Adjusting Swine Feed Rations Helps Ensure Weight Gains During Hot Weather
As the temperature and humidity increase during the summer, the threat of heat stress to the herd will also increase.
Finishing pigs, boars and sows will experience heat stress at temperatures of 21°C (70°F), and performance will decrease after two to four days of continuous temperature exceeding 80°F (27°C).
Making small changes in rations can help minimize the decrease in average daily earnings; reduce the amount of calories produced when digesting, absorb and assimilate dietary nutrients; and promote the deposition of fat on adipose during summer heat .
Just through food consumption, today's lean, high-muscle pigs will produce a lot of calories. Dr. Lance Baumgard, Professor of Nutritional Physiology at Jacobson Department of Animal Science at Iowa State University, explained: "The increase in feeding calories results in an increase in pig body temperature due to feed digestion.
The combination of elevated ambient temperatures and increased caloric intake will quickly exacerbate the effects of heat stress.
Pigs experiencing heat stress immediately reduce feed consumption and increase water intake, which triggers a series of metabolic events within the animal. Heat stress will not only reduce the average daily weight gain but also produce carcasses with higher fat content.
Encourage feed consumption
Increasing fat content and reducing crude protein and fiber in rations can help reduce calorie production during digestion while boosting feed intake. Increasing the nutrient density of rations also helps to ensure that the demand for vitamins, minerals and trace minerals is met during the reduction in feed consumption.
"Adding supplemental fat to rations can not only increase the density of the diet, it can also reduce the amount of heat that is produced during digestion," said Baumgard. "The increase in fat calories is lower than protein and carbohydrate."
By using synthetic amino acids to reduce the crude protein content by 2%, the negative effects of a decrease in feed intake due to heat stress can be reduced. "Excessive dietary crude protein costs energy to remove excess nitrogen and generate extra calories in the process," he explained.
Another dietary adjustment that affects heat production is reducing fiber levels. "Fibers are responsible for the largest incremental calorie production in the diet," added Baumgard.
Changing the physical properties of the feed by adding water or using a liquid feeding system can promote consumption in hot weather.
Under heat stress, daily water usage can increase by 6 times the normal amount - up to 30 gallons per day per finishing pig. All animals must use good quality water around the clock, with no more than 12 to 15 pigs per nipple or in the finishing barn.