National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
The present investigation included the chronological sequence of appearance of ossification centers and their individual development in the sternum and development of ribs in Nellore sheep fetuses. The development of individual sternebra from 78-139 days of gestation was analyzed. Forty eight apparently healthy Nellore sheep fetuses irrespective of sex were used for this study. The modified double staining for bone and cartilage, radiography and histological staining procedures were used to study the sternebrae of different age groups. Each sternebra ossified from two centers except the first, which has single ossification centre. In most specimens seventh sternebra appeared first at 58 days, followed by third, fourth, fifth, second and then first sternebrae between 60-63 days of estimated age. The Sixth sternebra was the last one to appear at 69 days. In most cases right center of sixth sternebra ossified first than the left one. The relative growth in length (L) and breadth (B) of the seven sternebra (S1, S2, S3, S4, S5, S6, and S7) among the prenatal growth periods of 78-97 days (group I), 98-117 days (Group II) and118-137 days (Group III) was significant (p< 0.05). The relative increase in the length of all the sternebra was more in Group I followed by Group III except in the length of fourth sternebra, which showed more growth during prenatal age of 98-117 days(Group II). In the present study first twelve pairs of ribs were ossified by the estimated age 45days and the thirteenth pair was ossified at 46 th day.
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