Summertime in July means there are often two pasture requirements: shade and reliable water. There is plenty of debate whether shade is required or not in arid parts of the country as well as beyond the pasture setting. However, settling the debate on requirements is not the goal this month, rather looking at how shade and water source can impact cattle performance.
Cattlemen’s intuition would suggest shade availability and water intake should be linked. Stand out in the sun very long and one is certainly warmer than standing in the shade. Despite the increased heat load due to solar gain there is little research evaluating the combined effects of shade and water on cattle performance. Recent Brazilian research in the Journal of Cleaner Production by Taisla Novelli and coworkers addressed the question of shade availability and water use efficiency.
Before we look at results, the environment and cattle merit some discussion. The experiment used 991 lbs. Nelore bulls fed in a lot located in Sao Carlos, Brazil. While humidity was not reported this was a tropical climate where the regional spring temperature ranged from 54.3 to 95.9 degrees with an average of 73.4 degrees.
The artificial shades within the experimental pens allowed for 65 square feet of 78–83% shade. Amount of shade recommended per head is as variable as whether shade is required or not. Depending on the reference, shade recommendations range from 20 to 60 square foot per head with greater space attributed to heavier weight and/or more mature cattle.
Most consider Nelore cattle as heat tolerant compared to the native beef breeds so the conditions of this experiment reflect the combination of heat tolerant cattle with abundant shade area during a season of marginal heat stress.
Looking at water intake relative to shade availability, the shaded cattle drank 9.7 gallons per day while those without shade drank 10.6 gallons. Water intake increased by 9% or about a gallon per head day due to absence of shade. Average daily gain was numerically improved by shade where shaded cattle gained 3.4 lbs./d while unshaded gained 3.2 lbs./d.