Annual reproductive rythm in Merino sheep related to the choice of a mating time at Trangie, Central Western New South Wales

1960 ◽  
Vol 11 (5) ◽  
pp. 805 ◽  
Author(s):  
RB Dun ◽  
W Ahmed ◽  
AJ Morrant

The ovaries from slaughtered Peppin Merino ewes were examined at Trangie for a 12 month period commencing in April 1954. A seasonal rhythm was demonstrated for the percentage of ewes ovulating and for the percentage of multiple ovulations. The seasonal peak was in March–April, with a trough in November–December. Data were compared from a series of autumn and spring matings over the years 1953–1959 using genetically comparable flocks of similar age distribution, mated by identical methods. The overall incidence of oestrus was significantly higher in the first 3 weeks of mating (artificial insemination) in the autumn. The patterns of incidence of oestrus also differed, oestrus being much higher at the commencement of mating in the autumn. Differences between years in the incidence of oestrus were more pronounced in the spring, low incidence being correlated with poor nutrition. In only one mating — spring of 1954, a drought year — was the incidence of oestrus low initially, with a sharp rise commencing at 14 days. The conception rate for autumn-mated ewes was 10 percent. higher than for spring-mated ewes. Little difference was observed in the number and motility of sperm used at the seasonal matings. Lambing percentages strongly favoured the autumn mating: 15 percent. more wet ewes, 25 per cent. more twins mothered, 37 per cent. more lambs mothered, and 33 per cent. more lambs weaned. There was little difference between seasons in ewe deaths prior to and during lambing, or in deaths of lambs between mothering and weaning. The relative importance of the factors causing the 37 per cent. more lambs mothered in the autumn mating was as follows: incidence of oestrus, 11 per cent.; pattern of oestrus, 5 per cent.; incidence of multiple ovulation, 57 per cent.; conception rate, 27 per cent. The importance of the conception rate could be largely an associated effect of the higher autumn incidence of multiple ovulation. The weaning weight of lambs tended to be slightly higher for autumn matings, although there was great variation between years, both in the size and in the sign of differences. These differences had almost disappeared by 17 months of age. The choice of a mating time in central western New South Wales is discussed relative to these findings.

2004 ◽  
Vol 31 (4) ◽  
pp. 421 ◽  
Author(s):  
David Priddel ◽  
Robert Wheeler

A total of 85 brush-tailed bettongs (Bettongia penicillata) from Western Australia and two sites in South Australia were translocated to Yathong Nature Reserve (YNR) in western New South Wales in October 2001. Aerial baiting to control the introduced red fox (Vulpes vulpes) had been undertaken on YNR since 1996. Thirty-one bettongs were fitted with radio-transmitters at the time of release, and two subsequently. Trapping took place at irregular intervals after the translocation. In all, 73% of telemetered bettongs died within the first six months; all were dead within 13 months. Eight bettongs died within the first eight days immediately following their release, due to causes other than predation. These eight all originated from St Peter Island (SPI), South Australia. A low incidence of breeding on SPI supports the belief that this source population was in poor condition and unsuited for translocation. Overall, 19 of the 33 telemetered bettongs were killed by predators: 14 (74%) by feral house cats (Felis catus), two (11%) by birds, and three (16%) by predators, which, although they could not be fully identified, were not foxes. One month after release, surviving bettongs weighed less than they did at the time of their release (mean decrease in mass = 9.7%, range 2.6–22.4%, n = 11). Within two months of their release most had regained any lost mass (mean change in mass since release = –0.3%, range –5.9 to 10.5%). Food resources on YNR appeared sufficient to sustain adult brush-tailed bettongs, despite a period of severe drought. Small pouch young present at the time of release were subsequently lost. Females gave birth and carried small pouch young (up to 50 mm), but no young-at-foot were recorded. Bettongs did not disperse further than 10 km from their release site. Overall, 50% of aerial-tracking locations were no further than 3.2 km from the release site, and 92% no further than 7.0 km. This experimental translocation of brush-tailed bettongs failed due to predation by cats. It demonstrated that foxes were no longer a threat to wildlife on YNR and identified cats as the major impediment to the restoration of locally extinct fauna.


1995 ◽  
Vol 43 (6) ◽  
pp. 601 ◽  
Author(s):  
G Mcdonald ◽  
TR New ◽  
RA Farrow

Surveys for juvenile Mythimna convecta throughout the agricultural and arid regions of eastern Australia were conducted from 1986 to 1989. Armyworm populations north of 33 degrees S were generally dominated by M. convecta, and further south by Persectania ewingii. M. convecta was most widely distributed in spring. Incidence during autumn and winter ranged from very low in Victoria to high in northern New South Wales and southern Queensland. Summer infestations were found mostly on the south-east coast where favourable habitats were abundant. Colonised habitats included extremely arid regions, where small numbers of larvae were associated with grasses in temporary watercourses, and the higher-rainfall, eastern regions. The largest infestations occurred in south-east Queensland and north central and north-east New South Wales, particularly after heavy autumn rains. There appeared to be two generations of M. convecta over the autumn/winter period: the first a synchronised event starting on the autumn rains and the second commencing in June/July and comprising a wide spread in age distribution. The progeny of the winter generation are probably the source of most economic outbreaks. Mythimna convecta larvae were collected from subtropical and temperate grasses. In the former, most larvae were found in tussocks, particularly of Dichanthium sericeum and Chloris truncata, which provided a dense, fine-leaf crown and canopy. After good autumn rainfall and vegetative growth, the wiry-stemmed tussocks, including Astrebla spp. and C. ciliaris, were also common hosts. The temperate grasses, particularly Avena fatua and Hordeum leporinum, were the main winter hosts although the greatest densities were found only in thick swards of growth, particularly those that contained dried grass. Two of the largest surveys, in autumn 1987 and 1988, followed periods of heavy rain and provided strongly contrasting results. The 1987 survey of central and south-west Queensland located no M. convecta larvae, indicating that densities were below detection thresholds. The paucity of larvae was attributed to lack of suitable atmospheric conditions to assist moth immigrations and absence of adequate populations in potential source areas. The 1988 survey revealed a major outbreak of M. convecta larvae in south-east Queensland and northern New South Wales. The area received record rains during early April of that year, and the outbreak probably arose from moth migrations from the east and south-east coast. An outbreak of similar scale occurred after further heavy autumn rains in 1989.


1975 ◽  
Vol 2 (1) ◽  
pp. 1 ◽  
Author(s):  
GR Wilson

Skulls were aged for 4623 grey kangaroos (of both species), 1030 red kangaroos and 84 wallaroos taken by professional shooters in 1973 around eight towns in New South Wales. There was no significant difference in the proportion of adult (4-9 y) to old (10+ y) animals between areas, but there was a difference between red and grey kangaroos. The proportion of young (0-3y) animals, however, varied significantly between areas; this is attributed partly to variation between shooters. A time-specific life table was constructed on the basis of a stationary age distribution; the annual survival was 0.661 for grey kangaroos, 0.729 for wallaroos and 0.790 for red kangaroos. These rates seem influenced by the minimum carcass weights of 12, 13 and 16 kg for the three species respectively, and by the greater tolerance of graziers for red than grey kangaroos. The limitations and potentialities of these observations are discussed and the direction of future investigations indicated.


1988 ◽  
Vol 41 (4) ◽  
pp. 571 ◽  
Author(s):  
I R Littlejohns ◽  
RW Burton

Three surveys of cattle for bluetongue (BLU) antibody were conducted over the years 1978-1980 in coastal areas of New South Wales. In each survey the samples were identified by age.


2019 ◽  
Vol 10 (4) ◽  
pp. 24-30
Author(s):  
Hannah Visser ◽  
Megan Passey ◽  
Emma Walke ◽  
Sue Devlin

Objective: Ongoing transmission of tuberculosis (TB) continues in Indigenous communities in New South Wales (NSW), Australia. In a pilot project, a Public Health Unit TB team partnered with an Aboriginal Community Controlled Health Service (ACCHS) in a community with a cluster of TB to augment screening for latent TB infection (LTBI) using interferongamma release assay (IGRA). This study examined screening data and programme outcomes at 12 months post hoc to advise practice and policy formulation. Methods: We conducted a retrospective, cross-sectional analysis of demographic and clinical data of ACCHS patients, stratified by IGRA testing status. Differences in sex and age distribution between the groups and cases of a genetically and epidemiologically linked TB cluster in Aboriginal people in NSW were assessed using non-parametric tests. Results: Of 2019 Aboriginal and Torres Strait Islander people seen by general practitioners during the study period, 135 (6.7%) participated in the screening. Twenty-four (17.8%) participants were IGRA positive. One person was diagnosed with active TB. Twelve participants received a chest X-ray at the time of the positive test, and six participants had an additional chest X-ray within 12 months. None commenced preventive treatment for LTBI. Discussion: ACCHS screening for LTBI reached individuals in the age group most commonly affected by TB in these Aboriginal communities. No conclusions can be made regarding the population prevalence due to the low screening rate. Further strategies need to be developed to increase appropriate follow-up and preventive treatment.


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