| Separately from different temperature change, milk yield and adding with heat resistant stress, the test researches on the influence to trace elements and some biochemical indexes in cows' blood, milk, and hair.First part, selecting 5 healthy cows, which have similar weight,constitution, appearance and produce performance. Everyone of them can produce about 15kg milk per day. Keeping them under 10 Centigrade degree, 10-20 Centigrade degree, 20-30 Centigrade degree and 30-40 Centigrade degree for 15 days, adopting blood, milk and hair from testing cows separately and treating them with digestant, we studied the influence of temperature change to trace element and some biochemical indexes in cows' blood, milk, and hair. The result indicates when the temperature is up to more than 20 Centigrade degree, Zn content begins to drop in cow' s blood. The Zn content is minimum in cow' s blood when the temperature is up to 30-40 Centigrade degree. The difference is remarkable (P<0.01). Moreover, Fe density obviously drops (P<0. 05), Cr content reduces sharply (P<0.01), the content of Cu, Mn, Co increase, Se content reduces, and the difference is not remarkable (P> 0. 05). The environmental temperature change obviously increases to Zn, Fe content in milk (P<0. 01), Se, Cr, Mn content increase, the content of Co reduces, the difference is remarkable (P<0. 05). Its influence to Cu content is irregular. Environmental change of temperature has irregular influence to Zn, Fe, Cu in hair, Se, Mn content increase, Cr, Co content reduce, the difference is remarkable (P<0. 05). The results also showed that with the rise of the temperature, the contents of Zn Fe Cr Co in cow' s body were obviously down; the quantities of egesta were up; the content of Se showed the rising tide; the content of Mn was no changes in rule.The temperature change has not obviously influenced GPT and GOT. TP and CRE obviously drops in serum(P <0. 01), and the blood sugar increases. The difference is remarkable (P<0. 05).Second part, in hot August (room temperature is 30-40 Centigrade degree) and cold January (room temperature is 5-15 Centigrade degree), selecting 5healthy cows respectively whose milk yields are 5-10kg, 10-20kg and above 20kg, maintaining the temperature for 15 days, adopting the whole blood, milk, and hair from testing cows separately and treating them with digestant, we studied the influence of milk yield to trace elements in blood, milk and hair between the period of the heat stress and non heat stress. The result shows, (1) Among 7 kinds of trace elements in the whole blood, when it is non heat stress, the cow is in milk yield 10-20kg in the blood, the content of Zn , Mn obviously increases (P <0. 05). The content of Fe reduces. The difference is obvious (P<0. 05). Milk yield has no obvious influence on Se, Cu, Cr and Co content in the blood (P>0.05). During the heat stress, the content of Fe and Cu is reduce while milk yield is increasing gradually. Zn content increases, the content of other elements does not have regular change. (2) Among 7 kinds of trace elements in milk, when it is in the heat stress, milk yield increases, Zn eliminated in the milk obviously increases. When it is non heat stress, Cr eliminated in the milk obviously increase while milk yield is increasing (P<0.05). On the contrary, the content of Cr obvious reduces (P<0. 05) who it is in the non heat stress. Se content is obviously higher in cows' bodies whose milk yield is higher (P<0.05). When milk yield is 5-10kg, the content of Mn eliminated in the milk is higher than other milk stage obviously (P<0.05). Different milk yield does not have regular influence on Fe, Co, Cu, Cr content change in cow' s milk. (3) Among the 7 trace elements in hair, when it is non heat stress , different milk yield has obvious influence to Fe , Cr , Se in hair (P<0. 05). It does not have regular influence to Zn , Co , Cu , Mn in hair, and it is not obvious too. During the period of the heat stress, different milk yield has extremely obvious influence to Fe , Se , Co in hair (P<0.01). Mn pr... |
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