The Influences Of Chornic Cold And Heat Stress On Activity Of Enzyme, Endocrine Hormones And Behavior In Holstein Cow

In order to study the Influences of Chornic Cold and Heat Stress on Activity of Enzyme, Endocrine Hormones and Behavior in Holstein, we selected 5 cows duiring defferents lactation period from 300 basic flock of cows according to their produce date, fetal degree, avoirdupois and age. We had examined cow's blood serum enzyme activity, determined the cow's internal secretion hormone level and observed the change of experimental cow's individual maintenance behavior by using the color method to, the enzyme association immunity analytic method and the track range estimate method. We carried on 3 proof experiments. There are the results:Enzyme activity and albumin change in serum of cows in differents lactation period had been conducted in test 1. The result indicated that: creatine kinase(CK) and the Glutamic-pyruvic transaminase (GPT) activity in serum of cows during Heat Stress (HS) time is remarkably higher than non-stress (NS) time (P<0.05), but the alkaline phosphatase (AKP) activity remarkably to be lower than NS time (P<0.05), Glutamic-oxaloacetia transaminase (GOT) and the Lactate Dehydrogenase (LDH) activity not remarkably changes; Except that GPT activity of cows in differents lactation period during Cold Stress (CS) time higher than that during NS time, other enzymes activity do not have prominent change. Both HS and CS reduced the content of TP in serum while the content of Blood Urea Nitrogen (BUN) had remarkably rised (P<0.05). The change of enzyme activity of cows was basically identical, the influence on enzyme activity described above of prelactation period cows were greater during HS and CS.The Influences of Chornic Cold and Heat Stress on endocrine hormones had conducted in test 2. The levels change of Epinephrine (E), HPA hormones and orther hormones, which playing a regulating role during HS and CS had carried on research. The result indicated that: Both HS and CS improved the content of E, Glucagon (PG) and Aldosterone (ALD) in serum notably of cows (P<0.05), remarkably reduced the content of Growth hormone (GH) and Prolactin (PRL) in serum (P<0.05), but the Influences of HS and CS on the content of Adrenocorticotropin (ACTH), Cortisol (Cor), Triodothyroxine (T3), Thyroxine (T4) were not notably. The change was basically identical that hormone described above of defferents lactation period, but obvious with the prelactation period cow's change particularly, this had proved that HS was a bit greater influence to prelactation...