Diagnostic relevance of rumen chloride and protozoal activity in gastrointestinal disorders in cattle

Introduction

Gastrointestinal (GIT) disorders are major cause of economic losses in cattle globally (Enemark, 2008; Plaizier et al., 2009; Steele et al., 2009) [12,27,29] . Disorders such as enteritis, ruminal alkalosis, bloat, intestinal obstruction, and ruminal impaction often presented with nonspecific signs like anorexia, reduced milk yield, abdominal distension, altered rumen motility, and dehydration (Radostits et al., 2007) [28] . These overlapping clinical signs of GIT disorders make diagnosis challenging (Desiye and Mersha, 2012; Kahn, 2011) [10,20] . Ruminants are exclusively capable of digesting plant cell wall polysaccharides i.e. cellulose, hemicellulose, and pectin; converting them into meat and milk (Bradford et al., 2003) [4] . However, this fermentation process depends on the functional and microbial integrity of the rumen. Disruption in rumen health leads to indigestion, metabolic imbalances, reduced feed conversion efficiency, and ultimately, financial loss (Kirbas et al., 2014) [22] . Many GIT disorders arise from poor-quality feed or abrupt dietary transitions, triggering syndromes like bloat, ruminal alkalosis, or ruminal impaction (Radostits et al., 2007) [28] . Field diagnosis is often based on clinical signs, which may be insufficient due to their overlapping nature across various conditions. Therefore, rumen fluid analysis has gained prominence in the diagnostic algorithms. Among rumen fluid parameters, chloride concentration is a sensitive biomarker. Elevated ruminal chloride concentration suggests abomasal or duodenal reflux due to obstructions (Braun et al., 2024) [5] , while lower levels may indicate excessive salivation or absorption disturbance, as observed in ruminal alkalosis. Dirksen et al. (2006) [11] similarly associated high ruminal Cl⁻ with abomasal reflux secondary to intestinal blockage. Additionally, rumen protozoal activity offers insight into the fermentative status of the rumen. A decline in count and motility of protozoa may reflect microbial depression resulting from pH imbalance, starvation, or abomasal reflux. This study aims to study, evaluate and compare the clinical, hematobiochemical, and ruminal fluid profiles-particularly chloride concentration and protozoal count and motilitycin cattle affected with major GIT disorders.

Materials and Methods

A total of forty-eight cattle diagnosed with various gastrointestinal disorder were enrolled during the study period along with six healthy cattle during the period of June 2022 to November 2023 at Department of Veterinary Medicine, DGCN College of Veterinary and Animal Sciences, CSK Himachal Pradesh Agriculture University, Palampur, Himachal Pradesh, India. The affected cattle were categorized into five groups based on clinical signs and diagnostic findings: enteritis (n = 16), ruminal alkalosis (n = 6), bloat (n = 14), intestinal obstruction (n = 6), and ruminal impaction (n = 6). All cattle underwent thorough clinical examination including rectal temperature, heart and respiratory rates, rumen motility, and fecal consistency. Blood samples were collected aseptically for hematological and serum biochemical analysis. Serum electrolyte concentrations of sodium (Na⁺), potassium (K⁺), and chloride (Cl⁻) were measured using an automated electrolyte analyzer (CB Lyte, Chariot's Biotechnology, Mumbai, India). Rumen fluid (5-10 mL) was collected aseptically from the left paralumbar fossa using a 16G, 6-inch hypodermic needle (Kiro, 2017). Physical characteristics (color, odor, consistency) were assessed, and pH was measured using pH paper and a digital meter. Microscopic examination for protozoal motility was performed and scored semiquantitatively (0 to 3 scale) as per Chakrabarti (2006). Rumen fluid was centrifuged at 3000 rpm for 5 minutes, and the supernatant was analyzed for electrolyte concentrations. Rumen chloride estimation was done using the CB Lyte analyzer, with levels >30 mmol/L interpreted as indicative of abomasal reflux or ileus. Statistical analysis was performed using ANOVA and Mann-Whitney U-test. Results were presented as Mean ± Standard Error, with significance set at p< 0.05 and p< 0.01.

Results and Discussion

The present study evaluated clinical, hemato-biochemical, electrolyte, and rumen fluid changes in various gastrointestinal (GIT) disorders in cattle i.e. enteritis, ruminal alkalosis, bloat, intestinal obstruction, and ruminal impaction. Clinical signs recorded were anorexia and absence of water intake, majorly in ruminal alkalosis (66.67%), bloat (71.43%), and intestinal obstruction (83.33%). Rumination was absent in all cattle affected with ruminal alkalosis and reduced in bloat (66.67%) and obstruction (83.33%). Reduced fecal output was noted in bloat (78.57%) and intestinal obstruction (83.33%), while increased defecation was observed in all cattle affected with enteritis. Weak body condition and dullness were observed in enteritis and intestinal obstruction (66.67%). Abdominal signs like looking at flank (78.57%) and severe left flank distension (64.29%) were typical of bloat. Fecal character like scanty, mucus-laden feces were observed in intestinal obstruction, while ruminal impaction cases had hard and mucoid feces. An increased heart and respiratory rates was observed in cattle affected with bloat and obstruction, which could be due to diaphragmatic compression and systemic hypoxia. These findings were in alignment with the findings of Constable et al. (2017a) [7] . Heart rate was within normal limits in cattle with ruminal alkalosis and ruminal impaction (Constable et al., 2017b) [8] . Rumen motility was reduced in bloat and ruminal impaction. These findings were consistent with the findings of Braun et al. (2024) [5] and Athar et al. (2010a) [2] . Rumen contractions were moderately reduced by enteritis and ruminal alkalosis. The haematological, biochemical and electrolyte changes of cattle affected with various gastrointestinal disorder are presented in Table 1. Haematological findings revealed leukocytosis and neutrophilia in enteritis, bloat, and intestinal obstruction, suggestive of inflammation, while lymphopenia in intestinal obstruction and ruminal impaction indicated stress. These findings were similar to the findings of Hassan et al. (2022) [17] , Hailat et al. (1996) [16] , and Feldman et al. (2000) [13] . Biochemical alterations included significantly elevated AST in ruminal alkalosis, intestinal obstruction, and ruminal impaction; indicating hepatic stress or muscle catabolism (Garry, 2002; Kaneko et al., 2008) [14,21] . Total protein concentration was decreased in enteritis and ruminal impaction, likely due to anorexia, protein-losing enteropathy, and reduced protein absorption, whereas it was elevated in intestinal obstruction due to dehydration leading to haemoconcentration and inflammatory protein response. Elevated BUN and blood glucose were seen in most disorders, suggesting prerenal azotemia and stress-induced hyperglycemia and were in alignment with the findings of Avery et al., 1986; Braun et al., 2023; Mudroň et al., 2005 [3, 6, 26] . Electrolyte imbalances included hyponatremia in enteritis and hypernatremia in ruminal alkalosis. Hypokalemia was seen in intestinal obstruction and ruminal impaction. Chloride was significantly reduced in enteritis, ruminal alkalosis, and intestinal obstruction. These findings were similar to that of Aref et al. (2017) [1] and Kaneko et al. (2008) [21] . [1] . Rumen fluid electrolyte analysis (Table 4) showed a significant decrease in sodium levels in ruminal impaction cases (p<0.01), which could be due to reduced intake, prolonged stasis, and intracellular electrolyte shifts, corresponding to the findings of Aref et al. (2017) [1] . Potassium concentration was also decreased in both ruminal alkalosis (p<0.01) and ruminal impaction (p<0.05), indicating depletion caused due to anorexia, decreased rumen turnover, and intracellular redistribution, similar to observations noted by Kaneko et al. (2008) [21] . A marked elevation in ruminal chloride was observed in intestinal obstruction, indicating abomasal reflux (Braun et al., 2024) [5] , whereas chloride levels were significantly reduced in ruminal alkalosis (p<0.05), that could be due to excessive salivary dilution and impaired mucosal absorption (Dirksen et al., 2006) [11] . These findings highlight the diagnostic importance of combining clinical assessment with hematobiochemical changes and rumen fluid evaluation-particularly pH, protozoal activity, and chloride concentration-for differentiating GIT disorders in cattle under field conditions. The varying degrees of protozoal motility observed (+ and +++) are represented in Fig. 1 and Fig. 2, respectively.

Acknowledgement

AcknowledgmentsThe authors formally acknowledge and express their profound appreciation to the Department of Veterinary Medicine, CSKHPKV, Palampur, particularly to the Head of Department and Dr. Ajay Katoch, for the essential facilities and comprehensive support provided for the execution of this research. Furthermore, sincere gratitude extended to Dr. Ankur Sharma and Dr. Amit Kumar for their invaluable technical guidance and collaborative assistance throughout the duration of the study. The crucial contributions of all co-workers, field assistants, and local stakeholders are also gratefully recognized. The authors formally declare that no conflict of interest exists concerning the subject matter or findings of this work.

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