Extreme temperature events are becoming more and more frequent because of climate change, and this increases the likelihood of heat stress. Summer heat poses a challenge to all Hungarian pig farms, independent of housing conditions or genetics. Besides farm management strategies, feeding strategies adapted to extreme conditions are also of major importance. To maintain production results and reproductive parameters the problems have to be approached in a complex manner.
The effects of heat stress in different age groups
Hybrid pig breeds reared under intensive conditions are more susceptible to environmental changes and can only perform according to their genetic potential under thermoneutral conditions. The adaptation to unfavourable conditions is energy demanding and as a consequence leads to lower levels of production (Babinszky, 2014).
Figure 1. Optimum temperatures for farm animals, based on NRC (1981)
The animal’s body counteracts the negative effects of heat stress by increasing heat loss and decreasing heat production. Pigs have a limited ability to reduce body heat, as they have a small number of functioning sweat glands to facilitate heat loss by evaporation. They loose heat by increasing respiratory frequency (from the normal 15-25/minute to 50-60/minute) and by lying on the cool floor.
An animal produces heat mainly by movement, digestion and metabolism. The animals try to minimise heat production due to digestion by decreasing the amount of feed they eat, decreasing feed intake and increasing water intake in summer.
Thermoneutral zones differ according to species and the age of the animals. In lactating sows a temperature above 25 °C implies heat stress. Heat stress leads to decreased feed intake, which causes a drop in milk production and results in lower quality weaned piglets and the deterioration of the health status of the herd. The low milk intake will drive the piglets to drink the urine of the sow, which leads to bacterial diarrhoea, with further negative effects on water and electrolyte balance. Loss of appetite may lead to a critical loss of back fat in the sows (over 4 mm), while the appearance of shoulder ulcers may lead to early weaning of the piglets.
Heat stress in boars will lead to the deterioration of fertility, the animals will produce less semen and the number of abnormal sperm cells will increase. These changes can be observed as soon as the temperature exceeds 29.5 °C for at least 72 hours.
Temperatures above 28 °C may lead to cardiovascular problems in fatteners above 80 kg, especially if relative humidity is also very high.
Heat stress abatement with the products of Bonafarm-Bábolna Takarmány
Optimising feed formulations can help achieve the best possible performance and health status in pigs during heat stress. Summer formulations generally contain nutrients in a more concentrated form, a large portion of the energy content is provided by fat supplementation. In this period it is important to adapt crude protein levels to feed intake, in order to fulfil the nutritional requirements of the pigs while maintaining the optimal amino acid to energy ratio. Regarding specific ingredients, the quantity of fibre sources should be reviewed as well, since their digestion is accompanied by substantial heat production. It is very important to use NSP enzymes in summer to improve the efficiency of fibre digestion. Bonafarm-Bábolna Takarmány Ltd. has developed special feed additives for summer that help counteract the effects of heat stress and contain high amounts of betaine and other vitamins with antioxidant characteristics that improve heat tolerance in animals. The deterioration of production parameters due to heat stress can be prevented by using feed supplemented with these summer additives.
Our Platino Milk+ product can be used in case of decreased milk production and contains vitamin C, probiotics and immunoglobulins. It dissolves and mixes easily to enhance availability. In case of increased urine production we recommend the product Cremolit elektrolitpótló to replenish lost electrolytes and prevent dehydration. This product is optimally formulated to contain not only the necessary electrolytes but also easily absorbable sources of energy. Its probiotics help restore the gut microflora, while its vitamin and organic microelement content provides support for the immune system.
What else can we do?
Besides adapting the ingredients and the nutritional content of the feed it is of utmost importance to provide good quality drinking water in optimum amounts. The animals may drink up to six times as much water as they normally would when environmental temperatures are high. Drinkers must be checked regularly to insure that they are operating properly and water flow is adequate. It is also important to feed the animals in the cooler periods of the day!
If possible, space allowance should be increased during heat stress periods. The use of fogging systems and ventilation also have a major impact on the thermal comfort of pigs.
In heat stress periods our main goal is to maintain production despite high environmental temperatures. By improving management technologies, adapting nutritional concepts to the conditions and using summer additives we can make the heat less of a challenge for our sows.
Tamás Gurmai
consultant
Bonafarm-Bábolna Takarmány Ltd.
