Feces are increasingly used as a non-invasive biological material in both human
39,40 and veterinary medicine
41,42 and has therefore become the focus of numerous clinical and experimental studies. Changes in fecal characteristics may reflect underlying alterations in gastrointestinal physiology, inflammation, or nutrient absorption, making fecal evaluation clinically relevant not only through biochemical or molecular biomarkers but also through practical assessment of physical properties.
In both human medicine 43,44 and veterinary practice—including dogs 45,46, pigs 47, cats 48, calves 41,49, and horses 50—fecal scoring systems are widely used to support diagnosis, disease monitoring, and assessment of treatment response. Across the majority of studies in both veterinary and human medicine, fecal scoring systems primarily rely on fecal consistency or fluidity as the main quantitative parameter 43,48,50,51. In some studies, additional fecal characteristics—including shape, color, odor, or the presence of mucus—have also been evaluated; however, these parameters are generally recorded descriptively or considered supportive observations rather than being incorporated as independent scoring criteria 28,41. Similarly, in human medicine, stool scoring systems are predominantly consistency-based 43, while features such as stool color or amount are occasionally documented as complementary parameters rather than central components of the scoring framework 44.
In farm animals, fecal scoring is commonly applied in the assessment of diarrhea and gastrointestinal disorders in both adult cattle 51,52 and calves 28,41. However, the majority of scoring systems in farm animal practice have been developed for neonatal calf diarrhea, where three-point, four-point 28,41,52, or five-point 25,51 scales based mainly on fecal consistency are widely used, and in some cases color or odor is also considered. These systems have proven useful for monitoring calf health and disease progression under field conditions.
In adult cattle, fecal scoring is applied more selectively than in neonatal animals and has primarily been used in the evaluation of digestive disturbances and feeding-related disorders 28,41. In particular, fecal consistency scoring has been incorporated into the assessment of subacute ruminal acidosis and related nutritional imbalances in lactating dairy cows 53. In addition, fecal scoring has been used as a practical tool for the general assessment of digestive function and ration adequacy during lactation, especially in relation to dietary fiber content and feeding management 25,52. Within the multi-component scoring system proposed by Zaaijer and Noordhuizen 25—which integrates rumen fill, fecal consistency, the undigested fecal fraction, and rectal reproductive assessment—fecal consistency and the undigested fecal fraction were identified as rapid, field-based indicators of energy balance and feeding efficiency in dairy cows. Deviations in these fecal parameters were shown to be associated with an increased risk of fertility disorders, highlighting their value as supportive markers of nutritional inadequacy rather than standalone diagnostic tools. Similarly, Ireland-Perry and Stallings 52 demonstrated that fecal consistency in lactating Holstein cows is responsive to dietary composition, particularly fiber level and protein source, with lower dietary fiber being associated with more liquid feces and lower fecal scores. However, these authors also reported that fecal consistency could not be accurately predicted based on dietary and cow-level parameters alone, indicating that fecal scoring in adult cattle is best interpreted as a practical and rapid indicator of dietary effects, rather than a precise quantitative measure.
Despite the well-recognized occurrence of altered fecal consistency in adult cattle affected by paratuberculosis 1,10, the literature addressing fecal scoring in MAP-seropositive cattle remains limited 30, and fecal assessment in this disease has largely been descriptive rather than systematic. In one of the few longitudinal studies addressing this issue, Vass-Bognár et al. 30 evaluated fecal consistency in MAP-infected dairy cows across the lactation period and demonstrated that fecal scores remained largely stable in subclinically infected animals and did not show a progressive decline. In contrast, cows progressing to clinical paratuberculosis exhibited a pronounced and continuous deterioration in fecal consistency, accompanied by body condition loss and increased bacterial shedding. Collectively, these findings indicate that fecal scoring reflects disease progression and clinical severity rather than serving as an early or stand-alone marker of subclinical MAP infection.
In the present study, fecal consistency and fecal stickiness were evaluated for the first time in MAP-seropositive adult cattle. Our findings demonstrate that, with increasing clinical severity of paratuberculosis—as defined by the presence of chronic weight loss, poor body condition, reduced milk yield, and persistent diarrhea consistent with clinical classification criteria—fecal stickiness increased more consistently and more markedly than fecal consistency. Although fecal consistency scores tended to be higher in moderate-to-severe cases, this difference did not reach statistical significance, whereas fecal stickiness scores showed a clear and statistically significant increase. This observation suggests that, particularly in chronically affected animals classified based on clinical examination findings, fecal stickiness may represent a more sensitive indicator of disease severity than fecal consistency alone.
To the best of our knowledge, fecal stickiness has not previously been evaluated in cattle. In other animal species, however, fecal stickiness or adhesiveness has been assessed using different visual scoring approaches. Ray et al. 34 evaluated fecal stickiness in poultry by visually scoring the amount of feces adhering to wire floors on a six-point scale ranging from 0 to 5, with higher scores indicating greater fecal adhesion. Takemori et al. 35 assessed fecal characteristics in mice using a four-point scoring system, in which fecal stickiness was defined by adherence of feces to forceps during handling. Yamka et al. 36 evaluated fecal quality in dogs using separate visual scoring systems for volume, stickiness, and adhesiveness, with stickiness assessed by insertion of a metal spatula and graded on a five-point scale from non-sticky to very sticky. These studies indicate that fecal stickiness represents a distinct physical property reflecting alterations in intestinal function beyond simple changes in moisture or consistency. Building on these approaches, we adapted and simplified previously described methods to develop a practical three-point fecal stickiness scoring system for routine clinical evaluation in adult cattle with paratuberculosis.
In this research, fecal stickiness exhibited a pronounced and statistically significant increase in the moderate-to-severe paratuberculosis group compared with mildly affected animals (2.10 vs. 1.00; p<0.001), indicating that this parameter may reflect disease severity more sensitively than fecal consistency alone. The increased fecal stickiness observed in moderate-to-severe cases may be related to the chronic granulomatous inflammation of the intestinal mucosa characteristic of MAP infection, supported in our cases by descriptively higher inflammation scores, lower goblet cell counts, and variations in villus length and crypt depth in the moderate-to-severe group compared with the mild group.
Classical descriptions of bovine paratuberculosis emphasize that diarrhea is typically not accompanied by grossly visible blood or mucus 5,6,11; therefore, increased fecal stickiness observed in the present study is more likely to be associated with the intensity of inflammatory cell infiltration and villus–crypt degeneration, leading to impaired intestinal absorption and altered fecal physical properties that are not fully captured by conventional fecal consistency scoring 5. This interpretation is further supported by previous observations indicating that the occurrence of clinical signs is not necessarily related to the severity of histological lesions in paratuberculosis 7. From a clinical perspective, fecal stickiness is easily assessed during routine examination, does not require additional equipment, and may serve as a practical adjunct indicator of disease severity under field conditions.
The absence of a significant correlation between fecal stickiness and fecal consistency indicates that these parameters reflect distinct aspects of gastrointestinal alteration in paratuberculosis. While fecal consistency primarily relates to changes in water content and motility, fecal stickiness may be more closely associated with inflammatory processes, mucosal alterations, or changes in microbial composition. Thus, fecal stickiness may provide complementary clinical information beyond conventional fecal consistency scoring, particularly in animals with moderate-to-severe disease.
An important strength of this study is the standardized assessment of fecal characteristics by a single, blinded observer, which minimized inter-observer variability and reduced potential bias related to knowledge of MAP serostatus. Furthermore, the use of a simplified scoring system enhances the feasibility of applying fecal stickiness evaluation in routine herd health monitoring and clinical practice.
Several limitations should be acknowledged. The study relied on serological classification without fecal culture or PCR confirmation, which precluded precise staging of MAP infection and assessment of fecal shedding status. Additionally, the sample size was limited, particularly for subgroup analyses based on clinical severity. Despite these limitations, the present study demonstrates that fecal stickiness is a distinct and clinically relevant feature of paratuberculosis in adult cattle and may serve as a practical adjunct to fecal consistency scoring. The significant increase in fecal stickiness in moderate-to-severe cases highlights its potential utility in assessing clinical severity and disease progression. Incorporating fecal stickiness into routine clinical evaluation may improve the field diagnosis and monitoring of paratuberculosis, particularly in chronic cases where conventional fecal consistency scoring alone may be insufficient. Future studies incorporating combined diagnostic approaches, larger populations, and longitudinal follow-up—particularly focusing on earlier or subclinical stages of infection—are warranted to further validate fecal stickiness as a marker of disease severity and progression and to better define its clinical relevance across different stages of MAP infection.