Browsing by Author "Nguyen TT"
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- ItemDairy Cows Grazing Plantain-Based Pastures Have Increased Urine Patches and Reduced Urine N Concentration That Potentially Decreases N Leaching from a Pastoral System(MDPI (Basel, Switzerland), 2023-02-02) Nguyen TT; Navarrete S; Horne D; Donaghy D; Bryant RH; Kemp P; De La Fuente GThe objective of this study was to determine the effect of grazing plantain-based pastures on urine volume, urination frequency, and urinary nitrogen (UN) concentration of dairy cows under a typical pastoral dairy practice offering approximately 25% supplemented feeds. The experiment was a completely randomised design with three pasture treatments (perennial ryegrass-white clover (RGWC); RGWC + low plantain rate (PLL); and RGWC + high plantain rate (PLH)), five replicate plots, and repeated in two sequential grazing periods. Forty-five lactating Friesian × Jersey cows were randomly assigned into three groups of 15 animals each to graze over six days in adaptation paddocks and three days in experimental plots. Urine flow sensors were used to measure urine volume and urinary frequency, while spot urine sampling was conducted to determine nitrogen (N) concentration in cow urine. The results showed that including 25% plantain in the diet (PLH) increased daily urine volume by 44% and the daily number of urinations by 28%, compared to grazing the RGWC pasture. In addition, N concentration in cow urine was decreased by 18 and 29% when the diet contained 18% and 25% plantain, respectively. In conclusion, under a typical dairy farm practice, incorporating plantain into the RGWC pasture with the proportion of 25% plantain in the diet can increase the number of urine patches and reduce the concentration of N in the urine, thereby providing the opportunity to decrease N leaching from pastoral systems.
- ItemProvision of lucerne in the diet or as a manipulable enrichment material enhances feed efficiency and welfare status for growing-finishing pigs(2022-10-01) Nguyen TT; Chidgey KL; Wester TJ; Morel PCHThis research investigated the effects of including lucerne in a diet and as manipulable enrichment material on growing-finishing pig growth performance and behaviour. Forty-eight intact male Duroc × (Large White × Landrace) pigs with an initial live weight (LW) of 26.4 ± 2.32 kg (mean ± SD) were blocked by LW and randomly assigned to two dietary treatments (control vs lucerne), and two manipulable material treatments (without and with lucerne chaff for manipulable material). The barley and soybean meal-based control diet was formulated according to a commercial standard, while the lucerne diet replaced 100 g/kg of the barley and soybean oil in the control diet with lucerne chaff. The diets were formulated to have the same amount of digestible energy and apparent ileal digestible lysine. Manipulable material (lucerne chaff) was provided daily at 100 g/pig. Pigs had ad libitum access to diets via electronic feeders until they reached approximately 90 kg LW, at which time they were slaughtered. There were no interactions between dietary treatment and provision of manipulable material on pig production and behaviour. Feeding the lucerne diet reduced average daily feed intake, LW gain, feed intake per feeder visit, and feeding rate, but increased feed efficiency (P < 0.05). Access to manipulable material did not affect any growth traits, but the number of feeder visits per day was greater and the duration of visits to the feeder was lower in pigs that had access to lucerne chaff (P < 0.001). Compared to the other groups, pigs that consumed the lucerne diet or had access to manipulable material rested for a shorter duration but engaged in more social interactions and exploration behaviour. In conclusion, including 10% lucerne in growing-finishing diets improved feed efficiency and lucerne chaff appears to be an attractive enrichment source to pigs.
- ItemSpatiotemporal analysis of forest cover change and associated environmental challenges: a case study in the Central Highlands of Vietnam(2022-01-01) Tran DX; Tran TV; Pearson D; Myint SW; Lowry J; Nguyen TTSpatiotemporal regression combining Theil-Sen median trend and Man-Kendall tests was applied to MODIS time-series data to quantify the trend and rate of change to forest cover in the Central Highlands, Vietnam from 2001 to 2019. Several MODIS data products, including Percent Tree Cover (PTC), Evapotranspiration (ET), Land Surface Temperature (LST), and Gross Primary Productivity (GPP) were selected as indicators for forest cover and climate and carbon cycle patterns. Emerging hot spot analysis was applied to identify patterns of long-term deforestation. Spatial regression analysis using Geographically Weighted Regression (GWR) was performed to understand variations in the relationship between vegetation changes and trends in LST, ET, and GPP. Our analysis reveals that deforestation occurred significantly in the study area with a total decrease of 14.5% in PTC and a total of 7314 deforestation hot spots were identified. Results indicate that forest cover loss explains 72.9%, 67.7%, and 89.4% of the changes in ET, GPP, and LST, respectively, and the levels of influence are heterogenous across space and dependent on the types of deforestation hot spots. The approach introduced in our study can be performed worldwide to address complex research questions about environmental challenges that emerge from deforestation.