Summer effect on cow's performance in different parts of Spain

In mid-June this year, I realized a professional visit to Spain, where I lectured at a national conference organized by one of the country’s most popular dairy newspaper, Vaca Pinta, followed by a week of lecturing and consultancy for large scale dairy farms with MSD, realized in different regions of Spain. Among the visited regions were Talavera, south of Madrid, Galicia, in the northwest of the country, in the Atlantic coast and then the regions close to the cities of Girona and Valencia, on the Mediterranean coast. Managers of each of the visited farms provided me, previous to the visit, the information which allowed me to analyze the condition of each farm, mostly related to summer impact on the cows. Mainly, information was provided through an Excel file, which included monthly production and fertility data, for the past three years (2019 – 2021).

The analysis of the data, as will be presented later in the article, brought me insights into the differences in cow’s response to summer conditions in different “climatic zones” of the same country, in terms of the conditions prevailing in the summer and the extent of their impact on the performance of the cows. In this article, I will present data of about 2000 cows from the Galicia region and put in front of them, data of about 2000 dairy cows in the Valencia city region. The Galicia region is characterized by a relatively temperate and comfortable climate in summer, due to its proximity to the Atlantic Ocean. The Valencia region is characterized by a Mediterranean climate, with high hot and humidity conditions throughout the day and for nearly five months a year (a climate that is very similar to that of the Israeli coastal plain). Most farms in the temperate zone do not yet have heat mitigation means installed and operated in the summer (except for fans in the resting area in some of them). In contrast, in the farm located in the warm region, intensive cooling means were installed (using similar methods used in Israel), but these were installed in a manner and extent that was not sufficient, and have not been operated properly and for the required time per day, to date.

The indices included in the Excel file filled out by farm managers of each farm in the two regions include monthly averages per cow (in separate for first lactation and adult cows), several years back of daily milk production, milk yield in peak lactation, conception rates from all inseminations provided, and average days in milk. A comparative presentation of these indices (the average in 2019 - 2021), for cows in the two regions is presented in the following figures. Figures 1 and 2 show the average daily milk yields per cow in both regions. In figure 1, the average daily milk yield for the total cows in the herd (including dry cows), and in figure 2, the average milk yield for only the milked cows.

Figure 1 - Average daily milk per cow in the herd (kg), in both regions.

Fig 2 - Average daily milk per cow in milk (kg), in both regions.

From the figures 1 and 2, a great difference can be seen between the two regions, with regard to the daily milk yield. Unlike cows in the region characterized by a relatively comfortable summer, where there is almost no difference in daily yield per cow between seasons, in the “warm region” there is a significant decrease in daily milk yield between winter and summer. The daily yield per cow in the herd in this farm decreases from 40 kg per day in winter, to 26 kg in summer (summer:winter ratio of 0.65), while the average yield per cow in milk decreases from 41 kg per day in winter to 31 kg in the summer (summer:winter ratio of 0.75). The difference is due, as we will see below, to differences in the summer conception rate of cows in the two regions, and its effect on the average number of days in milk and in peak lactation, in both regions and seasons.

Figures 3 and 4 show the Conception Rate (CR), from all inseminations given in the different months of the year, in both regions, and the average number of days in milking, a figure that is greatly affected by the rate of conception.

Figure 3 - The monthly average of the Conception Rate for all inseminations given in the two regions.

Fig 4 – The monthly average of the days in milk in the two regions.

From the information shown in figure 3 it is possible to learn about the clear effect of the summer season on the overall conception rate of cows in the warm region, with a decrease from a rate of around 40% in winter, to less than 10% in summer. In the temperate region on the other hand, the conception rate is fairly constant throughout the year, but is found to be relatively low in the winter, as compared to that obtained in the warm region, and for a reason unknown to me, a topic that deserves to be examined by professionals in this area.

The data shown in figure 4 is largely based on the effect of summer on conception rate in both regions. Differently from the temperate region, where average days in milk range between 160 and 180, in the warm region the variation is bigger, from an average of 160 days in the winter, an average of 240 days in the summer, mainly as a result of the low conception in summer obtained in this farm.

Finally, figure 5 shows data on the peak of adult cow's lactation. This index does not depend on the conception rate and the average days in milk, and is affected only by the direct effect of climate conditions in the summer, and possible effects of heat stress in the “transition period”, including the time from calving until cows reach their peak, as well as the last weeks of cow’s pregnancy.

Figure 5 - The average peak lactation (Kg/day) of cows in the different months of the year in the two regions.

From the data shown in figure 5 it can be seen that while the gap in peak lactation between seasons in cows from temperate region is about 2 kg per day, it reaches close to 10 kg, in the cows of the warm region. The cows in the warm region reach higher peaks in winter, and lower in summer, due to the more severe climatic conditions prevailing around the time of calving of the cows in the summer, which is most probably, the main reason for lower peaks in summer.

What have we learned from all that has been presented so far?

First, we learned that there is great significance to the geographical location of each farm and its “summer characteristics”. In cows in the warm region, the climatic effect on the cows is clear and hence, the need for proper installation and operation of heat mitigation means.

The findings presented for this farm indicate that the “cooling means” currently installed and operate do not provide the expected results and require modifications and improvement. Currently, this farm is losing money by investing in cooling, without getting the expected results performance. However, the fact that the production levels and fertility rates of cows in the temperate region are lower in the winter than those recorded in the warm region, requires professional check. This is with the aim to understand if it is a problem that requires solution, or a results of farms adaptation to region special conditions, mainly from feeding and management practices point of view, being of local farmers interest. Regarding the need to operate heat mitigation means in this region, I would rely on each farm data before making a decision, taking in account farm’s climate and barn conditions. In any case, I have no doubt that even in the event that such need is detected, it will be much less intense, in terms of hours operation per day and days per year, than that recommended for the warm regions.

Once again, it was confirmed in my short visit to Spain that there is nothing like systematic work and professional analysis of the data, in order to reach the right conclusions, which will help dairy farmers of every region to make the right decision. In one region, it will be just when to start turning cooling system and in what intensity, and in another region, whether this installation should be, for the moment, carefully avoided.