Much needed rains following a long, dry period should have livestock producers on the lookout for increased incidences of internal parasites and hoof problems. Livestock hooves soften if animals are pastured on wet ground or housed in damp pens for an extended time.
Softer hooves are more susceptible to cuts, tears or abrasions creating an opening for organisms that cause hoof rot. “Producers should avoid placing animals on hard or gravel surfaces until their hooves have dried out and hardened to reduce the likelihood of cuts, tears or abrasions,” said David Fernandez, Cooperative Extension Program livestock specialist at the University of Arkansas at Pine Bluff.
Organisms that cause hoof rot thrive in moist conditions. Fusobacterium necrophorum and Dichelobacter nodosus cause hoof rot and hoof scald in cattle, goats and sheep. Producers should be on the lookout for lame animals. Examine their hooves. Foul-smelling odors, heat and inflammation at the coronary band where the hoof adjoins the pastern and pain are common signs of the disease. A vaccine against hoof rot is available for sheep but not for goats.
Fernandez advises trimming the hoof to remove damaged or dead tissue and then treating the affected hoof with one of the following:
- Antibacterial sprays (20 percent cetrimide and 1.3 percent oxytetracycline in water and alcohol).
- Footbaths (10 percent zinc sulfate, 10 percent copper sulfate or 5 percent formaldehyde solutions).
- Footsoaks (1 hour in a solution of 10 percent zinc sulfate and 1.2 percent v/v of laundry detergent containing nonionic surfactants or the surfactant sodium lauryl sulfate).
In addition to hoof problems, wet weather creates conditions favorable for internal parasites that infect animals on pasture. “Liver flukes, which can cause death in sheep (usually via black disease which destroys liver tissue) and significant economic losses in dairy and beef cattle, are more common in wet weather,” said Fernandez. Also, Haemonchus placei (barber pole worm, large stomach worm and wire worm) Ostertagio ostertagi (medium or brown stomach worm) and Trichostronglylus axei (small stomach worm) are aided by wet weather.
After long periods of drought -- as experienced in the Southeast, Texas and parts of Arkansas -- once-dormant eggs have been freed by recent rains and a wet pasture environment fosters larval development. This means greater numbers of infectious larvae than usual are present to infect livestock, said Fernandez.
Scours, anemia and unthriftiness are common signs of heavy internal parasite infestation. In sheep, goats and calves, “bottle jaw” -- swelling under the jaw caused by fluid escaping from blood vessels -- is a serious indicator of Haemonchus infestation. Unfortunately, many dewormers used again Haemonchus are becoming ineffective, said Fernandez, who recommends that producers work closely with their veterinarians to develop a plan to reduce the impact of internal parasites over the next few weeks.