Anemia is a pathological condition in various diseases of livestock. It affects the economy of farmers by reducing the production and performance of sheep and goats. The present investigation was carried out to study the prevalence, causes, hematobiochemical, and histopathological changes in various organs of anemic sheep and goat flocks in and around Anantapur. A total of 494 and 178 sheep and goats respectively were screened for anemia from July 2021 to December 2021. Overall prevalence of anaemia in sheep and goats was 30.56% and 66.8%. In sheep and goats, anemia was most prevalent in 3-6 months age groups, more in females than in males, higher incidence in July compared to other months. Predominant cause of anemia were ectoparasites followed by various internal parasites, mostly strongyles. Theileria was the only hemoprotozoan found positive.

Common clinical signs observed were pale mucous membranes, anorexia, weakness, diarrhoea, dehydration and nasal discharges. Significant decrease (P<0.05) in Hb, TEC, PCV and lymphocytes was observed. TLC, neutrophils and eosinophils were significantly increased (P<0.05). Significant difference was not observed in MCV, MCH, MCHC, monocytes and RBC diameter. Biochemically, in most of sheep and goats significant increase (P<0.05) in SGOT, SGPT and BUN was observed. TP and albumin were decreased significantly (P<0.05). No significant difference in creatinine, calcium and phosphorous was observed. Most of sheep and goats were mild anemic. Normocytic and normochromic anemia was commonly observed among anemic sheep and goats. Abnormal forms of RBCs observed were acanthocytes, agglutination, rouleaux formation, crenation, target cells, poikalocytes, dacrocytes, echinocytes, triconcave knizocyte, macrocytes, microcytes, leptocytes, sphero-cytes, schistocyte, discocytes, and ghost cells.

Postmortem examination of anemic sheep and goats revealed apparent changes in kidneys, liver, lungs and intestines, whereas heart, lymph node, and spleen changes were inconspicuous. Emaciation, pale conjunctiva, sunken eye balls, gelatinisation of subcutaneous fat was most striking futures observed externally. In most of the cases, the organs were pale, hemorrhagic and congested. In heart, hydropericardium, gelatinisation of epicardial fat was observed. Enlargement, thickened Glissons capsule, hard consistency, Cystericus teunicollis cyst was seen in liver. Oedema, consolidation, froth in trachea, bronchi and bronchioles in was observed in lungs. Hemonchus worms in stomach, tapeworms in intestinal lumen, serosanguinous fluid in the peritoneal cavity, enlarged lymphnodes was observed in various cases. Histopathologically, in most of organ’s congestion, hemorrhages, inflammatory cells infiltration, and necrosis was observed. Thickened Glisson's capsule, cloudy swelling, fatty change, thickened portal triad, proliferated bile ductular epithelium, sinusoidal dilatation was observed in the liver. Thickened pleura, oedema, peri bronchiolar lymphoid aggregation, hyperplasia and metaplasia of bronchiolar epithelium, papillary projection alveolar epithelium, atelectasis, and dilated bronchiole was observed in the lungs. Diphtheritic layer, parasitic eggs cut section was seen in the intestine. Separated glomerular cells, glomerular oedema, glomerular hypercellularity, increased glomerular space, cystic glomerulus and tubules, mesangial cell proliferation, casts in tubules were observed in the kidney. Thickened pericardium, and cloudy swelling in heart, thickened capsule, engorged red pulp, white pulp depletion and haemosiderin in the spleen was observed. In bone marrow, red cell aplasia, granulocyte and lymphocyte precursors were noticed.

In scanning electron microscopy acanthocytes, knizocytes, and poikilocytes were observed. In PCR gel document, bands were positive for theileria obtained at 426-430 bp.