Influence of dietary monensin sodium, yeast metabolites and neem (Azadirachta indica) leaf supplementation on faecal condition score of lactating Sahiwal cows

Introduction

Efficient nutrient utilization and optimal rumen function are essential prerequisites for sustaining milk production, animal health, and profitability in dairy production systems. The rumen ecosystem plays a central role in feed digestion through complex interactions among microorganisms, dietary substrates, and host metabolism. Any alteration in ruminal fermentation, microbial balance, or digesta passage rate may affect nutrient digestibility and subsequently influence productive performance. Therefore, evaluation of indicators associated with digestive efficiency is important for assessing the response of dairy animals to nutritional interventions. Among the various field-based indicators of digestive health, faecal condition score (FCS) has gained recognition as a practical, non-invasive, and economical tool for monitoring rumen function and feed utilization in cattle. Faecal consistency reflects the combined effects of dietary composition, nutrient digestibility, microbial fermentation, water balance, and rate of passage of digesta through the gastrointestinal tract. Consequently, changes in faecal characteristics may provide valuable information regarding the adequacy of nutritional management and digestive status of dairy animals. Petrovski et al. (2022) [12] described faecal scoring as an important "cow sign" that can be utilized for evaluating the quality of rumen fermentation, digestion, and nutritional adequacy in dairy herds. Similarly, Skidmore et al. (1996) [17] suggested that faecal consistency scoring can serve as a useful indicator of ration utilization and digestive [9,5,15] . Recent studies have further demonstrated that monensin supplementation enhances milk production efficiency while maintaining favorable rumen function under modern feeding systems (Horst et al., 2024) [6] . Because ruminal fermentation characteristics directly influence nutrient digestibility and digesta flow, monensin-induced changes in rumen metabolism may also be reflected in faecal consistency and manure characteristics. Yeast metabolites and Saccharomyces cerevisiae-derived products are another group of feed additives extensively used to improve rumen stability and digestive function in dairy cattle. These products have been reported to stimulate beneficial microbial populations, enhance fiber degradation, improve dry matter intake, and support gastrointestinal health (Mahasneh et al., 2023) [8] . In addition to their effects on rumen ecology, yeast fermentation products have been shown to modulate microbial populations in both the rumen and hindgut, improve epithelial barrier integrity, and reduce digestive disturbances associated with nutritional and environmental stressors (Chae et al., 2024) [2] . [7,14] . Neem leaves and their derivatives have been traditionally utilized in livestock feeding and have demonstrated beneficial effects on animal health and productive performance (Adhana et al., 2023) [1] . Furthermore, neem-based feed resources have been explored as alternative nutritional supplements in dairy cattle because of their potential to influence digestive processes and nutrient utilization (Raj et al., 2016) [13] . However, information regarding their effects on faecal characteristics and digestive indicators remains limited.

Despite substantial research on monensin sodium, yeast metabolites, and neem-based supplements, most studies have focused primarily on production performance, feed efficiency, rumen fermentation, immune function, and metabolic responses. Comparatively fewer investigations have evaluated faecal condition score as an indicator of digestive efficiency following supplementation with these feed additives. Moreover, comparative information regarding the effects of these additives under similar management conditions in indigenous dairy breeds such as Sahiwal cattle is scarce. Therefore, the present study was undertaken to evaluate the effect of dietary supplementation of monensin sodium, yeast metabolites, and neem (Azadirachta indica) leaf on the faecal condition score of Sahiwal cows and to assess their potential influence on digestive health and nutrient utilization. All animals were dewormed with fenbendazole (7.5-10 mg/kg body weight) before the start of the experiment. The feeding trial was conducted for a duration of 90 days.

Materials and Methods

Feeding and Management

All experimental animals were maintained under a uniform housing system (double-row conventional barn with concrete flooring). The diet consisted of green fodder (Hybrid Napier, Sudan grass, Berseem and local grasses as per availability), dry fodder and concentrate mixture. The concentrate contained 20% crude protein, 0.93% ether extract, 18% crude fiber and was offered during morning and evening milking. The animals were allowed routine grooming and had ad libitum access to clean drinking water.

Faecal condition Score

Faecal consistency was evaluated to assess the digestive status and rumen function of lactating Sahiwal cows under different dietary treatments. Fresh faecal samples were collected manually by rectal evacuation immediately after milking. Sampling was carried out at the beginning of the experiment (Day 0) and subsequently at monthly intervals throughout the experimental period. Faecal consistency was assessed visually using a five-point scoring system as described by Skidmore et al. (1996) [17] with slight modifications. For uniform evaluation, fresh faeces were dropped from a height of approximately 1 m onto a clean concrete floor and observed for consistency, shape, and splatter characteristics. Scores ranged from 1 to 5, where Score 1 represented very liquid faeces and Score 5 represented extremely firm and dry faecal balls. A score of 3 was considered the optimum faecal consistency, indicating adequate digestion and a balanced diet.

Statistical Analysis

Data on body condition score were analyzed using SPSS 26.0 software (SPSS Inc., USA). One-way analysis of variance (ANOVA) was applied to compare treatment means at each observation period as described by Snedecor and Cochran (1994) [18] . The means were compared using a Tukey test LSD and P≤0.05 was considered statistically significant.

Results

The faecal condition score (FCS) of lactating cows under different dietary treatments is presented in Table 1 and illustrated in Fig. 1 and2. At the beginning of the experiment (Day 0), the mean FCS values ranged from 3.17 Similarly, within-group analysis indicated that faecal condition score did not differ significantly (p>0.05) over the experimental period in any treatment group. The withingroup P values for T₀, T₁, T₂ and T₃ were 0.861, 0.756, 0.704 and 0.747, respectively. Overall, the faecal condition scores remained close to the ideal score of 3 throughout the study, indicating normal digestive function and adequate utilization of the experimental diets. The results suggest that supplementation of monensin sodium, yeast metabolites and neem leaf did not adversely affect faecal consistency or gastrointestinal health of lactating Sahiwal cows. [17] . Petrovski et al. (2022) [12] further emphasized that faecal consistency is an important "cow sign" that can be used to assess rumen fermentation quality, digestive function, and the adequacy of dairy cattle nutrition.

The absence of significant differences among treatment groups observed in the present study may be attributed to the fact that all experimental animals remained clinically healthy and were maintained on nutritionally balanced diets throughout the experimental period. Under such conditions, rumen fermentation and digestive processes are generally stable, resulting in faecal scores within the normal physiological range. Therefore, the opportunity for substantial treatment-induced alterations in manure consistency may have been limited. This finding suggests that the evaluated feed additives maintained normal digestive function without causing any adverse effects on gastrointestinal health. Monensin sodium supplementation did not significantly affect faecal condition score in the present investigation.

Monensin is a polyether ionophore that selectively inhibits gram-positive rumen bacteria and shifts ruminal fermentation toward greater propionate production, thereby improving feed efficiency and energy utilization (Russell and Strobel, 1989; Duffield et al., 2008) [16,5] . Recent studies have demonstrated that monensin enhances feed efficiency and milk production efficiency primarily through modifications in ruminal microbial activity and fermentation pathways rather than through changes in the physical characteristics of digesta (Robinson, 2020; Horst et al., 2024) [15,6] . Consequently, the lack of significant changes in faecal consistency observed in the present study is not unexpected and suggests that monensin improved rumen fermentation without disrupting normal digestive processes. [3,4] . Furthermore, yeast fermentation products have been reported to improve rumen and hindgut microbial balance, enhance epithelial barrier integrity, and reduce digestive disturbances under stressful conditions (Mahasneh et al., 2023; Chae et al., 2024) [8,2] . The maintenance of normal faecal scores in the yeastsupplemented group suggests that yeast metabolites supported efficient digestion and rumen stability without substantially altering manure consistency. Similar observations have been reported in previous studies where yeast supplementation improved rumen function and productive performance while maintaining normal faecal characteristics.

Neem leaf supplementation also failed to produce significant changes in faecal condition score. Neem contains several biologically active compounds, including azadirachtin, flavonoids, tannins, and other phytochemicals possessing antimicrobial, antioxidant, and immunomodulatory properties (Patra and Saxena, 2009; Patra, 2012) [11,10] . These compounds may influence rumen microbial populations and nutrient utilization; however, their effect on manure consistency appears limited under normal feeding conditions. The lack of significant variation in faecal score observed in the present study indicates that neem supplementation maintained normal digestive activity and gastrointestinal function. Similar findings have been reported for several phytogenic feed additives, where improvements in rumen fermentation and nutrient utilization occurred without measurable changes in faecal consistency or manure characteristics (Windisch et al., 2008; Patra, 2012) [19,11] . Overall, the results of the present study indicate that supplementation of monensin sodium, yeast metabolites, and neem leaf maintained faecal scores within the normal physiological range throughout the experimental period. The absence of significant differences among treatments suggests that these feed additives supported normal rumen function and digestive health without adversely affecting manure consistency in lactating Sahiwal cows.

Conclusion

The present study demonstrated that dietary supplementation of monensin sodium, yeast metabolites, and neem (Azadirachta indica) leaf had no significant effect (p>0.05) on the faecal condition score of lactating Sahiwal cows. Faecal scores remained within a narrow range (3.17-3.83) and were maintained within the normal physiological limits throughout the 90-day experimental period, indicating stable rumen fermentation and normal digestive function. Neither treatment nor period exerted a significant influence on faecal consistency, suggesting that supplementation with monensin sodium, yeast metabolites, and neem leaf did not adversely affect gastrointestinal health or digestive efficiency. The findings indicate that these feed additives can be safely incorporated into the diets of lactating Sahiwal cows without causing undesirable changes in faecal characteristics.

Acknowledgement

AcknowledgmentsThe authors are thankful to the Dean, College of Veterinary Science and Animal Husbandry, Anjora, Durg, for providing facilities to conduct this research.

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