In a previous article published some years ago here, dealing with cooling project that I accompanied in northern Mexico, I described the results from the first and second years of its implementation. The data were presented in a limited way, for a series of dairy farms belonging to the "Alpura" dairy cooperative, located in the warm regions of northern Mexico and characterized by long summer months, with extreme heat load conditions for dairy cows. These farms are mainly large and high-performance farms, located in a desert area, where approximately 60% of year hours of the year experience heat stress conditions.
The “cooling project” started in the summer of 2014, the first summer of our activity and defined as a “learning summer”, in which we examined the best way to operate the cooling in the dairy farms. Already in the initial stages of deciding about the “cooling strategy” for this kind of dairy farms, particularly large (between 1,000 and 3,500 cows), and with long milking sessions (all the farms milk the cows 3 times a day, for about 21 hours a day). Milking in these parlors is very fast and therefore, the time spent by the cows in the waiting yard before milking is very short and does not allow cooling for the required time. The solution we came up with was to build “special cooling yards”, located near the holding yard and the milking parlor, which allowed providing the cows with additional time to be cooled in each milking session (before and after being milked), as well as by bringing the cows to be cooled, also between milking sessions.
In the summer of 2015, we started cooling in a format that combines cooling in the waiting yard and in the special cooling yards, in five barns of the cooperative members. Cows received a one-hour “cooling treatment” around each milking session, as well as one hour of cooling treatment, approximately four hours from the end of each milking session. In total, the cows received 6 accumulated hours of cooling per day, where cycles combining wetting and forced ventilation were provided, once every 4 hours, day and night.
In this article, I have chosen to present, six years after the beginning of the project, data from La Cantabra dairy farm, one of those farms where cooling principles described above have been optimally applied. Farm owner persisted in collecting data and sending it to us until the date.
About La Cantabra dairy farm
The pictures presented show the improvements done in this farm to decrease the negative impact of summer heat stress including shading the walkways to and from the milking parlor and the construction of “special cooling yards” in operation since summer of 2015.
These are four “cooling tunnels” adjacent to each other and equipped with fans of about 2 meters diameter and large droplets sprinkling system, operating alternately. In two of these tunnels, the cows stayed before and after each milking session, allowing the cows to be cooled (together with the cooling treatment given in the waiting yard), for one complete hour at a time. The other two tunnels were used to cool the cows for an hour at a time, between milking sessions. The cows in this farm were cooled for a total of 6 hours a day, and in order to bring the cows to and from the cooling site, 6 additional workers were hired, working in three shifts, 24 hours a day, throughout summer.
The results after six years of operating the cooling system in La Cantabra farm
To examine the effect of the cooling treatment on the summer performance of the cows, I calculated the average conception rate per month of all the inseminations, as well as the average daily production per cow. This was done for the four years prior to the implementation of the cooling project (2011-2014), comparing them with the six years since it started (2015 - 2020). The results are shown in figure 1, for the conception rate and figure 3, for the milk production, with figure 2, showing the average “days in milk” of the herd in the different months, for 2014 (the year before the project started) and the end of 2020.
Figure 1 - Average conception rate, of all inseminations given in the different months of the years 2011-2014 (before the start of the cooling project), and in the years 2015-2020, (where intensive cooling was provided).
From the presented in figure 1, a significant improvement in the conception rate can be seen in the summer months, after the implementation of intensive cooling. In the years prior to the beginning of the project, the conception rate started declining already in April and returned to its normal level only in December. Conception rate during this period decreased from 40% in the inseminations done in the winter, to approximately 15% in the summer.
Differently from that, during the period in which intensive cooling was implemented, a conception rate of 30% or more was maintained, during all summer months. From the presented in figure 2, it can be seen that the improvement in conception rate in the six years since the beginning of the cooling project contributed to the reduction of the average number of "days in milk", mostly in summer months, a significant factor causing the improvement of the annual average milk yield per cow, as shown in figure 2.
Figure 2 - Average “days in milk” in the different months of the years 2011-2014 (before the cooling project started) and in 2020 (six years after the beginning of the implementation of the cooling treatment).
From the presented in figure 2, a significant reduction in the number of “days in milk” can be seen, after five years of intensively cooling the cows in the summer, as a result of the improvement in summer fertility, at the end of the 6th years of the project. As expected, reducing the number of “days in milk” means that the cows are closer to calving date, which positively affects cow's production, as in fact can be seen in figure 3.
Figure 3 - Average milk production per cow (lit./day), in the different months, in the years 2011-2014 (before the beginning of the cooling project) and in the years 2015-2020, in which intensive cooling was implemented in summer.
From the presented in figure 3, a significant reduction is seen in the degree of summer decrease in milk production per cow, between the period prior to the implementation of intensive cooling, and the period in which it was operated.
The difference in milk production between winter and summer, and the summer to winter production ratio, between summer and winter, in 2014, before implementing cooling and 2020, six years from the beginning of its implementation, are presented in table 1.
Table 1 - The difference in average daily milk production and the ratio of average daily milk production, between summer and winter, in 2014, before implementing the cooling project and in 2020, six years after its implementation.
The economic aspect
The implementation of cooling system implies a high financial investment for the installation and operation of the cooling treatment. Based on current data in Mexico, we estimate that the investment for the construction of the cooling tunnels and the cooling equipment, similar to those that exist in La Cantabra, with today prices, can reach about $ 400,000 (approximately $ 150 per cow). We assume also that the cost of operating the cooling system during the summer is expected to be $ 45 per cow, covering electricity, additional labor, and equipment maintenance expenses.
Using special computer software that I developed, I examined the economic effect of investing in cooling cows. For the calculation I took the real results obtained in La Cantabra farm (an increase of 10% in cow’s annual production), assuming also a 5% improvement in nutritional efficiency during the summer months. The study didn’t take into account the economic improvements expected from the improvement of summer health and fertility traits.
Based on the professional results described above, an increase in annual income per cow of US $ 235, and $ 470,000 in annual income for a dairy farm with 3,000 cows are expected. In this case, the investment in cooling the cows can be paid back at the end of the first year of operation and since then, farm annual income can increase by 500,000 US $ each year, being this investment one of the best, a dairy farmer located in warm region can do.