Heat stress impacts milk production in Maharashtra’s dairy cattle

Sunil Patil, a farmer from Chikhali, a village in Maharashtra’s Kolhapur has three buffaloes and seven cows, producing an average of 100 litres of milk per day. However, since 2018, Sunil has reported a decline in production, down to 75 to 80 litres per day during the summers from March to June. Heat stress is suspected to be the cause. His attempts to cool them down are resource-intensive: they are bathed twice daily and kept under fans. During the summers they are fed dry fodder. This is another reason attributed to low milk production. Green fodder promotes better health in cattle, and in turn, better milk. But it is expensive in the summer months and Patil feeds it to his cattle only when he can afford it.

Around two crore (20 million) farmers from over two lakh (2,00,000) villages across the country engage in the dairy industry, with at least six lakh (6,00,000) milk producers depending solely on the industry for a livelihood. A majority of them are women, according to the National Dairy Development Board (NDDB). A Lancet study finds that increasing temperatures could reduce milk production by 25% by 2085 in India’s arid to semi-arid areas.

A recent review study found that rising ambient temperature and humidity affect dairy cows’ body temperature and feed intake, and thus milk output and reproduction. Heat stress varies with breeds, individuals of a breed, and management approaches. Some of these approaches that are relevant to heat stress are open cattle shed practices that help lower the body temperature of cows and let them roam around the shed freely and consume adequate water.

Relying only on the Temperature Humidity Index (THI), a practical indicator for the degree of stress on dairy cattle caused by both temperature and relative humidity doesn’t give an accurate picture of heat stress on dairy cows. A comprehensive assessment of environmental indices and physiological parameters is crucial. The development of technologies to monitor the body temperatures of cows is aiding in evaluating heat stress more closely by combining THI and other relevant aspects.

Another study published by the National Dairy Research Centre in Karnal, Haryana, predicts that in Punjab, Haryana and western Uttar Pradesh, milk production losses owing to heat stress are expected to rise to 3,39,000 tonnes during this decade (2020-29), and 6,29,000 tonnes during the next (2030-39). Considering that milk is currently priced at Rs. 45 per litre, this means milk producers could suffer a loss of Rs 15.25 billion in 2020-29 and approximately Rs. 28.30 billion in the next decade. Research also shows that heat stress adversely impacts feed intake, milk yield, follicular development, and reproduction capacities of dairy cows.

Sharad Patil, a milk producer in Ambewadi has nine cows of the Holstein Friesian breed. “I get an average of 80 to 90 litres per day. But in the summers, we face a loss in milk production of 20%. Cows need to be medicated frequently. I installed an open shed, bathe them twice a day, and feed them green fodder and tonic. We have been facing these issues since 2017. Veterinary doctors advised us to use fans, but there is no regular electricity, and we can’t afford the bills.”

Ajit Yashwant, another milk producer from Prayag has four cows that produce a total of 50 litres each day. “During summers, we see a decline of up to to 40 litres. We are helpless to see our cattle struggling with the rising temperature. We humans can complain, but animals cannot. So we are taking care of them as much as possible.”

Anil Amble, secretary of Mahalaxmi Cooperative Dairy (MCD) in Chikhali also mentions that MCD often observes a drop in milk production during the summer. During this time, to meet annual targets, additional milk is collected from migrating sugarcane cutters who travel with their cattle.

Vishwas Patil, Chairman of Gokul or Kolhapur District Cooperative Milk Producers Union Ltd, says, “We are facing an annual loss of 11% in milk collection owing to heat stress in cows, according to the NDDB report for the year 2020-2021. The decline in milk collection can be seen from March to September. We are trying to help farmers to keep their livestock healthier to mitigate the gap in milk production.”

Gokul is one of the largest milk processors in Maharashtra, having processed 476 million litres last year. “Milk producers are forced to manage expenses for temperature maintenance, medication, and green fodder. This is resulting in reduced production and ultimately increase in prices.” Gokul has approximately 6,000 cooperative dairy societies with 8.53 lakh (8,53,000) cattle of which 2.54 lakh (2,54,000) are cows, and the remaining are buffaloes.

Mumbai Fresh Milk Association recently declared a 10% hike in loose milk. The new rates from September 1, 2022 are around Rs. 89 per litre. Patil brought up the issue of declining milk collection caused by heat stress in a meeting organised by Gokul and told Mongabay-India that Gokul is considering ayurvedic supplements to enhance livestock health on hot days.

U.V. Mogale, veterinary head at Gokul, said that many symptoms of heat stress are quite visible, like reduction or loss of lactation and increased frequency of contracting illnesses. “We often see cattle stop feeding, panting uncomfortably and having low metabolism, which leads to malnutrition and lowered milk production. When their body temperatures cross 37 degrees Celsius, cattle use much of their energy attempting to reduce it and dangerously slow down their other important bodily functions. We are providing optimum guidelines and aid to farmers coping with these new issues,” Mogale said.

Gokul advises farmers to take precautionary steps to prevent heat stress in cows. They include the installation of water systems, fans, or other animal cooling systems in cattle sheds, planting trees around the area, and silage pits and bags to keep fodder green for longer periods of time.

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Banner image: Sunil Patil mixes cattle feed. Heat stress has resulted in low milk production. Patil worries about the rise in prices of cattle feed. Photo by Abhijeet Gurjar/Mongabay.