New Delhi: Heat stress is known to impact cows and affect the quantity of milk they produce, but new research from Cornell University has found that warming temperatures also reduce the fat and protein content in their milk.
The study, titled ‘Milk composition responses amplify economic damages from heat stress’, published in the journal Environmental Research Letters, is one of the largest of its kind. Researchers looked at 6.5 millions cows and 120 millions milk records across 43 US states from 2007 to 2016.
Researchers found that the amount of milk cows produced dropped sharply after heat and humidity crossed a certain threshold. However, what was more surprising is that the composition of milk also began to be negatively impacted at higher temperatures.
“The heat-induced dilution of these valuable milk components is happening a bit under the radar,” senior author Ariel Ortiz-Bobea, associate professor of agricultural economics at Cornell University, said in a university statement.
What makes this study relevant is that farmers in the US are not compensated for milk based on quantity alone—they are compensated for the fat and protein content too. If these components are lower, it reduces the overall yield for farmers.
Researchers found that the reduction of quantity led to a 1.2 per cent lower milk output, but the diluted milk led to a 2.8 per cent lower annual revenue for farmers. As per their calculations, this amounts to a nearly $1.65 billion annual loss for the dairy industry.
What is even more alarming is that so far no research has suggested that cows are becoming heat-resilient. The study saw that cows across ages and regions reacted to heat in a similar manner.
The study also noted that heat could have a significant impact on the quality and not just quantity of other agricultural produce, whether it be major stable crops or other vegetables and fruits.
“A growing set of studies on fruits and vegetables show that extreme weather can also alter quality in meaningful ways. In contrast, we still have very limited large-scale observational evidence on how climate influences the quality of animal products, even though these account for roughly half of the total value of global agricultural output,” the study read.
As temperatures rise, the challenge is not just about producing enough food but also finding ways to preserve its quality.
(Edited by Theres Sudeep)