A Comparison of Methods for Describing Irregular Animal Growth and Testing for Treatment Effects

In many designed experiments with animals liveweight is recorded several times during the trial. Such data are commonly referred to as repeated measures data. An aim of such experiments is generally to compare the growth patterns for the applied treatments. This paper discusses some of the methods of analysing repeated measures data and illustrates the use of cubic smoothing splines to describe irregular cattle growth data. 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.

A universal test to determine the integrity of RNA, and its suitability for reverse transcription, in animal tissue laboratory specimens

Degradation of RNA in diagnostic specimens can cause false-negative test results and potential misdiagnosis when tests rely on the detection of specific RNA sequence. Current molecular methods of checking RNA integrity tend to be host species or group specific, necessitating libraries of primers and reaction conditions. The objective here was to develop a universal (multi-species) quality assurance tool for determining the integrity of RNA in animal tissues submitted to a laboratory for analyses. Ribosomal RNA (16S rRNA) transcribed from the mitochondrial 16S rDNA was used as template material for reverse transcription to cDNA and was amplified using polymerase chain reaction (PCR). As mitochondrial DNA has a high level of conservation, the primers used were shown to reverse transcribe and amplify RNA from every animal species tested. Deliberate degradation of rRNA template through temperature abuse of samples resulted in no reverse transcription and amplification. Samples spiked with viruses showed that single-stranded viral RNA and rRNA in the same sample degraded at similar rates, hence reverse transcription and PCR amplification of 16S rRNA could be used as a test of sample integrity and suitability for analysis that required the sample's RNA, including viral RNA. This test will be an invaluable quality assurance tool for determination of RNA integrity from tissue samples, thus avoiding erroneous test results that might occur if degraded target RNA is used unknowingly as template material for reverse transcription and subsequent PCR amplification.

Concordant molecular and phenotypic data delineate new taxonomy and conservation priorities for the endangered mountain yellow-legged frog

The mountain yellow-legged frog Rana muscosa sensu lato, once abundant in the Sierra Nevada of California and Nevada, and the disjunct Transverse Ranges of southern California, has declined precipitously throughout its range, even though most of its habitat is protected. The species is now extinct in Nevada and reduced to tiny remnants in southern California, where as a distinct population segment, it is classified as Endangered. Introduced predators (trout), air pollution and an infectious disease (chytridiomycosis) threaten remaining populations. A Bayesian analysis of 1901 base pairs of mitochondrial DNA confirms the presence of two deeply divergent clades that come into near contact in the Sierra Nevada. Morphological studies of museum specimens and analysis of acoustic data show that the two major mtDNA clades are readily differentiated phenotypically. Accordingly, we recognize two species, Rana sierrae, in the northern and central Sierra Nevada, and R. muscosa, in the southern Sierra Nevada and southern California. Existing data indicate no range overlap. These results have important implications for the conservation of these two species as they illuminate a profound mismatch between the current delineation of the distinct population segments (southern California vs. Sierra Nevada) and actual species boundaries. For example, our study finds that remnant populations of R. muscosa exist in both the southern Sierra Nevada and the mountains of southern California, which may broaden options for management. In addition, despite the fact that only the southern California populations are listed as Endangered, surveys conducted since 1995 at 225 historic (1899-1994) localities from museum collections show that 93.3% (n=146) of R. sierrae populations and 95.2% (n=79) of R. muscosa populations are extinct. Evidence presented here underscores the need for revision of protected population status to include both species throughout their ranges.

The influence of animal mobility on the assumption of uniform distances in aerial line-transect surveys

Line-transect distance sampling is a widely used method for estimating animal density from aerial surveys. Analysis of line-transect distance data usually relies on a requirement that the statistical distribution of distances of animal groups from the transect line is uniform. We show that this requirement is satisfied by the survey design if all other assumptions of distance sampling hold, but it can be violated by consistent survey problems such as responsive movement of the animals towards or away from the observer. We hypothesise that problems with the uniform requirement are unlikely to be encountered for immobile taxa, but might become substantial for species of high mobility. We test evidence for non-uniformity using double-observer distance data from two aerial surveys of five species with a spectrum of mobility capabilities and tendencies. No clear evidence against uniformity was found for crabeater seals or emperor penguins on the pack-ice in East Antarctica, while minor non-uniformity consistent with responsive movement up to 30 m was found for Adelie penguins. Strong evidence of either non-uniformity or a failure of the capture-recapture validating method was found for eastern grey kangaroos and red kangaroos in Queensland.

Management of mould mite Tyrophagus putrescentiae (Schrank) (Acarina: Acaridae): A case study in stored animal feed

An integrated pest management (IPM) strategy was developed to manage infestations of mould mite Tyrophagus putrescentiae (Schrank) in stored animal feed, due to the increasing importance of these mites as pests of feed processing and storage facilities in Australia. This strategy involved several aspects such as limiting the moisture content of the processed feed to 12%, admixing vegetable oil to some feed (2% w/w), strict hygiene practice in and around the processing and storage facility, and rejection of infested grain at the receiving point. Additionally, seven contact insecticides and the fumigant phosphine were evaluated for their effectiveness against the mould mite to assess their potential integration into the IPM strategy. Among them, pyrethrin synergised with piperonyl butoxide, the insect growth regulator s-methoprene and a newly developed bacterium-based material spinosad controlled the mites. Moreover, the fumigant phosphine at 1 mg/litre over a six days exposure period also controlled these mites. So far, the IPM strategy, without any involvement of insecticides or fumigant has resulted in a complete eradication of the mite population in this particular case of stored animal feed.

Impacts of grazing management options on pasture and animal productivity in a Heteropogon contortus (black speargrass) pasture in central Queensland. 4. Animal production.

Steer liveweight gains were measured in an extensive grazing study conducted in a Heteropogon contortus (black speargrass) pasture in central Queensland between 1988 and 2001. Treatments included a range of stocking rates in native pastures, legume-oversown native pasture and animal diet supplement/spring-burning pastures. Seasonal rainfall throughout this study was below the long-term mean. Mean annual pasture utilisation ranged from 13 to 61%. Annual liveweight gains per head in native pasture were highly variable among years and ranged from a low of 43 kg/steer at 2 ha/steer to a high of 182 kg/steer at 8 ha/steer. Annual liveweight gains were consistently highest at light stocking and decreased with increasing stocking rate. Annual liveweight gain per hectare increased linearly with stocking rate. These stocking rate trends were also evident in legume-oversown pastures although both the intercept and slope of the regressions for legume-oversown pastures were higher than that for native pasture. The highest annual liveweight gain for legume-oversown pasture was 221 kg/steer at 4 ha/steer. After 13 years, annual liveweight gain per unit area occurred at the heaviest stocking rate despite deleterious changes in the pasture. Across all years, the annual liveweight advantage for legume-oversown pastures was 37 kg/steer. Compared with native pasture, changes in annual liveweight gain with burning were variable. It was concluded that cattle productivity is sustainable when stocking rates are maintained at 4 ha/steer or lighter (equivalent to a utilisation rate around 30%). Although steer liveweight gain occurred at all stocking rates and economic returns were highest at heaviest stocking rates, stocking rates heavier than 4 ha/steer are unsustainable because of their long-term impact on pasture productivity.

Impacts of grazing management options on pasture and animal productivity in a Heteropogon contortus (black speargrass) pasture in central Queensland. 3. Diet composition in autumn

The diet selected in autumn by steers fistulated at the oesophageous was studied in a subset of treatments in an extensive grazing study conducted in a Heteropogon contortus pasture in central Queensland between 1988 and 2001. These treatments were a factorial array of three stocking rates (4, 3 and 2 ha/steer) and three pasture types (native pasture, legume-oversown native pasture and animal diet supplement/spring-burning native pasture). Seasonal rainfall throughout this study was below the long-term mean and mean annual pasture utilisation ranged from 30 to 61%. Steers consistently selected H. contortus with levels decreasing from 47 to 18% of the diet as stocking rate increased from 4 ha/steer to 2 ha/steer. Stylosanthes scabra cv. Seca was always selected in legume-oversown pastures with diet composition varying from 35 to 66% despite its plant density increasing from 7 to 65 plants/m(2) and pasture composition from 20 to 50%. Steers also selected a diet containing Chrysopogon fallax, forbs and sedges in higher proportions than they were present in the pasture. Greater availability of the intermediate grasses Chloris divaricata and Eragrostis spp. was associated with increased stocking rates. Bothriochloa bladhii was seldom selected in the diet, especially when other palatable species were present in the pasture, despite B. bladhii often being the major contributor to total pasture yield. It was concluded that a stocking rate of 4 ha/steer will maintain the availability of H. contortus in the pasture.

Impacts of grazing management options on pasture and animal productivity in a Heteropogon contortus (black speargrass) pasture in central Queensland. 2. Population dynamics of Heteropogon contortus and Stylosanthes scabra cv. Seca.

The dynamics of Heteropogon contortus and Stylosanthes scabra cv. Seca populations were studied in a subset of treatments in an extensive grazing study conducted in central Queensland between 1988 and 2001. These treatments were 4 stocking rates in native pasture and 2 of these stocking rates in legume oversown and supplement/spring burning treatments. For the 1999-2000 summer, population data for H. contortus in 5 of these native pasture and supplement/burning treatments were compared with those for an additional burnt treatment. Seasonal rainfall throughout this study was below the long-term mean and mean annual pasture utilisation ranged from 24 to 61%. Increasing stocking rate from 5 to 2 ha/steer in native pasture reduced H. contortus plant density. Increasing stocking rate reduced seedling recruitment as a result of its effect on soil seedbanks. Seedling recruitment was the major determinant of change in plant density, although some individual H. contortus plants did survive throughout the study. Burning in spring 1999, particularly at light stocking rate, promoted seedling recruitment above that in both unburnt native and legume oversown pasture and resulted in increased H. contortus plant density. In the legume oversown treatments, S. scabra cv. Seca density increased rapidly from 15 plants/m2 in 1988 to 140 plants/m2 in 2001 following a lag phase between 1988 and 1993. This increased S. scabra density was associated with an eventual decline in H. contortus plant density through reduced seedling recruitment. It was concluded that H. contortus population density is sustainable at stocking rates of 4 and 5 ha/steer (30% pasture utilisation) and that spring burning at light stocking rate can promote H. contortus populations. Increasing densities of S. scabra need to be managed to prevent its dominance.

Taxonomy, distribution and ecology of Zoysia macrantha desv., an Australian native species with turf breeding potential

Only three of the 11 species in the genus Zoysia Willd. have thus far contributed to commercially available turfgrass varieties. One of the neglected taxa is Z. macrantha Desv., an Australian native species further divided into two subspecies. The coarser Z. macrantha subsp. macrantha occurs on sand dunes, headlands and tidal areas along eastern and southeastern coasts from about 23 to 38°S latitude. The shorter, denser-growing Z. macrantha subsp. walshii M.E. Nightingale is found on the southern mainland (South Australia and Victoria from longitude 137° to 148°E and at latitudes higher than 36°S), adjacent offshore islands, and northern, eastern and central Tasmania to 43°S growing on the edges of coastal, sub-coastal and even inland salt lakes, in riverine environments, and from moist grassy depressions (both coastal and inland) to rocky headlands. The latter subspecies has the more discontinuous and specialised distribution, largely determined by the need for an appropriate level of peat, clay or silt in the soil to maintain adequate moisture during the dry summers in southern Australia while at the same time avoiding anything more than temporary waterlogging. It grows on low fertility soils ranging from strongly acid to neutral or mildly alkaline, and is often very closely grazed by marsupials. Both subspecies are salt and drought tolerant, but not notably shade tolerant. Their potential to add greater drought tolerance in particular to the Asian Zoysia material in current use through future breeding programs is discussed.

Technical highlights: Invasive plant and animal research 2009-10

Technical highlights 2009–10, with detailed progress reports on the latest invasive plant and animal research undertaken by Biosecurity Queensland, a service unit of the Department of Employment, Economic Development and Innovation.

Technical highlights: Invasive plant and animal research 2008-09

Technical highlights 2008–09, with detailed progress reports on the latest invasive plant and animal research undertaken by Biosecurity Queensland, a service unit of the Department of Employment, Economic Development and Innovation.

Technical highlights: Invasive plant and animal research 2007-08

Technical highlights 2007–08, with detailed progress reports on the latest invasive plant and animal research undertaken by Biosecurity Queensland, a service unit of the Department of Primary Industries and Fisheries.

Male traits and herd reproductive capability in tropical beef cattle. 1. Experimental design and animal measures

Research into the genetics of whole herd profitability has been a focus of the Beef Cooperative Research Centre for Beef Genetic Technologies over the past decade and it has been identified that measures of male reproduction may offer a potential indirect means of selecting for improved female reproduction. This paper describes the experimental design and provides a descriptive analysis of an array of male traits in Brahman and Tropical Composite genotypes managed under the medium to high stress, semi-extensive to extensive production systems of northern Australia. A total of 1639 Brahman and 2424 Tropical Composite bulls with known pedigrees, bred and raised in northern Australia, were evaluated for a comprehensive range of productive and reproductive traits. These included blood hormonal traits (luteinising hormone, inhibin and insulin-like growth factor-I); growth and carcass traits (liveweight, body condition score, ultrasound scanned 12-13th rib fat, rump P8 fat, eye muscle area and hip height); adaptation traits (flight time and rectal temperature); and a bull breeding soundness evaluation (leg and hoof conformation, sheath score, length of everted prepuce, penile anatomy, scrotal circumference, semen mass activity, sperm motility and sperm morphology). Large phenotypic variation was evident for most traits, with complete overlap between genotypes, indicating that there is likely to be a significant opportunity to improve bull fertility traits through management and bull selection.

Food-borne pathogens - a key issue for all food animal industries

The modern consumer has an attitude that food safety is non-negotiable issue – the consumer simply demands food to be safe. Yet, at the same time, the modern consumer has an expectation that the food safety is the responsibility of others – the primary producer, the processing company, the supermarket, commercial food handlers and so on. Given this environment, all food animal industries have little choice but to regard food safety as a key issue. As an example, the chicken meat industry, via the two main industry funding bodies – the Rural Industries Research and Development Corporation (Chicken Meat) and the Poultry CRC – has a comprehensive research program that seeks to focus on reducing the risks of food-borne diseases at all points of the food processing chain – from the farm to the processing plant. The scale of the issue for all industries can be illustrated by an analysis of the problem of campylobacterosis – a major food-borne disease. It has been estimated that there are around 230,000 cases of campylobacterosis per year. In 1995, it was estimated that each case of food-borne campylobacterosis in the USA was costing between $(US) 350-580. Hence, a reasonable conservative estimate is that each Australian case in 2010 would result in a cost of around $500 (this includes hospital, medication and lost productivity costs). Hence, this single food-borne agent could be costing Australian society around $115 million annually. In the light of these types of estimated costs for just one food-borne pathogen, it is easy to understand the importance that all food animal industries place on food safety.