title: Disbudding of dairy goat kids: Refining protocols to reduce or eliminate pain

authors: Hempstead, Melissa Nicole

subjects: Disbudding

abstract: The aim of this thesis was to investigate potential improvements for disbudding dairy goat kids to eliminate or reduce pain. Behavioural and physiological measures were used to evaluate: (1) pain associated with four disbudding methods, and (2) the effect of pain mitigation on cautery disbudded goat kids. Caustic paste and cryosurgical disbudding and clove oil injection initially showed promise as less painful alternatives to cautery disbudding. However, caustic paste and cryosurgical disbudding were found to be more painful, as cortisol concentrations and the frequencies of head-directed behaviours were higher than for cautery disbudded kids. Clove oil injection appeared to cause no more pain than cautery disbudding based on similar cortisol concentrations and head-directed behaviour, but caused less tissue damage. Alternatives to current practices must be efficacious in preventing horn or scur growth, therefore the effect of clove oil injection and two cautery disbudding techniques (horn bud removed vs. left intact) on horn growth were evaluated. Clove oil was ineffective at preventing horns or scurs compared with cautery disbudding. In addition, cautery disbudding by removing the horn bud was more successful at preventing growth than leaving the horn bud intact. As using a cautery iron to remove the horn bud appeared to be the most efficacious method evaluated in this thesis, the effect of isoflurane and meloxicam on pain associated with cautery disbudding was investigated. Goat kids disbudded under isoflurane, with or without meloxicam, had lower cortisol concentrations and displayed fewer head-directed behaviours than goat kids that were cautery disbudded without pain relief, suggesting that isoflurane can reduce pain associated with cautery disbudding. Overall, the results of this thesis suggest that cautery disbudding is an effective practice but should ideally be carried out using isoflurane to reduce pain; also, complete horn bud removal lowers the risk of horn or scur development. These results support the continued use of cautery disbudding by the dairy goat industry but suggest pain relief could significantly improve the welfare of dairy goats on farm.

text: Disbudding of dairy goat kids: Refining protocols to reduce or eliminate pain The aim of this thesis was to investigate potential improvements for disbudding dairy goat kids to eliminate or reduce pain. Behavioural and physiological measures were used to evaluate: (1) pain associated with four disbudding methods, and (2) the effect of pain mitigation on cautery disbudded goat kids. Caustic paste and cryosurgical disbudding and clove oil injection initially showed promise as less painful alternatives to cautery disbudding. However, caustic paste and cryosurgical disbudding were found to be more painful, as cortisol concentrations and the frequencies of head-directed behaviours were higher than for cautery disbudded kids. Clove oil injection appeared to cause no more pain than cautery disbudding based on similar cortisol concentrations and head-directed behaviour, but caused less tissue damage. Alternatives to current practices must be efficacious in preventing horn or scur growth, therefore the effect of clove oil injection and two cautery disbudding techniques (horn bud removed vs. left intact) on horn growth were evaluated. Clove oil was ineffective at preventing horns or scurs compared with cautery disbudding. In addition, cautery disbudding by removing the horn bud was more successful at preventing growth than leaving the horn bud intact. As using a cautery iron to remove the horn bud appeared to be the most efficacious method evaluated in this thesis, the effect of isoflurane and meloxicam on pain associated with cautery disbudding was investigated. Goat kids disbudded under isoflurane, with or without meloxicam, had lower cortisol concentrations and displayed fewer head-directed behaviours than goat kids that were cautery disbudded without pain relief, suggesting that isoflurane can reduce pain associated with cautery disbudding. Overall, the results of this thesis suggest that cautery disbudding is an effective practice but should ideally be carried out using isoflurane to reduce pain; also, complete horn bud removal lowers the risk of horn or scur development. These results support the continued use of cautery disbudding by the dairy goat industry but suggest pain relief could significantly improve the welfare of dairy goats on farm.

year: 2018

title: Effect of thermomechanical processing on the mechanical properties of cost-effective powder metallurgy titanium-based materials

authors: Romero Villarreal, Carlos

subjects: Titanium alloys

abstract: Despite their excellent balance of properties, titanium alloys are still a niche material whose range of applications is limited by the high cost of their manufacturing. With recent developments, powder metallurgy (PM) approaches, in particular the blended elemental (BE) route, are able to reduce considerably the cost of manufacturing while keeping a reasonable performance, mostly in terms of tensile strength and ductility. The cost reduction of the BE approach derives from the simplification of the process by removing a large amount of re-melting and ingot breakdown operations, regardless of the use of the approach as a net-shape technology. However, in terms of fatigue behaviour, the performance of these alloys is generally worse than conventional processes unless additional steps are applied. This thesis aims to study the mechanical behaviour, with emphasis on the fatigue behaviour, of two cost-effective titanium alloys in order to find the key processing, microstructural and texture parameters that control their performance, with the goal of achieving similar properties to conventional wrought alloys with a reduction of the cost. These alloys, a conventional Ti-6Al-4V composition and a non-conventional low-cost Ti-5Fe composition, were processed following the blended elemental approach and thermomechanical processing, via hot extrusion, was subsequently applied. A variety of microstructures and textures were achieved under different extrusion conditions, which were further modified by applying additional heat treatments.
The tensile behaviour of both Ti-6Al-4V and Ti-5Fe alloys is strongly dependent on the processing conditions. Fully lamellar microstructures (from processing in the β phase) showed similar strength levels but considerably lower ductility compared to alloys with bimodal microstructures and stronger texture (from processing in the α+β phase). In the case of Ti-5Fe, moreover, there was a Fe partitioning effect that, when the processing temperature is low enough, leads to a sharp increase in both the strength and the ability to deform past necking took place. Heat treatments in Ti-6Al-4V alloys were useful in order to increase the strength as well as to keep the ductility similar or even increase it to higher values. The tensile behaviour of Ti-5Fe alloys was more tuneable, achieving higher differences in strength and ductility with the as-extruded conditions, even though this happened by trading-off. Overall, Ti-6Al-4V alloys outperformed Ti-5Fe alloys as their strength was typically higher (associated to their higher amount of alloying elements) as well as their ductility, due to their higher ability to deform past necking, which was very limited for Ti-5Fe alloys in most cases.
The fatigue behaviour of the alloys was found to as dependent on the chemistry as on the microstructure and the texture. While the Ti-6Al-4V alloy is not affected by the residual porosity left after thermomechanical processing, the Ti-5Fe alloy shows pores in the region where fatigue damage begins. In the Ti-6Al-4V alloy, it was found that texturing had a much stronger effect on the fatigue strength of the alloy than microstructural refinement. Therefore, the PM Ti-6Al-4V alloy processed in the α+β phase had a higher fatigue strength than alloys processed in the β phase, regardless if the latter has fully lamellar or acicular microstructure. In the case of the Ti-5Fe alloy, two conditions processed in the α+β phase were studied, and it was found that the Fe concentration in transformed β (which is higher when there is a larger amount of primary α) had a critical effect on the fatigue behaviour, overriding the effect of texture or microstructural refinement. This leads to the Ti-5Fe alloy processed at a lower temperature in the α+β phase showing a much lower fatigue strength compared with the alloy processed just below the β transus, despite the fact that its texture and microstructure were, in theory, optimal for fatigue behaviour.
It is concluded that, in order to process cost-effective Ti alloys with fatigue performance comparable to wrought alloys with conventional compositions (with fatigue strength in the range of 650 MPa), thermomechanical processing in the α+β phase must be applied to make use of the strong texturing of the alloy. However, in the case of alloys containing β-eutectoid elements like Fe, the range of temperatures is limited as the partitioning of the alloying element results in severe reduction of the fatigue strength.

text: Effect of thermomechanical processing on the mechanical properties of cost-effective powder metallurgy titanium-based materials Despite their excellent balance of properties, titanium alloys are still a niche material whose range of applications is limited by the high cost of their manufacturing. With recent developments, powder metallurgy (PM) approaches, in particular the blended elemental (BE) route, are able to reduce considerably the cost of manufacturing while keeping a reasonable performance, mostly in terms of tensile strength and ductility. The cost reduction of the BE approach derives from the simplification of the process by removing a large amount of re-melting and ingot breakdown operations, regardless of the use of the approach as a net-shape technology. However, in terms of fatigue behaviour, the performance of these alloys is generally worse than conventional processes unless additional steps are applied. This thesis aims to study the mechanical behaviour, with emphasis on the fatigue behaviour, of two cost-effective titanium alloys in order to find the key processing, microstructural and texture parameters that control their performance, with the goal of achieving similar properties to conventional wrought alloys with a reduction of the cost. These alloys, a conventional Ti-6Al-4V composition and a non-conventional low-cost Ti-5Fe composition, were processed following the blended elemental approach and thermomechanical processing, via hot extrusion, was subsequently applied. A variety of microstructures and textures were achieved under different extrusion conditions, which were further modified by applying additional heat treatments.
The tensile behaviour of both Ti-6Al-4V and Ti-5Fe alloys is strongly dependent on the processing conditions. Fully lamellar microstructures (from processing in the β phase) showed similar strength levels but considerably lower ductility compared to alloys with bimodal microstructures and stronger texture (from processing in the α+β phase). In the case of Ti-5Fe, moreover, there was a Fe partitioning effect that, when the processing temperature is low enough, leads to a sharp increase in both the strength and the ability to deform past necking took place. Heat treatments in Ti-6Al-4V alloys were useful in order to increase the strength as well as to keep the ductility similar or even increase it to higher values. The tensile behaviour of Ti-5Fe alloys was more tuneable, achieving higher differences in strength and ductility with the as-extruded conditions, even though this happened by trading-off. Overall, Ti-6Al-4V alloys outperformed Ti-5Fe alloys as their strength was typically higher (associated to their higher amount of alloying elements) as well as their ductility, due to their higher ability to deform past necking, which was very limited for Ti-5Fe alloys in most cases.
The fatigue behaviour of the alloys was found to as dependent on the chemistry as on the microstructure and the texture. While the Ti-6Al-4V alloy is not affected by the residual porosity left after thermomechanical processing, the Ti-5Fe alloy shows pores in the region where fatigue damage begins. In the Ti-6Al-4V alloy, it was found that texturing had a much stronger effect on the fatigue strength of the alloy than microstructural refinement. Therefore, the PM Ti-6Al-4V alloy processed in the α+β phase had a higher fatigue strength than alloys processed in the β phase, regardless if the latter has fully lamellar or acicular microstructure. In the case of the Ti-5Fe alloy, two conditions processed in the α+β phase were studied, and it was found that the Fe concentration in transformed β (which is higher when there is a larger amount of primary α) had a critical effect on the fatigue behaviour, overriding the effect of texture or microstructural refinement. This leads to the Ti-5Fe alloy processed at a lower temperature in the α+β phase showing a much lower fatigue strength compared with the alloy processed just below the β transus, despite the fact that its texture and microstructure were, in theory, optimal for fatigue behaviour.
It is concluded that, in order to process cost-effective Ti alloys with fatigue performance comparable to wrought alloys with conventional compositions (with fatigue strength in the range of 650 MPa), thermomechanical processing in the α+β phase must be applied to make use of the strong texturing of the alloy. However, in the case of alloys containing β-eutectoid elements like Fe, the range of temperatures is limited as the partitioning of the alloying element results in severe reduction of the fatigue strength.

year: 2020

title: Understanding the context of hospital transfers and away-from-home hospitalisations for Māori

authors: Cormack, Donna

subjects: Humans

abstract: In Aotearoa New Zealand, people regularly travel away from their home to receive hospital care. While the role of whānau support for patients in hospital is critical for Māori, there is little information about away-from-home hospitalisations. This paper describes the frequency and patterning of away-from-home hospitalisations and inter-hospital transfers for Māori. Data from the National Minimum Dataset (NMDS), for the 6-year period of 1 January 2009-31 December 2014, were analysed. Basic frequencies, means and descriptive statistics were produced using SAS software. We found that more than 10% of all routine hospitalisations constituted an away-from-home hospitalisation for Māori; that is, a hospitalisation that was in a district health board (DHB) other than the DHB of usual residence for the patient. One quarter (25.19%) of transfer hospitalisations were to a DHB other than the patient's DHB of domicile. Away-from-home hospital admissions increase for Māori as deprivation increases for both routine and transfer admissions, with over half of Māori hospital admissions among people who live in areas of high deprivation. This analysis aids in understanding away-from-home hospitalisations for Māori whānau, the characteristics associated with these types of hospitalisations and supports the development and implementation of policies which better meet whānau Māori needs. The cumulative impact of the need to travel to hospital for care, levels of poverty and a primarily reimbursement-based travel assistance system all perpetuate an unequal cost burden placed upon Māori whānau.

text: Understanding the context of hospital transfers and away-from-home hospitalisations for Māori In Aotearoa New Zealand, people regularly travel away from their home to receive hospital care. While the role of whānau support for patients in hospital is critical for Māori, there is little information about away-from-home hospitalisations. This paper describes the frequency and patterning of away-from-home hospitalisations and inter-hospital transfers for Māori. Data from the National Minimum Dataset (NMDS), for the 6-year period of 1 January 2009-31 December 2014, were analysed. Basic frequencies, means and descriptive statistics were produced using SAS software. We found that more than 10% of all routine hospitalisations constituted an away-from-home hospitalisation for Māori; that is, a hospitalisation that was in a district health board (DHB) other than the DHB of usual residence for the patient. One quarter (25.19%) of transfer hospitalisations were to a DHB other than the patient's DHB of domicile. Away-from-home hospital admissions increase for Māori as deprivation increases for both routine and transfer admissions, with over half of Māori hospital admissions among people who live in areas of high deprivation. This analysis aids in understanding away-from-home hospitalisations for Māori whānau, the characteristics associated with these types of hospitalisations and supports the development and implementation of policies which better meet whānau Māori needs. The cumulative impact of the need to travel to hospital for care, levels of poverty and a primarily reimbursement-based travel assistance system all perpetuate an unequal cost burden placed upon Māori whānau.

year: 2022-11-11