PROFILE
Bruno Silva, PhD, aged 38, has been professor and researcher in swine nutrition and environmental adap- tation at the Universidade Federal de Minas Gerais (UFMG/ICA), Brazil since December 2012. Prior to that, he was a researcher and a nutrition- ist for – then called – Topigs, as from 2008, giving support to the Amer- icas as well as Spain and Portugal. He did his undergraduate in Animal Science in Brazil at the Universi- dade Federal de Viçosa, in Minas Gerais, where he also obtained his PhD, in cooperation with French National Institute for Agricultural Research (INRA), which also has a research centre on environmental adaptation in the Caribbean island of Guadeloupe.
a different temperature. This environmental gradient will allow a normal heat flow from the pig’s body to the environment. Its sec- ond option would be using the respiratory frequency as its main mechanism to dissipate heat.”
Panting is not a permanent solution. “The problem with that is that it generates heat too. So a higher activation of the lung functioning – the lungs are muscles in the end – increase endogenous heat production. This means that if the animal is maintained under heat stress conditions for a long period or when the temperature rises even more, there’s a risk that the animal will overheat and this will bring the animal to death via hyperthermia. It is very common in Brazil. Lactating sows of some genetic lines can have up to 15% mortality during Brazilian summers due to heat stress conditions.”
Which of your focus areas is more important for sows to relieve heat stress – nutrition or environmental adaptation? “Changing the environment is much more effective. Pigs have a very limited thermoregulatory system. In other words, they have a hard time losing heat to the environment. Nutrition comes as an alternative to alleviate the negative impacts of heat stress on pigs.”
What kind of environmental solutions are you thinking of? “In my opinion, localised cooling systems are more effective than changing the macro-climate of the barn. After all, cooling down the whole barn, using evaporative cooling systems, could create a stressful situation for the piglets. Floor cooling systems in this
sense are a good example – they give direct contact and are the most effective one; others include snout cooling systems and drip loss cooling systems. “One other very interesting solution is cooling the drinking water. Only one research has been done in the past with this, for sows, and it showed to be very effective. We recently developed a drink- ing water cooling system which we will start evaluating this sum- mer in Brazil. Initial pilot studies indicated an improvement of 700 g of feed intake per day per sow – a 20% increase in feed intake. It shows there is a good opportunity in systems like this under heat stress conditions.”
How about nutritional solutions? “Our research indicates that under heat stress animals need a different profile of vitamins, minerals and amino acids. Amino acids like arginine, leucine and threonine are highly relevant for maintaining the integrity of the intestinal tract. “In addition, when applying nutritional strategies one has to consider the ‘thermal effect of feed’. This includes reducing fi- bres and crude proteins, because they generate a lot of heat. So all in all, by reducing the crude protein content of diets and by supplementing industrial amino acids it is possible to yield a better performance.” “We also could work out strategies to improve digestibility. During heat stress sows will reduce milk production. One of the things we looked at is whether we can change the milk compo- sition. So piglets might get less milk, but if it is more concentrat- ed, this can help them keep up performance. In the past three years, we have tested to improve the composition of the milk
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