title: Dairy calves' preference for rearing substrate

authors: Worth, Gemma

subjects: Dairy calves

abstract: Rearing substrate is an important component of the pre-weaning environment of dairy calves. Traditional substrate types, such as sawdust, are becoming difficult and/or expensive for farmers to obtain in New Zealand. Therefore, there is a need to evaluate alternative rearing substrates for dairy calves that that are economically viable for farmers, readily available and provide an acceptable level of animal welfare. The preference of dairy calves for four different rearing substrates and the effects on behaviour and physiology were evaluated. At 1 wk of age, 24 calves were housed in groups of four, in pens which were evenly divided into four rearing substrates: sawdust, rubber, sand and stones. During the first 3 d calves were given free access to all four substrates. Calves were then restricted to each substrate type for 48 h. In order to rank preference, calves were subsequently exposed to two surfaces simultaneously for 48 h until calves experienced all six treatment combinations. Finally, calves were given free access to all four substrates simultaneously for 48 h. Lying behaviour and location in the pen was recorded for 24 h at the end of each experimental period using handycams and accelerometers. Preference was determined based on lying times on each substrate. The insulating properties of each substrate were assessed using iButtons®. 
During the initial free choice period, the proportion of time spent standing (p < .001) and lying (p < .001) was influenced by substrate. Calves spent a higher proportion of time on sawdust (88%) than all other substrates (rubber: 6%, sand: 4% and stones: 3%). 
When restricted to each substrate, calves spent more (p <.05) time running on sawdust, rubber and sand compared to calves on stones. There were no effects (p > .05) of rearing substrate on the frequency of jumps, buck/kicks, head to object and mount/frontal pushing. Calves spent more (p < .05) time lying on sawdust and rubber in comparison to sand and stones. There were no effects (p > .05) of rearing substrate on the number and duration of lying bouts. We detected no effect (p > .05) of rearing substrate on concentrations of cortisol, lactate, glucose, or white blood cell, neutrophil and lymphocyte count or the neutrophil:lymphocyte ratio. The insulating properties were greatest for sawdust and lowest for sand.
During the pairwise choice period, calves had a strong preference for one substrate over another, spending on average, 89% of their time on the preferred surface. Calves preference ranking was for sawdust, rubber, sand then stones as determined by the proportion of time spent on each surface. At the end of the study, when given free access to all rearing substrates again, calves spent a higher proportion of time on sawdust (85%) than all other substrates (rubber: 5%, sand: 7% and stones: 3%). 
In conclusion, dairy calves showed a clear preference for sawdust over rubber, sand and stones. This preference remained consistent over the course of the study. The calves’ preference for sawdust may be associated with the physical and thermal properties in comparison to the alternative substrates. However, factors such as cost to the farmer, availability and practicality of alternative substrates need to be considered along with animal preferences before any recommendations can be made.

text: Dairy calves' preference for rearing substrate Rearing substrate is an important component of the pre-weaning environment of dairy calves. Traditional substrate types, such as sawdust, are becoming difficult and/or expensive for farmers to obtain in New Zealand. Therefore, there is a need to evaluate alternative rearing substrates for dairy calves that that are economically viable for farmers, readily available and provide an acceptable level of animal welfare. The preference of dairy calves for four different rearing substrates and the effects on behaviour and physiology were evaluated. At 1 wk of age, 24 calves were housed in groups of four, in pens which were evenly divided into four rearing substrates: sawdust, rubber, sand and stones. During the first 3 d calves were given free access to all four substrates. Calves were then restricted to each substrate type for 48 h. In order to rank preference, calves were subsequently exposed to two surfaces simultaneously for 48 h until calves experienced all six treatment combinations. Finally, calves were given free access to all four substrates simultaneously for 48 h. Lying behaviour and location in the pen was recorded for 24 h at the end of each experimental period using handycams and accelerometers. Preference was determined based on lying times on each substrate. The insulating properties of each substrate were assessed using iButtons®. 
During the initial free choice period, the proportion of time spent standing (p < .001) and lying (p < .001) was influenced by substrate. Calves spent a higher proportion of time on sawdust (88%) than all other substrates (rubber: 6%, sand: 4% and stones: 3%). 
When restricted to each substrate, calves spent more (p <.05) time running on sawdust, rubber and sand compared to calves on stones. There were no effects (p > .05) of rearing substrate on the frequency of jumps, buck/kicks, head to object and mount/frontal pushing. Calves spent more (p < .05) time lying on sawdust and rubber in comparison to sand and stones. There were no effects (p > .05) of rearing substrate on the number and duration of lying bouts. We detected no effect (p > .05) of rearing substrate on concentrations of cortisol, lactate, glucose, or white blood cell, neutrophil and lymphocyte count or the neutrophil:lymphocyte ratio. The insulating properties were greatest for sawdust and lowest for sand.
During the pairwise choice period, calves had a strong preference for one substrate over another, spending on average, 89% of their time on the preferred surface. Calves preference ranking was for sawdust, rubber, sand then stones as determined by the proportion of time spent on each surface. At the end of the study, when given free access to all rearing substrates again, calves spent a higher proportion of time on sawdust (85%) than all other substrates (rubber: 5%, sand: 7% and stones: 3%). 
In conclusion, dairy calves showed a clear preference for sawdust over rubber, sand and stones. This preference remained consistent over the course of the study. The calves’ preference for sawdust may be associated with the physical and thermal properties in comparison to the alternative substrates. However, factors such as cost to the farmer, availability and practicality of alternative substrates need to be considered along with animal preferences before any recommendations can be made.

year: 2014

title: Ecology of Restored Gully Forest Patches in Hamilton Ecological District

authors: MacKay, David Bruce

subjects: restoration

abstract: Attempts to protect and restore gully and bush remnants began about 20 years ago in the Hamilton Ecological District especially near Hamilton City. Research was carried out to evaluate the restoration efforts. Factors affecting the ecological failure or success of the restoration plantings were investigated.

Sixty-six experimental plots were set up in both public and privately owned areas within Hamilton City and adjacent gully systems. The plots were assessed to compare vegetation change in patches planted in native species with naturally regenerating patches and mature native forest. A range of variables measured key ecosystem functional, structural and compositional attributes.  Different planting and maintenance regimes and environmental factors likely to be implicated in the success of plantings were also evaluated. Analysis included ANOVA comparisons between experimental blocks and ordination and classification of the plots using principal components and dendrogram clustering.

Vegetation change in the most significant variables, towards the reference mature forest ecological state was found to be more rapid in four of the experimental blocks comprised of twenty plots. Three of the experimental blocks, comprised of 12 plots, are deteriorating. In the deteriorating blocks, native species recruitment and species diversity of regeneration were low, and exotic liana species were increasing. The presence of and increase with age in the number of native lianas and epiphytes in restoration plots was generally poor. 

Treatments that generally appeared beneficial for patch ecological condition included good quality maintenance and low level of human disturbance. Planting a diverse range of species and enrichment planting appeared more beneficial if they were linked to good maintenance. Close proximity of seed sources was also indicated as a factor in good ecological condition of patches. Use of exotic canopy species as a nurse for restoration appeared to reduce success of the restoration. However, the canopy effect may be due to soil condition (compaction) or allelopathic effects of canopy species.

In the cluster and principal components analysis, the plots clustered into three distinct groups, based on soil texture: one with heavier soils and two with lighter soils. Within each group, there was a trend towards more advanced ecological condition with age. The signature species associations identified with each cluster reflected the likely soil water availability. Species composition was shown to be related to age but less related to the functional and structural condition of restoration patches. 

In terms of the theoretical aspects of restoration, the findings suggest that restoration in isolated urban restoration patches, requires assistance in the form of enrichment within or peripheral plantings in the neighbourhood of the patches. The research emphasizes the importance of the human and alien species context and in particular the value of controlling human disturbance. It supports the concept of multiple restoration pathways and the concept of restoration as a means to speed up vegetation change if accompanied by appropriate management. 

However, the research does not support the idea of a closely defined assembly order for the vegetation community. Attending to the structure and function, particularly the regeneration and dispersal functions, of restoration patches appears to be more important for successful restoration. Composition appears to follow from appropriate structure and function.

Recommendations include the following: The community should set clear goals for restoration. Species should be selected for initial establishment and future seed sources and combined with careful site-species matching. Soil conditioning should be considered on difficult sites. The choice of methods should balance rapid cover needs with the need to maintain species diversity. Maintenance should be minimally disturbing but of a high quality. Human disturbance should be actively managed. Planting within the vicinity of restoration patches, should be designed to enhance native and minimise alien species seed sources.

Further exploration of the effects of exotic nurse species on restoration would be useful in order to reach conclusions that are more definite. Further research into low disturbance methods of enrichment would be valuable. Attempting restoration by enrichment of weed-dominated sites would also be an interesting trial.

text: Ecology of Restored Gully Forest Patches in Hamilton Ecological District Attempts to protect and restore gully and bush remnants began about 20 years ago in the Hamilton Ecological District especially near Hamilton City. Research was carried out to evaluate the restoration efforts. Factors affecting the ecological failure or success of the restoration plantings were investigated.

Sixty-six experimental plots were set up in both public and privately owned areas within Hamilton City and adjacent gully systems. The plots were assessed to compare vegetation change in patches planted in native species with naturally regenerating patches and mature native forest. A range of variables measured key ecosystem functional, structural and compositional attributes.  Different planting and maintenance regimes and environmental factors likely to be implicated in the success of plantings were also evaluated. Analysis included ANOVA comparisons between experimental blocks and ordination and classification of the plots using principal components and dendrogram clustering.

Vegetation change in the most significant variables, towards the reference mature forest ecological state was found to be more rapid in four of the experimental blocks comprised of twenty plots. Three of the experimental blocks, comprised of 12 plots, are deteriorating. In the deteriorating blocks, native species recruitment and species diversity of regeneration were low, and exotic liana species were increasing. The presence of and increase with age in the number of native lianas and epiphytes in restoration plots was generally poor. 

Treatments that generally appeared beneficial for patch ecological condition included good quality maintenance and low level of human disturbance. Planting a diverse range of species and enrichment planting appeared more beneficial if they were linked to good maintenance. Close proximity of seed sources was also indicated as a factor in good ecological condition of patches. Use of exotic canopy species as a nurse for restoration appeared to reduce success of the restoration. However, the canopy effect may be due to soil condition (compaction) or allelopathic effects of canopy species.

In the cluster and principal components analysis, the plots clustered into three distinct groups, based on soil texture: one with heavier soils and two with lighter soils. Within each group, there was a trend towards more advanced ecological condition with age. The signature species associations identified with each cluster reflected the likely soil water availability. Species composition was shown to be related to age but less related to the functional and structural condition of restoration patches. 

In terms of the theoretical aspects of restoration, the findings suggest that restoration in isolated urban restoration patches, requires assistance in the form of enrichment within or peripheral plantings in the neighbourhood of the patches. The research emphasizes the importance of the human and alien species context and in particular the value of controlling human disturbance. It supports the concept of multiple restoration pathways and the concept of restoration as a means to speed up vegetation change if accompanied by appropriate management. 

However, the research does not support the idea of a closely defined assembly order for the vegetation community. Attending to the structure and function, particularly the regeneration and dispersal functions, of restoration patches appears to be more important for successful restoration. Composition appears to follow from appropriate structure and function.

Recommendations include the following: The community should set clear goals for restoration. Species should be selected for initial establishment and future seed sources and combined with careful site-species matching. Soil conditioning should be considered on difficult sites. The choice of methods should balance rapid cover needs with the need to maintain species diversity. Maintenance should be minimally disturbing but of a high quality. Human disturbance should be actively managed. Planting within the vicinity of restoration patches, should be designed to enhance native and minimise alien species seed sources.

Further exploration of the effects of exotic nurse species on restoration would be useful in order to reach conclusions that are more definite. Further research into low disturbance methods of enrichment would be valuable. Attempting restoration by enrichment of weed-dominated sites would also be an interesting trial.

year: 2006

title: Low copper levels measured in the aortic wall of New Zealand patients with non-syndromic ascending thoracic aortic aneurysm

authors: El-Gamel, Adam

subjects: Ascending aortic aneurysm

abstract: OBJECTIVES: Studies in animals have shown causal relationships between copper (Cu) deficiency and the development of thoracic aortic aneurysms (TAAs) [1, 2]. Cu deficiency is widespread in New Zealand (NZ) soils; the high soil pH from the use of lime fertilizers reduces the bioavailability of Cu for grazing animals and growing plants; this, in turn, reduces Cu availability in the NZ human food chain. Our study is a pilot study to explore associations between Cu and TAA. We measured Cu levels in aneurysmal aortic tissues in patients undergoing Bentall procedures and non-aneurysmal aortic tissue from coronary artery bypass graft patients. METHODS: Aortic samples were collected from 2 groups of patients during elective open-heart surgery over 4 months between November 2017 and February 2018. The groups were a TAA group, patients with non-syndromic aortic aneurysm and without the bicuspid aortic valve or known infectious or inflammatory condition (ANEURYSM; n = 13), and a control coronary artery bypass graft group (CONTROL; n = 44). Standardized digested dry tissue weighed samples were analysed from both groups. Tissue extraction of trace elements was carried out using HCl-H2O2 digestion and a highly sensitive analytical technique, inductively coupled plasma mass spectrometry-used to measure elemental concentrations. RESULTS: Cu concentration (mean ± SD) was significantly lower in ANEURYSM (3.34 ± 0.16 µg/g) when compared to the CONTROL group tissues (4.33 ± 0.20 µg/g) (dry weight; mean ± SD; Student's t-test, P < 0.05). Over 46% of the Aneurysm patients were Maori and live in a geographically Cu-deficient NZ territory. CONCLUSIONS: Cu deficiency may play a role in the development or progression of non-syndromic ascending aortic aneurysms in NZ. Maori patients are more at risk as they commonly live in rural NZ, dependent on locally grown nutritional sources. Further studies are required to confirm this exciting finding and to establish cause and effect relationship.

text: Low copper levels measured in the aortic wall of New Zealand patients with non-syndromic ascending thoracic aortic aneurysm OBJECTIVES: Studies in animals have shown causal relationships between copper (Cu) deficiency and the development of thoracic aortic aneurysms (TAAs) [1, 2]. Cu deficiency is widespread in New Zealand (NZ) soils; the high soil pH from the use of lime fertilizers reduces the bioavailability of Cu for grazing animals and growing plants; this, in turn, reduces Cu availability in the NZ human food chain. Our study is a pilot study to explore associations between Cu and TAA. We measured Cu levels in aneurysmal aortic tissues in patients undergoing Bentall procedures and non-aneurysmal aortic tissue from coronary artery bypass graft patients. METHODS: Aortic samples were collected from 2 groups of patients during elective open-heart surgery over 4 months between November 2017 and February 2018. The groups were a TAA group, patients with non-syndromic aortic aneurysm and without the bicuspid aortic valve or known infectious or inflammatory condition (ANEURYSM; n = 13), and a control coronary artery bypass graft group (CONTROL; n = 44). Standardized digested dry tissue weighed samples were analysed from both groups. Tissue extraction of trace elements was carried out using HCl-H2O2 digestion and a highly sensitive analytical technique, inductively coupled plasma mass spectrometry-used to measure elemental concentrations. RESULTS: Cu concentration (mean ± SD) was significantly lower in ANEURYSM (3.34 ± 0.16 µg/g) when compared to the CONTROL group tissues (4.33 ± 0.20 µg/g) (dry weight; mean ± SD; Student's t-test, P < 0.05). Over 46% of the Aneurysm patients were Maori and live in a geographically Cu-deficient NZ territory. CONCLUSIONS: Cu deficiency may play a role in the development or progression of non-syndromic ascending aortic aneurysms in NZ. Maori patients are more at risk as they commonly live in rural NZ, dependent on locally grown nutritional sources. Further studies are required to confirm this exciting finding and to establish cause and effect relationship.

year: 2022-09-09