Seeking happiness for both cows and people

Miyazaki Prefecture located in southeastern Kyushu is called “Nihon no Hinata (Japan’s sunny place).” Miyazaki is among the top-ranked prefectures in daylight hours and the number of clear days. Agriculture making the most of the warm weather is flourishing. The livestock farming accounts for 63% of the prefecture’s agriculture production. Jittoko chicken and Miyazaki beef are Japan’s leading brands. There is growing concern about impacts on livestock from a rise in summer temperatures, such as a decrease in cow’s milk yield, a reduction in conception rate and a fall in liveweight gain. The Miyazaki Livestock Research Institute is carrying out various testing and research to reduce environmental stresses, including measures against heat. We interviewed Hidehiro Tokutome, Director of the Miyazaki Livestock Research Institute, Norio Arima, Research Planner / Senior Manager, Tetsuya Suzaki, Domestic Animal Biotechnology Department Manager, Noriko Kitano, Senior Technical Staff, and Mami Matsuo, Technical Staff

Measures against heat in livestock farming

Please tell me the outline of the Miyazaki Livestock Research Institute.

Arima: In 1920, the institute was first set up as the Miyazaki Livestock Breeding Center on a site rented from the warhorse procurement department. The year 2020 marks the centenary of the foundation. Today, we have 101 beef cows, 62 dairy cows and 1107 chickens on a 130-ha site. The Kawaminami Branch has 237 pigs and 3,644 chickens.

How are cows affected by a temperature rise in summer?

Suzaki:Dairy cows are more sensitive to changes in temperature and humidity than humans. For example, if the humidity is 100%, cows are affected even with a temperature of 19°C. If the temperature exceeds 25°C, cows are affected regardless of the humidity. Recently, the milk yield in summer is drastically decreasing. The yield has fallen by 10% in August compared with April when the milk yield is the highest (Figure 1).

Demand in the market is the highest in summer. It is important for farmers to produce a large amount of quality milk in this season. To target the summer when the market value is high, cows must become pregnant in July to September in the previous year. Due to global warming, there is concern about a fall in the conception rate. In addition, demand for fertilized eggs of Japanese Black cattle as the prices of Japanese Black calves are soaring. Normally, about six fertilized eggs are produced by a session of superovulation. According to a test by the Miyazaki Livestock Research Institute, the number of fertilized eggs is reduced to one under heat stress.

What measures against heat has the institute implemented?

Suzaki:In 2011, we conducted verification tests on 19 model farmers on the slogan “approach toward profitable dairy management.” We set up a study group consisting of technical instructors and extension workers as well as researchers at our institute. The group wrote a prescription for each farmer based on a fact-finding survey. After examining the actual cowshed structure, existing measures and problems, we examined countermeasures.
The institute had developed a heat stress meter to visualize changes in temperature and humidity and we gave the meter to all the cattle farmers (316 households) in the prefecture. That alone didn’t produce a much effect. It was necessary to propose measures that suit the actual situation, not satisfied with only giving out the meter. The study group compiled a manual for identifying the actual situation and implementing appropriate measures and mounted campaigns to encourage the farmers’ awareness. In addition, we tested new measures including the introduction of an automatic sprinkling system for cattle body and the application of a thermal insulation paint to the cowshed roofs.

Do you keep something particular in mind when providing farmers with new technology?

Suzaki:Research and development by our institute are inspired by requests extension workers hear from farmers. We try to develop technology farmers can introduce at low cost. We also try to verify the cost-effectiveness and provide the data to farmers. It is important to explain clearly to them that taking measures against heat will improve the milk yield by season and consequently enhance the profitability.

Devoting ourselves to tests and research

What tests and research are you conducting now?

Matsuo:The Domestic Animal Biotechnology Department is conducting (1) the application test of thermal insulation paint to a cowshed roof and (2) the verification of cooling by a cow jacket. About the test (1), we divided the cowshed into a heat insulated area with the thermal insulation paint applied to the roof and a control area without the paint and compared the areas in early August. For the verification (2), we put a jacket on cows and compared the cows in a shower area where they were showered with water while being fed and those in a control area where they were not showered in July to September.

What are their results?

Matsuo:The test (1) has indicated that the application of the paint has an effect on the environment in a cowshed. When thermal insulation paint was applied to the roof, the radiant heat under the roof was suppressed by 20°C compared with the control area and the temperature in the cowshed was lower in the heat insulated area than the control area. The somatic cell count in milk used as an indicator of the onset of garget increased by 94% in the control area whereas little changes were observed in the heat insulated area (Figure 2). The result showed that the application of thermal insulation paint was expected to reduce stress on dairy cattle and improve the productivity.

In the verification (2), we compared the vaginal temperature, blood characteristics and reproductive capacity between cows in the shower area and the control area. There was little difference between the two areas. In comparison of the blood characteristics, an indicator of a cow’s health, the state of nutrition was improved in the shower area.

Suzaki:During the verification (2), the cooling time was four hours a day while cows were fed in stanchions. We presume that was why no noticeable changes were observed. Stress on cows are caused in relation to the facility environment including coolness and ventilation. It is necessary to take measures considering various factors. Cows are homeotherms and it’s not that the body temperature is changed by temporarily cooling the cow body. Now, we are conducting a continuous cooling test to cool the cow body continuously. Test results are publicized in the magazine “Rakuno Miyazaki (dairy farming Miyazaki)” to all the farmers. We will continue to drive appropriate measures against heat on site.

Arima: In reality, various other factors besides climate contribute to cows’ stress. Collecting necessary data and identifying impacts of heat is one of the challenges we are to address.

What is your motivation for carrying out day-to-day operations?

Arima: I am working to put into action the Miyazaki Prefecture Livestock Farming Growth Plan. My goal is to establish safe and profitable livestock farming that will present a model for the livestock industry across the country, based on the prefecture’s agricultural plan.

Kitano:At the moment, I am tackling measures against heat for Japanese Black cattle. It is not easy to develop a practical mechanism like the heat stress meter but it is challenging and rewarding to engage in the development of technologies and measures truly useful for farmers.

Matsuo:Not all the tests and studies lead to positive results. I consider all the tests and studies, including those that deliver no result, are necessary.

Suzaki:In on-site verification, it is important to work closely with the farmers. As the term “cow comfort” suggests, it is important to create an environment that keep cows comfortable. Reducing cows’ stress will boost the productivity. I would like to contribute to raising farmers’ awareness of that fact. Our institute accepts trainees from universities and young farmers. I hope the institute will keep developing better and better technologies making the most of flexible ideas of the next generations and it will also serve as educational facility.