A USDA webinar during July reemphasized a message that pork producers have known for a while: heat stress can be detrimental to the wellbeing of their livestock. Jay Johnson, a research animal scientist dedicated to livestock behavior research, listed numerous different production losses that rising global temperatures will create for the industry:
How can the pork industry respond? By helping pigs build up their heat resilience.
In some trials, producers are seeing a positive impact on the resilience of their animals at the gut level, especially when they use Ascophyllum nodosum as part of those swine health management strategies. Before you make a choice, here’s why you can overcome heat stress in pigs with the right diet and how brown seaweed supplements can help you stay profitable in the sweltering summer months.
Since pigs have few functional sweat glands, they are particularly susceptible to spikes in ambient heat. Part of the reason they have less voluntary intake during hot weather is because the fermentation of digestion, especially at normal speeds, can increase their already precarious body temperature.
That’s only part of the issue. When a pig experiences heat stress, their bodies tend to dissipate the heat by increasing blood flow to the periphery (think skin) and away from internal organs. This limits the amount of oxygen and nutrients making it into the GI tract, which causes villi—little fingerlike projections in the small intestines that move nutrients into the bloodstream—to shrink. In turn, these pigs suffer from what is called hypoxia, as well as a lack of nutrients absorption which hinders their growth.
The resumption of blood circulation again isn’t all good either. Pigs can suffer from reoxygenation when hypoxic tissue encounters free radicals, damaging intestinal tissue and making it more permeable. When the GI tract is more permeable, more nutrients are excreted out without being absorbed. Plus, more endotoxins, toxins released when bacteria cells disintegrate, pass through the usual defensive barriers of tight junctions. As a result, producers waste more feed to achieve the same results, and pigs are vulnerable to prolonged health issues or premature mortality.
Feed ingredients and supplements can help in two critical ways. One, the right swine feed ingredients can provide pigs with antioxidants, which helps to reduce the impact of free radicals and keep cells intact. Two, they can provide pigs with dietary fiber, which feeds beneficial microbes that can act as both a net positive for their immune system and an increase in the speed and efficiency of digestion.
Supplements which include Ascophyllum nodosum seaweed can achieve both benefits. They’re rich in polyphenols which fight inflammation and free radicals as well as containing plenty of prebiotics, the dietary fiber that probiotic gut microbes need to thrive. In theory, these all-natural supplements are a great way to offset some of the worst outcomes of heat stress. But what are they like in practice?
In 2005, we collaborated with farmers in central Iowa to demonstrate the viability of using seaweed to help 1,158 finisher pigs overcome heat stress with the right feed supplement. The year before, these farmers had lost 8.61% of their 1,278 pigs during higher summer temperatures, and they wanted to determine whether our seaweed could help them reduce heat stress and maintain overall performance.
The farmers were already using curtain-sided housing to effectively push warmer stagnant air away from their livestock. Now, they would elevate their response by adding about five pounds of Tasco® seaweed feed to one ton of traditional corn and soy feed rations (a 0.25% inclusion rate). Average daily gains, feed conversion, and death loss of pigs were recorded to determine the impact of our organic swine feed supplement. The results surpassed their expectations.
At the end of the demonstration, the Tasco® fed pigs had an average daily gain of 1.61 pounds compared to 1.53 pounds the year before. Thanks to the increased probiotic activity, the Tasco® fed group was much better at converting the nutrients in their feed into energy and weight gain. Typically, as animals add mass, they lose their thermal resilience (due to their increased surface area), but that wasn’t the case with the seaweed fed pigs.
From June to October of that year, the heat exceeded that of the year before. However, the trail group of pigs only had a death loss percentage of 4.66%, helping producers elevate their cost efficiency.
How did that shake out for these farmers? In 2005, pork prices during the fall and winter were lower per carcass than 2004, so pork producers needed every extra animal they could bring to market. If the death loss percentage had remained the same (it likely would have gone up in a hotter year), they would have likely had a minimum of 46 fewer pigs to sell if they hadn’t used seaweed feed.