Characterization of heat waves affecting mortality rates of broilers between 29 days and market age

Abstract

Climate may affect broiler production, especially where there are heat waves, which may cause high mortality rates due to the heat stress. Heat wave prediction and characterization may allow early mitigation actions to be taken. Data Mining is one of the tools used for such a characterization, particularly when a large number of variables is involved. The objective of this study was to classify heat waves that promote broiler chicken mortality in poultry houses equipped with minimal environmental control. A single day of heat, a heat-shock day, is capable of producing high broiler mortality. In poultry houses equipped with fans and evaporative cooling, the characterization of heat waves affecting broiler mortality between 29 days of age and market age presented 89.34% Model Accuracy and 0.73 Class Precision for high mortality. There was no influence on high mortality (HM) of birds between 29 and 31 days of age. Maximum temperature humidity index (THI) above 30.6 ºC was the main characteristic of days when there was a heat wave, causing high mortality in broilers older than 31 days. The high mortality of broilers between 31 and 40 days of age occurred when maximum THI was above 30.6 ºC and maximum temperature of the day was above 34.4 ºC. There were two main causes of high mortality of broilers older than 40 days: 1) maximum THI above 30.6 ºC and minimum THI equal or lower than 15.5 ºC; 2) maximum THI above 30.6 ºC, minimum THI lower than 15.5 ºC, and the time of maximum temperature later than 15:00h. The heat wave influence on broiler mortality lasted an average of 2.7 days

Effect of a simulated heat wave in thermal and aerial environment broiler-rearing environment

“…This condition was observed by VALE et al The raise of ammonia concentrations observed in this experiment added to a low thermoregulatory capacity of the birds when exposed to high levels of ammonia may represent a synergistic factor that intensify the effect of environment temperature on the high mortality during these heat waves, as reported by VALE et al (2010).…”

“…Besides the temperature rising associated with the ammonia increasing (Figure 2), the lower oxygen availability during the hottest period of the day may justify the higher mortality within heat wave events as already highlighted by VALE et al (2010) or even give reasonable explanations for the lowest performance of the animals.…”

Cloacal temperature responses of broiler chickens administered with betaine and ascorbic acid during the hot-dry season

“…In the present study, recordings were made on days 28, 35 and 42, when the birds were most susceptible to heat stress. After 28 days of age, heat stress leads to mortality rates up to 89.34% (Vale et al 2010), and this susceptibility persists until the birds attain market age (Chepete et al 2005). The results indicate that the environmental conditions prevailing during the hot-dry season were unfavourable for the rearing of broiler chickens, and might induce heat stress.…”

Response to withdrawal of vitamin and trace mineral premixes from finisher diet in broiler chickens under the hot and humid tropical condition

“…The relatively higher mortality rates noted in this study could be attributed to the hot and humid environment, as the birds were raised in a naturallyventilated house. The detrimental effect of heat stress on broiler chickens particularly at market age is well established (Vale et al 2010).…”