Fibre Transfer in Merino Ewes Mated with Damara, Merino or Dorper Rams in Central Western Queensland

Considerable concern has been expressed by the Australian wool industry regarding the contamination of the clip with coloured or kempy fibres from imported breeds of sheep. As part of the evaluation of imported sheep meat breeds in western Queensland, a study is examining fibre growth and transfer of fibres and the potential to cause physical contamination of Merino fleeces. The breeds of concern in this study are the Damara, a fat-tailed breed with a hairy, coloured fleece and the Dorper which has both pigmented fibres and a kempy fleece which is shed cyclically. Three groups of Merino 27 ewes were mated to Merino, Damara and Dorper rams respectively and fibre transfer to the Merino ewes during mating, from lambing to weaning and during grazing, assessed. Both a direct field method and a laboratory method (Hatcher 1995) are being used. Those measured by direct count were measured immediately after joining and 2, 4 and 8 weeks subsequently. and the other ewes were shorn and sampled and measured in the laboratory using the dark fibre detector. This paper presents preliminary findings of those ewes monitored by the direct field method. 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.

Genetic Parameters for Staple Length and Staple Strength of Merino Wool Produced in Central and North West Queensland

Estimates of genetic parameters are presented for staple length and staple strength for 15 month old, medium Peppin sheep at Longreach and Julia Creek Queensland. The effects of birth type, sex and year of birth are shown. There were significant interactions for sex by site and for sex by year of birth. Heritability of staple length and strength were respectively 0.75 and 0.37 for the Longreach flock and 0.70 and 0.23 for the Julia Creek flock. The heritability of staple strength agrees with other published data however the estimate for staple length is very high. Phenotypic and genetic correlations with greasy fleece weight, yield, clean fleece weight, average fibre diameter and liveweight are in general agreement with other published estimates. 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 University of New South Wales, Sydney, Australia.

Alkane Profiles in Tropical Forages

The role of n-alkanes in animal nutrition research has recently been reviewed by Dove and Mayes (1996). The measurement of voluntary intake (VI) using the naturally occurring odd chain length alkanes C31 or C33 in conjunction with administered even chain length alkanes such as C32 and C36 provides several advantages over the more conventional methods. Much of the development work involving this technology has been carried out with sheep or dairy cattle fed predominantly temperate pasture. Laredo et al., (1991) have published alkane profiles for a number of introduced tropical pasture grasses but no alkane profiles have been published for native tropical pasture grasses. 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.

Reclassification of [Pasteurella] trehalosi as Bibersteinia trehalosi gen. nov., comb. nov.

[Pasteurella] trehalosi is an important pathogen of sheep, being primarily associated with serious systemic infections in lambs but also having an association with pneumonia. The aim of the present investigation was to characterize a broad collection of strains tentatively identified as [P.] trehalosi in order to reclassify and rename this taxon to support improvements in our understanding of the pathogenesis and epidemiology of this important organism. The type strain for [P.] trehalosi, strain NCTC 10370T, was included along with 42 field isolates from sheep (21), cattle (14), goats (1), roe deer (3) and unknown sources (3). An extended phenotypic characterization was performed on all 43 strains. Amplified fragment length polymorphism (AFLP) was also performed on the isolates. Two of the field isolates were subjected to 16S rRNA gene sequencing. These sequences, along with five existing sequences for [P.] trehalosi strains and 12 sequences for other taxa in the family Pasteurellaceae, were subjected to a phylogenetic analysis. All the isolates and the reference strains were identified as [P.] trehalosi. A total of 17 out of 22 ovine isolates produced acid from all glycosides, while only four out of 14 bovine isolates produced acid from all glycosides. All 22 ovine isolates were haemolytic and CAMP-positive, while no other isolate was haemolytic and only two bovine isolates were CAMP-positive. Nineteen AFLP types were found within the [P.] trehalosi isolates. All [P.] trehalosi isolates shared at least 70% similarity in AFLP patterns. The largest AFLP type included the type strain and 7 ovine field isolates. Phylogenetic analysis indicated that the seven strains studied (two field isolates and the five serovar reference strains) are closely related, with 98.6% or higher 16S rRNA gene sequence similarity. As both genotypic and phenotypic testing support the separate and distinct nature of these organisms, we propose the transfer of [P.] trehalosi to a new genus, Bibersteinia, as Bibersteinia trehalosi comb. nov. The type strain is NCTC 10370T (=ATCC 29703T). Bibersteinia trehalosi can be distinguished from the existing genera of the family by the observation of only nine characteristics; catalase, porphyrin, urease, indole, phosphatase, acid from dulcitol, (+)-D-galactose, (+)-D mannose and (+)-D-trehalose.

Stem injection: a control technique often overlooked for exotic woody weeds

In the rangelands of northern Australia, basal bark, cut stump, hand applied residual herbicides and foliar spraying have traditionally been the main herbicide techniques for control of individual exotic woody weeds growing within scattered to medium density infestations. In this paper we report on the preliminary results of stem injection as an alternate technique for the control of yellow oleander ( Cascabela thevetia (L.) Lippold), a woody weed that is difficult to kill. A randomised complete block experiment comprising 12 herbicide treatments (including a control) and three replicates was undertaken. Two rates of triclopyr + picloram, hexazinone, glyphosate, 2,4- D + picloram and metsufuron methyl and one rate of imazapyr were tested. At 15 months after application, triclopyr + picloram, glyphosate, 2,4-D + picloram and imazapyr all recorded high mortality (>90%) for at least one application rate. These results suggest that stem injection warrants further investigation as a control technique for other exotic woody weeds growing in rangelands.