Mathematical equations to describe lactation curves for Holstein- Friesian cows in New South Wales

1999 ◽  
Vol 50 (3) ◽  
pp. 431 ◽  
Author(s):  
P. R. Tozer ◽  
R. G. Huffaker

Researchers have characterised dairy milk production using a wide variety of statistically estimated equations that regress the average yield per unit time of cows in a given parity against time. The various functions employed to explain average daily milk yield include the incomplete gamma, the inverse polynomial, the Mitscherlich exponential form, and the multiphasic curve. Most of the lactation research has been carried out in the Northen Hemisphere and the applicability of the results to Australian conditions is limited due to differences in herd and feed management practices. The usefulness of some functions in developing management strategies is also limited, as it is difficult to determine lactation characteristics, such as time to peak yield and the milk production at this peak. Herd recording data from New South Wales were used to estimate equations for ‘average’ Holstein-Friesian dairy cows of varying parities. Of the 4 functions used in this study, one was not statistically appealing, the multiphasic function, and of the others, 2 functions, the incomplete gamma function and the inverse polynomial, performed well statistically and in replicating the underlying data. Thus, the simplest functions were more robust.

2010 ◽  
Vol 50 (12) ◽  
pp. 1043 ◽  
Author(s):  
G. A. Kelly ◽  
L. P. Kahn ◽  
S. W. Walkden-Brown

An experiment was conducted over 2 years on six commercial farms to quantify the costs of gastrointestinal nematode parasitism on grazing Merino ewes on the Northern Tablelands of New South Wales. To determine the effect of worm management practices, three farms implemented integrated parasite management (IPM) strategies and three farms continued to implement regionally typical industry practice (TYP). On each farm, 120 ewes born in 2006 and 120 mature age ewes were selected at shearing in 2007. Of these, 60 in each flock were serially treated with anthelmintics (CAP treatment) to suppress worm populations and the other 60 ewes were managed according to their respective farm management strategies (NOCAP treatment). Among NOCAP ewes, worm egg counts were significantly reduced over both years by IPM compared with TYP despite IPM farms requiring fewer anthelmintic treatments (3.5 vs 4.5 per year). In Year 1, mortality of sheep because of worms (CAP vs NOCAP) was significant on TYP farms (10.5%, P < 0.01) but was not apparent on IPM farms. Throughout the study, NOCAP ewes had significantly lower growth rates (–2.8 ± 0.1 kg/year, P < 0.01), produced less greasy wool (–170 ± 20 g, P < 0.01) and had reduced fibre diameter (–0.28 ± 0.05 μm, P < 0.01) when compared with CAP ewes. These effects were apparent for both TYP and IPM management. The results confirm the significant production loss caused by worms in a northern, summer rainfall region and show that IPM reduces the effect of worms and frequency of anthelmintic treatment compared with typical methods currently used by the industry.


Toxins ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 446 ◽  
Author(s):  
Hazel Farrell ◽  
Penelope Ajani ◽  
Shauna Murray ◽  
Phil Baker ◽  
Grant Webster ◽  
...  

An end-product market survey on biotoxins in commercial wild harvest shellfish (Plebidonax deltoides, Katelysia spp., Anadara granosa, Notocallista kingii) during three harvest seasons (2015–2017) from the coast of New South Wales, Australia found 99.38% of samples were within regulatory limits. Diarrhetic shellfish toxins (DSTs) were present in 34.27% of 321 samples but only in pipis (P. deltoides), with two samples above the regulatory limit. Comparison of these market survey data to samples (phytoplankton in water and biotoxins in shellfish tissue) collected during the same period at wild harvest beaches demonstrated that, while elevated concentrations of Dinophysis were detected, a lag in detecting bloom events on two occasions meant that wild harvest shellfish with DSTs above the regulatory limit entered the marketplace. Concurrently, data (phytoplankton and biotoxin) from Sydney rock oyster (Saccostrea glomerata) harvest areas in estuaries adjacent to wild harvest beaches impacted by DSTs frequently showed elevated Dinophysis concentrations, but DSTs were not detected in oyster samples. These results highlighted a need for distinct management strategies for different shellfish species, particularly during Dinophysis bloom events. DSTs above the regulatory limit in pipis sampled from the marketplace suggested there is merit in looking at options to strengthen the current wild harvest biotoxin management strategies.


Soil Research ◽  
2010 ◽  
Vol 48 (3) ◽  
pp. 248 ◽  
Author(s):  
Matthew Miklos ◽  
Michael G. Short ◽  
Alex B. McBratney ◽  
Budiman Minasny

The reliable assessment of soil carbon stock is of key importance for soil conservation and mitigation strategies related to reducing atmospheric carbon. Measuring and monitoring soil carbon is complex because carbon pools cycle and rates of carbon sequestration vary across the landscape due to climate, soil type, and management practices. A new methodology has been developed and applied to make an assessment of the distribution of total, organic, and inorganic carbon at a grains research and grazing property in northern New South Wales at a high spatial resolution. In this study, baseline soil carbon maps were created using fine resolution, geo-referenced, proximal sensor data. Coupled with a digital elevation model and secondary terrain attributes, all of the data layers were combined by k-means clustering to develop a stratified random soil sampling scheme for the survey area. Soil samples taken at 0.15-m increments to a depth of 1 m were scanned with a mid-infrared spectrometer, which was calibrated using a proportion of the samples that were analysed in a laboratory for total carbon and inorganic carbon content. This combination of new methodologies and technologies has the potential to provide large volumes of reliable, fine resolution and timely data required to make baseline assessments, mapping, monitoring, and verification possible. This method has the potential to make soil carbon management and trading at the farm-scale possible by quantifying the carbon stock to a depth of 1 m and at a high spatial resolution.


Soil Research ◽  
2009 ◽  
Vol 47 (3) ◽  
pp. 340
Author(s):  
B. Kelly ◽  
C. Allan ◽  
B. P. Wilson

'Soil health' programs and projects in Australia's agricultural districts are designed to influence farmers' management behaviours, usually to produce better outcomes for production, conservation, and sustainability. These programs usually examine soil management practices from a soil science perspective, but how soils are understood by farmers, and how that understanding informs their farm management decisions, is poorly documented. The research presented in this paper sought to better understand how dryland farmers in the Billabong catchment of southern New South Wales use soil indicators to inform their management decisions. Thematic content analysis of transcripts of semi-structured, face-to-face interviews with farmers suggest several themes that have implications for soil scientists and other professionals wishing to promote soil health in the dryland farming regions of south-eastern Australia. In particular, all soil indicators, including those related to soil 'health', need to relate to some clear, practical use to farmers if they are to be used in farm decision making. This research highlights a reliance of the participants of this research on agronomists. Reliance on agronomists for soil management decisions may result in increasing loss of connectivity between farmers and their land. If this reflects a wider trend, soil health projects may need to consider where best to direct their capacity-building activities, and/or how to re-empower individual farmers.


1994 ◽  
Vol 34 (7) ◽  
pp. 921 ◽  
Author(s):  
DC Godwin ◽  
WS Meyer ◽  
U Singh

Evidence exists that night temperatures <18�C immediately preceding flowering in rice crops can adversely affect floret fertility and, hence, yields. It has been suggested that sterility induced by low temperature is also influenced by floodwater depth and nitrogen (N) rate. In southern New South Wales, low night-time temperatures are believed to be a major constraint to the achievement of consistently high yields. The availability of a comprehensive model of rice growth and yield that is sensitive to this constraint would aid the development of better management practices. CERES RICE is a comprehensive model that simulates the phasic development of a rice crop, the growth of its leaves, stems, roots, and panicles, and their response to weather. It also simulates the water and N balances of the crop and the effects of stresses of water and N on the yield-forming processes. The model has been extensively tested in many rice-growing systems in both tropical and temperate environments. However, the original model was unable to simulate the level of chilling injury evident from yield data from southern New South Wales. This paper reports modifications made in the model to simulate these effects and the evaluation of the model in environments of low night temperature. Inclusion of the chilling injury effect greatly improved the accuracy of estimated yields from treatments in an extensive field experiment. However, additional testing with a wider range of data sets is needed to confirm the international applicability of the modifications.


2012 ◽  
Vol 52 (7) ◽  
pp. 675 ◽  
Author(s):  
R. D. Bush ◽  
R. Barnett ◽  
I. J. Links ◽  
P. A. Windsor

The prevalence of Caseous lymphadenitis (CLA) in Australia was estimated to be 5.2% using 2009 abattoir surveillance data from all States supplied by Animal Health Australia involving 5029 lines comprising 1 339 463 sheep. This is a decrease from the 26% estimated in a similar study in 1995. There was a significant difference (P < 0.001) in CLA prevalence between all states except Tasmania and Victoria (P = 0.75) with prevalences of 12.8 and 12.9%, respectively. Western Australia recorded the lowest prevalence with 1.0%. The average CLA prevalence for New South Wales was 5.3% and within three surveyed Livestock Health and Pest Authority regions (Tablelands, Central North and Central West) was 2.9, 4.9 and 4.4%, respectively. The attitude of the majority of producers surveyed in these three Livestock Health and Pest Authority areas was that CLA was of little or no significance (75%) but were aware of the need for CLA control with ~68% using 6-in-1 vaccine, though only 39.9% as recommended. It appears that the prolonged use of CLA vaccination has been successful in reducing the prevalence of CLA across Australia and particularly in New South Wales. Further improvements in communication of information on preventative management practices associated with lice control, importance of using an approved vaccination program, plus increasing producers’ awareness of the importance of CLA control, are indicated.


1990 ◽  
Vol 12 (2) ◽  
pp. 67 ◽  
Author(s):  
ND Macleod

Uany pastoral leases in western New South Wales are too small to ensure that viable pastoral enterprisu will persist in the medium to longer term. Apart from attendant welfare problems for leaseholders and their dependants, there is some evidence that this has exacerbated overgrazing problems which creates undesirable and potentially irreversible degradation of vegetation and soil resources. Arguably, the small size problem has sufficiently weakened the economic welfare of many lessees to make private acquisition of additional areas andl or adoption of conservation oriented management practices non-economic. The future scenario is then one of greater public involvement in property adjustment measures; or a growing population of non-viable pastoral enterprises with its attendant efficiency, welfare and resource conservation problems. The paper examines trends in property enterprise size, structure and concentration and the existence and extent of size economies for wool and livestock production in western New South Wales. Several issues are addressed concerning the economic viability of pastoral properties and several public policy prescriptions are presented for addressing the sizehiability problem.


Soil Research ◽  
2009 ◽  
Vol 47 (2) ◽  
pp. 234 ◽  
Author(s):  
B. Kelly ◽  
C. Allan ◽  
B. P. Wilson

‘Soil health’ programs and projects in Australia’s agricultural districts are designed to influence farmers’ management behaviours, usually to produce better outcomes for production, conservation, and sustainability. These programs usually examine soil management practices from a soil science perspective, but how soils are understood by farmers, and how that understanding informs their farm management decisions, is poorly documented. The research presented in this paper sought to better understand how dryland farmers in the Billabong catchment of southern New South Wales use soil indicators to inform their management decisions. Thematic content analysis of transcripts of semi-structured, face-to-face interviews with farmers suggest several themes that have implications for soil scientists and other professionals wishing to promote soil health in the dryland farming regions of south-eastern Australia. In particular, all soil indicators, including those related to soil ‘health’, need to relate to some clear, practical use to farmers if they are to be used in farm decision making. This research highlights a reliance of the participants of this research on agronomists. Reliance on agronomists for soil management decisions may result in increasing loss of connectivity between farmers and their land. If this reflects a wider trend, soil health projects may need to consider where best to direct their capacity-building activities, and/or how to re-empower individual farmers.


Soil Research ◽  
2015 ◽  
Vol 53 (6) ◽  
pp. 683 ◽  
Author(s):  
Jonathan M. Gray ◽  
Greg A. Chapman ◽  
Brian W. Murphy

A new evaluation scheme, land management within capability (LMwC), used to guide sustainable land management in New South Wales (NSW), is presented. The scheme semi-quantitatively categorises the potential impacts of specific land-management actions and compares these with the inherent physical capability of the land in relation to a range of land-degradation hazards. This leads to the derivation of LMwC indices, which signify the sustainability of land-management practices at the scale of individual sites up to broader regions. The LMwC scheme can be used to identify lands at greatest risk from various land-degradation hazards. It can help to guide natural resource agencies at local, regional and state levels to target priorities and promote sustainable land management across their lands. Few other schemes that assess the sustainability of a given land-management regime in a semi-quantitative yet pragmatic manner are found in the literature. The scheme has particular application for regional soil-monitoring programs and it was applied in such a program over NSW in 2008–09. The results suggested that the hazards most poorly managed across the state are wind erosion, soil acidification and soil organic carbon decline. The LMwC scheme, or at least its underlying concepts, could be readily applied to other jurisdictions.


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