Cooling means to reduce heat stress from cows was developed over the last four decades in Israel, and are applied to a different degree of success in many farms in the world.
Cooling cows in the farm is based on the daily routine, which includes of cooling the cows by a combination of wetting and forced ventilation in the waiting yard and in the feeding line. In addition, cows are force ventilated in resting area.
The farm consist of approximately 1,100 Holstein cows, housed in two free stall barns and milked 3 times a day, for approximately 18 hours per day. Until summer 2017, before the "cooling project" started, no effective cooling treatment was provided to the cows, except a small and insufficient number of fans installed in waiting yard and operated during milking time, as well as poor ventilation and wetting system.
In preparation to cooling the cows in the summer of 2018, fans were installed in waiting yard, to "cover" a wind speed of 3 meters/second in all yard (see picture). Sprinklers (300 lit/h) were installed above yard surface, to provide good wetting of the cows in the shortest time possible. Cooling was operated by timer, for 45 seconds of wetting session every 5 minutes, provided before each cooling session. Cows were cooled also in feed line, were fans were installed along all feed lines and operated in combination with wetting system, when cows were back from each milking session. Cows were provided also special cooling treatment in feed line, between milking sessions. Cows were forced ventilated in free stalls, all time cows were not presented in one of the two "cooling sites".
Evaluation of cooling effectiveness - In order to evaluate the effectiveness of the treatment given, we monitored cow's body temperature along all summer 2018, making use of intra vaginal data loggers. Results showed that the cooling treatment provided to the cows in this herd "worked well", and cows were maintained in thermal comfort (below 39.0 C), most of the 24 hours of the day, as can be seen in figure 1.
Figure 1 - Average vaginal temperature measured in 10 milking cows, in 10 minutes interval (starting at night time), along the 24 hours of a typical summer day.
Milk production - Average per cow milk production was increased significantly in summers 2018, as compared to summer 2017, when cows where kept without any effective cooling (Figure 2). Analyzing the performance results at almost the end of summer 2019, when this article is written, show even a greater improvement in cow's annual milk production.
Figure 2 – Average daily milk production per cow (lit/day), in 2017 (before cooling was provided), as compared to 2018 and part of 2019 (when cows were intensively cooled).
The annual milk production per cow in the farm is expected to increase between 2017 and 2019 (assumption done at October 2019), in approximately 1600 liters (annual increase from 6,500 to around 8,000 liters per cow). Assuming that only part of this increase can be related to the improvement related to cow cooling, we can consider a 1,000 liters increase in annual production per cow due to the intensive cooling in summer (increase of 15%). According to previous studies, we can assume that the increase of 15% in annual production due to cooling treatment, can be related also to an improvement of at least 5%, in feed efficiency (feed conversion to milk), in the 100 days of summer.
Fertility results - Intensive cooling the cows improved also cow's fertility. Conception rate of cows inseminated in most of summer month in 2019 was higher from those obtained in 2017 and was close or above 30%, considered as good result. Fertility results shown in figure 3.
Figure 3 – Average conception rate from all insemination given to the cows in the herd, in 2017 (before cooling was provided), as compared to 2018 and 2019 (partial data, when cows were intensively cooled).
We assume that the conception rates reached in last two summers have the potential to reduce "open days" by at least 5 days per cow, with a total value of at least of at least 25 USD per cow/year.
Economic aspects of cooling - based on the real results obtained in summer 2018, I conducted an economical study, with the aim to evaluate the cost effectiveness of the implementation of the intensive cooling in this farm. The study was carried out by making use of a special computer Excel program, in which I took part in developing. The study took in account an increase of 15% in annual production per cow (1,000 lit. per lactation), a 5% improvement in feed efficiency in the 100 summer days and a reduction of 5 "open days" above optimal, with the value of 5 USD for each day (total benefit of 25 USD per cow/year).
The investment for the installation of cooling equipment, done according to the recommendations, was of 290.000 USD (265 USD per cow). The farm gate price for milk was of 0.42 USD and the price of 1 kg of DM feed mix for milking cows was of 0.22 USD. An increase of 0.5 kg DM feed mix for every additional liter of milk taken in account. The cost of operating the cooling system in the 120 summer days was of 50 USD per cow. For running the calculation, we assumed that investment in cooling system done by taking a bank loan for 5 years, with annual interest of 10%.
Based on the data presented above, the net income, due to the implementation of intensive cooling system in summer 2018 was of 240 USD per cow and 265,000 USD per farm. In such results, investment could be payback in one year.
Picture 1 – Fans and sprinkling system installed in waiting yard.
Picture 2 – Fans installed along the feeding line and resting area.
Picture 3 – Fans and sprinkling system, installed along the feeding line.