Estimating mortality in laying hens as the environmental temperature increases

Abstract

Layer mortality due to heat stress is an important economic loss for the producer. The aim of this study was to determine the mortality pattern of layers reared in the region of Bastos, SP, Brazil, according to external environment and bird age. Data mining technique were used based on monthly mortality records of hens in production, 135 poultry houses, from January 2004 to August 2008. The external environment was characterized according maximum and minimum temperatures, obtained monthly at the meteorological station CATI in the city of Tupã, SP, Brazil. Mortality was classified as normal (≤ 1.2%) or high (> 1.2%), considering the mortality limits mentioned in literature. Data mining technique produced a decision tree with nine levels and 23 leaves, with 62.6% of overall accuracy. The hit rate for the High class was 64.1% and 59.9% for Normal class. The decision tree allowed finding a pattern in the mortality data, generating a model for estimating mortality based on the thermal environment and bird age.

Technical Feasibility of the Acclimatization System in Aviary of Posture: A Case Study

“…The previous day when there were several interruptions in the electricity supply was recorded in the shed maximum BGHI of 86.31. The ability to acclimatization laying hens at high temperatures is obtained after 7 days of exposure to heat (Sylkes & Fataftah, 1986;Yahav, 2009), a fact observed by Pereira et al (2010) which verified a higher mortality rate in aviaries in Bastos-SP from September to October, months in which occur the first heat waves in relation to December and January, when is recorded the highest temperatures. The hens in the acclimatized shed were not acclimatized to high temperatures when power supply failures occurred, so mortality was well above the lineage standard.…”

Effect of Dietary β-Mannanase Supplementation and Palm Kernel Meal Inclusion on Laying Performance and Egg Quality in 73 Weeks Old Hens

“…Recently, the profit of egg production against the cost of feed became even worse due to the price hike of feed ingredients. The decrease in feed consumption and following decline in egg production in old aged hens could be attributed to the decreased metabolic rate in the old aged hens compare to young hens (Lin et al, 2006;Pereira et al, 2010). To recover the disadvantage of old aged hens, producers have sought the ways to reduce feed cost as well as to enhance metabolic efficiency in the old aged hens.…”

Climate Change in Layer Poultry Farming: Impact of Heat Waves in Region of Bastos, Brazil

“…Yet, in relation to the annual production period, considerable increases in temperature values have been recorded in August and September, during the winter. Pereira et al (2010) observed that the mortality rate of broiler breeders during this period was significantly higher compared with the other months. It is very likely that the hens will be strongly affected by these higher temperatures, as they have not yet acclimated to higher temperatures of the hottest months of spring and summer (Sykes & Fataftah, 1986;Yahav & McMurtry, 2001;Pereira et al 2010).…”