The economic benefit of intensively cooling the cows in high yielding dairy farms

Heat stress (HS) has detrimental effects during all stages of dairy cattle life. Cows that experience HS reduce dry matter intake, milk yield, and its composition. In addition, HS has major effects on a cow's health and fertility and negatively impacts a cow's welfare. The decrease in the efficiency of milk production in such conditions increases the negative contribution of the world dairy sector to the environment and brings large economic losses to dairy farmers and the entire world dairy industry. 

Almost three years ago, the International Dairy Federation (IDF) decided to deal with the problem by establishing a professional committee that would work to centralize all existing knowledge regarding the topic. The aim of this committee was to assist dairy producers by providing guidelines on how to deal with heat stress and thus contribute to improving cow welfare, reduce the scope of cows' greenhouse gas emissions into the atmosphere, and lower milk production cost. Lowering cost of milk production would improve producers' profitability and lower the price of milk for consumers. This article consists of data from the chapter in the IDF bulletin to be published soon, which describes the economic benefits that may result from the correct implementation of intensive heat mitigation measures to relieve heat from cows. We assume that bringing this information to the knowledge of dairy producers and farmers organizations will encourage them to invest in the installation and proper operation of heat mitigation measures adapted to their specific farm conditions and necessities.

Much progress has been made in recent years in the improvement of the effectiveness of cooling treatments, which influences the economic benefit expected from its implementation. The effectiveness of cooling mitigation strategy based on the combination of wetting and forced ventilation is influenced by the times during the day that the cooling system operates. An experiment carried out in Israel (Honig et al. 2012), showed that by increasing the frequency of cooling sessions (45 minutes per session) from five (3.5 cumulative hours per day), to eight times (six cumulative hours per day), increased dry matter intake and milk production by 9.3% and 9.6%, respectively. In addition, it has been suggested that through intensive cooling management, using fans and sprinklers for a total of six cumulative hours per day during the hot summer, milk production can approach up to 96% of the cool winter production level (Flamenbaum and Ezra, 2007) and almost double the summer conception rate (Flamenbaum and Galon 2010). To evaluate the impacts of these cooling intensities the cost effectiveness of such cooling was studied, based on a model published more than 20 years ago (St. Pierre et al. 2003). A recent article published by Espinoza-Sandoval and Calsamiglia 2023, used also St Pierre model to evaluate cost effectiveness of different cooling intensities in different regions of the Mediterranean Sea with annual heat load ranging between 6000 and 31000 units and found, as could be expected, that the economic benefit was greater in the warmest regions. Differently from St Pierre, our study considers the improvements in milk yield, but also, fat and protein yield, dry matter intake and reproduction, for different climate conditions and US farm economic numbers in 2024.

For the illustration of cooling system effectiveness, a scenario of intensive cooling was evaluated and compared to no heat stress and no cooling scenarios.  Intensive cooling treatment was comprised of repeated cycles of 0.5 min of sprinkling to soak the cow's skin, and 4.5 min of forced ventilation, providing wind speeds of at least 3 m/sec. over all cows (without sprinkling), to evaporate water and cool the cow. Intensive cooling was comprised of cows receiving 6 cumulative hours of cooling per day, which implies a cooling treatment almost every 3 – 4 hours. The expected improvement in milk production (lit./d) in the different scenarios is presented in Table 1.

The economic benefit due to the expected improvement in milk production arising from the implementation of intensive cooling was calculated as the increased amount of milk fat and protein (kg) multiplied by milk fat and protein prices in the US in 2024. The economic benefit related to the improvement in fertility was calculated as the expected reduction in days open per cow, multiplied by a cost of $3 per each day less.

Cooling costs of dairy cows were calculated based on fixed and variable costs. The fixed costs consisted of investment in fans and sprinklers, and were around $20/cow per year. The cost of operating an intensive cooling system consisted mostly of the cost of electricity power to operate the fans for 6 cumulative hours in the cooling site and 18 cumulative hours in the resting area. Cost of water was negligible.     

The present study compares 3 different climate zones in the US: Florida (humid subtropical climate), California (hot Mediterranean) and Wisconsin (continental temperate climate). A fourth climate zone, no heat stress ever, was also assumed.  The economic analyses included annual financial losses due to HS in each climate zone, when cows are not cooled, and compared to the economic losses when intensive cooling was provided, taking into account the cost of cooling. Results are expressed per cow per year, as well as a return on cooling system investment (net financial gain from cooling divided by the cost of cooling) and payback time for the investment in fans and sprinklers.

The effect of intensive cooling on cow performance is shown in Table 2. As expected, the effect of HS when cooling was not applied was the greatest in the subtropical humid climate and the smallest in the continental temperate climate. The intensive cooling treatment (6 cumulative hours/day) reduced the negative effects of HS almost completely in every location.

Data presenting the economic results from intensively cooling the cows, as compared to no cooling, is presented in Table 3.

From the results presented in Table 3, it can be seen that the economic losses occurring when cows are not cooled in the summer are greater than $800 per cow per year in Florida and close to $100 per cow in Wisconsin. Intensive cooling reduces significantly the losses, as compared to cows without any cooling, although cooling had a cost of around $70/cow per year.

The advantage of the intensive cooling treatment is $652/cow per year in Florida and $46/cow in Wisconsin, while return on investment ($ net profit per $ invested) is almost 1000%, in Florida and 120% in Wisconsin. Payback time is less than one year in Florida and California, and less than 2 years in Wisconsin. These pay back results are considered very fast.

The results of this study agree with those of St-Pierre et al. (2003) who found that an intensive cooling treatment (although defined differently than in our study) is highly profitable, in almost all US states. These results show and confirm (as expected), that the economic benefit of cooling dairy cows is large in warm climates, with many stressful days per year, but also is justified in the temperate climates, where a shorter period of heat stress is expected. The investment in cow cooling is therefore likely one of the most worthwhile investments in the global dairy industry.