This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Perinatal lamb mortality is a major source of reproductive loss, particularly for twins. A study ... more Perinatal lamb mortality is a major source of reproductive loss, particularly for twins. A study was conducted to determine whether provision of shelter in the form of shrub belts (a 'maternity ward') could increase survival of twin lambs compared with hedgerows, and whether hedgerows improve survival of single lambs compared with unsheltered paddocks. Measurements were recorded for Merino x Poll Dorset cross twin lambs born in hedgerows (phalaris or hessian) or shrub belts and single lambs born in hedgerows or unsheltered paddocks over the years 2007 to 2009. Records for 382 single and 726 twin lambs were used. The survival of single lambs was not increased (P=0.06) by hedgerow shelter. The survival of twin lambs in shrubs was 10% higher (P<0.05) than in hessian hedgerow shelter in 2008 to 2009 (0.77 cv 0.70), associated with a reduction in deaths from starvation/mismothering/exposure. The hessian shelter was associated with an increased (P<0.05) growth rate to weaning of single lambs, but the growth rates of twin lambs were lower (P<0.05) in shrub compared with hessian shelter. In 2010 a second study of 178 twin Merino x Poll Dorset cross lambs found that survival of lambs born alive was not improved by shrubs compared with unsheltered paddocks (0.80 vs 0.77; P>0.05). It is concluded that shrub belts which forced twin-bearing ewes to lamb in a sheltered environment reduced perinatal mortality in one of three data sets, but was not repeated. The shrubs take time to establish, and the benefit will be small if weather is mild during lambing.
Flaxleaf fleabane (Conyza bonariensis (L.) Cronquist) has been considered a major weed in dryland... more Flaxleaf fleabane (Conyza bonariensis (L.) Cronquist) has been considered a major weed in dryland cropping systems in Australia. Resistance in populations of C. bonariensis to glyphosate has also been confirmed. The weed is very difficult to control with any single herbicide application especially when herbicides are applied after the bolting stage. Anecdotal evidence suggests that some chemicals might affect fleabane seed viability and/or dormancy based on the observations that seeds collected from certain paddocks did not germinate. Glasshouse experiments were conducted to investigate whether applications of glyphosate and paraquat could sterilise the weed seeds and affect seed dormancy of fleabane. Results showed that both herbicides affected the seed viability and dormancy, depending on the application timing and the herbicide. The herbicide-induced dormancy decreased during storage under laboratory conditions.
Weeds are a major impediment to crop and pasture production and profitability in Australian farmi... more Weeds are a major impediment to crop and pasture production and profitability in Australian farming systems, and knowledge of their occurrence is vital in devising weed management solutions. This study examined the relationships between weed and crop species from observations made during surveys of randomly selected fields in grain and/or pasture production. Between 2013 and 2017, 996 fields across New South Wales (NSW) were surveyed to record the occurrence and density of weed species. Annual ryegrass (Lolium rigidum) (69% of fields), wild oats (Avena spp.) (60%), and sowthistle (Sonchus oleraceus) (34%) were the most common species identified, with a total of 65 weed species recorded to be occurring in NSW cropping fields. Densities of occurring weeds were low, at one plant per square metre or less. Multiple species of wild oats were recorded, with their occurrence varying between survey regions; for example, Avena sterilis subsp. ludoviciana was more prevalent in the north and Av...
Bovine maternal behavior is known to be influenced by a variety of factors including hormonal med... more Bovine maternal behavior is known to be influenced by a variety of factors including hormonal mediation, breed, age, parity, host genetics and general management practices. Following centuries of varying levels of domestication processes, the behavior of the bovine cow has altered from that of her original wild ungulate ancestors, although many maternal instincts have remained unchanged. The influence of maternal behavior on calf health and performance is of interest to cow-calf beef production operations, as in most instances, the cow is solely responsible for rearing the calf until weaning. However, investigating the magnitude of this influence is challenging, in part because objective measurement of behavioral traits is difficult, particularly in extensive settings. In recent years, while a number of remote monitoring devices have been developed that afford opportunities for objective measurement of behavioral traits in livestock, characterization of physiological mechanisms that...
Barley grass (Hordeum spp.) is an annual weed of southern Australian mixed farming regions causin... more Barley grass (Hordeum spp.) is an annual weed of southern Australian mixed farming regions causing significant crop revenue loss and carcass damage in grazing sheep. Increased reliance on herbicides for management of barley grass has led to the development of herbicide resistance across southern Australia. Integrated weed management tactics have recently been used to manage barley grass populations, and have proven effective in reducing reliance on herbicides for management. Field studies performed in 2016 and 2017 examined the use of post-emergent herbicides and strategic defoliation through mowing on a barley grass infestation in a mixed legume pasture in Wagga Wagga, NSW. This paper presents data from the first year of the study. Significant differences between herbicide-only treatments revealed propaquizafop to be 99% effective in reducing barley grass survival and seed production in contrast to paraquat, which was generally ineffective. A significant interaction between mowing ...
Chaff lining and chaff tramlining are forms of Harvest Weed Seed Control (HWSC) that, owing to th... more Chaff lining and chaff tramlining are forms of Harvest Weed Seed Control (HWSC) that, owing to their low cost and ease-of-implementation, have potential for wide-spread adoption. The chaff environment is likely to be suboptimal (compacted soil and chaff covering) for seed persistence and seedling establishment, therefore, this practice has the potential to be as effective as other forms of HWSC in driving down weed seed banks. To examine the efficacy of chaff lining and chaff tramlining treatments, a series of field experiments were set up at three locations (Wagga Wagga, Narrabri and Irongate) during the 2017 harvest. The aim of these studies was to investigate the survival of 100 seed lots of annual ryegrass, brome grass, wild oats, wild radish, turnip weed, Impact of chaff lining/tramlining on the seed persistence and emergence of weeds
The weed control environment Weed control in Australian crops has been through a revolution over ... more The weed control environment Weed control in Australian crops has been through a revolution over the last three decades, transforming from a dependency on cultivation, with associated soil degradation issues, to herbicide reliance in conservation agriculture (CA) systems. The resulting dramatic change in the crop production environment has resulted in a similarly significant impact on weed control practices. The adoption of CA is underpinned by the availability of highly efficient, selective herbicides, but the absence of alternate weed control technologies has led to an overreliance on herbicides. The widespread evolution of herbicide resistance now threatens the sustainability of CA systems (Powles and Yu 2010). Australian farmers, like those elsewhere, are continually confronted by weeds that impact crop yields, quality and profitability (Oerke 2006). A study by Llewellyn et al. (2016) determined that the cost of weeds to Australian grain growers was $3.3 billion per year due to a combination of lost production ($0.75 billion) and weed control expenditure ($2.57 billion). Herbicide resistance is already a significant component of weed control costs ($187 million) and with no new herbicides in the foreseeable future this cost will continue to escalate (Llewellyn et al. 2016). Historical perspective on weed control in cropping systems Cropping systems and weed control prior to 1980s The impact of weeds on crop yields has been a challenge since crop production began. Initially it was addressed by shifting agriculture from place to place and then, as implements became available, by cultivation practices to destroy weeds (Pratley and Rowell 1987). Some weeds, notably skeleton weed (Chondrilla juncea) readily adapted to this and fields were converted to pasture for a period to enable livestock to control weeds (Cuthbertson 1967, Wells 1970)a stimulus for 'ley farming' in the 1930s. Weed seed collection was a part of the harvest operation for years prior to 1987 and well before the introduction of the current harvest weed seed control (HWSC) technologies. Harvesting equipment used during this period allowed the collection of some weed seed as well as small and broken grain via the screening of grain as it entered the grain tank. This material, referred to as 'seconds' was subsequently collected in an additional storage tank. This technology was relatively effective in that the seconds were 'bagged-off' and fed to the farm poultry or otherwise disposed of. This capability became obsolete from the 1970s with changes in harvester threshing and cleaning systems that enabled increased processing efficiency, and therefore harvester capacity. Weed seeds, however, were dispersed with the chaff back onto the soil. Cropping systems and weed control 1980s-2020 The need to improve soil structure, retain nutrients and conserve soil moisture has driven the widespread adoption of conservation cropping practices based on reduced tillage and stubble retention (FAO 2015, Kassam et al. 2012, Llewellyn et al. 2012). The introduction and development of conservation cropping practices in Australia began in the 1970s and was initially based on the restricted use of cultivation prior to, and at seeding. During this period there was much experimenting with the use of 'knockdown' herbicides paraquat plus diquat (Spray.Seed®) and glyphosate. Adoption rates were initially low but rapidly increased through the 1990s as seeding implement technology developed and the benefits of this approach was realised. Subsequently, tillage operations were further restricted at seeding with knife-point fitted tynes or disc seeding systems.
Take home message • Glyphosate resistant weeds are present in the northern region. Glyphosate fai... more Take home message • Glyphosate resistant weeds are present in the northern region. Glyphosate failed to control all of the fleabane populations tested. Glyphosate resistance was also prevalent in feathertop Rhodes grass, windmill grass and awnless barnyard grass, with resistance detected in 68%, 58% and 36% of populations, respectively. Only 14% of sowthistle populations were resistant to glyphosate • Evolved herbicide resistance to haloxyfop was also detected in feathertop Rhodes grass, albeit at a low frequency • Other herbicides such as 2,4-D amine, propaquizafop and clethodim provided good control of the broadleaf and grass weeds tested • Farmers and agronomists should incorporate non-chemical weed management tactics to ensure sustainability of current herbicides • These survey results provide a first glimpse into the state of herbicide resistance in key crop weeds for Queensland and the Northern region.
Grass seed contamination of sheep carcasses and skins results in significant losses across the Au... more Grass seed contamination of sheep carcasses and skins results in significant losses across the Australian lamb and mutton value chains. Seven grass species found across Victoria (VIC) and New South Wales (NSW) are known to significantly impact carcass quality, with barley grass and brome grass as key perpetrators. To evaluate current trends associated with carcass weed seed contamination, extensive abattoir datasets (2009–2014) provided by Animal Health Australia (AHA) were analysed by state and biogeographic region. Significant differences in regional infestation were noted, with reduced contamination observed in Tasmania (TAS) and VIC in contrast to other states. No significant differences were observed in contamination between NSW and Queensland (QLD). Highest contamination occurred throughout the mixed cropping and pastoral zones, with notable events also in the high rainfall zone. Sex and age of animal were identified to have impacted seed contamination. These findings have imp...
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Perinatal lamb mortality is a major source of reproductive loss, particularly for twins. A study ... more Perinatal lamb mortality is a major source of reproductive loss, particularly for twins. A study was conducted to determine whether provision of shelter in the form of shrub belts (a 'maternity ward') could increase survival of twin lambs compared with hedgerows, and whether hedgerows improve survival of single lambs compared with unsheltered paddocks. Measurements were recorded for Merino x Poll Dorset cross twin lambs born in hedgerows (phalaris or hessian) or shrub belts and single lambs born in hedgerows or unsheltered paddocks over the years 2007 to 2009. Records for 382 single and 726 twin lambs were used. The survival of single lambs was not increased (P=0.06) by hedgerow shelter. The survival of twin lambs in shrubs was 10% higher (P<0.05) than in hessian hedgerow shelter in 2008 to 2009 (0.77 cv 0.70), associated with a reduction in deaths from starvation/mismothering/exposure. The hessian shelter was associated with an increased (P<0.05) growth rate to weaning of single lambs, but the growth rates of twin lambs were lower (P<0.05) in shrub compared with hessian shelter. In 2010 a second study of 178 twin Merino x Poll Dorset cross lambs found that survival of lambs born alive was not improved by shrubs compared with unsheltered paddocks (0.80 vs 0.77; P>0.05). It is concluded that shrub belts which forced twin-bearing ewes to lamb in a sheltered environment reduced perinatal mortality in one of three data sets, but was not repeated. The shrubs take time to establish, and the benefit will be small if weather is mild during lambing.
Flaxleaf fleabane (Conyza bonariensis (L.) Cronquist) has been considered a major weed in dryland... more Flaxleaf fleabane (Conyza bonariensis (L.) Cronquist) has been considered a major weed in dryland cropping systems in Australia. Resistance in populations of C. bonariensis to glyphosate has also been confirmed. The weed is very difficult to control with any single herbicide application especially when herbicides are applied after the bolting stage. Anecdotal evidence suggests that some chemicals might affect fleabane seed viability and/or dormancy based on the observations that seeds collected from certain paddocks did not germinate. Glasshouse experiments were conducted to investigate whether applications of glyphosate and paraquat could sterilise the weed seeds and affect seed dormancy of fleabane. Results showed that both herbicides affected the seed viability and dormancy, depending on the application timing and the herbicide. The herbicide-induced dormancy decreased during storage under laboratory conditions.
Weeds are a major impediment to crop and pasture production and profitability in Australian farmi... more Weeds are a major impediment to crop and pasture production and profitability in Australian farming systems, and knowledge of their occurrence is vital in devising weed management solutions. This study examined the relationships between weed and crop species from observations made during surveys of randomly selected fields in grain and/or pasture production. Between 2013 and 2017, 996 fields across New South Wales (NSW) were surveyed to record the occurrence and density of weed species. Annual ryegrass (Lolium rigidum) (69% of fields), wild oats (Avena spp.) (60%), and sowthistle (Sonchus oleraceus) (34%) were the most common species identified, with a total of 65 weed species recorded to be occurring in NSW cropping fields. Densities of occurring weeds were low, at one plant per square metre or less. Multiple species of wild oats were recorded, with their occurrence varying between survey regions; for example, Avena sterilis subsp. ludoviciana was more prevalent in the north and Av...
Bovine maternal behavior is known to be influenced by a variety of factors including hormonal med... more Bovine maternal behavior is known to be influenced by a variety of factors including hormonal mediation, breed, age, parity, host genetics and general management practices. Following centuries of varying levels of domestication processes, the behavior of the bovine cow has altered from that of her original wild ungulate ancestors, although many maternal instincts have remained unchanged. The influence of maternal behavior on calf health and performance is of interest to cow-calf beef production operations, as in most instances, the cow is solely responsible for rearing the calf until weaning. However, investigating the magnitude of this influence is challenging, in part because objective measurement of behavioral traits is difficult, particularly in extensive settings. In recent years, while a number of remote monitoring devices have been developed that afford opportunities for objective measurement of behavioral traits in livestock, characterization of physiological mechanisms that...
Barley grass (Hordeum spp.) is an annual weed of southern Australian mixed farming regions causin... more Barley grass (Hordeum spp.) is an annual weed of southern Australian mixed farming regions causing significant crop revenue loss and carcass damage in grazing sheep. Increased reliance on herbicides for management of barley grass has led to the development of herbicide resistance across southern Australia. Integrated weed management tactics have recently been used to manage barley grass populations, and have proven effective in reducing reliance on herbicides for management. Field studies performed in 2016 and 2017 examined the use of post-emergent herbicides and strategic defoliation through mowing on a barley grass infestation in a mixed legume pasture in Wagga Wagga, NSW. This paper presents data from the first year of the study. Significant differences between herbicide-only treatments revealed propaquizafop to be 99% effective in reducing barley grass survival and seed production in contrast to paraquat, which was generally ineffective. A significant interaction between mowing ...
Chaff lining and chaff tramlining are forms of Harvest Weed Seed Control (HWSC) that, owing to th... more Chaff lining and chaff tramlining are forms of Harvest Weed Seed Control (HWSC) that, owing to their low cost and ease-of-implementation, have potential for wide-spread adoption. The chaff environment is likely to be suboptimal (compacted soil and chaff covering) for seed persistence and seedling establishment, therefore, this practice has the potential to be as effective as other forms of HWSC in driving down weed seed banks. To examine the efficacy of chaff lining and chaff tramlining treatments, a series of field experiments were set up at three locations (Wagga Wagga, Narrabri and Irongate) during the 2017 harvest. The aim of these studies was to investigate the survival of 100 seed lots of annual ryegrass, brome grass, wild oats, wild radish, turnip weed, Impact of chaff lining/tramlining on the seed persistence and emergence of weeds
The weed control environment Weed control in Australian crops has been through a revolution over ... more The weed control environment Weed control in Australian crops has been through a revolution over the last three decades, transforming from a dependency on cultivation, with associated soil degradation issues, to herbicide reliance in conservation agriculture (CA) systems. The resulting dramatic change in the crop production environment has resulted in a similarly significant impact on weed control practices. The adoption of CA is underpinned by the availability of highly efficient, selective herbicides, but the absence of alternate weed control technologies has led to an overreliance on herbicides. The widespread evolution of herbicide resistance now threatens the sustainability of CA systems (Powles and Yu 2010). Australian farmers, like those elsewhere, are continually confronted by weeds that impact crop yields, quality and profitability (Oerke 2006). A study by Llewellyn et al. (2016) determined that the cost of weeds to Australian grain growers was $3.3 billion per year due to a combination of lost production ($0.75 billion) and weed control expenditure ($2.57 billion). Herbicide resistance is already a significant component of weed control costs ($187 million) and with no new herbicides in the foreseeable future this cost will continue to escalate (Llewellyn et al. 2016). Historical perspective on weed control in cropping systems Cropping systems and weed control prior to 1980s The impact of weeds on crop yields has been a challenge since crop production began. Initially it was addressed by shifting agriculture from place to place and then, as implements became available, by cultivation practices to destroy weeds (Pratley and Rowell 1987). Some weeds, notably skeleton weed (Chondrilla juncea) readily adapted to this and fields were converted to pasture for a period to enable livestock to control weeds (Cuthbertson 1967, Wells 1970)a stimulus for 'ley farming' in the 1930s. Weed seed collection was a part of the harvest operation for years prior to 1987 and well before the introduction of the current harvest weed seed control (HWSC) technologies. Harvesting equipment used during this period allowed the collection of some weed seed as well as small and broken grain via the screening of grain as it entered the grain tank. This material, referred to as 'seconds' was subsequently collected in an additional storage tank. This technology was relatively effective in that the seconds were 'bagged-off' and fed to the farm poultry or otherwise disposed of. This capability became obsolete from the 1970s with changes in harvester threshing and cleaning systems that enabled increased processing efficiency, and therefore harvester capacity. Weed seeds, however, were dispersed with the chaff back onto the soil. Cropping systems and weed control 1980s-2020 The need to improve soil structure, retain nutrients and conserve soil moisture has driven the widespread adoption of conservation cropping practices based on reduced tillage and stubble retention (FAO 2015, Kassam et al. 2012, Llewellyn et al. 2012). The introduction and development of conservation cropping practices in Australia began in the 1970s and was initially based on the restricted use of cultivation prior to, and at seeding. During this period there was much experimenting with the use of 'knockdown' herbicides paraquat plus diquat (Spray.Seed®) and glyphosate. Adoption rates were initially low but rapidly increased through the 1990s as seeding implement technology developed and the benefits of this approach was realised. Subsequently, tillage operations were further restricted at seeding with knife-point fitted tynes or disc seeding systems.
Take home message • Glyphosate resistant weeds are present in the northern region. Glyphosate fai... more Take home message • Glyphosate resistant weeds are present in the northern region. Glyphosate failed to control all of the fleabane populations tested. Glyphosate resistance was also prevalent in feathertop Rhodes grass, windmill grass and awnless barnyard grass, with resistance detected in 68%, 58% and 36% of populations, respectively. Only 14% of sowthistle populations were resistant to glyphosate • Evolved herbicide resistance to haloxyfop was also detected in feathertop Rhodes grass, albeit at a low frequency • Other herbicides such as 2,4-D amine, propaquizafop and clethodim provided good control of the broadleaf and grass weeds tested • Farmers and agronomists should incorporate non-chemical weed management tactics to ensure sustainability of current herbicides • These survey results provide a first glimpse into the state of herbicide resistance in key crop weeds for Queensland and the Northern region.
Grass seed contamination of sheep carcasses and skins results in significant losses across the Au... more Grass seed contamination of sheep carcasses and skins results in significant losses across the Australian lamb and mutton value chains. Seven grass species found across Victoria (VIC) and New South Wales (NSW) are known to significantly impact carcass quality, with barley grass and brome grass as key perpetrators. To evaluate current trends associated with carcass weed seed contamination, extensive abattoir datasets (2009–2014) provided by Animal Health Australia (AHA) were analysed by state and biogeographic region. Significant differences in regional infestation were noted, with reduced contamination observed in Tasmania (TAS) and VIC in contrast to other states. No significant differences were observed in contamination between NSW and Queensland (QLD). Highest contamination occurred throughout the mixed cropping and pastoral zones, with notable events also in the high rainfall zone. Sex and age of animal were identified to have impacted seed contamination. These findings have imp...
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