CASE STUDY

Hematology and Clinical Pathology Datain Chronically Starved HorsesAna Munoz, DVM, PhD,a,b Cristina Riber, DVM, PhD,a,b Pablo Trigo, DVM,b

and Francisco Castejon, DVM, PhDb

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ABSTRACT

Hematology and serum/plasma biochemistry are impor-tant diagnostic aids to assess metabolic status in starvedhorses and to rule out pathologic conditions that presentas emaciation. This article reviews the interpretation ofthese parameters, using 10 chronically starved horses asexamples.The studywas conductedon these10neglectedhorses belonging to both sexes, aged between 4 and 25years. The animals were divided into two groups accord-ing to their body condition scoring (BCS): A (n ¼ 6;BCS of 3 or lower) and B (n ¼ 4; BCS higher than 3). Acomplete clinical examinationwas carriedout, and venousblood samples were taken to perform hematological,biochemical, and serological determinations. The find-ings indicated that the most emaciated horses (group A)presented normocytic normochromic anemia, withhigher numbers of both immature and mature neutro-phils, monocytes, and eosinophils, and lower number oflymphocytes. Furthermore, horses in group A showedlower serum concentrations of urea, triglycerides, bileacids, alkaline phosphatase, and a lower urea/creatinineratio. Both groups of horses presented with hypomagne-semia. In conclusion, the knowledge of the laboratorialfindings in emaciated horses is useful in scoring the inten-sity of the emaciation, and in establishing a prognosis anda plan to recover the health status of these animals.

Keywords: Clinical biochemistry; Emaciation; Hema-tology; Horses; Starvation

INTRODUCTIONEquine welfare cases can be a result of cruelty or neglect, aswell as related to ignorance or inexperience of the owner,delegation of care, or economic hardship.1,2 The role ofequine clinicians who are involved in equine welfare cases

rom the Department of Animal Medicine and Surgery, School of Veterinary

edicine, University of Cordoba, Cordoba, Spaina; and Equine Sport Medicine

entre (CEMEDE), School of Veterinary Medicine, University of Cordoba, Cordoba,

painb.

eprint requests: Ana Munoz, DVM, PhD, Department Animal Medicine and

urgery, School of Veterinary Medicine, University of Cordoba, Campus Universitario

e Rabanales, Crt. Cordoba-Madrid, Km. 14071 Cordoba, Spain.

737-0806/$ - see front matter

2010 Elsevier Inc. All rights reserved.

oi:10.1016/j.jevs.2010.09.002

ournal of Equine Veterinary Science � Vol 30, No 10 (2010)

is to provide clear and irrefutable clinical evidence so as tohelp the court in deciding whether the condition of thehorse is the result of abuse, neglect, disease, or lack of vet-erinary care, and to determine ways to aid in the recovery ofthe horse to normal health on the basis of the findings.Examination of neglected horses starts with the identifi-

cation of the animal, as welfare cases of groups of horses of-ten involve animals that look superficially similar.2 Thefollowing factors are included in the identification of the an-imal: age, breed, type of horse, gender, color coat andmark-ings, whorls, and other identifying features. It is a normalpractice to photograph the animals so that each horse canbe properly identified with the help of the photograph.After that, a complete clinical examination is carried out.An initial body condition score should be included. Mea-surement of body weight does not help much in providingevidence of emaciation,3 and thewastage ofmuscle, not theabsence of fat, is the significant factor to assess malnutritionand suboptimal nutrient intake.3-5 Several systems ofassessing body condition have been proposed.3-7 Hennekeet al3 described a 9-point system based on a standardizedpalpation of neck, ribs, spinal column, and tailhead. Score1 is considered as “extreme emaciation,”with no fatty tissueand with protruding bones, that is, marked spinous andtransverse processes, and bones in the neck, tailhead andribs. Score 9 is considered as “obese,” with bulging fat inneck, withers, thighs, and tailhead. Figure 1 shows anextreme case of emaciation in a neglected horse (score 1).Complete clinical examination should include evaluating

conditions of the mouth and teeth (Fig. 2); lesions of theskin (Fig. 3); rectal temperature; heart rate; arterial pulsecharacter (normal, hyperkinetic, or hypokinetic); respira-tory rate and character of breathing pattern (rapid, shallow,or profound, withmarked abdominal component); appear-ance of mucous membranes; signs of weakness; responsive-ness and behavior; conditions of the feet (Fig. 4) andshoeing; abnormalities of the limbs, neck, back, pelvis, tho-rax, and abdomen; evidence of lameness; ability to eat; andgross evaluation of feces (volume, consistency) and urine.Samples for laboratory analysis, mainly blood for hematol-ogy and clinical pathology analysis and feces for coprolog-ical studies, should be obtained.Hematological and clinical biochemical determinations

are commonly performed in equine medicine for a varietyof reasons; screening tests are conducted on clinically

581

Figure 1. A 22-year-old gelding with extremeemaciation (body condition scoring: 1 over 9). Thishorse has congestive heart failure, with systolic murmurcompatible with mitral regurgitation, anemia (packedcell volume: 27.4%), hypoalbuminemia (2.0 g/dL), anddecreased urea/creatinine ratio (11.94).

Figure 2. An important reason of chronic malnutritionand/or starvation in horses is the lack of dental care.This horse presents an extreme overuse of teeth.

582 A Munoz et al � Vol 30, No 10 (2010)

healthy or normal animals to diagnose subclinical diseases;to identify conditions that might make a horse a poor can-didate for surgery or anesthesia; to diagnose systemic, in-fectious, and some parasitic disorders; to determine theseverity and the consequences of a disease; to formulatea prognosis; to monitor the response to a therapy or pro-gression of the disease; and in the cases of equine welfare,to assess the metabolic state. Because of this latter reason,hematology and clinical biochemistry parameters are con-sidered to be very useful in evaluating starvation; more-over, there is a wide range of medical conditions that willcause emaciation and laboratory parameters can help torule out these disorders before a diagnosis of starvation ismade.The present article describes the main hematological and

biochemical alterations in emaciated horses in 10 cases ofneglected horses that were sent to the Hospital of our Vet-erinary School for recovery. The aim of the present study isto provide an insight into the interpretation of hematologyand clinical biochemistry in equine welfare cases to beapplied in a clinical setting.

MATERIALS AND METHODS

Data of the PatientsIn all, 10 neglected horses of different breeds (threeAndalusian, one pony, and six cross-bred), ages (15.30 �7.4 years, range of variation: 4–25 years), and sex (fourmares, four gelding, and two stallions) were sent to theHospital of our Veterinary School for treatment and recu-peration. All the animals belonged to the same owner and

were from the same premises. The horses had been withoutveterinary and hoof care for a minimum of 9 months, vac-cination and deworming procedures had not been appliedduring the past 1 year, feeding regimens were unknown,and the animals had free access to clear water.

Clinical DataOn arrival at the Veterinary School, all horses were isolated,were identified, and a complete clinical examination wasperformed. General examination started with body condi-tion scoring (BCS), using the 9-point system proposed byHenneke et al.3 BCS was performed by three equineclinicians (C.R., P.T., and A.M.) and the score taken intoconsideration was the one on which at least two cliniciansagreed upon. According to the score system of Hennekeet al,3 horses were divided into two groups: those witha BCS of �3 (n ¼ 6; group A) and those with a BCS of>3 (n ¼ 4; group B).Rectal temperature; respiration rate and heart rate; qual-

ity of the pulse, including digital pulse; and assessment ofthe oral mucosa were checked. Regular and complete ex-aminations of the digestive, cardiovascular, respiratory,and locomotor systems were made by the same equine cli-nician (A.M.). Digestive examination consisted of teethand oral mucosal assessment, score of the intestinal motilityin the four quadrants of the abdomen, and rectal examina-tion when considered to be appropriate. Respiratoryexamination included assessment of uni/bilateral nasal dis-charge, size of the (sub)mandibular and retropharyngeallymph nodes, and auscultation of trachea and lungs. Acareful heart auscultation was also performed and the pres-ence of significant murmurs (more than three over six)and/or heart arrhythmias was annotated. Finally, a general

Figure 3. Conditions of the skin should also beannotated in starved horses. This horse shows abundantmelanomas located under the tail and in the perinealarea.

Figure 4. Lack of hoof care is a common finding inneglected horses.

A Munoz et al � Vol 30, No 10 (2010) 583

locomotor exploration was made, with special emphasis onhoof status and scoring main attitude, rhythm, and propul-sion. Flexion tests of both forelimbs and hindlimbs wereperformed.

Clinical Pathology DataFeces were taken from all the horses so as to carry out cop-rological examinations for detecting eggs of parasites. Fur-thermore, a blood sample was taken from the externaljugular vein before feeding the animals, which was dividedinto three fractions. The first fraction was poured intotubes with EDTA-3K as anticoagulant for hematology.The second fraction was introduced in tubes without anti-coagulant to obtain serum for biochemistry and serology.The third fraction was poured into tubes with citrate for fi-brinogen (FIB) concentrations. A last drop of blood wasused to make a blood smear directly from the syringe. Allthe blood smears were air-dried.The following hematological variables were analyzed us-

ing a semi-automatic cell counter (Sysmex-F820): redblood cells (RBC); hemoglobin concentration (HB);packed cell volume (PCV); mean corpuscular volume,mean corpuscular hemoglobin, and mean corpuscular he-moglobin concentration; white blood cells (WBC); andplatelet count. The differential count of WBC was madein the blood smears after staining (Diff-Quick), and the

number of band neutrophils (BNEU), segmented neutro-phils (SNEU), total neutrophils (TNEU), lymphocytes(LYM), eosinophils (EOS), monocytes (MON), andbasophils were obtained.In serum, the concentrations of total proteins (TP), albu-

min (ALB), globulins (GLOB), urea (BUN), creatinine(CREAT), triglycerides (TG), cholesterol (CHOL),bile acids(BAC), direct bilirubin, total bilirubin, sodium, chloride,potassium, calcium, magnesium, and phosphorus, weremeasuredby spectrophotometricmethods (spectrophotome-ter Termo Spectronic) using specific reagents (Biosystems).Furthermore, activities of alkaline phosphatase (AP), creatinekinase (CK), aspartate aminotransferase (AST), lactate dehy-drogenase (LDH), gamma-glutamyl dehydrogenase (GGT)were also determined by spectrophotometry. FIB concentra-tions weremeasuredwith a coagulometer (RAL,Clot-SP) onthe basis of the measurement of the time needed to clot,inversely proportional to FIB concentrations when highconcentrations of thrombin were provided.Finally, the horses were checked for the most common

infectious and parasitic diseases that were prevalent inSpain. Serologic diagnosis was made for Babesia caballiand Theileria equi (indirect fluorescent antibody test),Anaplasma phagocytophilum (polymerase chain reaction[PCR]), equine infectious anemia (agar gel immunodiffu-sion), and equine viral arteritis (complement enhancedmicroneutralization test).

Statistical AnalysisData are presented as mean � standard deviation. Thedifferences between groups with different BCS (groups A

Table 1. Mean values and standard deviation for the clinical parameters determined in two groups of chronically starvedhorses with different BCS

Clinical Parameter Group A Group B Reference Values

RT (8C) 37.87 � 0.216 37.93 � 0.310 37.50–38.50RR (breaths/min) 20.67 � 9.266 21.00 � 3.830 12.00–24.00HR (beats/min) 44.67 � 6.890 42.00 � 7.659 32.00–44.00

RT, rectal temperature; RR, respiratory rate; HR, heart rate.

Table 2. Mean values and standard deviation for the hematological parameters in two groups of chronically starvedhorses with different BCSa,*

Laboratory Parameter Group A Group B Reference Values

RBC (106/mL) 6.228 � 1.320* 7.510 � 2.201 7.000–13.00HB (g/dL) 10.13 � 2.238* 12.13 � 3.763 11.00–14.00PCV (%) 29.60 � 5.485* 32.73 � 7.541 32.00–45.00MCV (fL) 47.77 � 3.003 46.17 � 5.773 37.00–55.00MCH (g/dL) 16.25 � 0.683 16.10 � 1.411 12.30–15.70MCHC (g/dL) 34.08 � 1.332 35.03 � 1.245 31.00–36.00PLT (103/mL) 151.0 � 18.09* 199.0 � 20.05 100.0–350.0BNEU (103/mL) 0.263 � 0.248* 0.000 � 0.000 0.000–0.100SNEU (103/mL) 5.460 � 1.749* 4.300 � 0.651 2.500–7.500TNEU (103/mL) 5.723 � 1.886* 4.300 � 0.634 2.500–7.600LYM (103/mL) 2.687 � 0.825* 5.840 � 4.634 1.500–5.000EOS (103/mL) 0.307 � 0.416* 0.177 � 0.106 0.000–1.000MON (103/mL) 0.770 � 0.615* 0.470 � 0.168 0.000–0.500BAS (103/mL) 0.000 � 0.000 0.000 � 0.000

MCV, mean corpuscular volume; MCH, mean corpuscular hemoglobin; MCHC, mean corpuscular hemoglobin concentration; PLT, platelet count;

BAS, basophils.a Reference values established for adult horses in our University with the same analytical methods.

* Significant differences between groups at P < .05.

584 A Munoz et al � Vol 30, No 10 (2010)

and B) were studied with an analysis of variance. Significantdifferences were set at P < .05.

RESULTSThemean BCS values were 2.17� 0.76 and 4.50� 0.57 ingroups A and B, respectively, which represent a range be-tween extreme emaciation and moderate BCS.3,8 Therewere significant differences in age between both groups(group A: 20.33 � 4.0 years; group B: 7.76 � 3.3 years).The mean values and the standard deviation for the clinicaldata are presented in Table 1. Tables 2 and 3 show the he-matological and the biochemical data, respectively. Horsesof group A presented significantly lower values for RBC,HB, PCV, platelet count, LYMP, BUN, BUN/CREAT,TG, BAC, AP, and Mg, and higher values for BNEU,SNEU, TNEU, EOS, and MON as compared with horsesof group B. All the animals presented negative serologicdiagnosis for the checked infectious and parasitic diseases.

Tables 4 and 5 summarize the interpretation of the mainhematological and serum biochemical parameters instarved horses.

DISCUSSIONSeveral reports have addressed similar issues of starvedhorses,1,6,7,9 the response to different type of diets,10 therole of the equine clinician involved in welfare cases,2 oreconomic and ethical considerations.11 Most of the articlesconcerning the hematological and biochemical conse-quences of fasting in equids have focused on ponies anddonkeys because of the development of hypertriglyceride-mia after periods of anorexia or starvation.12-16

Laboratory studies, that is, hematological and serum/plasma biochemical parameters, are important in neglectedhorses because these findings can help to assess metabolicstatus and to rule out diseases other than emaciation. Forthis reason, the present article reports the laboratory find-ings in neglected horses divided into two groups according

Table 3. Mean values and standard deviation for serum biochemical parameters in two groups of chronically starvedhorses with different BCSa,*

Laboratory Parameter Group A Group B Reference Values

TP (g/dL) 7.033 � 0.477 7.123 � 0.531 6.000–7.500ALB (g/dL) 2.595 � 0.260 2.588 � 0.130 2.500–3.500FIB (g/dL) 0.268 � 0.068 0.270 � 0.105 0.200–0.500GLOB (g/dL) 4.014 � 0.575 4.265 � 0.327 3.500–4.500ALB/GLOB 0.675 � 0.141 0.608 � 0.032 Close to the unityBUN (mg/dL) 17.50 � 0.837* 28.58 � 3.508 10.00–35.00CREAT (mg/dL) 1.390 � 0.098 1.400 � 0.251 0.800–1.800BUN/CREAT 12.63 � 0.989* 20.76 � 3.341 >15TG (mg/dL) 19.33 � 3.670* 48.00 � 40.78 4.000–45.00CHOL (mg/dL) 73.83 � 16.18 79.00 � 12.70 45.00–180.0BAC (mmol/L) 12.23 � 3.125* 17.11 � 5.099 10.00–20.00DB (mg/dL) 0.512 � 0.053 0.453 � 0.090 0.000–0.040TB (mg/dL) 2.242 � 1.148 2.123 � 0.641 1.000–2.000AP (IU/L) 397.5 � 80.65* 471.0 � 114.0 140.0–600.0CK (IU/L) 105.7 � 35.13 135.5 � 40.02 150.0–350.0AST (IU/L) 218.0 � 54.54 256.8 � 50.39 220.0–500.0LDH (IU/L) 570.7 � 364.9 504.5 � 88.97 140.0–500.0GGT (IU/L) 16.60 � 5.367 27.75 � 9.465 4.00–40.00Na (mmol/L) 140.0 � 2.280 138.5 � 1.291 135.0–145.0K (mmol/L) 4.550 � 0.394 5.075 � 1.091 3.000–5.000Cl (mmol/L) 102.0 � 2.530 100.3 � 2.062 98.00–110.0Ca (mmol/L) 12.72 � 2.194 11.53 � 0.723 11.20–13.60P (mg/dL) 2.512 � 0.461 2.805 � 0.832 3.100–4.600Mg (mg/dL) 2.065 � 0.341* 1.800 � 0.254 2.200–2.800

DB, direct bilirubin; TB, total bilirubin.a Reference values established for adult horses in our University using the same analytical methods.

* Significant differences between groups at P < .05.

A Munoz et al � Vol 30, No 10 (2010) 585

to their BCS. The main finding of this article was thathorses with a BCS of �3 have a more intense normocytichypochromic anemia, with higher numbers of both imma-ture and mature neutrophils, MON, and EOS, and lowernumber of LYM. Additionally, horses in group A showedlower serum concentrations of BUN, TG, BAC, AP, anda lower BUN/CREAT ratio. Both groups of horsespresented hypomagnesemia.

Interpretation of Hematological ParametersA normocytic normochromic anemia was found in horsesbelonging to group A. Although RBC, HB, and PCVvalues were also low in horses of group B, the mean valueswere within the reference range. Classically, anemias are di-vided into regenerative and nonregenerative, although dis-tinction between them is difficult, because reticulocytes arenot commonly seen in equine blood samples, and thereforetheir presence or absence is not a reliable method of deter-mining regeneration or nonregeneration.17,18 The mostcommon causes of anemia in horses are chronic bloodloss associated with mild and/or moderate parasitism,

chronic inflammation, and neoplasia. In Spain, the mostcommon causes of mild anemia are subclinical infectionsof B caballi, Theileria equi, Anaplasma phagocytophilum,and internal parasitism.19,20 The neglected horses includedin the present study were found to be serologically negativefor these infectious agents. However, more than 300 eggsof Strongylus per gram of feces were found in four horses ofgroup A, and this infestation could have been implied inthe development of anemia, as confirmed by the higherEOS count in the animals of this group. Furthermore, ane-mia is a common clinical and laboratory sign that accom-panies starved or malnourished horses2 and many chronicdiseases. In fact, the most marked anemia was found inhorse 2, which presented tachycardia (64 beats/min),with a systolic murmur in the left hemithorax, of intensity4/6, and systemic signs compatible with congestive heartfailure, such as jugular regurgitation, peripheral venousdistension, dependent edema in hindlimbs, and diffusecrackles in both lung fields.A variety of alterations in total WBC and subsets were

observed in the neglected horses. An increased number

Table 4. Interpretation of hematological parameters in starved horses

Parameter Comments and Diagnostic Value in Starved Horses

RBC, HB Increase in hemoconcentration because of reduced water intake. Decrease in chronicinflammation/infection, internal parasitism, and starvation

PCV, MCV Limited utility to diagnose regenerative anemia. Increase in intenseregenerative anemia

MCH, MCHC Decrease in hypochromic anemia. Increase in some hemolytic anemiasWBC Increase in acute/subacute inflammations and infections. Decrease in peracute

inflammations and infections as endotoxemia

BNEU, SNEU, TNEU Increase in infectious and inflammatory conditions. Increase in acute/subacuteinflammations and infections. Decrease in peracute inflammations and infections asendotoxemia

LYM Increase in chronic viral infections, chronic immune stimulation, and lymphoidneoplasia (lymphoma). Decrease in starvation and initial phases of viral insults

MON Monocytosis in processes with increased tissue demand for phagocytosis (tissuenecrosis, chronic suppurative diseases). Common in recovery phase following a viralinsult

EOS Increase in antigen-antibody response in tissues rich in mast cells. Increase inparasitism (unreliable indicator of internal parasitism; more common in nematodeinfection with systemic migration)

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of circulating immature neutrophils (ie, metamyelocyteand BNEU) is one sensitive indicator of infectious and/or inflammatory diseases, whereas mature neutrophiliacan be found after splenic contraction, in response tochronic stress and during infectious and non-infectious in-flammatory conditions.12 The higher numbers of BNEU,SNEU, and TNEU in horses of group A could indicatethat starvation is seen in animals affected by subclinical in-flammations/infections and/or the horses deprived offood have increased susceptibility to infections.21

Naylor and Kenyon21 also found a progressive decreasein circulating LYM count in horses deprived of food fora period of 5 days, with a subsequent increased susceptibil-ity to bacterial infections. In our study, a significant lowerLYM count was found in group A. Themain differential di-agnoses of lymphopenia in horses are endogenous releaseand/or exogenous administration of glucocorticoid ste-roids, severe systemic bacterial infections, and viral infec-tions.18,22 The findings of physical examination and thelaboratory analysis did not reveal clinical signs indicativeof pituitary pars intermedia dysfunction, even thoughdexamethasone suppression test or other dynamic hor-monal tests to rule out Cushing’s syndrome were not per-formed. The most common viral infections were ruled outby serology, and no clinical signs compatible with influenzaor herpesvirus infection were observed. Therefore, it seemsplausible that the lower LYM in group A was related toa more intense starvation.Lymphocytosis was found only in one horse of group B

(horse 9, LYM higher than 10,000/mL). Lymphocytosis is

found after splenocontraction by release of epinephrine, inchronic inflammatory conditions, and in lymphoid neopla-sia as lymphoma or chronic lymphocytic leukemia.18,22,23

Horse 9 was excited during blood withdrawal, its BCS wasfive, anemia was not detected, and he was the youngest an-imal included in this article (4 years). Therefore, this case oflymphocytosis was associated with stress of venipunctureand splenic contraction after epinephrine release.The higher MON count in horses of group A could have

been linked to conditions that cause increased tissue de-mand for phagocytosis of macromolecular particles, as isseen in tissue necrosis, and chronic suppurative diseases.Furthermore, monocytosis is common in the recoveryphase after a viral insult.24 Therefore, the higher MON,BNEU, SNEU, and TNEU in group Amay reveal the sub-clinical presence of inflammation or infections in the morestarved horses.

Interpretation of Serum Biochemical ParametersTP and ALB are reported to be increased in horses withdeprivation of food because of hemoconcentration second-ary to a reduced water intake.16 However, hypoproteine-mia and hypoalbuminemia are not consistent findings instarved horses.2 In contrast, hypoproteinemia and hypoal-buminemia are two common laboratory features of someinflammatory disorders, protein-losing enteropathies, ne-phropathies, and some cases of liver failure. This last find-ing is not a consistent finding, as only 13% of the horseswith liver failure have hypoalbuminemia.25-27 Hypoalbu-minemia is also found in inflammatory disorders, as ALB

Table 5. Interpretation of the main serum biochemical parameters in starved horses

Parameter Comments and Diagnostic Value in Starved Horses

TP, ALB Increase in hemoconcentration because of reduced water intake. ALB decrease in chronicinflammatory disorders, protein-losing diseases and some cases of liver failure.Hypoproteinemia and hypoalbuminemia are not consistent findings in starved horses

FIB Increase in some inflammatory disorders (chronic parasitism and bacterial and virus infections)GLOB Increase a1 in starvation, increase a2 in acute inflammation and parasitism by cyathostomas,

increase in b-globulins in Strongyle larve migration, hepatopathy, and inflammation,increase in g-globulins in chronic infection, lymphoma, and plasma cell myeloma

ALB/GLOB Decreased ratio in inflammatory diseases, lymphoma, and other lymphocyte neoplasia,and in selective hypoproteinemia (protein-losing enteropathies, nephropathiesand some liver disorders)

BUN/CREAT Decreased ratio in protein deprivation/starvationTG, CHOL Increase in starvation, particularly in ponies and donkeysBAC, DB, TB Not affected by fasting. Increase of BAC in impaired biliary function. Elevations after periods of

anorexia or starvationAP, CK Decrease in starvation because reduced amount of intestinal isoenzyme caused by lack of intestinal

activity. Increase in young animals or in animals with a high osteoblastic activityAST, LDH Decrease because of reduced muscle activity. Mild increase because of muscle catabolic stateGGT Mild elevation found sometimes in starved animalsNa, Cl Increased natremia and chloremia in reduced water intakeK, Ca Decrease in acute anorexiaP, Mg Decreased phosphatemia and magnesemia in starvation because of reduced food intake

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is a negative acute-phase protein.28 In the present study,there were no significant differences between groups ofhorses and it should be noted that the animals with thelowest BCS did not present the lowest serum ALB concen-trations; these result agree with those of Green and Tong.2

The most intense hypoalbuminemia was found in horse 2,with congestive heart failure. Serum ALB concentrationsmay be slightly low in horses with chronic heart failure.29

a-GLOB are elevated in acute inflammation and parasit-ism, especially in cyathostomiasis, as well as in some cases ofstarvation.22 b-GLOB are elevated in large and mixedStrongyle larval migration, hepatopathy, and inflamma-tion, as FIB runs in the same electrophoretic range.30 g-GLOB are increased in chronic infection or inflammationwith antibody production, in lymphoma and in plasmacell myeloma.22,23 The low ratio ALB/GLOB in all thehorses in the present study is consistent with chronic in-flammatory conditions. The finding that the FIB concen-trations were normal in all the horses was unexpected,despite showing changes in the leukogram consistentwith chronic infections. FIB is an acute phase reactive pro-tein and its concentration might help in the diagnosis andprognosis of cases with chronic inflammation, such as in-ternal abscessation, chronic parasitism or infections.22,30,31

Kronfeld4 reported that one sensitive marker of reducedprotein intake in horses is the BUN/CREAT ratio. BUNconcentration is a function of protein intake (deaminationof amino acids and BUN synthesis) and excretion by the

kidney. CREAT concentrations depend on renal clearanceand muscle activity, with the breakdown of creatine phos-phate, although this breakdown is assumed to be constant.Because both metabolites are affected by glomerular filtra-tion rate, this influence can be reduced by calculating theratio between both variables. According to Kronfeld,4

a BUN/CREAT ratio of <15 mg/dL is indicative of pro-tein deprivation and/or starvation. In the present study,the mean BUN/CREAT ratio was lower than 15 in groupA but not in group B, and therefore, it is concluded thatthis ratio is a better marker of protein wasting than serumALB or TP concentrations. None of the animals presentedabnormal serum BUN and CREAT concentrations, andtherefore, renal dysfunction was ruled out.Malnutrition and starvation can result in hyperlipidemia,

with increases in serumTG and CHOL concentrations aftermobilization of lipids from the adipose tissue for energy.This fact is more common in ponies and donkeys than inhorses,10,14,15 although it has been described that it mightbe underestimated in horses.32 In the present study, serumTG and CHOL concentrations were within the normallimits in both groups of horses. However, the highest valuesof serum TG (96 mg/dL) found in the pony (BCS 4) agreewith the findings presented previously by other authors.13-15

BAC are synthesized from CHOL in hepatocytesthrough various metabolic pathways and excreted intothe bile. Approximately 90% of the BAC pool is restrictedto the enterohepatic circulation and it is estimated to cycle

588 A Munoz et al � Vol 30, No 10 (2010)

about 40 times a day in ponies.33 Consumption of foodstimulates bile excretion, and thus, in species that havea gall bladder and consume fatty diets, the BAC concentra-tions increase postpandrially. However, in horses, feedingand fasting do not significantly alter BAC concentrations.All the horses in this study showed normal BAC concentra-tions. As a consequence, increased BAC concentrations inhorses are suggestive of impaired biliary function. It shouldbe noted that weight loss and emaciation are clinicalfeatures of 50% of horses with hepatic disease.34

As expected, the studied horses presented hyperbilirubi-nemia. It has been shown that either direct and conjugatedor indirect and unconjugated bilirubin increases in horsesduring feed deprivation and anorexia. No significant differ-ences were found when comparing horses with BCS <3 orwith a BCS >3. According to our results, direct bilirubinand total bilirubin are important markers of acute fooddeprivation, but their serum concentrations are not directlyrelated to the degree of emaciation.Some enzymes modify their activity when starvation is

seen. The lower serum AP concentration in group A wasprobably because of the decreased amount of intestinal iso-enzyme, which in turn was caused by a lack of intestinal ac-tivity. It has been demonstrated that serum activities of APdiffer with age, with higher values for foals, because ofmarked osteoblastic activity in growing bones. Despitethe difference in age between horses of group A and B,nine of the studied horses were adult and as a consequence,the differences in AP between groups cannot be associatedwith the different age. Some authors have reported a reduc-tion in serum CK in starved horses, consistent with a re-duced release of creatine-bound phosphate metabolismbymuscle energy,12,16 whereas others have found amild el-evation in CK because of catabolic states.2 Serum AST ac-tivities do not change with fasting in ponies,12 althoughDeegen et al35 described a moderate increase in this en-zyme. LDH is an enzyme associated with anaerobic metab-olism of glucose, and a decrease in its activity is linked toa decreased degradation of carbohydrates. Therefore,mild elevations in GGT and LDH are found sometimesin starved horses and although they resolve spontaneously,a differential diagnosis with hepathopaties should bemade.2 There were no significant differences in serum ac-tivities of CK, AST, LDH, and GGT between groups Aand B in the present study.Changes in serum electrolytes and minerals concentra-

tions in starved horses are not always present. Guptaet al16 reported increased natremia and chloremia after sev-eral days of food deprivation in donkeys, probably associ-ated with a reduced water intake. No significantdifferences in serum Na, Cl, K, Ca, and P concentrationswere observed between groups. An interesting findingwas the high concentrations of K, as a period of anorexiais consistent with hypokalemia. Probably, this fact was

related with the release of K from muscle cells because ofthe physical activity and/or stress of the animals associatedwith the adaptation to a new premise.36 Finally, it shouldbe emphasized that both groups of horses presented hypo-phosphatemia and hypomagnesemia and in fact, serumMgconcentrations were significantly lower in group A than inB, consistent with reduced food intake.In conclusions, there are some hematological and bio-

chemical changes that happen in starved horses. Thesemodifications should be known by equine clinicians to as-sess the metabolic status of these animals, to decide whichanimals should be euthanized because their age, theirintense emaciated status and/or the presence of chronicdiseases, and to establish a plan to recover health statusof these animals.

ACKNOWLEDGMENTS

The authors thank the equine clinician who denounced thesecases to the court and the people who adopted the animals af-ter recovery. The help of the Police for their assistance in thehandling and the removal of the animals from the facilitiesand their intervention in the prosecution of the owner aremuch appreciated.

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