservation District for more information. To find your local Conservation District, please go to https://conservation.ok.gov/conservation-district-directory/.

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.