CHARACTERISATION OF THE HAEMATOLOGICAL PROFILE IN THE POSAVJE HORSE BREED

The aim of this study was to investigate the influences of sex and age on haematological values in the Posavje Horse breed. A total of 163 healthy Posavje horses (30 foals, 94 mares and 39 stallions) were used in this study; their complete blood counts and a leucogram were obtained with a haematological analyser. The horses were classified into five groups: foals (1 to 6 months, n = 30), 3 to 6 years (n = 8 stallions/21 mares), 7 to 9 years (n = 9 stallions/22 mares), 10 to 13 years (n = 8 stallions/20 mares), 14 to 15 years (n = 6 stallions/10 mares) and 16 and over (n = 8 stallions/21 mares). The results obtained show an influence of sex on haematological parameters, with red blood cell count (RBC), haematocrit (HCT) and haemoglobin concentration (HGB) being higher in stallions (P < 0.001) and white blood cell count (WBC) being higher in mares. Differences between the age groups of the Posavje horses examined indicate a decrease in RBC and HGB with a compensatory increase in mean corpuscular volume and mean corpuscular haemoglobin, a decrease in WBC and platelet counts (PLT) and proportion of lymphocytes, and an increase of neutrophil to lymphocyte ratio (N/L) with age (P < 0.001). Although the Posavje horse is classified as a draft horse breed, its haematological parameters show characteristics common to warm-blooded breeds, with the exception of the N/L ratio. One of the most important findings of this study is a higher neutrophil count in reproductively active breeding stallions. Higher levels of RBC, HGB, HCT and neutrophil count in the Posavje stallions suggest an effect of androgens (testosterone), which may be an effective mechanism to prevent infections, that can affect the survival of the stallions and thus the evolution of the species. KARAKTERIZACIJA HEMATOLOŠKEGA PROFILA PRI POSAVSKEM KONJU Izvleček: Cilj raziskave je bil proučiti vpliv spola in starosti na hematološke parametre pri pasmi posavski konj. V raziskavo je bilo vključenih 163 konj posavske pasme (30 žrebet, 94 kobil in 39 žrebcev), pri katerih smo v vzorcih krvi določali hematološke parametre s hematološkim analizatorjem. Diferencialna bela krvna slika in razmerje med nevtrofilci in limfociti (N/L) je bilo določeno na krvnih razmazih. Konje smo razdelili v pet starostnih skupin: žrebeta (od 1 do 6 mesecev, n = 30), 3 do 6 let (n = 8 žrebcev/21 kobil), 7 do 9 let (n = 9 žrebcev/22 kobil), 10 do 13 let (n = 9 žrebcev/20 kobil), 14 do 15 let (n = 6 žrebcev/10 kobil) ter 16 in več let (n = 8 žrebcev/21 kobil). Rezultati naše raziskave kažejo vpliv spola na preiskovane hematološke parametre; pri žrebcih so število rdečih krvnih celic (RBC), hematokrit (HCT) in koncentracija hemoglobina (HGB) značilno višji (P < 0,001), pri kobilah pa je višje število belih krvnih celic (WBC). Med starostnimi skupinami posavskih konj smo ugotovili zmanjšanje RBC in HGB in posledično kompenzacijo s povečanjem povprečnega volumna in hemoglobina eritrocitov, zmanjšanjem števila levkocitov, trombocitov (PLT) in limfocitov ter povečanjem razmerja med nevtrofilci in limfociti (N/L) s starostjo (P < 0,001). Posavski konj po zunanjosti spada med hladnokrvne konje, v raziskavi ugotovljeni hematološki profil pa kaže značilnosti, ki so skupne toplokrvnim pasmam konj, z izjemo razmerja N/L. Ena od pomembnejših ugotovitev te študije je večje število nevtrofilcev pri aktivnih plemenskih žrebcih. Višje vrednosti RBC, HGB, HCT in števila nevtrofilcev pri posavskih žrebcih kažejo učinek androgenov (testosterona), kar bi lahko bil učinkovit mehanizem za preprečevanje okužb, ki lahko vplivajo na preživetje žrebcev in s tem na evolucijo vrste. Ključne besede: avtohtone pasme; posavski konj; hematologija; starost; spol