The main aim in analysing data for animal movement is to reveal behavioural mechanisms by which t... more The main aim in analysing data for animal movement is to reveal behavioural mechanisms by which the animal utilises complex and variable environments. Movement data also reflects behaviours that are heterogeneous. Statistical analysis of multidimensional, auto-correlated and irregular interval movement data is difficult. Animal tracking devices such as collars with global positioning system (GPS) capabilities enable continuous and automatic tracking of an animal's position and the value of suck spatial-temporal information is improved if the corresponding activity of the animal is known. GPS animal tracking devices (collars) were used in the spring (Sep-Nov) of 2008 and 2009 to monitor movement of 20 pregnant grazing fine wool Merino ewes. Mean daily velocities (m/s) were calculated for three time periods within a day: 0500-1100h, 1200-1800h and 1900-0400h and subjected to Bayesian change-point analysis (BCP) in an attempt to identify when a change in behaviour (reduction in vel...
This experiment was done to investigate microbial contamination and in situ disappearance rates o... more This experiment was done to investigate microbial contamination and in situ disappearance rates of dry matter (DM), N and 15N of fresh labeled ryegrass. Perennial ryegrass (Lolium perenne) were labeled with 15N during growth in a glasshouse, harvested at 4th leaves stage and were incubated up to 34 h in situ in the rumen of 3 individually housed sheep. The animals were fed 800 g/d chopped alfalfa and had free access to drinking water. Six bags were placed in the rumen of each sheep simultaneously and removed after 0, 3, 7, 12, 21 and 33 h after incubation. The results were fitted to a model describing the degradation of DM and total N with time. It was found that residues from the washed zero time bags had lower 15N enrichments (7.7% vs. 8.3% enriched) than the original fresh samples. Under-estimation of effective degradability (ED) of protein in fresh forages by about 4% would have potential consequences for predictions of ruminally fermentable and escape protein and thus for dieta...
Time spent feeding by grazing cattle is an important predictor of intake and feed efficiency. Thi... more Time spent feeding by grazing cattle is an important predictor of intake and feed efficiency. This study examined the use of automatic supplement weighing (ASW) units for monitoring voluntary access of breeding cows (n = 430) to mineral block supplements in an extensive rangeland of northern Australia. The ASW units (n = 10) were located within each of experimental sites (5 units per site; Bore and Eldons). Over the 62 days of data collection, 85%, 13%, and 2% of cows spent <600, 600–1200, >1200 min accessing supplements, respectively, with between-animal variation (CV) of 107%. A total of 133 cows visited both sites while 142 and 155 cows visited only Bore and Eldons, respectively. Most visits (80–90%) were recorded during the day (800–1700 h), 7–17% during the night (1800–2300 h), and 3% during the dawn (0–700 h). Time spent accessing supplements differed between ASW units across the two sites (p < 0.001) and varied according to the day of visits (p < 0.001). There was...
Identifying the licking behaviour in beef cattle may provide a means to measure time spent lickin... more Identifying the licking behaviour in beef cattle may provide a means to measure time spent licking for estimating individual block supplement intake. This study aimed to determine the effectiveness of tri-axial accelerometers deployed in a neck-collar and an ear-tag, to characterise the licking behaviour of beef cattle in individual pens. Four, 2-year-old Angus steers weighing 368 ± 9.3 kg (mean ± SD) were used in a 14-day study. Four machine learning (ML) algorithms (decision trees [DT], random forest [RF], support vector machine [SVM] and k-nearest neighbour [kNN]) were employed to develop behaviour classification models using three different ethograms: (1) licking vs. eating vs. standing vs. lying; (2) licking vs. eating vs. inactive; and (3) licking vs. non-licking. Activities were video-recorded from 1000 to 1600 h daily when access to supplement was provided. The RF algorithm exhibited a superior performance in all ethograms across the two deployment modes with an overall accu...
Pharmacokinetics of leptin in mammals has received limited attention and only one study has exami... more Pharmacokinetics of leptin in mammals has received limited attention and only one study has examined more than two time points and this was in ob/ob mice. This study is the first to observe the distribution of leptin over a time course in female mice. A physiologic dose (12 ng) of radiolabelled leptin was injected in adult female mice via the lateral tail vein and tissues were dissected out and measured for radioactivity over a time course up to two hours. Major targets for administered leptin included the liver, kidneys, gastrointestinal tract and the skin while the lungs had high concentrations of administered leptin per gram of tissue. Leptin was also found to enter the lumen of the digestive tract intact from the plasma. Very little of the dose (<1 %) was recovered from the brain at any time. Consequently we confirm that the brain is not a major target for leptin from the periphery, although it may be very sensitive to leptin that does get to the hypothalamus. Several of the ...
Behaviour is a useful indicator of an individual animal’s overall wellbeing. There is widespread ... more Behaviour is a useful indicator of an individual animal’s overall wellbeing. There is widespread agreement that measuring and monitoring individual behaviour autonomously can provide valuable opportunities to trigger and refine on-farm management decisions. Conventionally, this has required visual observation of animals across a set time period. Technological advancements, such as animal-borne accelerometers, are offering 24/7 monitoring capability. Accelerometers have been used in research to quantify animal behaviours for a number of years. Now, technology and software developers, and more recently decision support platform providers, are integrating to offer commercial solutions for the extensive livestock industries. For these systems to function commercially, data must be captured, processed and analysed in sync with data acquisition. Practically, this requires a continuous stream of data or a duty cycled data segment and, from an analytics perspective, the application of movin...
Journal of Animal Physiology and Animal Nutrition, 2019
Nitrate (NO3¯) is an effective non‐protein nitrogen source for gut microbes and reduces enteric m... more Nitrate (NO3¯) is an effective non‐protein nitrogen source for gut microbes and reduces enteric methane (CH4) production in ruminants. Nitrate is reduced to ammonia by rumen bacteria with nitrite (NO2¯) produced as an intermediate. The absorption of NO2¯ can cause methaemoglobinaemia in ruminants. Metabolism of NO3¯ and NO2¯ in blood and animal tissues forms nitric oxide (NO) which has profound physiological effects in ruminants and has been shown to increase glucose uptake and insulin secretion in rodents and humans. We hypothesized that absorption of small quantities of NO2¯ resulting from a low‐risk dose of dietary NO3¯ will increase insulin sensitivity (SI) and glucose uptake in sheep. We evaluated the effect of feeding sheep with a diet supplemented with 18 g NO3¯/kg DM or urea (Ur) isonitrogenously to NO3¯, on insulin and glucose dynamics. A glucose tolerance test using an intravenous bolus of 1 ml/kg LW of 24% (w/v) glucose was conducted in twenty sheep, with 10 sheep receivi...
The main aim in analysing data for animal movement is to reveal behavioural mechanisms by which t... more The main aim in analysing data for animal movement is to reveal behavioural mechanisms by which the animal utilises complex and variable environments. Movement data also reflects behaviours that are heterogeneous. Statistical analysis of multidimensional, auto-correlated and irregular interval movement data is difficult. Animal tracking devices such as collars with global positioning system (GPS) capabilities enable continuous and automatic tracking of an animal's position and the value of suck spatial-temporal information is improved if the corresponding activity of the animal is known. GPS animal tracking devices (collars) were used in the spring (Sep-Nov) of 2008 and 2009 to monitor movement of 20 pregnant grazing fine wool Merino ewes. Mean daily velocities (m/s) were calculated for three time periods within a day: 0500-1100h, 1200-1800h and 1900-0400h and subjected to Bayesian change-point analysis (BCP) in an attempt to identify when a change in behaviour (reduction in vel...
This experiment was done to investigate microbial contamination and in situ disappearance rates o... more This experiment was done to investigate microbial contamination and in situ disappearance rates of dry matter (DM), N and 15N of fresh labeled ryegrass. Perennial ryegrass (Lolium perenne) were labeled with 15N during growth in a glasshouse, harvested at 4th leaves stage and were incubated up to 34 h in situ in the rumen of 3 individually housed sheep. The animals were fed 800 g/d chopped alfalfa and had free access to drinking water. Six bags were placed in the rumen of each sheep simultaneously and removed after 0, 3, 7, 12, 21 and 33 h after incubation. The results were fitted to a model describing the degradation of DM and total N with time. It was found that residues from the washed zero time bags had lower 15N enrichments (7.7% vs. 8.3% enriched) than the original fresh samples. Under-estimation of effective degradability (ED) of protein in fresh forages by about 4% would have potential consequences for predictions of ruminally fermentable and escape protein and thus for dieta...
Time spent feeding by grazing cattle is an important predictor of intake and feed efficiency. Thi... more Time spent feeding by grazing cattle is an important predictor of intake and feed efficiency. This study examined the use of automatic supplement weighing (ASW) units for monitoring voluntary access of breeding cows (n = 430) to mineral block supplements in an extensive rangeland of northern Australia. The ASW units (n = 10) were located within each of experimental sites (5 units per site; Bore and Eldons). Over the 62 days of data collection, 85%, 13%, and 2% of cows spent <600, 600–1200, >1200 min accessing supplements, respectively, with between-animal variation (CV) of 107%. A total of 133 cows visited both sites while 142 and 155 cows visited only Bore and Eldons, respectively. Most visits (80–90%) were recorded during the day (800–1700 h), 7–17% during the night (1800–2300 h), and 3% during the dawn (0–700 h). Time spent accessing supplements differed between ASW units across the two sites (p < 0.001) and varied according to the day of visits (p < 0.001). There was...
Identifying the licking behaviour in beef cattle may provide a means to measure time spent lickin... more Identifying the licking behaviour in beef cattle may provide a means to measure time spent licking for estimating individual block supplement intake. This study aimed to determine the effectiveness of tri-axial accelerometers deployed in a neck-collar and an ear-tag, to characterise the licking behaviour of beef cattle in individual pens. Four, 2-year-old Angus steers weighing 368 ± 9.3 kg (mean ± SD) were used in a 14-day study. Four machine learning (ML) algorithms (decision trees [DT], random forest [RF], support vector machine [SVM] and k-nearest neighbour [kNN]) were employed to develop behaviour classification models using three different ethograms: (1) licking vs. eating vs. standing vs. lying; (2) licking vs. eating vs. inactive; and (3) licking vs. non-licking. Activities were video-recorded from 1000 to 1600 h daily when access to supplement was provided. The RF algorithm exhibited a superior performance in all ethograms across the two deployment modes with an overall accu...
Pharmacokinetics of leptin in mammals has received limited attention and only one study has exami... more Pharmacokinetics of leptin in mammals has received limited attention and only one study has examined more than two time points and this was in ob/ob mice. This study is the first to observe the distribution of leptin over a time course in female mice. A physiologic dose (12 ng) of radiolabelled leptin was injected in adult female mice via the lateral tail vein and tissues were dissected out and measured for radioactivity over a time course up to two hours. Major targets for administered leptin included the liver, kidneys, gastrointestinal tract and the skin while the lungs had high concentrations of administered leptin per gram of tissue. Leptin was also found to enter the lumen of the digestive tract intact from the plasma. Very little of the dose (<1 %) was recovered from the brain at any time. Consequently we confirm that the brain is not a major target for leptin from the periphery, although it may be very sensitive to leptin that does get to the hypothalamus. Several of the ...
Behaviour is a useful indicator of an individual animal’s overall wellbeing. There is widespread ... more Behaviour is a useful indicator of an individual animal’s overall wellbeing. There is widespread agreement that measuring and monitoring individual behaviour autonomously can provide valuable opportunities to trigger and refine on-farm management decisions. Conventionally, this has required visual observation of animals across a set time period. Technological advancements, such as animal-borne accelerometers, are offering 24/7 monitoring capability. Accelerometers have been used in research to quantify animal behaviours for a number of years. Now, technology and software developers, and more recently decision support platform providers, are integrating to offer commercial solutions for the extensive livestock industries. For these systems to function commercially, data must be captured, processed and analysed in sync with data acquisition. Practically, this requires a continuous stream of data or a duty cycled data segment and, from an analytics perspective, the application of movin...
Journal of Animal Physiology and Animal Nutrition, 2019
Nitrate (NO3¯) is an effective non‐protein nitrogen source for gut microbes and reduces enteric m... more Nitrate (NO3¯) is an effective non‐protein nitrogen source for gut microbes and reduces enteric methane (CH4) production in ruminants. Nitrate is reduced to ammonia by rumen bacteria with nitrite (NO2¯) produced as an intermediate. The absorption of NO2¯ can cause methaemoglobinaemia in ruminants. Metabolism of NO3¯ and NO2¯ in blood and animal tissues forms nitric oxide (NO) which has profound physiological effects in ruminants and has been shown to increase glucose uptake and insulin secretion in rodents and humans. We hypothesized that absorption of small quantities of NO2¯ resulting from a low‐risk dose of dietary NO3¯ will increase insulin sensitivity (SI) and glucose uptake in sheep. We evaluated the effect of feeding sheep with a diet supplemented with 18 g NO3¯/kg DM or urea (Ur) isonitrogenously to NO3¯, on insulin and glucose dynamics. A glucose tolerance test using an intravenous bolus of 1 ml/kg LW of 24% (w/v) glucose was conducted in twenty sheep, with 10 sheep receivi...
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