MANILA — Extreme heat, which is expected to exceed dangerous levels in the Philippines in May, is not only exacting a heavy toll on humans, but on animals as well.
Based on the study “Effects of Heat Stress on Animal Physiology, Metabolism, and Meat Quality: A Review” in Science Direct, “heat stress is one of the most stressful events in the life of livestock with harmful consequences for animal health, productivity and product quality”.
The study, written by Paula Gonzales-Rivas, Surinder Chauhan, Minh Ha, Narelle Fegan, Fran Dunshea, and Robyn Warner, said that ruminants, pigs and poultry are susceptible to heat stress because of their fast metabolic rate and growth.
Even their high level of production and species-specific characteristics such as rumen fermentation, sweating impairment, and skin insulation are factors to consider, too.
Last week, the president of the Philippine Egg Board Association, Mr Francis Uyehara, told Teleradyo Serbisyo that “farm producers are already experiencing problems because of the extreme heat”, pointing out that egg production is affected as a result of feed-intake reduction.
The problem, he said, is that eggs are getting smaller.
According to the study “Impact of Heat Stress on Poultry Production” that was published by the US National Center for Biotechnology Information, a 12-day heat stress period caused a daily feed intake reduction of 28.58g per bird, resulting in a 28.8 per cent decrease in egg production.
The researchers, Lucas Lara and Marcos Rostango, referring to previous studies, said that a 31 per cent decrease in feed conversion resulted in a 36.4 per cent and 3.41 per cent decrease in egg production and egg weight, respectively.
Even eggshell thickness is affected by extreme heat.
As for meat, the study “Effects of Heat Stress on Animal Physiology, Metabolism, and Meat Quality: A Review” stated that acute heat stress immediately before slaughter can result in pale, soft and exudative meat characterised by low water holding capacity.
Chronic heat stress, meanwhile, can result in dark, firm and dry meat. Heat stress likewise leads to oxidative stress, lipid and protein oxidation, and reduced shelf life and food safety because of bacterial growth and shedding.
Based on the government’s 2023 El Nino National Action Plan, the phenomenon can cause a wide range of consequences on agriculture such as a decline in food production, increase in food prices, and drop in farm incomes.
As the Department of Agriculture stated in its bulletin as at April 16, losses and damage to agriculture have already reached 4 billion peso (S$94 million), including 6.95 million peso in livestock and poultry sectors.
Based on data from Veterinaria Digital and the US Department of Agriculture, which was compiled by wellness brand Dr. Shiba, in the US, heat stress generates a 0.5 per cent to 7.2 per cent decrease in egg production and costs the dairy industry US$1.2 billion (S$1.6 billion) yearly.
‘Look out for signs’
As Dr. Shiba said, considering how heat indices often exceed safe thresholds, it would be significant to shed light on the effects of extreme heat on critters, who are really defenceless against heat waves.
Dr Glenn Albert Almera, founder of Pet Partner Philippines Inc, told Inquirer.net on April 22 that heat stress in animals is seen in different casts, depending on the stage of stress.
“Initially, it can be seen with increased salivation and faster breathing, and as it progresses with no medical intervention, animals become lethargic and immobile. They can vomit, as well, and in extreme cases, animals experiencing heat stress can have a seizure attack,” he said.
Based on the Australian government website Agriculture Victoria, increased respiration rate, loss of appetite, increased water intake, and loss of consciousness are signs of heat stress in animals, too.
It was stated in the study by Rivas R. et al that pigs and poultry are specifically prone to heat stress because of the lack of functional sweat glands and skin insulation provided by the subcutaneous fat in pigs and by feathers in birds.
However, Dr Almera said other animals are vulnerable, too, with amphibians and reptiles considered to be at greatest risk.
“But if we are to focus on small animals such as dogs and cats, old, thick coated and short nose breeds are the most vulnerable to extreme heat,” he said.
This, as “old pets have less capability to thermoregulate, while thick coated breeds collect more heat but have less capability to remove them from the body”, he said. Short nose breeds, meanwhile, are prone to some breathing problems when having heat stress.
‘Keep them safe’
For Dr Almera, it is important to keep animals hydrated, saying that water should always be available and that exercises should be minimised, especially when it is already beyond 8am.
He said animals should be kept cool, as well, by placing them in a well-ventilated area throughout the day.
“Keep their fur short and clean, too,” he said, as he stressed the need for caretakers to always be on the lookout for signs of heat stress and heat stroke.
As the Philippine Atmospheric, Geophysical and Astronomical Services Administration (Pagasa) said, temperatures could reach over 40 deg C in the coming weeks, or next month.
That would usually translate to heat indices of plus two to three deg C so when the temperature reading is 40, the usual heat index is between 40 deg C and 43 deg C.
Likewise, as weather specialist Dr John Manalo told GMA Integrated News, some areas in the Philippines may hit extreme danger levels, or temperatures at 52 deg C or higher, in May.
“Based on Pagasa’s ongoing monitoring of the discomfort index or heat index, there is a possibility that some areas in the country will experience levels of extreme danger, which is 52 deg C or higher,” said Ms Ana Liza Solis, officer in charge of Pagasa’s climatology and agrometeorology division.
“With this heat level, heatstroke is imminent or probable (for) people who are directly exposed to sunlight, which is why we need to take precautions,” she said. PHILIPPINE DAILY INQUIRER/ASIA NEWS NETWORK
