East Tennessee's shift from summer to fall is gentle for people and surprisingly busy for veterinarians. Nights cool off, but ticks, mosquitoes, and intestinal parasites stay active until hard freezes. Wild mushrooms and acorns appear, antifreeze and rodent bait come out, hunting season starts, and livestock operations move into weaning, breeding, and winter feed planning.
This checklist covers what we watch for from late September through the first frosts, organized by species. It is general educational information, not a substitute for an exam. Your veterinarian will tailor recommendations to your animal, your farm, and your goals.
1. Parasites stay active longer than you think
Fleas, ticks, and mosquitoes do not switch off on the first cool morning. They slow down with sustained freezing temperatures, and East Tennessee often has stretches of mild weather well into November.
Fleas, ticks, and heartworm in dogs and cats
Year-round parasite prevention is the standard recommendation. The American Heartworm Society recommends heartworm prevention for all twelve months of the year, along with annual testing, because mosquito activity varies with weather and a missed dose can leave a gap in protection. Ticks are a particular fall concern. Adult blacklegged ticks become active in the fall and can feed whenever temperatures are above freezing, and tick-borne diseases such as ehrlichiosis and anaplasmosis occur in our region. Fleas thrive indoors all year and often peak in fall, when outdoor populations move toward warmth.
Intestinal parasites
Roundworms, hookworms, whipworms, and giardia spread through contaminated soil and water, and dogs spend more time outdoors as the weather cools. A fecal test at the annual visit, and any time stools change, finds infections that prevention products do not always cover. Several intestinal parasites can also infect people, which is one more reason to test.
2. Toxins that peak in fall
Antifreeze (ethylene glycol)
Ethylene glycol antifreeze tastes sweet, and even small amounts can cause fatal kidney failure in dogs and cats. Cold weather brings radiator flushes and leaks onto driveways and garage floors. Early signs can look like drunkenness: stumbling, vomiting, and excessive thirst. Those signs can fade while kidney damage continues, and treatment only works when it starts early. If you think your pet licked antifreeze, call us immediately. Do not wait for symptoms. Store antifreeze sealed and clean spills right away. Propylene glycol products are less toxic but not harmless.
Rodenticides
As rodents move into barns, garages, and homes, so does bait. Anticoagulant rodenticides cause bleeding, and signs such as weakness, pale gums, cough, bruising, or blood in stool or urine may not appear for several days after ingestion. Other bait types cause neurologic signs or kidney failure. Pets can also be poisoned by eating a poisoned rodent. If you suspect exposure, call us and bring the packaging.
Wild mushrooms
Fall rains bring mushroom flushes. Some species cause liver failure, and most owners cannot reliably tell them apart. If your dog has eaten a wild mushroom, take a photo and save a sample if you can, and call right away.
Halloween candy
Chocolate (dark and baking chocolate are the most dangerous), xylitol in sugar-free candy and gum, raisins, and swallowed wrappers or lollipop sticks are the usual Halloween problems. Xylitol can cause a rapid drop in blood sugar and liver injury in dogs. Keep treat bowls out of reach, and call us if your pet eats any of these, even if they seem fine.
3. Hunting and working dogs
Bird dogs, hounds, and cow dogs cover a lot of ground in the fall, and we see the same problems each season: tick-borne disease, leptospirosis, cut pads, torn nails, eye and ear injuries, and stomach upset from drinking pond water or eating something they should not.
Leptospirosis is a bacterial infection spread through the urine of wildlife in standing water and wet soil, and it can also infect people. The vaccine is not part of every dog's routine schedule, but it is worth discussing for dogs that hunt, swim, or drink from ponds and creeks. Tick prevention should be in place before the season starts. A dog that has been on the couch all summer needs conditioning before long days in the field. After a hunt, check feet, ears, eyes, and skin, and watch appetite and energy for a few days. Learn more on our dog care page.
4. Joints, skin, and weight in cooler weather
Arthritis. As temperatures drop, arthritis becomes more noticeable: stiffness after rest, reluctance to jump or use stairs, and slowing on walks. Cats often hide it and show it only as less jumping or grooming. Osteoarthritis is manageable, and earlier treatment works better.
Seasonal allergies. Ragweed and mold spores peak from late summer through fall in the Southeast. Dogs with allergies may itch, lick their paws, or develop ear infections. Itching that persists deserves an exam, because skin infections often follow scratching.
Weight. Shorter days usually mean less exercise. A body condition check now is easier than a winter of weight gain. See our cat care page for senior cat guidance.
5. Horses
Red maple leaves
Wilted or dried red maple leaves, common after fall storms, are toxic to horses and can destroy red blood cells. Signs include lethargy, pale or yellow gums, and dark urine. This is an emergency. Keep horses away from red maples and remove fallen branches from pastures.
Acorns
Oak acorns and young oak leaves contain tannins that can cause colic, diarrhea, and kidney damage. Risk rises when grass is short and acorns are plentiful. Supplement forage and keep horses off heavily littered areas.
Fall grass and laminitis
Cool nights and sunny days can raise the sugar (non-structural carbohydrate) content of grass, which increases laminitis risk in overweight horses and those with equine metabolic syndrome or PPID. Limit pasture access for at-risk horses, and call promptly if you notice heat in the hooves, a bounding digital pulse, or reluctance to walk.
PPID testing, deworming, and vaccines
Horses normally produce more ACTH in the fall, so testing for PPID (Cushing's disease) in late summer and fall requires seasonally adjusted interpretation. Ask us when testing is most reliable. Deworming works best when guided by fecal egg counts, and tapeworm and bot treatments are often timed after the first hard frost. Fall is also a good time to review vaccines and dental care before winter. In Tennessee's long mosquito season, some horses benefit from a second dose of mosquito-borne disease vaccines. More on our equine care page.
6. Cattle
Weaning and respiratory disease
Weaning is stressful, and bovine respiratory disease (BRD) is one of the most costly illnesses in weaned calves. Preconditioning vaccinations given well ahead of weaning, low-stress handling such as fenceline weaning, and good nutrition lower the risk. Watch calves for cough, nasal discharge, a dull appearance, and fever, and treat early.
Pregnancy checks and breeding soundness
Weaning time is a practical moment to check cows for pregnancy and assess body condition, so open or thin cows are identified before winter feed is committed. Bulls should have a breeding soundness exam before each breeding season.
Frost, drought, and forage hazards
After a killing frost, sorghum-type plants such as Johnsongrass and sorghum-sudan can release prussic acid (cyanide), which can kill cattle quickly. Drought-stressed forages can also accumulate nitrates. Follow your veterinarian's and county Extension's guidance on when it is safe to graze, and consider testing suspect forage.
Fescue, lice, and body condition
Tall fescue is common across East Tennessee, and the toxin in endophyte-infected fescue can cause fescue foot in cold weather: lameness, swollen lower legs, and dry gangrene of the feet, tail switch, and ear tips. Lice populations also build as cold weather approaches, so watch for rubbing and patchy hair loss. Fall is the time to assess body condition and test hay so cows enter winter in good flesh. See our cattle care page.
7. Goats and sheep
Barber pole worm
Haemonchus contortus, the barber pole worm, thrives in warm, wet conditions and remains a leading killer of goats and sheep through the fall. It causes anemia, seen as pale inner eyelids, weakness, and swelling under the jaw (bottle jaw). Because dewormer resistance is widespread, treating on a calendar is no longer sound. FAMACHA scoring and fecal egg counts let us treat only the animals that need it.
Copper, breeding, and vaccines
Sheep are highly sensitive to copper, so feed sheep-specific minerals and keep goat and cattle minerals away from them. Fall is breeding season for many flocks and herds, and breeding sets the lambing and kidding calendar about five months later. Check body condition before breeding and confirm vaccines, including CD&T, which protects against overeating disease and tetanus. Wet weather also raises the risk of foot rot and scald. See our goat and sheep care pages.
8. Pigs
Pigs handle heat and drafts poorly. Large swings between warm days and cool nights raise the risk of respiratory disease, so provide dry bedding, block drafts, and watch for coughing and pigs that go off feed. Pet pigs tend to gain weight as activity drops. More on our pig care page.
Quick reference: fall hazards at a glance
| Hazard | Most at risk | What we see | What to do |
|---|---|---|---|
| Antifreeze | Dogs, cats | Stumbling, vomiting, thirst, then kidney failure | Call immediately |
| Rodent bait | Dogs, cats | Bleeding, weakness, pale gums, often delayed by days | Call and bring the packaging |
| Wild mushrooms | Dogs | Vomiting, lethargy, liver failure | Call and take a photo |
| Halloween candy | Dogs | Vomiting, tremors, low blood sugar (xylitol) | Call and note the product |
| Red maple leaves | Horses | Lethargy, pale or yellow gums, dark urine | Emergency, call immediately |
| Acorns | Horses, cattle, sheep, goats | Colic, diarrhea, kidney injury | Limit access and call |
| Frosted sorghum or Johnsongrass | Cattle | Sudden death, respiratory distress (prussic acid) | Delay grazing and call |
| Barber pole worm | Goats, sheep | Pale eyelids, bottle jaw, weakness | FAMACHA score and fecal egg count |
| Weaning stress and BRD | Calves | Cough, nasal discharge, fever | Precondition and treat early |
When to call us right away
Do not wait for these
- Known or suspected ingestion of antifreeze, rodent bait, xylitol, or wild mushrooms
- A horse with dark urine, pale or yellow gums, or hot hooves and reluctance to walk
- A male cat straining to urinate
- Any animal that is down and cannot rise, bleeding without explanation, or struggling to breathe
- Calves with fever and cough
- Goats or sheep with pale eyelids or bottle jaw
Emergency services are available for our farm animal patients after-hours and on weekends. Call (423) 438-3864. For dogs, cats and other companion animals after hours, see our emergency care information.
Make it a fall wellness visit
Many of these problems are easiest to prevent at a routine visit. Through October 31, 2026, our Grand Opening Specials include a free stool sample with every visit, 20% off parasite treatment, and 20% off dental cleanings with any wellness visit. Book an appointment or call (423) 438-3864.
Further reading
Trusted references we rely on: American Heartworm Society, Companion Animal Parasite Council, American Animal Hospital Association, American Association of Equine Practitioners, UT Extension, and the ASPCA Animal Poison Control Center (a consultation fee may apply).
This article is general educational information and does not replace a veterinary exam. Every animal is different. If your animal is sick or you suspect poisoning, call us or an emergency veterinary service right away.
