Studied On The Mechanism Of Pica Caused By Mineral And Vitamin Deficiencies In Stabling Tan Sheep

Healthy Tan sheep wethers fitted with permanent cannulas in rumen were selected and were used in a single-factor completely random design. Test wethers of each group were feed with a dietary that the content of copper(Cu),zinc(Zn),selenium(Se),vitamin A(VA) and vitamin E(VE) was lower than nutritional needs to build their pica model. By measuring feed intake, weight gain, rumen fermentation, blood parameters, urine and wool indicators to analyze the correlation between Tan pica sheep and indicators described above. In the actual production we could measure some indicators in order to quickly find out the causes of Tan sheep’s pica.The results showed that:the feed intake, weight gain, rumen acetic acid and propionic acid concentrations of Cu, Zn, Se deficiency groups were significantly reduced (P<0.01).Meanwhile, the concentrations of rumen butyric acid, TVFA, serum GLU, serum TP, serum BHBA, wools growth rate, the density of wool, and the copper content of wools were decreased, but the difference was not significant (P>0.05). The ratio of feed and weight, rumen pH value, serum BUN concentrations had an increasing trend. Moreover, the rumen NH3-N concentrations of pica caused by Cu deficiency group increased significantly (P<0.01). The density of wool and the ratio of acetic acid and propionic acid significantly decreased(P<0.01).The Zn, Se concentrations of wool significantly decreased(P<0.05). The pica sheep of Zn deficiency group, the rumen NH3-N concentrations were significantly increased (P <0.05), Zn concentrations and the density of wool were significantly decreased (P<0.01), Se concentrations of wool significantly decreased (P<0.05). The pica sheep of Se deficiency group, the rumen NH3-N concentrations had no significant changes(P>0.05),but the ratio of acetic acid and propionic acid significantly decreased(P<0.01),Zn concentrations and the density of wool were significantly decreased(P<0.05), Se concentrations of wool were significantly decreased(P<0.01).Rumen fermentation function of pica sheep caused by VA,VE deficiency diminished, so rumen acetic acid, propionic acid, butyric acid, TVFA and the ratio of acetic acid and propionic acid were decreased, meanwhile, rumen NH3-N concentrations increased. Serum GLU and serum TP content reduced. The wools growth rate, the density of wool and Cu, Zn, Se concentrations of wools decreased. However, all changes mentioned above were not significant (P>0.05). At the same time, the feed intake, weight gain and density of wool of VA deficiency group were significantly decreased (P<0.01), but the ratio of feed and weight was significantly increased (P<0.01). The feed intake and weight gain of VE deficiency group were significantly decreased (P<0.05), but the ratio of feed and weight was significantly increased (P<0.05). While the density of wool was significantly decreased (P<0.01).When the Tan sheep dietary was lack of Mineral elements Cu,Zn,Se and vitamin A,E they would suffer from pica. Compared with health sheep, the growth performance, rumen fermentation, blood parameters and the physical and chemical properties of wool in pica sheep showed different changes. In the actual production, the above indicators can be measured to find out real reasons that caused pica inTan sheep, then to make a quick diagnosis.