Morphometrical Studies on the Exterior of the Heart of Pre-natal Non-descript Sheep

The circulatory system plays a vital role in smooth working of the body of the animal (Jaiswal et al., 2017a, Jaiswal et al., 2017b and Janqueira and Carneiro, 2005). Heart is the central organ of circulatory system that pumps blood into the blood vessels and performs many vital functions (Sathapathy et al., 2013 and Sathapathy et al., 2014). The faulty development of heart may result in ectopia cordis, dextrocardia, hypoplasia, etc. Very often, these developmental anomalies of the heart cause foetal death and thereby severe economic loss to the farmers. Due to close similarities in many of the systems between the animals and human being, the animals have always become a choice of interest for research purpose, which indirectly help the human being. The detailed morphometry of different external parameters of heart especially in pre-natal sheep has not yet been reported. Hence, the present study has been undertaken to elucidate age wise morphometrical development of heart in prenatal sheep.

For this study, forty five foeti of either sex of non-descript sheep were collected from the local slaughter houses situated at Laxmisagar and Jadupur, Bhubaneswar during the period from July, 2020 to December, 2020. The adhering amniotic fluid from the body of the foeti was wiped by wet cotton. The crown rump length (CRL) for each foetus was measured in centimetres (cm) with the help of non-stretchable nylon thread and graduated scale. Further, the CRL was placed on the standard CRL-Gestation Age Curve to estimate the approximate age of the foeti in days (Noden and Lahunta, 1985). The collected sheep foeti were divided into three age groups viz. early prenatal (up to 50 days), mid prenatal (51-100 days) and late prenatal (101 to 150 days) with fifteen animals in each age group. This is a part of Doctoral research work, where 4 samples were taken in each mentioned age group to record the data. The average weight of the hearts of foeti was taken in digital weighing balance and the average volume of the organs was measured in a graduated measuring cylinder by water displacement method (Dahariya et al., 2020). Further, the various external parameters of the heart such as average width, length, circumference, dorso-ventral and cranio-caudal length of atria, dorso-ventral length of ventricles, cranio-caudal width of ventricles at the base, middle and apex of heart and distance between longitudinal grooves and borders of heart were measured by using digital Vernier’s calliper. The recorded data were subjected to routine statistical analysis (Snedecor and Cochran, 1994) and one way ANOVA with IBM SPSS 25.0 version software. 

The gross morphological parameters were recorded in the hearts of non-descript sheep (Fig 1) in early prenatal, mid prenatal and late prenatal age groups. The average weight of the sheep foetus was measured as 3.33±0.30 g, 109.18±24.75 g and 946.00±100.08 g in early prenatal, mid prenatal and late prenatal stages respectively. Similarly, the average weight of the heart was measured as 0.07±0.01 g, 1.16±0.24 g and 8.40±0.81 g in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences between the mid prenatal and late prenatal stages. The present findings were in agreement with the reports of Gupta et al., (2018). The average volume of the heart was measured as 0.09±0.01cc, 1.21±0.26cc and 8.26±0.70cc in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences between the mid prenatal and late prenatal stages. The present findings were in agreement with the reports of Gupta et al., (2018).



The average width of heart at base was measured as 4.82±0.22 mm, 10.52±0.72 mm and 21.57±1.03 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. Similarly, the average width of heart at the middle was measured as 4.64±0.20 mm, 8.91±0.54 mm and 18.00±1.17 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. Further, the average width of heart at apex was measured as 4.07±0.19 mm, 6.44±0.38 mm and 10.12±0.71 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. The present findings were in agreement with the reports of Gupta et al., (2018). The average length of heart was measured as 5.78±0.22 mm, 14.46±1.16 mm and 32.62±1.26 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. The present findings were in agreement with the reports of Gupta et al., (2018).                            

The average circumference of heart at base was measured as 14.51±0.45 mm, 31.78±2.18 mm and 64.02±2.04 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. Similarly, the average circumference of heart at middle was measured as 13.99±0.43 mm, 30.49±2.18 mm and 55.73±1.72 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. Further, the average circumference of heart at apex was measured as 12.60±0.34 mm, 28.42±2.21mm and 21.81±0.87 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. The present findings were in agreement with the reports of Gupta et al., (2018).

The average dorso-ventral length of right atrium of heart was measured as 1.13±0.12 mm, 4.60±0.29 mm and 10.07±0.38 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. Similarly, the average cranio-caudal length of right atrium of heart was measured as 2.86±0.15 mm, 8.18±0.52 mm and 11.49±0.43 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. Further, the average dorso-ventral length of left atrium of heart was measured as 2.13±0.13 mm, 4.63±0.29 mm and 10.54±0.43 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. The average cranio-caudal length of left atrium of heart was measured as 2.83±0.11 mm, 8.22±0.51 mm and 12.33±0.38 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages.

The average dorso-ventral length of right ventricle of heart was measured as 3.91±0.11 mm, 8.06±0.66 mm and 19.27±0.65 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. The average cranio-caudal width of right ventricle of heart at base was measured as 3.64±1.08 mm, 7.87±0.64 mm and 17.31±0.72 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. Similarly, the average cranio-caudal width of right ventricle of heart at middle was measured as 3.53±0.11 mm, 6.87±0.62mm and 14.95±0.64 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. Further, the average cranio-caudal width of right ventricle of heart at apex was measured as 2.35±0.09 mm, 5.78±0.64mm and 8.71±0.41 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages.

The average dorso-ventral length of left ventricle of heart was measured as 4.82±0.14 mm, 12.07±1.16 mm and 25.58±0.88 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. The average cranio-caudal width of left ventricle of heart at base was measured as 4.26±0.11 mm, 7.38±0.58 mm and 17.64±0.73 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. The average cranio-caudal width of left ventricle of heart at middle was measured as 4.03±0.13 mm, 6.92±0.51 mm and 15.08±0.63 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. Similarly, the average cranio-caudal width of left ventricle of heart at apex was measured as 2.75±0.11 mm, 5.94±0.50 mm and 8.79±0.41 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages.

The average distance between the left longitudinal groove and cranial border of heart at base was measured as 2.93±0.11 mm, 6.38±0.39 mm and 9.78±0.41 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. Similarly, the average distance between the left longitudinal groove and cranial border of heart at middle was measured as 2.74±0.10 mm, 5.41±0.37 mm and 9.38±0.40 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. Further, the average distance between the left longitudinal groove and cranial border of heart at apex was measured as 2.04±0.12 mm, 4.46±0.38 mm and 5.92±0.43 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. The average distance between the left longitudinal groove and caudal border of heart at base was measured as 3.16±0.11 mm, 6.45±0.39 mm and 12.65±0.53 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages.

The average distance between the left longitudinal groove and caudal border of heart at mid was measured as 3.18±0.09 mm, 5.49±0.36 mm and 11.02±0.44 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. Similarly, the average distance between the left longitudinal groove and caudal border of heart at apex was measured as 2.37±0.12 mm,4.56±0.36 mm and 8.59±0.26 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. The average distance between the right longitudinal groove and cranial border of heart at base was measured as 2.15±0.11 mm, 5.65±0.33 mm and 11.10±0.65 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) among the ages. Further, the average distance between the right longitudinal groove and cranial border of heart at middle was measured as 1.96±0.09 mm, 5.01±0.34 mm and 8.31±0.50 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. The average distance between the right longitudinal groove and cranial border of heart at apex was measured as 1.58±0.09 mm, 4.04±0.28 mm and 6.08±0.43 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages.

The average distance between the right longitudinal groove and caudal border of heart at base was measured as 1.98±0.09 mm, 5.35±0.29 mm and 9.28±0.55 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. Similarly, the average distance between the right longitudinal groove and caudal border of heart at mid was measured as 1.72±0.11mm, 4.71±0.31 mm and 8.31±0.43 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages. Further, the average distance between the right longitudinal groove and caudal border of heart at apex was measured as 1.24±0.06 mm, 3.85±0.26 mm and 6.38±0.31 mm in early prenatal, mid prenatal and late prenatal stages respectively with significant (p≤0.01) differences among the ages.

The various external parameters of the heart recorded in this study showed significant variations (p≤0.01) among different ages in the pre-natal sheep. Further, the present study provided a detailed baseline data on the age wise morphometrical development of heart especially of external parameters in pre-natal sheep that could help in studying various congenital developmental anomalies in different animals. 

The authors are grateful to the Dean, CVSc. and A.H., OUAT, Bhubaneswar for providing necessary facilities and support for the successful completion of this research work within time. The authors are grateful to Dr. S.M. Nanda, MVSc., Department of Veterinary and Animal Husbandry Extension, CVSc. and A.H., OUAT, Bhubaneswar for statistical analysis of the gross morphometrical data.