Effects Of Fly-repelling, Skin Temperature, Heart Rate And Immune Function Of The Cattle Caused By Diptera Insect Invasionin The Farm

Inner Mongolia is an important province of cattle industry in China, milk cow industry was suffered serious damage caused by Diptera in summer. Therefore, this paper conducted a survey about the species, quantities and habits of Diptera in the main cattle raising areas of Inner Mongolia, then explored to the effects of Diptera Insect fly-repelling behaviors, heart rates, body temperature and the immune system of dairy cows caused by Diptera Insect. After that, Stomoxys calcitrans-a harmful Diptera Insect was selected. Fly-repelling behaviors model was set up. The relationship between the quantity of Stomoxys calcitrans, the heart rate and skin temperature of cattle, and the influence mechanism of immune system caused by the flies were considered. Reasonable controlled the number of Diptera insects especially Stomoxys calcitrans was provided.1. Research was made to survey on the species, quantity and habits of Diptera in the main cattle raising areas of Inner Mongolia. Ten head of cattle were investigated which selected from2-3pastures of each area randomly. Then, Diptera were random captured and made specimens, classification and identification. The results showed that:(1)No significant correlation between the number of Diptera Insect and the difference of the climate in the main cattle raising areas of Inner Mongolia(P>0.0.5).(2)The main species of Diptera Insect which invasion cattle were house fly and Stomoxys calcitrans, a large number of Eastern horn fly were existed in some areas.(3)Fly-repelling behaviors were caused by the invasion of Diptera Insect. There was a significant correlation between number of insects in specific parts of the body and pendulum ear, fibrillation skin, kicking and head skin(P<0.05). Furthermore, there was a higher frequency of tail wagging, but no significant correlation with the number of insects (P>0.05).2. Ten Holstein cattle with similar body condition were selected, conducted as the experimental group and the control group, respectively. Then, fly-repelling behaviors, body temperature, heart rate and immune system of the cattle were determined. The cattle in experimental group were invaded by Diptera under natural conditions, the cattle in control group had none Diptera invaded. The results showed that:(1) The activity of Diptera had a significant positive correlation with ambient temperature(P<0.05), and negative correlation with wind speed(P<0.05).(2) Among the five kinds of fly-repelling behaviors, tail wagging had the highest frequency, followed by skin fibrillation, kicking legs and swing ear had a lower frequency, throwing head had a lowest frequency of occurrence.(3) The heart rate and skin temperature of the cattle increased significantly when Diptera Insect invaded it(P<0.05). In addition, heart rate and skin temperature of cattle had a significantly positive correlation with the frequency of kick and throw head(P<0.05). The number of white blood cells in blood increased significantly when the cattle were invaded by Diptera(P<0.05). And because of the level of NE were significantly increased(P<0.05), the level of CD8+increased significantly (P<0.05), presented state of immune suppression.3. Nine Holstein cattle with similar body condition were selected, conducted as high treatment group, low treatment group and control group, respectively. Then, fly-repelling behaviors, body temperature, heart rate and immune system of the cattle were determined. The results showed that:(1) There was a significantly positive correlation between the frequency of fly-repelling behaviors of the cattle and the quantities of stable fly(P<0.05). The kicking legs(R2=0.7546, P<0.0001) and fibrillating skins (R2=0.8174, P<0.0001) had stronger linear regression relationship with the number of stable fly. So the number of stable fly among the cattle could estimated roughly through the cow kicking legs and fibrillating skin,(2) There was significant positive correlation between the number of stable fly among the cattle with the skin temperature and heart rate(P<0.05), furthermore, with the increasing of the number of stable fly the heart rate of cattle fluctuated larger.(3) While stable fly invading cattle, the levels of CD8+and IL-2of high treatment group and low treatment group in bovine blood was significantly higher than that in control group(P<0.05), and high treatment group was higher than the low treatment group, but the difference was not significant(P>0.05); levels of IFN-y, DA, NE in high treatment group were significantly higher than those in the control group(P<0.05), low treatment group is lower than the high level group and higher than those of the control group, but the difference was not significant(P>0.05).Results above showed that, species of Diptera insects in the main cattle raising areas of Inner Mongolia were not the same, but mainly with the housefly and stable fly; when Diptera invading cattle, the cattle changed from the quiet stato to the excited state. Frequency of fly-repelling behaviors, heart rate and skin temperatur. increased, the immune system presented state of immune suppression; frequency of flv-repelling behaviors, heart rate and skin temperature had stronger linear regression relationsip with the number of stable fly. When there were25stable flies, the immune system of cattt would be suppressed, and as the number of stable flies increasing, the immune system suppressed more serious. Therefore, Diptera insects was a serious threat to the normal life and healthy of cattle.