Design A monitoring study over several years.
Sample population Two budgerigar ( Melopsittacus undulatus ) colonies with over 300 birds each.
Procedure The prevalence of megabacteria in the faeces in two budgerigar breeding colonies, colony 1 and 2, was determined by faecal examination of each bird. Following an initial survey (1990), most of the birds that were scored 2+ or more were culled and a management practice was implemented to discriminate against positive birds. Consecutive yearly surveys (1991, 1992) were conducted on the young birds bred in these colonies. The prevalence of megabacteria in colony 2 was also evaluated in 1994 and 1996 after all the birds were treated with amphotericin B administered in drinking water.
Results The prevalence of megabacteria in the two colonies was significantly (P < 0.001) different. Overall the prevalence of megabacteria adjusted for colony differences was significantly higher (P < 0.025) in males compared to females. Age was not an influencing factor. After the initial survey, the prevalence in the offspring did not significantly (P > 0.05) decrease in the following two annual breeding seasons but by inference it did significantly decrease after amphotericin B treatment.
Conclusion The practice of culling most birds with more megabacteria in faeces and discriminating against positive birds when selecting birds for breeding or culling birds on show quality does not decrease megabacteria prevalence in the offspring. However, a reduction in prevalence does occur with administration of amphotericin B. Birds may have amphotericin B-resistant organisms and these birds need to be identified and culled. 相似文献
Farms Four wool-growing farms in south western Victoria were selected from the clients of the Mackinnon Project, a farm consultancy service run from the University of Melbourne. Each farm had closely followed recommended procedures, kept comprehensive financial and physical records and had been clients for at least 5 years. The comparison group was the South Western Victoria Monitor Farm Project (SWVMFP), about 45 farms in the same region as the study farms that were monitored annually by Agriculture Victoria.
Procedure For a 7-year period, the financial and physical performance of both groups of farms was estimated. Stocking rate, wool production, gross farm income, farm operating costs, net farm income and return on assets were compared.
Results Mean gross farm income of the four study farms steadily rose from 86% of the average SWVMFP farm before the adoption of recommendations to an average of 155%. During the same period, net farm income rose from 70% to 207% of the average of the SWVMFP. Return on asset of the four farms rose irregularly from 26% to 145% of the average of the SWVMFP. Farm operating costs on the four farms were higher than for the SWVMFP group, but the ratio of costs remained relatively constant.
Conclusion The adoption of proven research results was associated with large increases in net farm income. An increase in gross income, rather than a reduction in costs was the main reason for this. Research results offer a way to increase the financial viability of wool-growing farmers, many of whom are currently unable to maintain their lifestyle, resources and infrastructure. 相似文献
The initial voluntary enrolment among the eligible farms was 99%. The median farm size was 1 acre. All the farms kept crossbreed pigs of Large White or Landrace (median nine pigs per farm). The median number of sows per herd was one. Most farmers engaged in farrow-to-finish pig-production system and most (60%) did not keep a breeding boar. The pigs were stall-fed the year round. Guard rails/piglet devices were present in 22% of the herds. Few (8%) farmers disinfected pig pens (especially the farrowing area). None of the farmers reported the use of vaccination against pig diseases. Most farmers (84 and 96%) indicated that they controlled for mange and worm infestations, respectively. To control mange, 50% of the farmers used acaricides, 34% used engine oil and 12% used both. Anthelmintics were used to control worms. No farmer had a particular control programme in place for both worms and mange. Artificial heating for piglets was not used in any of the farms. High costs of feeds (which were of variable qualities) lack of credit and genetically high-quality breeding boars and diseases were ranked highly by the farmers as the main production constraints. Thirteen percent (11/87) of farmers withdrew during the pilot study; 10 farmers had sold their pigs and one had died. Thirty-three percent (25/76) of the farms withdrew during the longitudinal study for various reasons that included death of pigs (3%; 2/76) and sale of the pigs (30%; 23/76)—mainly because of financial need. 相似文献