Establishment of Baseline Haematological Values for Canine Population in North-Central Nigeria: A Cross-Sectional Study in the Federal Capital Territory

Abbreviations

FCT: Federal Capital Territory; PCV: Packed Cell Volume; RBC: Red Blood Cell; WBC: White Blood Cell; HB: Haemoglobin Concentration; NID: Nigerian Indigenous Dog; MCHC: Mean Corpuscular Haemoglobin Concentration; MCH: Mean Corpuscular Haemoglobin; MCV: Mean Corpuscular Volume; PCV: Packed Cell Volume.

Introduction

Haematology plays a fundamental role in veterinary diagnostics, providing insight into the physiological and pathological status of animals. The evaluation of haematological parameters provides critical information necessary for diagnosing diseases, monitoring therapeutic responses, and conducting pre-surgical assessments in clinical veterinary practice [1, 2]. In dogs, haematological values can be influenced by several intrinsic and extrinsic factors, including age, sex, breed, environmental conditions, nutritional status, and underlying disease conditions [3, 4]. Consequently, understanding normal reference intervals specific to regional and demographic variations is essential to accurately interpret laboratory findings and guide effective clinical decision-making.

Previous studies have established haematological reference values for canine populations in various parts of the world. However, significant differences in canine haematological parameters have been reported between breeds, age categories, and sexes, necessitating region-specific baseline data [5, 6, 7]. In sub-Saharan Africa, especially in Nigeria, studies examining the haematological profiles of dogs remain relatively scarce and fragmented, with limited data available to guide clinicians in the interpretation of laboratory results. For instance, earlier investigations in Nigeria Igbokwe, et al. [4]; Ogbu, et al. [8] have reported regional differences in haematological values among dog breeds, but comprehensive evaluations encompassing a wide range of breeds, ages, and sexes within a defined geographic locale remain limited.

Breed-specific haematological studies are of particular relevance in countries like Nigeria, where a mixture of indigenous and exotic dog breeds coexist, often under varying management systems. Indigenous dogs, such as the Nigerian Indigenous Dog (NID), are typically reared under semi-intensive or extensive systems and are exposed to different environmental and parasitic challenges compared to exotic or imported breeds that are usually raised under intensive care [9]. These differences in genetics and husbandry practices may result in significant variation in blood parameters, which if not accounted for, can lead to misinterpretation of laboratory values and misdiagnosis. Similarly, age-related changes in erythrocytic and leukocytic parameters are important for distinguishing physiological variations from disease states, especially in growing puppies and ageing dogs [10].

Given the diagnostic importance of haematological values and the paucity of region-specific data, this study was conceived to evaluate the haematological profiles of dogs in the Federal Capital Territory, Nigeria, with particular focus on identifying variations associated with sex, age, and breed. The establishment of baseline haematological values in the canine population would not only contribute to the body of knowledge in veterinary haematology but also provide clinicians and pathologists in Nigeria and those within north-central Nigeria and beyond with practical reference data. Such data are vital for the improvement of diagnostic accuracy, tailoring of therapeutic interventions, and enhancement of overall animal health care delivery in diverse veterinary settings.

Discussion

The overall haematological profile in this study revealed a wide range of values across several parameters, reflecting significant physiological variation within the sampled dog population in FCT, Nigeria. The broad ranges for PCV (4.00–61.00%), HB (3.60–23.10 g/dL), and RBC (1.28–8.47 ×1012/L) may result from differences in breed, age, physiological state, health status, and environmental exposure. These variations emphasises the importance of contextual interpretation of haematological results, as standard reference values may not always account for such diversity. Similar ranges were reported in a study conducted in Nigeria and Ghana, highlighting the variability in canine haematological parameters in different regions due to factors such as nutrition, disease exposure, and genetics [4, 5, 7, 8].

The erythrocyte indices (MCV, MCH, and MCHC) recorded in this study were generally within expected canine reference ranges but exhibited moderate variation, suggesting differing erythrocyte morphologies among individual dogs. Such variation could be attributed to differences in hydration status, iron metabolism, or chronic disease presence. Notably, the MCHC values ranged widely (up to 8.10 g/dL SD), potentially indicating instances of spherocytosis or haemoconcentration in some animals. These findings align with those of other studies where similar haematological dynamics in mixed-breed and indigenous dogs were reported [4, 5, 8], thus, emphasising the diagnostic value of erythrocyte indices in the identification of subclinical anaemia and red cell disorders.

The white blood cell (WBC) and differential counts showed a considerable range, with some dogs having counts as high as 33.30 × 109/L. Elevated leukocyte counts could indicate inflammatory or infectious processes, while lower counts may reflect immune suppression or viral infections [12]. The high mean lymphocyte count (7.17 ± 4.40 ×109/L) may support the possibility of active immune surveillance in many dogs. These findings is consistent with those of Ogbu KI, et al. [13] and Umeakuana PU, et al. [14], who linked increased lymphocyte activity to endemic parasitic and viral challenges in Nigerian dog populations. Such observations are critical for pathologists, as the interpretation of WBC values without consideration for regional disease burdens can lead to diagnostic errors.

Platelet counts were notably variable, ranging from 0.00 to 1078 × 109/L, which is unusually broad. Thrombocytopenia could suggest bone marrow suppression, platelet destruction (e.g., immune-mediated), or consumption (e.g., DIC), while thrombocytosis might be reactive (e.g., due to inflammation or neoplasia) [15]. A similar variability was reported by Cortese L, et al. [16] in dogs, where exposure to toxins and infectious agents can influence platelet dynamics. For clinicians, this could imply that interpretation of platelet counts must be integrated with clinical signs and other laboratory findings to avoid misclassification of thrombocytopenic or thrombocytotic states.

Sex-based differences in haematological values were minimal, aligning with previous studies that sex generally has a limited impact on canine haematology [17]. The slightly higher PCV and HB values in males could be related to testosterone-induced erythropoiesis, but the differences were not statistically or clinically significant. Similarly, the marginally higher WBC and platelet counts in females might be linked to hormonal modulation of immune responses, particularly in intact bitches. However, the consistency across sexes reinforces the applicability of shared reference intervals in clinical practice, except in specific cases where hormonal influence is suspected.

Age-related trends showed a progressive increase in erythrocyte parameters with age, reflecting bone marrow maturation and increased oxygen demand in adult dogs. Puppies had lower PCV, HB, and RBC, which may result from ongoing haematopoietic development or subclinical nutritional deficiencies. Similar observations were made in other studies involving Nigerian dog breeds, where younger dogs had lower erythrocyte values due to physiological immaturity [4, 8]. This trend therefore, highlights the need for age-specific reference intervals, especially when evaluating young or geriatric animals, to avoid misdiagnosis of age- appropriate changes as pathological.

The WBC counts varied across age groups, with younger dogs exhibiting higher leukocyte levels, possibly due to greater exposure to novel antigens and a more reactive immune system. The elevated counts in the 7–12 months age group support the theory of immune priming during early development. These findings agrees with the report of McCourt MR, et al. [18], who documented increased lymphocyte activity in younger dogs. For veterinarians, such information could help in the differentiation between physiological leukocytosis in young animals and pathological leukocytosis due to infection or inflammation.

Interestingly, platelet counts declined with age, with puppies showing the highest mean counts. This observation may suggest a more active thrombopoietic response during early development or differences in platelet lifespan. Lower platelet counts in older dogs could indicate age-related marrow senescence or subclinical disease processes. The trend is in concordance with the findings of Cortese L, et al. [16], who reported decreasing thrombocyte levels with age in dogs. Such patterns are important for pathologists when considering differential diagnoses for bleeding disorders in geriatric patients.

Breed-related haematological variations were particularly striking, with Belgian Malinois showing the highest erythrocyte parameters, possibly due to their athletic nature and enhanced erythropoietin activity. These findings corroborate the work of Miglio A, et al. [6], who found elevated RBC counts in working dogs. In contrast, Boerboels had the lowest values, perhaps due to less physical activity or underlying genetic factors. For pathologists and clinicians, this reinforces the importance of breed-specific baselines when interpreting the haemogram to avoid over- or underestimating anaemic or polycythaemic conditions.

Furthermore, Nigerian indigenous dogs had the highest leukocyte and lymphocyte counts, likely reflecting their environmental exposure to endemic pathogens and greater immune system stimulation. This finding supports the results of Akinyemi T, et al. [9], who reported robust immune responses in local breeds compared to imported ones. The relatively high platelet counts in Samoyeds and Saint Bernards may be a breed specific trait, while the low values in American Eskimos could suggest breed- related hypoplateletism or genetic thrombocytopenia, but this assertion require further investigation. Such data are valuable for the development of breed-specific reference ranges, essential for accurate diagnostics, especially in diverse canine populations [19, 20].

Conclusion

The data emphasises the need for careful selection of control groups in studies involving canine subjects. Also, the study contributes to the global understanding of canine haematology by providing data from a region with limited existing information. Hence, there is need for continued research in diverse geographical and ecological settings to build a comprehensive picture of canine haematological health.

Acknowledgements

The authors gratefully acknowledge the support of the Tertiary Education Trust Fund (TETFund), Nigeria, for funding this research. The authors also express their sincere appreciation to the University of Abuja Institutional-Based Research Committee for their administrative, ethical, and logistical support throughout the conduct of this study. The technical assistance provided by staff of the Clinical Pathology Laboratory, Faculty of Veterinary Medicine, University of Abuja, is also gratefully acknowledged.