COMPLIANCE INFO_1993-1997 - Laserfiche WebLink

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'.,,. � '"'� � . �.�• �.r HPC; One way of improving control efficiency is Mite inspections were made on birds in by learning when mite populations are the lower deck only. A stratified random beginning to build, and knowing where sample of thirty hens per house was control is necessary. Obviously, this selected to compare differences between would require some method of monitoring cage rows and differences along the length the mite population. of the house. We also wanted to evaluate the relationship between the number of The northern fowl mite life cycle includes birds with mites, and the number of mites five stages: egg, larval, two nymph stages, found on each bird sampled. The mite and adult. The required time from egg infestation on each chicken was assigned a laying to adult is 5 to 7 days; but can be numerical index,based upon the estimated significantly prolonged because certain number of mites she had: 0= no mites stages can survive off the chicken for as observed, 1= 1 to 10 mites, 2= 10 to 50 long as 32 days. The shortest incubation mites, 3= 50 to 100 mites, 4= 100 to 500 and larval periods occur at temperatures mites, 5= 500 to 1,000 mites, 6= 1,000 to around 90 °F, and the lethal temperature 10,000 mites, and 7= more than 10,000 is about 102 °F. Optimum temperature mites. for the mite is thought to be 86 T. It is believed that higher summer temperatures The correlation between the mite index are responsible for the decline in mite (level of individual bird infestation) and the percent of the hens infested was quite populations during that season. , � '"r high (88 percent) and statistically Mites can complete their entire life cycle significant (figure 1). The relationship was on the feathers of birds. They are such that the greater the individual bird however, commonly observed in manure infestation, the higher the percentage of below the cages, in the feed and on cage birds in the house that were infested. This wires. Because some stages of then, suggests that we might be able to development can survive off the chicken predict the average level of infestation for extended periods of time, treatment of from the number of birds sampled that are both the birds and the premises is infested. probably required for complete eradication Evaluating mite populations requires individual bird examination. Mites usually Recently a field study was conducted on a accumulate on the feather shafts about southern California farm which monitored one inch from the skin, and on the skin mite populations in curtain sided open- itself. type lay houses. The cage system was five rows of staggered double deck cages with Most egg producers do not routinely automatic feeders and egg collection belts. monitor mite populations. Instead, they The flock (more than 60,000 hens), was postpone treatment until they receive monitored weekly for nineteen weeks. worker complaints, or they observe mites Stocking density was three to four birds on the eggs. While at times mites will be , . observed on the eggs when the mite per cage population is low, usually their appearance