Hydrops fetalis also referred as fetal hydrops is defined as the condition in which there is severe accumulation of fluid inside the thoracic and abdominal cavities of the fetus along with its extravascular compartments and generalized skin thickness of more than 0.5 cm (Bellini et al., 2009). This condition results into a rare congenital abnormality in bovines referred as Pulmonary hypoplasia and Anasarca syndrome (PHA) particularly evident in Dexter and Simmental calves (Yuksel et al., 2019). Developmental anomalies can occur due to defects in bone or cartilagenous  tissue development, or due to primitive mesenchymal tissue. Extreme subcutaneous edema (anasarca) and underdeveloped lungs (pulmonary hypoplasia) are the characteristic lesions of PHA syndrome. This syndrome is often associated with placental enlargement, pericardial and pleural effusion and ascites (Svara et al., 2015) and  many genetic diseases and is associated with alpha thalassemia (Bellini et al., 2015). Anasarca is an anomaly which is characterized by excessive fluid  accumulation between all the soft tissues of the calf (Dogan et al., 2022). PHA results in peculiar abnormalities as hereditary “Bulldog” like appearance of calves (Windsor et al., 2006). Certain significant histopathological changes were also reported in PHA such as perivascular and intralveolar edema, endocardial fibrosis, hydropic degeneration of liver cells (Dogan et al., 2022; Yuksel et al., 2019). In this article, a rare case of fetal anasarca in a calf fetus delivered by caesarean section from a cow are defined and the clinical, macroscopic and microscopic findings are presented.
 
Case history
 
A case of dystocia in a crossbred cow  in third parity, full term pregnant was presented to Teaching Veterinary Clinical Complex, DSVCKV, Durg with a history of severe labour pain for more than 24 hour. The water bag had ruptured 14 h before. One foetal hindlimb was protruding out of the vulva without any progress and the animal was straining severely. The animal appeared to be exhausted due to severe straining. Physical examination revealed edematous valval lips, congested mucus membrane and subnormal body temperature and severe dehydration. Per vaginal examination after proper lubrication revealed edematous vaginal tract, tin posterior longitudinal presentation of the fetus, dorso-sacral position with one hind-limb protruding from vulvas and another hind limb was unable to be palpated. The fetus was felt as deformed, fetal movements and other reflexes were found to be absent and limbs were short and were without hairs and appeared edematous and swollen with fatty deposition under the skin and suspected to be case of dystocia due to anasarca fetus (Fig 1). The animal was subjected to caesarean section through left ventro-lateral oblique approach and the dead fetus along with the fetal membranes was delivered successfully. The calf was abnormally enlarged and swollen (Fig 1 and 2) resembling a bull-dog like appearance due to swollen face (Fig 3), belly and extremities. Diffused subcutaneous edematous swelling was observed throughout. During the caesarean section, the right horn of the uterus was severely enlarged, filled with plenty of  fluid leading to excessive accumulation between the subcutaneous tissues. The present study recorded a case of fetal hydrops in calf delivered by cesarean section and its clinical, gross and histopathological findings are presented.



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Tissue samples, including the lungs, heart, liver and kidneys were collected and stored in 10% NBF for 72 hours at room temperature to ensure proper fixation. Subsequently, 0.5 cm thick tissue sections were cut from the fixed tissues and processed for routine histopathological examination. The cut tissue sections underwent dehydration using ascending grades of alcohol and were then cleared through two changes of xylene. Further, paraffin-embedded tissue sections were processed and 4 to 5-micron thick sections were cut using a semiautomatic microtome, placed on glass slides. For routine histopathological examination, the sections were stained with Haematoxylin and Eosin (H and E) as per standard protocol (Luna, 1968).
 

External examination
 
External examination further highlighted several notable observations: the carcass exhibited a emphysematous condition, protrusion of edematous tongue from mouth although the mucous membranes appeared pale, indicative of potential underlying tissues. Rigor mortis was not evident in the hind limbs, indicating the postmortem interval. Additionally, various signs were observed, including severe generalized subcutaneous edema, accumulation of fluid in thoracic and abdominal cavities, marked increase in the size of extremities and head. These findings collectively suggested a complex and potentially severe pathological process affecting the animal.
 
Gross examination
 
Aborted bovine fetus was severely malformed due to marked diffuse subcutaneous oedema and amber colored fetal fluid accumulation, mixture of allantoic and amniotic fluid (Fig 1), facial oedema (Fig 2). Subcutaneous tissue exhibited severe accumulation of yellowish tinged  serous fluid. There was marked hypoplasia of skeletal tissues (shortened rib cage) due to excessive accumulation of fluid inside thoracic cavity (hydrothorax; Fig 3) and pressure exerted by it. Accumulation of excessive fluid of fetal fetal urine) inside abdomen leading to ascitis (Fig 4) and severe disproportionatory enlargement of kidney (Fig 5a-c). Marked hypoplasia of lungs was observed  (Fig 6). Uncommon bilateral dilatation resulting in rounded appearance of heart (Fig 7). Spleen was normal without any  distortion in shape and size (Fig 8).










 
Histopathological examination
 
Tissue sections from lungs were evident of severe perivascular and interstitial edema  (Fig 9a) with intralveolar oedema (Fig 9b), desquamation of bronchiolar epithelium (Fig 9c,d) along with collapse of alveoli (atelectasis; Fig 10a), peripheral extravasation of mononuclear cells (Fig 10b). Other prominent microscopic findings were Interstitial pneumonia with thickening of the alveolar wall is observed and desquamation of bronchiolar epithelium with peripheral extravasation of leucocytes and mononuclear cells. Liver tissue sections revealed mild hydropic and vacuolar degeneration of hepatocytes (Fig 11a-d). Heart tissue sections were evident of myocardial necrosis (Fig 12a) and endocardial fibrosis characterised by extensive prolifration of fibrous connective tissue was observed (Fig 12b). Tissue sections from kidney were severely autolysed imparting non-significant pathological changes. Tissue section of liver was observed with mild hydropic and vacuolar degeneration of hepatocytes however autolytic changes were in abundance inside liver tissues so any substantial pathological change was not evident.








       
Gross and histopathological findings such as pulmonary hypoplasia, atelectasis in lungs, amber colored fetal fluid accumulation, anasarca, rounded misshapen appearance of heart, interstital, perivascular and intralveolar edema, endocardial fibrosis in the aborted fetus were in accordance with  the findings of Dogan et al., (2022), Sengodan et al., (2022), Švara  et al., (2015), Yuksel et al., (2019) and Monteagudo  et al. (2002). Edematous vaginal tract observed after per vaginal examination of cow was also reported by Rajput et al., (2024). Microscopic examination of tissue sections from liver showing hydropic degeneration in hepatocytes was also reported by Dogan  et al. (2022). “Bull dog” like  appearance of calf was observed as reported by Windsor et al., (2006). The occurrence of such lesions causing dystocia in bovines are extremely rare. The caesarean section was performed in the routine matter as outlaid by Kumar (2002). The cow recovered uneventfully in a period of twelve days post operation. Anomalies observed in the aborted fetus may be associated with the dystocia and abnormal posterior presentation of fetus leading to caesarian section. The cause of abortion in cow may be associated with BVDV (Bovine Viral Diarrhoea Virus) infection as reported by Yilmaz et al., (2016) corelated with the microscopic lesions like broncho-interstitial pneumonia, alveolar oedema etc. but confirmation of BVDV virus can be done through RT-PCR (Yilmaz et al., 2016).

In summary, the necropsy of the calf revealed anasarca and pulmonary hypoplasia syndrome along with marked renal hypertrophy resulting in severe fluid  accumulation in the thoracic and peritoneal cavity, bilateral abdominal distension leading to death due to excessive pressure exerted by the fluid on viscera, hydrothorax, hydroperitoneum and bilateral hypertrophy of kidneys highlighted the severity of the condition. Microscopic examination further elucidated pulmonary, hepatic and cardiac involvement with atelactasis, pulmonary oedema and hydropic degeneration of hepatocytes in liver tissues. These findings underscore the importance of comprehensive postmortem evaluation in understanding the developmental anomalies in calf.

The authors are thankful to the Head, TVCC, Dau Shri Vasudev Chandrakar Kamdhenu Vishwavidyalaya for providing the necessary facilities for the successfull expert suggestions  and support in completion of this case report.
 
Consent for publication
 
All the authors consent to the publication of this manuscript.
 
Ethics approval consent to participate
 
This research followed the instructions specified by Institutional Animal Ethics Committee (IAEC). All the experimental procedures were carried out as per the guidelines of the IAEC.

All authors declare that they have no competing interests.