Student Competition : Management and Production I 28 Effects of atmospheric pressure change on broiler breeder egg production

Atmospheric pressure (barometric pressure) is the pressure exerted by the earth’s atmosphere at a given location due to the mass of the atmospheric column above . Atmospheric pressure is often used to predict patterns and changes in weather. Atmospheric pressure influences many behavioral and physiologic aspects of living organisms. As such this field study was conducted to determine the effects of atmospheric pressure changes on broiler breeder egg production . All data were collected from a single broiler breeder farm in Arkansas by the farm manager . The objective of the study focused on effects of the direction of pressure change rather than the numerical measurement of pressure . Data were collected from 2 back-to-back broiler breeder flocks raised in the same house. Date, egg count, and direction of atmospheric pressure change were recorded daily . The daily atmospheric pressure change was categorized as one of the following: steady, rising, falling, fluctuating. Because egg production naturally increases to a peak then decreases over the life of a breeder flock because of age, the data were normalized by taking the average egg count (calculated in 2 week intervals) . This average was then compared with each day within the timeframe and its associated atmospheric pressure change category to find a percentage difference. All calculated differences from the same categorized atmospheric pressure change were then combined and compared with the other categories . Statistical analysis was carried out by ANOVA in SAS and means were compared using Tukey’s Studentized Range (HSD) Test . Overall there were 1 .48% more eggs produced on days with steady pressure compared with the 2 week averages, 1 .74% less on falling days, 1 .35% less on rising days, 2.45% less on fluctuating days. This evidence suggests that atmospheric pressure changes do effect egg production of broiler breeders . It can also be concluded from this study that the breeder hens did lay more eggs on days with steady atmospheric pressure compared with days with any direction of change in pressure or fluctuation (P < 0.0001). There is no significant difference in egg production between days of fluctuating, increasing, or decreasing pressure changes.