Influence of season and of reproductive status on the wool growth of Merino ewes in arid environment

1978 ◽  
Vol 18 (94) ◽  
pp. 648 ◽  
Author(s):  
H Hawker ◽  
JP Kennedy

At Fowlers Gap, an arid saltbush environment in far western New South Wales, the wool growth of South Australian Merino ewes was measured at intervals of about ten weeks for three years. Highest rates of wool growth on dry ewes were recorded each year in late winter (1 0.8, 14.9, 15.7 g day-1) and lowest in late summer (6.0, 7.7, 10.7 g day-1). Changes in the rate of wool growth were associated with changes in pastoral conditions in two of the three years. Relative to dry ewes, the rate of wool growth of wet ewes was reduced by 9 to 24 per cent in late pregnancy, 21 to 43 per cent in early lactation and 3 to 26 per cent in late lactation. The reduction was inversely related to current pasture growth.

1975 ◽  
Vol 15 (73) ◽  
pp. 250 ◽  
Author(s):  
RCG Smith ◽  
GG Johns

A water balance model predicting changes in soil moisture under temperate pasture at Armidale, New South Wales was developed and tested against soil moisture measurements made from 1967 to 1969. The model accounted for 96 per cent of the variance in observed soil moisture. The model was then used to predict the expected pattern of soil moisture for this area using daily Armidale rainfall data from 1878 to 1973 and pan evaporation data from 1951 to 1970. Expected soil moisture levels rise to a maximum in late winter and then progressively decline to a minimum in mid summer. Levels may increase again slightly during late summer but remain low through autumn before beginning to rise again during winter. On the basis of this analysis it is suggested that the safest time to establish new plant species into temperate pasture is probably early winter when expected soil moisture begins to rise rapidly. Because of the autumn deficiency in soil moisture it was concluded that fodder oats grown in this period would often be inhibited by a lack of soil moisture unless preceded by a fallow to conserve late summer rainfall. The need for soil moisture data in interpreting and extrapolating from field experiments is stressed.


1969 ◽  
Vol 9 (41) ◽  
pp. 610 ◽  
Author(s):  
EC Wolfe ◽  
FC Crofts

The seasonal productivity of eight perennial grasses at three nitrogen levels was measured in small pure-grass swards at Badgery's Creek, New South Wales. Highly significant differences in seasonal productivity were found between nitrogen levels in all four seasons, and between cultivars in summer, autumn, and winter. The response of the grasses to nitrogen was slightly greater at the high than at the medium level of nitrogen application in all seasons, and was highest in spring (about 40 lb of dry matter per lb of applied nitrogen) and lowest in mid-winter (about 8 lb/lb). Tall fescue was the most efficient responder to nitrogen in late summer and early autumn, Kangaroo Valley ryegrass in late autumn and late winter, and Currie cocksfoot in mid-winter. At a high level of nitrogen, the dry matter produced by Kangaroo Valley ryegrass and Currie cocksfoot in the late autumn to early spring period, the period of greatest feed shortage, was nearly as great as that produced over a similar period by sod-sown oats in earlier experiments at Badgery's Creek.


1988 ◽  
Vol 28 (5) ◽  
pp. 561 ◽  
Author(s):  
HL Davies ◽  
E Devaud

A March-April joining of Merino ewes was compared with a June-July joining in central New South Wales at a low stocking rate on subterranean clover based pastures over 3 years. In all years, ewes joined in June were heavier (P < 0.05) than ewes joined in March (55 v. 52 kg). Liveweights at the start of lambing and liveweight change from joining to lambing were also high and favoured the later lambing group. The proportion of ewes lambing (97% March v. 93% June) and proportion of ewes twinning (29% March v. 20% June) were not significantly different between the 2 groups, but consistently favoured the March-April joining. Perinatal mortality was low (9.4% March v. 7.1% June) and not significantly different between the 2 groups, but was consistently lower in the June joined group. Number of lambs weaned per 100 ewes joined was also not significantly different, but was higher each year in the March joined group (1 13% March v. 105% June). The growth rate of the lambs (both singles [24% greater, 248 v. 200 g/day] and twins [37% greater, 2 13 v. 155 g/day]) was consistently in favour of March joined ewes. Mean greasy fleece weights of the ewes were not significantly different between the 2 groups, but were in favour of the late joined group (4.83 v. 4.50 kg). Time of joining significantly affected liveweights and greasy and clean fleece weights of the progeny at the shearing in the year following their birth in favour of March joining. These data suggest that, despite a nutritional advantage to the ewes in late pregnancy and milder weather at lambing with a June-July joining, a March- April joining is the preferred option on the Central Tablelands of New South Wales.


1989 ◽  
Vol 40 (3) ◽  
pp. 605 ◽  
Author(s):  
KA Archer ◽  
GG Robinson

This paper reports the findings of a five-year study on the growth patterns, production and means of persistence of white clover in a cool temperate environment with summer dominant rainfall, on the Northern Tablelands of New South Wales. White clover essentially persisted as a perennial, but large and rapid declines in plant frequency occurred during late summer if soil moisture levels became depleted. The critical combination of conditions at which plant frequency was adversely affected occurred when available soil moisture levels declined below 35 mm and mean weekly maximum temperatures exceeded 20�C; conditions which often occur in late summer in this environment. During one prolonged period of moisture stress in the second spring and summer period of the study, all plants died. Regeneration was due to germination of seeds and seedling establishment, but plants subsequently persisted as perennials. Relationships were developed to predict the probability of survival of white clover over the range of temperatures and soil moistures recorded in these experiments. Germination occurred to a variable extent each year, but was observed only during winter and spring. Seedling establishment was effective in only one year, which followed the death of white clover in summer, 1980-81. The sward was slow to recover after seedling regeneration owing to low winter temperatures and competition from established temperate perennial grasses in spring. Seedlings contributed little to dry matter production in spring. These results indicate that white clover is unlikely to be of value as an annual in temperate pastures. Strategies aimed at improving white clover in cool temperate environments, either by management or selection/breeding programs, should therefore focus upon improving the ability of white clover to persist as a perennial.


1990 ◽  
Vol 41 (3) ◽  
pp. 411 ◽  
Author(s):  
FR Roubal

Seven monogenean, 1 digenean and 9 copepod species of ectoparasite were found on 179 juvenile Acanthopagrus australis collected bimonthly over two 12-month periods from a small estuary at Red Rock in northern New South Wales. The monogenean Allomurraytrema spari and the copepod Alella macrotrachelus showed a consistent cycle of spring-summer high and late summer-autumn low in prevalence and intensity of infection, whereas the digenean Prototransversotrema steeri was present only in winter. The monogenean Haliotrema spariensis was highly prevalent year-round, but other monogeneans were inconsistent in seasonal prevalence and intensity. The copepods Paraergasilus acanthopagri and Dermoergasilus acanthopagri showed inconsistent annual cycles, but their fluctuations in prevalence and intensity were nearly identical. The other species of ectoparasite had no consistent cycles or were rarely found. Temperature does not appear to directly regulate the abundance of ectoparasites on juvenile Acanthopagrus australis in Red Rock estuary.


1981 ◽  
Vol 29 (2) ◽  
pp. 121 ◽  
Author(s):  
GM Lodge

Emergence and survival of the seedlings of warm-season native perennial grasses Aristida ramosa R.Br., Bothriochloa macra (Steud.) S . T. Blake, Dichanthium sericeum (R.Br.) Camus, Sporobolus elongatus R.Br., Eragvostis leptostachya Steud. and Chloris truncata R.Br. and the cool-season species Stipa variabilis Hughes and Danthonia linkii Kunth were studied in both native pastures and sown monospecific plots on the north- west slopes of New South Wales. The most favourable period for the successful emergence and establishment of warm-season grasses was from mid summer to early autumn. Cool-season native perennial grasses established best from seedlings that appeared from mid autumn to late winter. Few seedlings were observed to germinate in spring, probably as a result of large variations in temperature, low minimum temperatures or intra and interspecific competition. Seedlings growing in native pasture spent long periods in the vegetative phase compared to the early flowering of seedlings in the sown plots. In the pasture studied only two seedlings flowered over 700 days after emergence, and many others after persisting for up to 2 years died without producing seed. These findings indicate that the seedlings in these native pastures were under considerable stress and that the adult populations of the species examined were relatively stable and little recruitment occurred.


1981 ◽  
Vol 21 (109) ◽  
pp. 179 ◽  
Author(s):  
SJ Gray ◽  
JP Kennedy

Internal parasitism and its effects on survival, wool growth and liveweight gain of weaner sheep were studied over 3 years from 1977 to 1979 at Fowlers Gap Research Station, Broken Hill, New South Wales. During this period, annual rainfall was 33, 152 and 141 % respectively, of the annual mean of 195 mm. Worm burdens and production of sheep given anthelmintic treatment at approximately monthly intervals were compared with those in untreated sheep. Total worm counts in untreated sheep were low, ranging from 1 5 to 3750. Nematodirus spp. were the most common nematode parasites recovered. lnfections with Trichostrongylus spp, were recorded in 2 of the 3 years; T. rugatus was the only species represented when species identification was made in 1979. Infections of Haemonchus contortus were only detected in the last year. Tapeworms (Moniezia spp.) were occasionally recovered. Anthelmintic treatment reduced worm burdens to a very low level but had no significant effect on survival rate, liveweight gain, or wool production. We concluded that in the arid areas of western New South Wales, worm infection would not limit production or cause mortality in young sheep, except in unusually wet years.


2002 ◽  
Vol 42 (8) ◽  
pp. 1087 ◽  
Author(s):  
C. R. Kidd ◽  
G. M. Murray ◽  
J. E. Pratley ◽  
A. R. Leys

Winter cleaning is the removal of grasses from pasture using selective herbicides applied during winter. We compared the effectiveness of an early (June) and late (July) winter cleaning with an early spring herbicide fallow (September), spring (October) herbicide and no disturbance of the pasture on development of the root disease take-all in the subsequent wheat crop. Experiments were done at 5 sites in the eastern Riverina of New South Wales in 1990 and 1991. The winter clean treatments reduced soil inoculum of Gaeumannomyces graminis var. tritici (Ggt) compared with the other treatments at all sites as measured by a bioassay, with reductions from the undisturbed treatments of 52–79% over 5 sites. The winter clean treatments also significantly reduced the amount of take-all that developed in the subsequent wheat crop by between 52 and 83%. The early and late winter clean treatments increased the number of heads/m2 at 3 and 1 sites, respectively. Dry matter at anthesis was increased by the winter clean treatments at 3 sites. Grain yield was increased by the winter cleaning treatments over the other treatments at the 4 sites harvested, with yield increases of the early winter clean over the undisturbed treatment from 13 to 56%. The autumn bioassay of Ggt was positively correlated with spring take-all and negatively correlated with grain yield of the subsequent wheat crop at each site. However, there was a significant site and site × bioassay interaction so that the autumn bioassay could not be used to predict the amount of take-all that would develop.


1972 ◽  
Vol 12 (59) ◽  
pp. 584 ◽  
Author(s):  
WR McManus ◽  
TG Kennedy

Merino ewe weaner lambs grazing at a high stocking rate for 32 weeks in the Wellington region of New South Wales were fed two levels (low, medium) of oat grain plus lucerne hay supplement. Insignificant fleece-adjusted liveweight gain and significant, but small, (2.8 per cent and 9.9 per cent) increases in clean fleece weight resulted for the low and medium groups. Feeding reduced fleece tenderness and altered wool handle and colour. Merino weaner ewes grazing improved pastures at Yass were supplemented with oat grain for 12 weeks in the late summer-early autumn. There was a temporary increase in woo1 production and liveweight but subsequent fertility was not improved. The responses obtained to treatment in both trials appear to be uneconomic


1974 ◽  
Vol 14 (68) ◽  
pp. 405 ◽  
Author(s):  
MH Campbell

In three experiments near Rockley and Gunning, New South Wales, non-arable areas of serrated tussock (Nassella trichotoma) were aerially sprayed with 2,2-DPA in late summer and, in the following autumn, aerially fertilized and sown with pasture species. Measurements of tussock density and the botanical composition of the pastures were made for up to ten years after sowing. The experiments commenced in 1963, 1964 and 1966. About 90 per cent of the tussock plants were killed by applying the herbicide at 16.6 kg a.e. ha-l; higher rates effected little improvement. Aerially sown pastures further reduced tussock numbers and provided long term control. Best results were obtained on fertile soil and where tussock has not been retarded by burning. Of the pasture species sown Trifolium subterraneum and Phalaris tuberosa were the most effective for long term control.


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