Evaluation of Inoculated Lablab Silage for Growing Dairy Heifers

A summer grown forage legume crop – Lablab (Lablab purpureus) harvested in autumn, was ensiled as plastic wrapped, large round bales. Of the 30 bales produced, 13 were inoculated with a bacterial inoculant containing Lactobacillus plantarum and Enterococcus faecium. Inoculant was premixed at 30 g/litre water, cultured overnight (18 hours) then sprayed onto cut forage during the baling and wrapping procedure at 1 litre per tonne of silage. A replicated feeding experiment was conducted in July - August 1998 (5 weeks), using 24 eight month old Holstein Friesian heifers group fed non-inoculated or inoculated silage to appetite plus 2 kg rolled sorghum grain/heifer.day. Chemical composition and nutritive value of well preserved bales of control and inoculated silages were similar (P>0.05) with 50% DM and 26 g N and 6.8 MJ ME per kg DM. Lactic acid and acetic acid concentrations were 11.4 v. 11.4 and 4.90 v. 3.75 g/kg DM for control and inoculated silages respectively (P>0.05). Heifers preferentially selected leaf from the silage offered and maintained liveweight gains of 0.70 and 0.61 kg/day respectively (P>0.05) during the silage feeding period. High DM and low WSC content of the parent forage may have reduced the opportunity for the bacterial inoculant to have effect. Animal production for a consuming world : proceedings of 9th Congress of the Asian-Australasian Association of Animal Production Societies [AAAP] and 23rd Biennial Conference of the Australian Society of Animal Production [ASAP] and 17th Annual Symposium of the University of Sydney, Dairy Research Foundation, [DRF]. 2-7 July 2000, Sydney, Australia.

Prevalence, persistence and control of Salmonella and Listeria in shrimp and shrimp products: A review.

Shrimp are an important commodity in the international fisheries trade and there is an indication of an increase in worldwide consumption of this crustacean. Salmonella and Listeria have been isolated from shrimps and shrimp products on a regular basis since the 1980s. The continued reporting of the presence of these pathogens in fresh and frozen shrimps, and even in the lightly preserved and ready-to-eat products, indicates that the existing practices used by the manufacturers or processors are insufficient to eliminate these pathogens. This paper reviews the information available on Salmonella and Listeria in shrimp and makes recommendations on control options and avenues for future research in order to improve shrimp safety and quality.

Development of profitable milk production systems for northern Australia: a field assessment of the productivity of five potential farming systems using farmlets.

Farmlets, each of 20 cows, were established to field test five milk production systems and provide a learning platform for farmers and researchers in a subtropical environment. The systems were developed through desktop modelling and industry consultation in response to the need for substantial increases in farm milk production following deregulation of the industry. Four of the systems were based on grazing and the continued use of existing farmland resource bases, whereas the fifth comprised a feedlot and associated forage base developed as a greenfield site. The field evaluation was conducted over 4 years under more adverse environmental conditions than anticipated with below average rainfall and restrictions on irrigation. For the grazed systems, mean annual milk yield per cow ranged from 6330 kg/year (1.9 cows/ha) for a herd based on rain-grown tropical pastures to 7617 kg/year (3.0 cows/ha) where animals were based on temperate and tropical irrigated forages. For the feedlot herd, production of 9460 kg/cow.year (4.3 cows/ha of forage base) was achieved. For all herds, the level of production achieved required annual inputs of concentrates of similar to 3 t DM/animal and purchased conserved fodder from 0.3 to 1.5 t DM/animal. This level of supplementary feeding made a major contribution to total farm nutrient inputs, contributing 50% or more of the nitrogen, phosphorus and potassium entering the farming system, and presents challenges to the management of manure and urine that results from the higher stocking rates enabled. Mean annual milk production for the five systems ranged from 88 to 105% of that predicted by the desktop modelling. This level of agreement for the grazed systems was achieved with minimal overall change in predicted feed inputs; however, the feedlot system required a substantial increase in inputs over those predicted. Reproductive performance for all systems was poorer than anticipated, particularly over the summer mating period. We conclude that the desktop model, developed as a rapid response to assist farmers modify their current farming systems, provided a reasonable prediction of inputs required and milk production. Further model development would need to consider more closely climate variability, the limitations summer temperatures place on reproductive success and the feed requirements of feedlot herds.

Classical Biological Control for the Protection of Natural Ecosystems.

Of the 70 cases of classical biological control for the protection of nature found in our review, there were fewer projects against insect targets (21) than against invasive plants (49), in part, because many insect biological control projects were carried out against agricultural pests, while nearly all projects against plants targeted invasive plants in natural ecosystems. Of 21 insect projects, 81% (17) provided benefits to protection of biodiversity, while 48% (10) protected products harvested from natural systems, and 5% (1) preserved ecosystem services, with many projects contributing to more than one goal. In contrast, of the 49 projects against invasive plants, 98% (48) provided benefits to protection of biodiversity, while 47% (23) protected products, and 25% (12) preserved ecosystem services, again with many projects contributing to several goals. We classified projects into complete control (pest generally no longer important), partial control (control in some areas but not others), and "in progress," for projects in development for which outcomes do not yet exist. For insects, of the 21 projects discussed, 59% (13) achieved complete control of the target pest, 18% (4) provided partial control, and 41% (9) are still in progress. By comparison, of the 49 invasive plant projects considered, 27% (13) achieved complete control, while 33% (16) provided partial control, and 47% (24) are still in progress. For both categories of pests, some projects' success ratings were scored twice when results varied by region. We found approximately twice as many projects directed against invasive plants than insects and that protection of biodiversity was the most frequent benefit of both insect and plant projects. Ecosystem service protection was provided in the fewest cases by either insect or plant biological control agents, but was more likely to be provided by projects directed against invasive plants, likely because of the strong effects plants exert on landscapes. Rates of complete success appeared to be higher for insect than plant targets (59% vs 27%), perhaps because most often herbivores gradually weaken, rather than outright kill, their hosts, which is not the case for natural enemies directed against pest insects. For both insect and plant biological control, nearly half of all projects reviewed were listed as currently in progress, suggesting that the use of biological control for the protection of wildlands is currently very active.

Improvement and Maintenance of Turf Demonstration Plots

DEEDI have built and maintained a living library of turf grass selections of 138 different turf cultivars. Material is also preserved in tubs in a protected growing environment. The maintenance and ongoing upgrading of these plots requires significant resources to maintain their integrity. As the plots have been in place since 2000, they are currently in need of significant repair. This project will assist in the improvement and maintenance of the turf library for the benefit of the turf industry producers and Australian turf research more generally.

Preservation of encapsulated shoot tips and nodes of the tropical hardwoods Corymbia torelliana × C. citriodora and Khaya senegalensis

Alginate encapsulation is a simple and cost-effective technique to preserve plant germplasm but there are only a few reports available on preservation of encapsulated explants of two highly valuable groups of tropical trees, the eucalypts (Myrtaceae) and mahoganies (Meliaceae). This study investigated alginate encapsulation for preservation of the eucalypt hybrid, Corymbia torelliana × C. citriodora, and the African mahogany, Khaya senegalensis. We assessed shoot regrowth of encapsulated shoot tips and nodes after storage for 0, 3, 6 and 12 months on media varying in sucrose and nutrient content, under storage conditions of 14°C and zero-irradiance. Encapsulated explants of both trees were preserved most effectively on high-nutrient (half-strength Murashige and Skoog) medium containing 1% sucrose, which provided very high frequencies of shoot regrowth (92–100% for Corymbia and 71–98% for Khaya) and excellent shoot development after 12 months’ storage. This technique provides an extremely efficient means for storage and exchange of eucalypts and mahoganies, ideally suited for incorporation into plant breeding and germplasm conservation programs.

Quantitative methods to measure pigmentation variation in farmed Giant Tiger Prawns, Penaeus monodon, and the effects of different harvest methods on cooked colour

Cooked prawn colour is known to be a driver of market price and a visual indicator of product quality for the consumer. Although there is a general understanding that colour variation exists in farmed prawns, there has been no attempt to quantify this variation or identify where this variation is most prevalent. The objectives of this study were threefold: firstly to compare three different quantitative methods to measure prawn colour or pigmentation, two different colorimeters and colour quantification from digital images. Secondly, to quantify the amount of pigmentation variation that exists in farmed prawns within ponds, across ponds and across farms. Lastly, to assess the effects of ice storage or freeze-thawing of raw product prior to cooking. Each method was able to detect quantitative differences in prawn colour, although conversion of image based quantification of prawn colour from RGB to Lab was unreliable. Considerable colour variation was observed between prawns from different ponds and different farms, and this variation potentially affects product value. Different post-harvest methods prior to cooking were also shown to have a profound detrimental effect on prawn colour. Both long periods of ice storage and freeze thawing of raw product were detrimental to prawn colour. However, ice storage immediately after cooking was shown to be beneficial to prawn colour. Results demonstrated that darker prawn colour was preserved by holding harvested prawns alive in chilled seawater, limiting the time between harvesting and cooking, and avoiding long periods of ice storage or freeze thawing of uncooked product.