# Research and Development of Automatic Monitoring System for Livestock Farms
## 4 Results and Discussions  
The experimental sites of this study were in the livestock farms of the National Pingtung University of Science and Technology. The barns were designed as semi-open spaces, and the study was carried out on the common dairy cow breed in Taiwan - Holstein-Friesian. The dairy cows of the European breeds generally show weak heat-resistant. However, the weather from July to August in Taiwan is hot and humid, which tends to cause a decrease in milk production and mastitis in dairy cows. To verify the impacts of weather on dairy cows, we may refer to the articles [29; 30; 31; 32]. To verify the impacts of weather on lactation yields, we acquired the data of lactation yields in March, August and November, representing the good and bad weather conditions respectively for the lactation of dairy cows. We retrieved the daily data during time interval of 9:00 a.m. to 4:00 p.m., that was the timing when dairy cows had increased sensitivity to heat stress. Comparing the experimental data with the lactation yields for dairy cows, the results were analyzed as follows:  
1. The Correlations Between Lactation Yield and Season  
In March, the cooler season, the values of temperature-humidity index (THI) mostly would fall within the range of mild heat stress, and it was showed in Figure 10 that the average lactation yield per dairy cow was 24.9102 L/day. On the other hand, in August, the hot and humid season, the values of temperature-humidity index (THI) would mostly fall within the range of moderate heat stress, and it was showed in Figure 11 that the average lactation yield per dairy cow was 20.8167 L/day, which was significantly 4.0935 L/day lower compared to the average lactation yield per dairy cow in March. \begin{table}
\begin{tabular}{c c c} \hline
**THI** & **Stress Level** & **Symptoms in Cattle** \\ \hline THI \({}^{1}<72\) & None & Optimum productive and reproductive performance \\
72 \(\leq\) THI \(<79\) & Mild & Dairy cows seek for shade, increase inrespiration rate and dilation of blood vessels \\  & & Increase in respiration rate and saliva secretion. Reduction in feed \\
80 \(\leq\) THI \(<89\) & Moderate & intake and water consumption. Body temperature is increased and reproductive performances are severely affected in cattle \\
90 \(\leq\) THI \(<98\) & Severe & There is rapid increase in respiration and excessive saliva production. The reproductive performances in animals are significantly decreased \\ \hline \end{tabular} \({}^{1}\) THI, Temperature-Humidity Index.  
\end{table} 
Table 3: Classification of zones based on temperature humidity index (THI) values in cattle with THI model [27]. The Correlation Between Lactation Yield and Short-term Temperature Changes  
Comparing Figure 10, it indicated that there was only one time that it reached the degree of moderate heat stress, resulting in a 0.4887 L/day reduction of average lactation yield per dairy cow. Furthermore, a strike of three-day cold current also caused a 1.0273 L/day reduction of average lactation yield per dairy cow due to a sudden environmental temperature change. It was found that a one-day heat stress showed little impact on the lactation yield, but the heat stress over a longer period showed significant impact on the lactation yield of dairy cows. 3. The Correlation Between Lactation Yield and Temperature-Humidity Under Moderate Heat Stress Status  
Figures 11 and 12 showed the correlation between temperature and the lactation yield per dairy cow under moderate heat stress status. It was found that the average lactation yield was 16.4354 L/day under the average temperature of 30.9856 \({}^{\circ}\)C during 1 to 11 August. Furthermore, the average lactation yield was 18.1641 L/day under the average temperature of 28.3183 \({}^{\circ}\)C during rainy days from 16 to 21 August. It indicated that the average lactation yield per dairy cow tended to decrease as the temperature increased under moderate heat stress status.