The Effect Of Forage Quality On Morphology Of Gastrointestinal Tract And Visceral Tissues Growth In Holstein Calves

14 healthy Holstein calves with similar body measurement, birth weight were selected randomly to two groups and fed corn straw (CS) and hay (H) for comparison.2 calves were slaughtered in the experiment1(sulking period)and experiment2(weaning to 6months)to study the effect of various forage quality on morphology of gastrointestinal tract and visceral tissues growth in Holstein Calves.The results in Exp.1 were showed that: A) BW in H group and CS group were 95.8kg and 98.6kg; B) DM/BW(g/kg) of rumen, reticulum ,omasum, abomasum and forestomach were 3.56 and 3.21 ,0.69 and 0.28 ,0.43 and 1.11 ,1.46 and 0.77,6.14and5.37. C) DM/BW of small intestine ,large intestine and gut were 4.65 and 3.51 ,2.13 and 2.57 ,6.78 and 6.08 .and their length was 24.80m and 25.07m,5.56m and 5.12m,30.36m and 30.19m. D) Gastrointestinal tract(GIT)DM/BW was 12.92 and 11.45,respectively. E)The ratio of total dry weights of liver,spleen,heart and lung to BW was 10.51 and 8.35,respectively. F) Ruminal muscle in CS group were thicker than in H group. But the thickness of muslce and corneum in reticulum,omasum and the thickness of muslce in abomasum were greater in calves given H than in those calves given CS.Villus in duodenum,jejunum were more developed in calves given H than in those calves given CS. Villus in ileum was more developed in CS group than in H group at 100 days.The thickness of intestinal muscle in CS group were greater than in H group.The results in Exp.2 showed that: A) BW in H group and CS group were 185.0kg and 145.0kg.B) DM/BW(g/kg) of rumen, reticulum ,omasum, abomasum and forestomach were 3.75 and 2.58,0.36 and 0.32,1.02 and 1.21,1.67 and 0.85,6.80 and 4.97.C) DM/BW of small intestine ,large intestine and gut were3.03 and 3.70,3.82 and2.31,6.83 and 5.98,and their length was 35.78 and 31.46,6.90 and 6.60,42.68 and 38.06.D) GIT DM/BW was 13.60 and 10.98, respectively.E) The ratio of total dry weights of liver,spleen,heart and lung to BW was 6.61 and 7.31,respectively. F) Ruminal papillae length and width in H were greater than CS.Except for corneum in rumen, the thickness of muslce and Corneum in rumen ,reticulum,omasum and the thickness of muslce in abomasum were greater in calves given H than in those calves given CS.Small intestine morphological idexes were greater in calves given H than in those calves given CS. Large intestine morphological indexes were greater in calves given CS than in those calves given H.