SURVEY ON THE RELATIONSHIP BETWEEN ENVIRONMENTAL FACTORS AND EGG QUALITY IN FOUR GEOGRAPHIC AREAS OF BRITISH COLUMBIA DIFFERING IN POPULATION DENSITY OF POULTRY

Abstract

Egg quality in British Columbia has been below the Canadian average for a number of years. A study, using regression procedures, on the relationship between 17 environmental factors calculated on a weekly basis and weekly grading station reports (proportion of grades A, B, C and cracks) was conducted using 1968 and 1969 data. It was concluded that there was very little relationship within a geographic area between the environmental factors and egg quality as determined in this study. Also, an analysis of variance was performed on the proportion of each grade to determine the effect of geographic area (Vancouver Island, Fraser Valley, Southern Interior, Central Interior), volume of eggs handled by a grading station, grading station, season and year and their interactions on egg quality. It was found, particularly with respect to the proportion of Grade A and cracks, that geographic area was the most important main effect, and grading station was the next most important. The Fraser Valley, which had the poorest egg quality, also had a very high population density of chickens. Therefore, it was hypothesized that population density may be associated with higher levels of disease, which would have deleterious effects on egg quality.