MHBA Animal Health Series

Summertime in Cattle Country

By Peggy Joseph-Potter RN, BSN, MHA

Summer, a time fun, family, fairs and if you raise cattle the challenge brought on by heat, flies, pinkeye and parasites. While we may live in different climates with varying levels of humidity, the stress brought to cattle by this warm weather onslaught is universal.

Heat stress can cause reduced productivity in cattle, the more severe the stress the more detrimental the effects are on performance. Reduction in reproductive ability, daily weight gain and reduced milk production are the main outcomes of this form of stress. Cattle are more sensitive to heat than humans are. Heat stress is a combination of temperature, relative humidity and wind speed. Other factors such as age, hair coat length, hair coat color and nutritional status all play a role in determining the severity of heat stress on your herd. Breeders need to watch their cattle, the environment and be familiar with the signs of heat stress.
Signs of Heat Stress:
•Restlessness and crowding under shade or at water tanks.
•Open-mouthed breathing (panting), and increased salivating.
•Increased respiration rates, (Moderate heat stress: 80 to 120 breaths per minute, Strong heat stress: 120 to 160 breaths per minute. Severe heat stress: over 160.)
•Gasping and lethargic.
The symptoms of heat stress may often present in the same manner as respiratory disease. Cattle do not sweat; therefore, they must use their respiratory system to eliminate excess heat from their bodies.
Heat stress interventions:
Provide ample water. Cattle may need more than 2 gallons of water per 100 pounds of body weight. Provide enough tanks for cattle to be able to get the water they need. If possible, water should be cooled and placed in a shaded area; tanks should be cleaned weekly to encourage water consumption.
Avoid handling cattle. Handling cattle can elevate their body temperature by as much as 3.5 degrees F. If cattle must be worked on hot days, try to do the work before 8:00 AM and keep the maximum time in the holding facilities to no more than 30 minutes
Change feeding schedules. On hot days, shift your feeding times toward the evening hours. Try to deliver 70% of the daily scheduled feed two to four hours after the peak air temperature. Providing only small amounts of feed during the heat of the day, will decrease the metabolic heat of digestion.
Provide shade and improve airflow. Shade can come in the form of trees or it can be constructed. Solid, reflective covering is preferable to slats or other more open forms of overhead roofing. When possible, two shaded areas are recommended, one over the feed area to increase feeding time, and another away from the feed area to encourage the cattle to rest. Water should be made available under both shaded areas, to increase the water consumption during heat stress period. Consider where the cattle are located and if there is any restriction to air flow. Box or barn fans provide increased circulation and when combined with a mister can decrease temperatures in barns and stalls.
Provide water mist. Providing a spray of water will help to cool the animals down. However, it is important to place misters over a clean, preferably concrete area. Misters should not be over dirt or allowed to create pooling or mud puddles, which increases the incidence of bacteria and flies. When possible, use a timer, this will allow cooling without getting the cattle wet
Fly Control:
The control of breeding flies is necessary to assure adequate animal health, rate of gain and to maintain weaning weights. There are two major species of flies that cause the most serious decreased in beef production and require the most control efforts, they are the horn fly and the face fly. Horn flies cause the economic loss for cattle breeders through blood loss and irritation. The reduction in weight gain can be as much as 10-14%
The adult horn fly, which is about one-half the size of a housefly, has piercing/ sucking mouthparts and feeds on blood and tissue fluids of cattle. They spend most of their adult life on cattle and feed 20 to 40 times a day. They are normally found on the animal’s back, but may migrate to the sides and the belly as the temperatures increase. The fact that they spend the majority of their time on the animal’s body makes them much easier to control.
The face fly is about the size of a housefly. They are non-biting, feed on secretions from the eyes, and muzzle. They avoid entering dark places, such as a barn, while on the animal. The female lays eggs on freshly deposited manure like the horn fly; however, unlike the horn fly they are present on cattle only about 10 percent of the time and may be found resting on fence posts, trees, bushes and other objects the other 90 percent of the time. Because they spend so little time on the animal and do not feed on blood, they are much harder to control than horn flies.
There are several methods of fly control, such as insecticide sprays dusts, pour-ons, oilers, dust bags, ear tags, oral larvicides in minerals and blocks and controlled release boluses. All of these methods are effective and have a place in the control program; however, the best fly control can most likely be obtained through an integrated fly control program.
Back rubbers and dust bags are effective and can be placed at gate openings. Insecticide-impregnated ear tags are easy and should be placed at the beginning of the season and removed in the fall. Make sure you fully protect your weaing calves with a pour-on and ear tags for the best coverage. Remember to rotate your insecticides to prevent the development of resistance and an overall decrease the program effectiveness. Organophosphates and pyrethroids are normally alternated based on their effectiveness against flies specific for that region.
Summer is the time to step up your parasite control program. Many of the products and methods used for fly control are also effective against internal and external parasites. Insectide tags, oral lavicides added to mineral blocks and mixes aid in the elimination of parasites from surfaces and manure. Dust bags and sprays are good for control only if used regularly. As with fly control, the best coverage is gained by a combination of methods and products.
Remember the accumulation of water or manure is a prime breeding ground for flies and other parasites. Consult you ranch veterinarian or local Ag extension for the products most effective in your region.
Pink Eye-Moraxella bovis:
Pink eye (moraxella bovis bacterial infection of the eye) in cattle can result in serious economic losses, through poor weight gain, eye damage and even blindness, if left untreated. It is highly contagious and is spread by face flies as they feed on the secretions from the eyes. Early treatment is most effective, the use of ointments, sprays and powders must be performed twice per day and this requires the eye to be protected against sunlight or further irritation from flies, dust and foreign objects with an eye shield. The administration of 1 ml Penicillin given under the eyelid in two places is usually effective enough for one treatment.
Symptoms of Pinkeye vary from watering and drainage of the eye in the early stages to a cloudy discoloratation or even ulcerations of the cornea in the latent phase. Early treatment is necessary to prevent advancement of the disease and prevent permanent damage.
Newer treatments such as the use of Veterycin VF TM are also very effective if started at the onset of symptoms. It is much less caustic, painful, and irritating to the animal than other treatments. Our personal experience with this product has been very good and we use it as a first line drug in the treatment of any bacterial, fungal, viral or spore forming infection. Its non-irritating formula makes it a great all purpose as a wound cleanser as well.
Summer is a great time to enjoy your animals so keep them healthy by being prepared. Purchase your ear tags, dust bags and sprays early. Combine these activities with pour-ons, vaccinations and other possible heat producing events early in the day. Diminish pest breeding grounds by ensuring your pens are free of standing water and accumulate manure. Healthy Herefords make for happy breeders, so be prepared and start early to assure your programs effectiveness.
Blazinger, S. P. Reduce Heat Stress in Cattle to Maintain Profit. Cattle Today.
John Maas, D. M. (April 2002). UCD, VetMed,Fly Control For Cattle. California Cattlemen.
LSU, A. C. Pinkeye in Beef Cattle. LSU Ag Center.
Oaklahoma State University, Cattle Stress Model. OSU

Peggy and her husband, Bob Potter, own and operate PJ Ranch LLC in Winton, California where they raise Miniature and Polled Herefords. They have been active participants in the MHBA since 2002. She is employed as a critical care nurse for a local medical center.


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