Lethargy in horses refers to a state of decreased energy, motivation, or enthusiasm, often observed as reduced activity or responsiveness. This condition may be indicative of underlying health issues, including metabolic disorders, infections, or nutritional deficiencies. Lethargy can manifest as a symptom associated with various equine diseases or stressors, impacting the horse's overall well-being and performance. Veterinary assessment typically involves a thorough examination to identify potential causes, which may include blood tests, physical evaluations, and diagnostic imaging. This page compiles peer-reviewed research studies and scholarly articles that explore the causes, diagnosis, and management strategies for lethargy in horses, providing insights into its implications for equine health and welfare.
Everett KA, Chaffin MK, Brinsko SP.A diaphragmatic hernia in which 90% of the large colon had herniated through a 16-cm linear tear in the diaphragm was found in a 12-year-old Quarter Horse mare. Clinical signs included lethargy and exercise intolerance. Diagnosis of diaphragmatic hernia was made based on careful thoracic auscultation, combined with ultrasonographic and radiographic examination of the thorax.
Uhlinger C.Black walnut toxicosis was diagnosed in 10 horses at one stable. The time from exposure to shavings to development of clinical signs was 8 to 12 hours. Most common clinical signs were moderate to severe laminitis (Obel grade 2 or 3), pitting edema of the distal portion of the limbs, and rapid respiratory rate. Two horses had clinical signs of colic and 2 other horses had anorexia and lethargy. All 10 horses recovered without complications.
Andrews FM, Rosol TJ, Kohn CW, Reed SM, DiBartola SP.Three horses less than or equal to 3 years old were evaluated because of stunted growth, weight loss, anorexia, depression, and lethargy of at least 1 month's duration. A neonatal foal was examined after its death. In each case, gross and microscopic renal lesions were compatible with bilateral renal hypoplasia (ie, cortical hypoplasia with severe medullary hypoplasia). In young horses with renal failure, bilateral renal hypoplasia should be considered in the differential diagnosis, and may represent a congenital lesion.
Kirkpatrick CE, Skand DL.Giardia infection was believed responsible for chronic diarrhea, weight loss, lethargy, inappetence, and dermatitis in a 4-year-old Thoroughbred horse. Fecal cysts were detected by the zinc sulfate centrifugal flotation method. All clinical signs resolved upon treatment with metronidazole suspension (5 mg/kg body weight per os, TID for 10 days).
Irvine CH.Hypothyroidism in the foal occurs as two entities because of the separate actions of thyroid hormones in regulation of metabolic rate and in cell differentiation. The hypometabolic state which results in inadequate thermogenesis and lethargy, occurs concurrently with a period when thyroid hormone secretion is inadequate. Also the severity of the concurrent symptoms is related to the degree of hormone inadequacy as measured by plasma concentrations of free T4 and T3. By contrast, the developmental lesions caused by hypothyroidism are often observed during periods when plasma thyroid hormone con...
Stowe HD.Thirty-four adult ponies were used to determine the effects of single oral doses of copper (Cu) supplements (0, 20, and 40 mg of Cu/kg of body weight) on the toxicity of oral doses of selenium (Se) supplements (0, 2, 4, 6, and 8 mg of Se/kg of body weight) administered 24 hours after the copper was given. Signs of Se toxicosis-sweating, diarrhea, tachycardia, tachypnea, mild pyrexia, lethargy, and colic-developed in ponies given 6 and 8 mg of Se/kg of body weight without Cu pretreatment. Two of 4 ponies given 6 mg of Se/kg and both ponies given 8 mg of Se/kg without Cu pretreatment died within...
Everett KA, Chaffin MK, Brinsko SP.A diaphragmatic hernia in which 90% of the large colon had herniated through a 16-cm linear tear in the diaphragm was found in a 12-year-old Quarter Horse mare. Clinical signs included lethargy and exercise intolerance. Diagnosis of diaphragmatic hernia was made based on careful thoracic auscultation, combined with ultrasonographic and radiographic examination of the thorax.
Längerer L.Bernardino P, James K, Barnum S et al. What have we learned from 7 years of equine rhinitis B virus qPCR testing in nasal secretions from horses with respiratory signs. Vet Rec 2021; 188 (10): e26. DAS EQUINE RHINITIS-B-VIRUS (ERBV) HAT EINE HOHE INZIDENZ, IST IN SEINER BEDEUTUNG JEDOCH NUR WENIG ERFORSCHT. EINE INFEKTION MIT DEM ERBV äUßERT SICH IN SYMPTOMEN WIE FIEBER, ANOREXIE, LETHARGIE, NASENAUSFLUSS, HUSTEN, LYMPHADENOPATHIE UND ÖDEMEN DER DISTALEN GLIEDMAßEN. AUßERDEM TRETEN HäUFIG SUBKLINISCHE INFEKTIONEN AUF. DAS ZIEL DIESER STUDIE WAR, DIE HäUFIGKEIT DES NACHWEISES VON ERBV IM...
Pinnell EF, Her J, Gordon D, Kinsella HM, Langston CE, Toribio RE.An adult American Quarter Horse mare presented for pigmenturia and lethargy of 12 hours' duration and was diagnosed with silver maple leaf toxicity. The mare had intravascular hemolysis and azotemia. The mare was treated with a transfusion of whole blood, fluids administered IV, antibiotics, oxygen insufflation, and supportive care. The azotemia persisted despite conventional medical management and hemodialysis was elected. After 2 intermittent hemodialysis treatments over 3 days, the azotemia almost resolved, clinical signs improved, and the mare was discharged. The blood urea nitrogen, c...
Yamarik TA, Wilson WD, Wiebe VJ, Pusterla N, Edman J, Papich MG.Using a randomized, cross-over study design, ciprofloxacin was administered i.g. to eight adult mares at a dose of 20 mg/kg, and to seven of the eight horses at a dose of 5 mg/kg by bolus i.v. injection. The mean C(0) was 20.5 μg/mL (±8.8) immediately after i.v. administration. The C(max) was 0.6 μg/mL (±0.36) at T(max) 1.46 (±0.66) h after the administration of oral ciprofloxacin. The mean elimination half-life after i.v. administration was 5.8 (±1.6) h, and after oral administration the terminal half-life was 3.6 (±1.7) h. The overall mean systemic availability of ...
Billmann P, Durham A, Christen G, Savioli G, Gross JJ, Gerber V, Fouché NE.Limited published data are available regarding the relationships among clinical signs associated with pituitary pars intermedia dysfunction (PPID), age, and concentrations of proopiomelanocortin-derived peptides and cortisol. Objective: Identify clinical signs associated with age, beta-endorphin (β-END), adrenocorticotropic hormone (ACTH), and cortisol concentrations and compare β-END and cortisol concentrations between horses with PPID and geriatric controls. Methods: A total of 113 horses aged 18-32 years. Methods: Cross-sectional study. Clinical signs were scored, plasma β-END, ACTH, an...