Goats widely dispersed across various agro-ecological zones of India and are playing a key part in socio-economic development of resource-poor farmers in rural areas as these are the main source of revenue of landless and marginal farmers for their livelihood. Parasitic infections in domestic ruminants represent one of the biggest challenges to small ruminant production in a wide range of agro-climatic zones (Pawar et al., 2019). Many parasites have the potential to cause disease, which can have a substantial impact on animal’s health. Among the parasitic diseases of small ruminants, coccidiosis is one of the major concerns causing ill health and loss of productivity which result in large global economic losses. Small ruminant coccidiosis is caused by different species of parasites belonging to the genus Eimeria, effects mainly in the young animals of 4-6 months of age. The disease is typically mild or asymptomatic in adult animals, or the adult animals may act as carriers. Drug resistance and residues in food products pose a threat to traditional control methods such anthelmintic medications (Debbarma et al., 2025). Amprolium, which is effective against the later phases of infection, has been previously explored in goats. A dosage of 50 mg/kg orally for 5 days resulted in a considerable decrease in fecal oocyst counts and improved clinical appearance compared to a 10 mg/kg dosage. Toxic amounts of amprolium (600 mg/kg) have produced cerebrocortical necrosis in sheep and cattle (Gibbons et al., 2016).
       
Toltrazuril is an anticoccidial drug widely used in chicken, turkeys, piglets, calves and lambs. This compound acts against asexual and sexual intracellular stages of Eimeria life cycle in poultry (i.e., schizogony and gamogony), especially affecting parasite mitochondria, the endoplasmatic reticulum and hampering nuclear division not only in schizonts (meronts) but also in microgamonts. The therapeutic effectiveness of ponazuril, a metabolite of toltrazuril, in lowering faecal Eimeria oocyst counts and the absorption of this chemical following a single oral dose application have been demonstrated in earlier studies conducted on goats. Basic pharmacological information is needed to define the dose rate and then determine the efficacy of different management programs for goat coccidiosis in arid and semi-arid zones, where this ruminant species represents one of the most important economic resources for farmers (Guedes et al., 2024). Therefore, the study has been carried out to evaluate the efficacy of toltrazuril and amprolium against Eimeria spp. infected goats.

A total of 120 faecal samples were collected from Sepahijala, West Tripura and Khowai Districts of Tripura, from goats that were presented with foul smelling diarrhoea, inappetence and weakness.
 
Collection of faecal samples and oocyst counts
 
The faecal samples were collected in the morning on a weekly basis directly from the rectum of all goat kids over a period of 14 days (the period of the experiment). The samples were immediately analysed by microscopical examination (Fig 1), Stoll’s technique (Soulsby, 1982) to estimate Oocysts per Gram (OPG) and polymerase chain reaction (PCR) as per the method of Bawm et al. (2020) (Fig 2).




 
Experimental design and treatment of animals
 
On the basis of clinical signs and the presence of coccidian oocysts in faeces (mean±SE of OPG), the kids were randomly assigned to two groups viz. Group II, Group III. Each group had six animals. For comparison, six apparently healthy animals were selected in Group I which were not detected with any ailments and for this group, no treatment was given. Group II was treated with toltrazuril @ 20 mg kg^-1 body weight orally once and Group III was treated with Amprolium @ 50 mg kg^-1 body weight once orally for five days. Supportive therapy was given with a mineral mixture, multivitamins and liver tonic for 14 days.
       
For therapeutic efficacy evaluation, approximately 7 mL of blood were aseptically collected from the jugular vein, in vials containing sodium ethylene diamine tetra acetic acid (EDTA) and clot activator vial on day 0, 7 and day 14 post treatments. Among this, 2 mL of blood were used for haematological studies and 5 mL of blood were used for serum biochemical studies (Singh et al., 2025; Singh et al., 2026).
       
Therapeutic efficacy was measured by improvement of clinical signs, negative results for coccidiosis and haemato-biochemical changes before (day 0^th) and after therapy (day 7^th and day 14^th).
 
Statistical analysis
 
Comparison was done among the groups with two-way ANOVA and comparison between 0, 7 and 14^th day of treatment.

The therapeutic efficacy of toltrazuril and amprolium against coccidial infection in goat kids was evaluated through parasitological, clinical, haematological and biochemical parameters over 14 days.
 
Parasitological findings
 
Before treatment, the infected groups (II and III) exhibited high faecal oocyst counts, with no significant difference (P>0.05) between them (Table 1). The parasitological response to treatment differed markedly between the two therapeutic agents. Kids treated with a single dose of toltrazuril (Group II) showed a complete elimination of oocyst output, with counts reduced to zero by day 7 post-treatment, which was maintained through day 14. In contrast, treatment with amprolium (Group III) resulted in a significant progressive reduction in oocyst counts, from 17,518.00±1,219.83 at day 0 to 209.00±22.47 by day 7 and 104.12±18.45 by day 14. The reduction within the amprolium group and the differences between the treatment outcomes at days 7 and 14 were statistically highly significant (P<0.0001).


 
Clinical recovery
 
Both treatment groups demonstrated a significant improvement in clinical health status (Table 2). The mean clinical score for Group II (toltrazuril) decreased from 7.5±0.42 at day 0 to 2.6±0.42 by day 14 (P<0.001). Similarly, Group III (amprolium) showed a decline from 7.6±0.56 to 2.8±0.41 over the same period (P<0.001). The rate and magnitude of clinical improvement were comparable between the two treatment regimens.


 
Haematological parameters
 
At the initiation of therapy (Day 0), infected kids in Groups II and III exhibited significant haematological alterations compared to the uninfected control (Group I), indicative of anaemia and an inflammatory state (Table 3). This include significantly (P<0.01) lower mean values for haemoglobin (Hb), red blood cell (RBC) count, haematocrit (Hct) and lymphocyte percentage, coupled with a significant elevation in total white blood cell (WBC) count. Following treatment, both groups showed a progressive recovery pattern which is highly significant (P<0.01). By day 14, the values for Hb, RBC, Hct and WBC in both treated groups had returned to statistically non-significant levels (P>0.05) from the healthy control group. Lymphocyte percentages also increased significantly (P<0.05) over time in the treated groups, converging towards normal values.


 
Biochemical parameters
 
Significant changes in biochemical values were observed in infected kids at day 0 (Table 4). Compared to Group I, Groups II and III had significantly (P<0.01) higher serum AST activity and globulin concentration, while total protein, albumin and the albumin-to-globulin (A/G) ratio were significantly lower.


       
Therapeutic intervention reversed these abnormalities. AST activity decreased significantly (P<0.01) in both treated groups, normalizing by day 14. Similarly, total protein and albumin concentrations showed a highly significant (P<0.01) increase over time, reaching levels comparable to the control by the end of the study. The initially elevated globulin levels and depressed A/G ratio also showed a significant (P<0.001) normalization trend, with values at day 14 showing no significant difference from the healthy control. Parameters including glucose, potassium, sodium, chloride and phosphorus showed no significant differences (P>0.05) among the groups at any time point.
       
The present study demonstrates the high therapeutic efficacy of both toltrazuril and amprolium against natural coccidial infection in goat kids, as evidenced by the comprehensive reversal of parasitological, clinical, haematological and biochemical aberrations over a 14 day treatment period. The results, however, reveal a critical distinction between parasitological clearance and systemic clinical recovery, offering valuable insights for clinical management.
       
The most striking finding was the superior and rapid parasitological efficacy of toltrazuril, which achieved complete cessation of oocyst excretion by day 7 post-treatment. This aligns with its known pharmacological action as a triazinetrione derivative that is coccidiocidal against all intracellular developmental stages (schizonts and gamonts) of Eimeria spp. (Shivaramaiah et al., 2014). Its long-acting metabolite, ponazuril, likely sustains this effect, explaining the persistent zero oocyst count at day 14 (Gibbons et al., 2016). This rapid and complete elimination is consistent with findings in calves and lambs, where toltrazuril significantly reduced oocyst output and improved weight gain more effectively than other coccidiostats (Mundt et al., 2003; Diaferia et al., 2013). Radostitis et al., (1994) stated that coccidiostats must be given early in the life cycle of the coccidia to suppress the development of the parasite. Earlier, the treatments with toltrazuril was also effective against coccidia in poultry [Haberkorn and Stoltefuss 1987; calves (Staschen, 2004) and lambs (Le Sueur et al., 2009]. Our findings suggest that toltrazuril is more effective than amprolium in reducing the number of excreted oocyst in naturally infected goat kids. These findings are in agreement with earlier observations (Tauseef et al., 2011).
       
In contrast, amprolium produced a significant but incomplete reduction in oocyst output. As a thiamine analogue, amprolium competitively inhibits thiamine uptake by the coccidia, primarily affecting the first-generation schizonts (Chapman, 1997; Kaur et al., 2019). This thiamine-static, predominantly coccidiostatic mechanism may be slower or less effective against all parasitic stages under field conditions, leading to the persistent, low-level shedding observed (Taylor and Catchpole, 1994). This result suggests that toltrazuril is more effective at rapidly reducing environmental contamination and potentially breaking the transmission cycle within a herd, a critical factor in intensive rearing systems (Daugschies and Najdrowski, 2005).
       
Despite this difference in parasitological outcome, the clinical and systemic recovery induced by both drugs was remarkably parallel and complete. By day 14, there was no significant difference between the two treated groups and the healthy controls in terms of clinical scores, haemoglobin levels, RBC counts, WBC profiles and key serum biochemistry (total protein, albumin, AST). This indicates that once the parasitic replication is sufficiently controlled, the host’s remarkable regenerative capacity can restore homeostasis. The initial pathology characterised by anaemia (low Hb, RBC, Hct), hypoalbuminaemia and elevated globulins is consistent with the established pathogenesis of coccidiosis, where intestinal epithelial damage and sloughing cause haemorrhage, plasma protein leakage and malabsorption (Levine, 1985; Mishra et al., 2025), alongside a concurrent acute-phase inflammatory immune response (Chapman et al., 2005). The normalization of these parameters confirms that healing of the intestinal mucosa and resolution of the systemic inflammatory state had occurred. The rapid correction of the albumin-to-globulin (A/G) ratio is particularly noteworthy. The severely depressed ratio at day 0 (0.38-0.41) reflected the dual hit of albumin loss due to enteropathy and increased globulin production from the immune stimulation (Kaneko et al., 2008).  Its normalization by day 14 underscores a halt in protein-losing enteropathy and a waning of the acute-phase protein response, serving as a robust biochemical marker of recovery (Hashemnia et al., 2011). Similarly, the resolution of leukocytosis and the rebound of lymphocyte counts point towards the containment of the infection and a shift away from a neutrophilic, acute inflammatory state towards immunological normalization (Jain, 1993).
       
The restoration of haematological parameters mirrors findings in other studies. The regenerative anaemia observed, evidenced by the final recovery of RBC parameters, is typical of coccidiosis where bone marrow response remains intact once the cause of blood loss is removed (Weiss and Wardrop, 2010). The initial elevated AST, indicative of hepatocellular damage or leakage, likely resulted from systemic inflammation and hypoxia secondary to anaemia and its return to baseline further supports full physiological recovery (Stockham and Scott, 2008).
       
An important practical implication of this study is that while toltrazuril may be the preferred choice for achieving rapid parasitological sterility and reducing pasture contamination, amprolium remains a highly effective therapeutic option for restoring animal health and productivity (Foreyt, 1990). The choice of drug may therefore depend on specific farm goals: toltrazuril for aggressive outbreak control and environmental decontamination and amprolium for effective treatment and clinical recovery, potentially at a different cost point (Chartier and Paraud, 2012). Both protocols successfully mitigated the disease’s detrimental effects on the haematopoietic system and protein metabolism.

In conclusion, this study confirms that both toltrazuril and amprolium are highly effective treatments for clinical coccidiosis in goats. Toltrazuril exhibits superior, rapid parasitological clearance. However, both drugs facilitate an equally complete clinical and physiological recovery within two weeks, allowing the animals to overcome the anaemia, protein loss and systemic inflammation characteristic of the disease. These findings provide veterinarians and producers with evidence-based options for therapeutic intervention, balancing the need for rapid parasite elimination with overall treatment efficacy and economic considerations.

The authors declare that there is no conflict of interest.