Silicon cast study on lung ventilation efficiency of gaddi sheep and goats

Acomparative study was conducted during 2015 to 2019 on silicon casts and fresh samples of the trachea and principal branches of the bronchial tree from the lungs of Gaddi sheep (17) and Gaddi goats (19), collected from slaughterhouses around Palampur (HP). Gaddi sheep and goats followed monopodial pattern of bronchial division, where every secondary bronchus arose from each longitudinal principal bronchus. The length of trachea from cricoid cartilage to right apical lobe was 22.14±0.50 and 29.41±0.71 cm in sheep and goats, respectively. At the level of 3^rd rib, the trachea gave off the right apical bronchus in sheep, where as in goats the right apical bronchus originated further caudal. The width of trachea at bifurcation was almost similar in both the species. The right principal bronchus gave rise to R1 bronchus which ventilated the cardiac lobe. R2 bronchus ventilated the intermediate lobe. Caudal to the origin of R2 bronchus, R3 to R6 branches of the right principal bronchus ventilated the right diaphragmatic lobe of the lung in both the species. The left principal bronchus gave series of branches, like those given off by the right principal bronchus. The left principal bronchi gave of L1 branch which ventilated the apical part of left cranial lobe, L2 branch ventilated the majority of cardiac part of left cranial lobe, L3 to L6 ventilated the diaphragmatic lobe of left side and continued as terminal segment. Total length and total diameter of secondary and tertiary bronchi of Gaddi goats were significantly (P<0.01) greater than Gaddi sheep, suggesting that Gaddi goats had better ventilation system in lungs.