Coccidiosis in Cattle

Coccidiosis in Cattle is a common disease of young cattle (1–2 months to 1 year) and usually is sporadic during the wet seasons of the year.

“Summer coccidiosis” and “winter coccidiosis” in range cattle probably result from severe weather stress and crowding around a limited water source, which concentrates the hosts and parasites within a restricted area.

Although particularly severe epidemics have been reported in feedlot cattle during extremely cold weather, cattle confined to feedlots are susceptible to coccidiosis throughout the year.

Outbreaks usually occur within the first month of confinement. Cows may contribute to environmental contamination of E bovis oocysts through a periparturient rise of fecal oocyst counts.

Etiology

• Twelve Eimeria species have been identified in the feces of cattle worldwide, but only three (E. zuernii, E. bovis, and E. alabarnensis) are most often associated with clinical disease.

Morphology of oocyst

• Oval shape with either presence or absence of micropyle and residual cyst.

Pathogenesis

• Time to onset of diarrhea after infection is 16–23 days for E. bovis and E. zuernii and 3–4 days for E. alabamensis.

Clinical manifestation

• The most typical syndrome of coccidiosis is chronic or subclinical disease in groups of growing animals. Calves may appear unthrifty and have faecal-stained perineal areas.
• In light infections, cattle appear healthy and oocysts are present in normally formed faeces, but feed efficiency is reduced.
• The most characteristic sign of clinical coccidiosis is watery faeces, with little or no blood, and animals show only slight discomfort for a few days. Severe infections are rare.
• Severely affected cattle develop thin, bloody diarrhoea that may continue for >1 wk, or thin feces with streaks or clots of blood, shreds of epithelium, and mucus. They may develop a fever; become anorectic, depressed, dehydrated and loss body condition.
• Tenesmus is common because the most severe enteritis is confined to the large intestine.
• Nervous signs (eg, muscular tremors, hyperesthesia, clonic-tonic convulsions with ventroflexion of the head and neck, nystagmus) and a high mortality rate (80%–90%) are seen in some calves with acute clinical coccidiosis.
• Outbreaks of this “nervous form” are seen most commonly during, or after, severely cold weather in midwinter in Canada and the northern USA; there are no reports of the “nervous form” outside this geographic location.
• Affected calves may die <24 hour after the onset of dysentery and nervous signs, or they may live for several days, commonly in a laterally recumbent position with a mild degree of opisthotonos.

Diagnosis

• Based on clinical signs.
• Finding  of oocysts on faecal flotation or direct smear or by the McMaster technique.
• Quantitative oocyst counts on individual rectal samples from at least five calves in a pen are helpful to confirm coccidiosis as a cause of clinical disease.

Differential diagnosis

• Salmonellosis
• Bovine viral diarrhoea
• Malnutrition
• Internal parasitism
• Copper deficiency
• Cobalt deficiency
• Hypomagnesaemia

Treatment

Coccidiosis in cattle is a self-limiting disease. Spontaneous recovery without specific treatment is common when the multiplication stage of the coccidia has passed.

Therapy for clinically affected animal:

1. Sulphadimidine at 100 mg/kg body weight is given either orally or parenterally and repeated at half the initial dose level on another two days.
2. Sulfaquinoxaline (6 mg/lb/day for 3–5 days).
3. Amprolium (10 mg/kg/day for 5 days).
4. Sulfaquinoxaline is particularly useful for weaned calves that develop bloody diarrhea after arrival at a feedlot.
5. Supportive oral or parenteral fluid therapy.
6. Corticosteroids are contraindicated, because they increase shedding of oocysts and have induced clinical disease in subclinically infected calves.

Prevention

• Sulfonamides in the feed at 25–35 mg/kg for ≥15 days.
• Amprolium at 5 mg/kg/day for 21 days.
• Decoquinate at 22.7 mg/45 kg/day for 28 days.
• lasalocid at 1 mg/kg/day to a maximum of 360 mg/head/day.
• Monensin at 100–360 mg/head/day can be used.
• Toltrazuril administered at 15 mg/kg as a single oral dose, 14 days after animals are moved into group housing.

Control

• Isolation of sick animals.
• All feed and water supplies should be high enough off the ground to avoid fecal contamination.
• Mass medication of the feed and water supplies may be indicated in an attempt to prevent new cases and to minimize the effects of an epidemic.
• Overcrowding of animal should be avoided.
• Calving grounds should be well drained and kept as dry as possible.
• Inadequate housing and ventilation should be corrected.