The structure, dynamics and movement patterns of the Australian sheep industry.

OBJECTIVE: To describe the structure of Australia's sheep industries and the movement of sheep to enable examination of the potential for animal movements to spread disease between farms. PROCEDURE: The structure, size, marketing and movement patterns of Australian sheep farms was determined through (i) review of data published by the Australian Bureau of Statistics and Australian Bureau of Agricultural and Resource Economics, (ii) interviews with producers and saleyard managers and (iii) expert opinion. RESULTS: Twelve geographic regions are described, based on the type and extent of sheep farming in each region. Five production sectors were identified within the Australian sheep industry, with the proportion of each varying between the geographic regions. Over the past 20 years, the industry has decreased in size and contracted from the northern and central areas of Australia. Movement of sheep onto the majority (79%) of properties was limited to the introduction of less than 50 stud rams annually, although cross-bred- and wether-based farms introduced up to 2000 sheep annually; 75% of sheep movements occurred over distances less than 200 km, but stud rams moved up to 500 km. An increasing percentage of movements off farms was direct to abattoirs and over 80% of sheep sold through saleyards were purchased by abattoirs. CONCLUSIONS: The majority of Australian sheep farms operate as self-replacing enterprises and introduce few stock. In addition, most sheep movements occur over distances of less than 200 km and therefore sheep movements within Australia have only a limited potential to spread disease over larger distances.

Psychrotrophic Growth of Microorganisms in a Cultured Milk Product.

Characterization of psychrotrophic bacteria from cultured milk has shown that most (72%) of the psychrotrophs which were isolated originated from the starter culture. Streptococcus lactis subsp. diacetilactis was the most abundant organism and dominated both Streptococcus cremoris and Leuconostoc cremoris , which was the least abundant. The doubling time of S. lactis subsp. diacetilactis at 7 C was 20 h and 54 h in Trypticase Soy Broth at pH 7.0 and 5.0, respectively. This indicates a growth potential which could be significant to the quality of the product over a long storage period. Psychrotrophic coliforms which had optimal growth temperatures within the range of 15 to 30 C could also be found in small numbers. Their survival in the product was limited and it was concluded that they have little effect on shelf-life.