Lecture 6 Flashcards
What two parasite strategies do you need in horses
Parasite control for first year of life
Parasite control for horses over 18 months
Goals of program for first year of life
Limit parasite burdens until young horses develop immunity
Goal of program for adults over 18 months
Minimize disease without inducing resistance to parasiticides
Major internal parasites
Small strongyles
Large strongyles
Anoplocephala perfoliata
Ascarids
Minor internal parasites
Gastrophilus intestinalis (bots) Habronema, drashcia (stomach worms) Oxyuris equi (pinworms) Strongyloides westeri (thread worms) Dictyocaulus (lungworms)
What is the most important parasite to manage in adult horses
Small strongyles/ cyathstomes
Prepatent period of small strongyles
5 weeks minimum
Describe small strongyles life cycle
Larvae migrate to cecum/colon for 4-6 weeks and encyst where they can live for months to years (mature and encysted doesn’t cause disease unless all encyst at the same time then it causes severe colitis)
Describe large strongyles
Migrate through abdominal tissues and live in lumen of the gut
Long prepatent period (6 months)
Clinical signs- colic, poor growth, weight loss
Very well controlled now with ivermectin
Major parasite concern for young horses
Parascaris equorum (roundworms)
Adult horses develop immunity but deadly for young foals
Eggs persist in environment for years
Round worms life cycle
Lives in small intestine and migrates to lymphatics, liver, lungs, pharynx, and back to small intestine (about a month for migration but takes over two months to shed eggs)
Clinical signs of roundworm infection (ascarids)
Coughing, diarrhea, colic, pot belly, rough hair coat, weight loss
**remember cannot be diagnosed prior to 80-90 days of infection by fecal float
What drugs have ascarids become resistant to
Ivermectin
Moxidectin
Pyrantel
Control of ascarids
Perform FECRT when possible
Deworm at 60 days of age and very frequently until 8-12 months
Describe tapeworms
Anoplocephala perfoliata
Live at ileo-cecal valve and cause spasmodic colic, intussusceptions, ileal impactions
Shed intermittently so have to do multiple fecals
Treatment of tapeworms
Praziquantel
Pyrantel
When should you deworm for tapeworms
Foals- prior to weaning
Adults- 1 to 2 times/ year
Describe botflies
Gastrophilus intestinalis
Little clinical disease
Treatment for botflies
Ivermectin or moxidectin
Remove eggs from legs
Describe stomach worms
Habronema, draschia Transmitted by stable flies No significant internal damage Cutaneous infections- granulomas on eyes, sheath, ventral midline Treat with ivermectin and steroid
Describe oxyuris equi
Pinworms
Live in small colon
Cements eggs to skin of anus and horses get very itchy and rub tail
Prepatent period- 3.5 to 5 months
Difficult to find on fecal float usually diagnosed based on clinical signs
What parasite causes diarrhea in foals 5 days- 4 months
Strongyloides westeri (threadworms)
Describe threadworms
Foals are infected via milk from dam
Resides in small intestine
Foals develop immunity quickly
Prepatent period is 5-7 days
Treatment for strongyloides westeri
Treat mares in late gestation with macrocyclic lactones
Treat foals as needed
Describe lungworms
Dictyocaulus
Donkeys can harbor infection with no CS and expose horses
Horses show cough and decreased performance
Treat with ivermectin
How to diagnose lungworms
Baermans test
Which parasites are a concern for juvenile horses
Ascarids- main concern
Strongyloides
Small and large strongyles
Refugia
Maintain population of parasites that do not receive drugs to keep resistance down
How to combat resistance
Use FECRT to determine effectiveness of drugs
Treat horses with FEC
Treat during peak transmission season
When should you treat based of FEC
Less than 200= do not treat
200-500= may treat
Greater than 500= treat
When will you worry about resistance in pyrantel and BNZ?
Macrocyclic lactones?
Pyrantel and BNZ= less than 90%
Macrocyclic lactones= less than 98%
When should you treat for worms based on season
Spring and fall- good climate for parasites
What is the expected egg reappearance period?
What is it for specific drugs?
Interval between treatment and resumption of FEC greater than 200
BZM= 4 weeks Pyrantel= 4 weeks Ivermectin= 8 weeks Moxidectin= 12 weeks
What is key with foals?
Prevention!
Describe normal neonate behavior
Sternal recumbency- 2 minutes
Suckle reflex- 30 min
Standing- 60 min
Nursing- 2 hours
What is the 1-2-3 rule
1 hour to stand
2 hours to nurse
3 hours to pass the placenta
When should the foal be examined
First 12-24 hours of life
Describe temp in foals
Normal- 99 to 102
Hypothermia is common in sick neonates
Unable to adequately cool in very hot climates
Describe foal heart
After birth- 40 to 80 bpm and increases to 100 to 120 during 1 week
Often have murmur that naturally resolves- PDA, innocent flow murmurs, ventricular septal defects
What is dr mallicotes favorite thing to look at on foals
MM
Describe resp
Transitioning from fluid filled to air filled lung Increase in minute ventilation Decrease from 80 to 30 bpm Inspiratory and expiratory crackles Normal is 30-40 bpm
What should you use for umbilical care in horse
Not iodine because its inflammatory!
Dip with chlorohexidine
Enemas
Give in first few hours of life
Clients should NOT give repeat enemas
Colostrum
Foals need 2 liters in 24 hours
First two hours of life are most critical because gut starts closing after that
When should you measure IgG and what does it mean
Measure at 12-24 hours
If less than 800, consider transfusion. If less than 400, definite transfusion
What vx/ antimicrobials should you use on foals
Tetanus antitoxin if mare was not properly vaccinated
Give abx if there is a non-observed birth and history of sepsis or if there is a history of problems on the farm
