“Voluntary cooling” – does it work?

Heat stress is one of the major loss factors in the dairy industry of many countries in the world, especially those located in warm regions. The loss caused to dairy farms raises from the decrease in cow’s annual milk production and in feeding efficiency, together with the impairment in cow’s health and fertility.

The most common cooling treatment provided to the cows today, combines cycles of wetting and forced ventilation. This treatment have the potential to significantly reduce these losses and improve farm profitability. In most cases, investment in additional labor is required, in order to move cows to and from the cooling sites, also during nighttime. For this reason, the "labor issue" is quite complicated to deal with, and, while participating in many projects in the world, I found it difficult for farm owners and managers to make sure that farm workers keep bringing the cows to be cooled, especially during the nights, weekends and holidays.

In last years, we gained much information and experience in what I call “voluntary cooling”. This means, allowing cows to get the cooling treatment in their own time along the day. No doubt that, in case it works, then farmers can save part of the expenses for cooling the cows, above all the labor required to move cows to and from the cooling sites.

Now, the great question is, does it work?

The first to give us an answer to this question, where the farms that implemented the Voluntary Milking System (VMS - robotic milking farms), where no fix milking time exists. In the last 20 years, I am involved in the implementation of cooling systems, based on wetting and forced ventilation, in “robotic farms” (De Laval and Lely), in Israel, Spain, Italy, Argentina, Chile and Holland. In all these farms, cows are cooled by a combination of short wetting session and forced ventilation, provided in the area close to robot machines. In some cases, “presence detecting sensors” located in the entrance to the “cooling site” activated the system, only with cows presence. In other cases, feed line is divided into sections, where cooling (fans and sprinklers) in each section, are activated when cows “cross the ray” and for the time they stayed there. The implementation of this cooling mode allowed these “robot farms” to properly cope with summer heat stress and significantly reduce the summer negative impact on milk production and fertility. In most of the cases, average per cow milk production in the summer reached above 40 kg and dropped very little from winter level. Cows inseminated in the summer in these farms reached a conception rate of 30% and more, much above the levels registered there, before the implementation of this cooling mode.

From the experience gained in last years in the robot milking farms we can learn that cows can “voluntarily” use the cooling system and reach good performance during summer months. By “letting the cows” choose their own cooling time, farm can save labor expenses, but still with the risk of spending more money in electricity and water consumption, in comparison to the “regular” cooling procedures, where all cows are cooled in fix periods, and cooling system is “shut down” in the rest of the time.

In order to avoid such possible extra expenses, a new “smart cooling” strategy, based on a new advanced technology, developed recently by an Israeli company named ENGS, and tested in Ginosar dairy farm, located in the Jordan Valley, one of the warmest places in Israel and on earth. Summer in Ginosar begins in early April, and ends in November, so the cows there experience heat stress for almost 250 days a year. Although these limiting conditions, the farm reached in 2021 a very high per cow annual milk production (13,300 kg). Until recently, cooling the cows in Ginosar farm was based on cycles of short wetting and forced ventilation, provided to the cows in the “waiting yard”. Cooling was provided before and between milking sessions, six times and 6 cumulative hours of treatment per day. In the summer of 2021, a “smart cooling” system was installed in this farm, where cooling was provided mainly in the feed alleys (except cows being cooled in waiting yard, just before being milked). Feed alleys in each barn were divided into 3 sections of wetting and forced ventilation. “sophisticated tags” on the cows, monitoring in real time cow’s physiological and behavioral parameters, performance history and location, communicate with feed alley cooling system, and according to farmers setting, can activate the cooling system in a certain section, according to each cow, or group of cows presence. In summer 2021, farm completely stopped bringing the cows for special cooling in the waiting yard, and most of the cooling treatment cows received was given in the feed alley, activated by the “smart cooling system”.

In order to evaluate the effectiveness of this new cooling procedure, I made use of the “summer-winter ratio” index, (S:W), which is calculated at the end of every year for every farm in Israel by the Israel Cattle Breeders Association. In the first step, I compared Ginosar farm results in 2021, to that of the 21 dairy farms located in the same region (Jordan Velley).

The results are presented in Table 1.

Table 1 – Summer to winter ratio index for milk production and fertility traits in 2021, in Ginosar dairy farm, as compared to the average of 21 dairy farms in the hot Jordan valley.

As can be seen in Table 1, the extent of the decrease in milk yield in all the warm Jordan valley farms was of 3.6 kg per cow/day, as compared to a decrease of only 1.3 kg per cow/ day in Ginosar farm. The somatic cells count in the milk is a good indicator for being the cow in stress. The S:W ratio for Somatic cells content was higher than 1.0 in the Jordan valley farms, indicating the thermal status of the cows in these farms, while that in Ginosar was less than 1.0 , where cows are most probably, in normal “thermal status”, and without stress. The data presented in table 1 clearly show that the Ginosar farm, when using the “voluntary cooling system” copes quite good with summer heat stress, even better than the farms in the same region, which use to cool the cows in regular way, by bringing cows to be cooled in the cooling site for few times along the day.

In second step, I compared the summer to winter ratio index, for milk production and fertility traits in Ginosar farm in 2021, when the “smart cooling system” was in use, to those reached a year before, when cows were brought for cooling in the waiting yard, for 6 times per day (Regular cooling). The data is presented in table 2.

Table 2 – The Summer to winter ratio index for milk production and conception rate in Ginosar dairy farm, in 2020, when cows were cooled regularly by bringing them to be cooled in waiting yard and in 2021, where cows received “voluntary” cooling, using the “smart cooling system” in feed line.

As can be seen in Table 2, the extent of the decrease in milk production from winter to summer was less, when cows were cooled "voluntarily" as compared to the year, when cows were cooled by regular cooling method (bringing the cows especially for cooling in waiting yard). Voluntary cooling allowed farm also reaching relatively “acceptable” conception rate in the summer, not different to that reached when cows were cooled in the regular mode.

From the presented in the two tables, we can clearly conclude that voluntary cooling “can do the Job” and have the potential to reach good productive and breeding results in summer. These results can be reached also when voluntary cooling is implemented in farms with high yielding cows, located in extremely warm regions, and having the benefit of avoiding the need to move cows to and from the cooling site. The results obtained in Ginosar farm are in accordance with the achievements obtained earlier, in the robot farms.

As part of the comparison between the two “cooling strategies”, I also examined the required investment in electricity power and water needed to cool the cows in the summer.

Electricity consumption was almost the same in both summers, when in summer 2021, using “voluntary cooling” more electricity was consumed during night hours, when electricity cost per KW use to be lower. As to water use, less water was required to cool the cows, when “voluntary cooling” was practiced, saving money to the farm in both ways, the direct cost of water, which is quite expensive in Israel, as well as the high cost of treating higher quantities of effluents.

The experience obtained in cooling cows in robot farms, and that reached from Ginosar farm in summer 2021, teaches us that “cows can be trusted” to effectively use “voluntary” cooling treatment. Using advanced technologies, which allow the activation of cooling per individual, or group of cows according to their “cooling needs” allow farms save labor, electricity and water expenses, while in the same time, reach satisfactory performance results in the summer, in high yielding cows, performing under extremely warm conditions.