Daily variations of water use with vapor pressure deficit in a plantation of I214 poplars.

Daily rates of whole tree water use were measured in a homogeneous 7-year-old plantation over 84 days. Two trees were selected in the two most contrasting ends, i.e., with mean water table at -1.5 m and -3.5 m. Results showed that the mean tree water use was close to 80 dm3 day–1 with a small mean difference between the two sites (5.4 dm3 day–1, about 7%). Higher daily variations were observed on a single tree over the season (from 17 to 138 dm3 day–1). These fluctuations could be modeled using linear regressions on the vapor pressure deficit (VPD). Results also indicated decreasing sap flux densities with radial sapwood depth and that the whole tree water use could be estimated from the sap flux densities measured at the 0–2 cm depth

Monitoring of water from the underground to the tree: first results with a new sap extractor on a riparian woodland

Riparian woodlands are characterized by variable hydrological conditions. Following the mapping of the complex underground water circulation of the wetlands, we studied the water uptake by trees. Although there are numerous analytical techniques available to monitor the water origin and water fluxes, no rapid technique for the extraction of xylem sap exists on the market. For this reason we designed and built a unique machine able to extract sap directly in the field from wood cores in a few minutes. A short description of the machine and its performance is given, prior to reporting the first experimental results obtained in a young riparian woodland along the Garonne River. The results compare the vertical water profile of the soil and the corresponding xylem sap at different roots horizons and in the trunk

Interactions between groundwater and surface water at river banks and the confluence of rivers

Riparian vegetation depends on hydrological resources and has to adapt to changes in water levels and soil moisture conditions. The origin and mixing of water in the streamside corridor were studied in detail. The development of riparian woodland often reflects the evolution of hydrological events. River water levels and topography are certainly the main causes of the exchange between groundwater and river water through the riverbank. Stable isotopes, such as 18O, are useful tools that allow water movement to be traced. Two main water sources are typically present: (i) river water, depleted of heavy isotopes, originating upstream, and (ii) groundwater, which comes mainly from the local rainfall. On the Garonne River bank field site downstream of Toulouse, the mixing of these two waters is variable, and depends mainly on the river level and the geographical position. The output of the groundwater into the river water is not diffuse on a large scale, but localised at few places. At the confluence of two rivers, the water-mixing area is more complex because of the presence of a third source of water. In this situation, groundwater supports the hydrologic pressure of both rivers until they merge, this pressure could influence its outflow. Two cases will be presented. The first is the confluence of the Garonne and the Ariège Rivers in the south-west of France, both rivers coming from the slopes of the Pyrénées mountains. Localised groundwater outputs have been detected about 200 m before the confluence. The second case presented is the confluence of the Ganges and the Yamuna Rivers in the north of India, downstream of the city of Allahabad. These rivers are the two main tributaries of the Ganges, and both originate in the Himalayas. A strong stream of groundwater output was measured at the point of confluence

Isotopic characteristics of the Garonne River and its tributaries

The Garonne is the largest river in the south-west of France, and its drainage basin stretches between the Pyrenees and the Massif Central mountains. Until now, no water stable isotope study has been performed on the whole Garonne river basin which is composed of different geological substrata, and where the water resources are limited during the dry summer period. This study focuses on the Garonne river and its tributaries from the Pyre´ne´es foothill upstream to its confluence with the Lot River downstream. The aim of the study is to determine the origins of the surface waters using their chemical and stable isotopic compositions (18O, D and 13C), to better understand their circulation within the drainage basin and to assess the anthropogenic influences. The Garonne displays a specific 18O seasonal effect, and keeps its Pyre´nean characteristics until its confluence with the Tarn River. The difference in the dissolved inorganic carbon (DIC) comes mainly from the change in lithology between the Pyre´ne´es and the Massif Central mountains. Agriculture activity is only detected in the small tributaries

Sap flow and water transfer in the Garonne river riparian woodland, France : first results on poplar and willow

This work is the first attempt at using Granier sap sensors on Populus nigra, Populus x euramericana cv I45/51 and Salix alba for the monitoring of sap flows in an active floodplain over two consecutive years. The main characteristic of these diffuse porous trees is their capacity to use several tree rings for xylem sap transfer. Results showed that the sap flux densities remained homogeneous on the external 4 cm of the trunk, then decreased with depth. For young trees, the active sapwood can represent half of the trunk. Results indicated that in the same environment and at the same age, daily differences existed between the two major native riparian tree species, the black poplar and the white willow. Their maximal sap flux density (2.6-3.6 dm 3 dm -2 h -1) was similar to other fast growing trees. The influence of age was the third important screened factor. Sap flow measurements over several months indicated that water uptake was variable throughout the season, depending on water availability, and was more pronounced for older trees. The sap flux densities for the planted poplar (I45/51) ranged from 2.2-2.6 dm 3 dm -2 h -1 (about 90 dm 3 day -1) in the wetter spring conditions and dropped to 1.6-1.7 dm 3 dm -2 h -1 (about 60 dm 3 day -1) in less favourable conditions. Under the worst conditions, e.g., the especially long drought in the summer of 1998, these values dropped to 1.0-1.2 (about 40 dm 3 day -1), and even to 0.35 dm 3 dm -2 h -1 (about 12 dm 3 day -1) for a few days. Complementary long-term studies are needed to better understand the complex sap flow changes and to be able to relate them to significant environmental factors. Priority should be given to the long-term monitoring of sap flows at different depths for a correct estimation of actual daily water uptakes by riparian softwood trees

The behaviour and health of dairy lambs reared artificially with and without early access to meal : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Animal Science at Massey University.

Many large-scale dairy sheep producers use lamb-rearing systems and provide lambs with milk replacer (MR) ad libitum and grain-based meal to accelerate rumen development to support early weaning methods. Lambs are raised inside for three weeks before being relocated to a pasture paddock and weaned off MR, followed by weaning off meal 3-4 weeks later onto a pasture-only diet. The potential to replace the early provision of meal with early access to good quality pasture before weaning has not been evaluated and may have effects on the development of feeding behaviour. Studies on feeding behaviour in lambs have focused on differences between restricted and ad libitum quantities of MR, with little research on differences in use of solid feed before weaning. Sixty East Friesian crossbred ewe lambs aged 3-4 days were randomly allocated to one of two treatment groups; MR ad libitum with access to meal (M) or MR ad libitum without meal (NM). Both groups had access to pasture at the beginning of week 4, and were abruptly weaned off MR at week 6 and gradually weaned off meal (M lambs only) beginning in the middle of week 8 until the end of week 10. It was hypothesised that; (1) while lambs were being reared inside, M lambs would initiate rumination earlier due to their early access to meal. (2) There would be no difference in the milk feeding behaviour between lambs on the two diets. (3) There would be no difference in the health of the lambs and lastly (4), once outside, M lambs would spend more time grazing and subsequently ruminating as a result of their earlier rumen development. All lamb behaviours were visually recorded during weeks 2, 3, 5, 7, 10 and 12 (nine hours/week). Milk feeding behaviour traits were automatically recorded hourly through the automatic MR dispenser while being reared inside for 23 days. Health scores were recorded twice daily and total days health incidences were recorded. Meal access accelerated onset of rumination, while NM lambs spent more time consuming wood shavings during week 3 (P<0.001). Once outside, NM lambs spent more time grazing during weeks 5 (P<0.05), 7 and 12 (P<0.001), and increased rumination time compared to M lambs by week 12 (P<0.001). Lambs with meal access on average had a greater number of rewarded meals (meals in which lambs consumed more than 1 ml), with a greater intake of MR per meal than lambs without meal access (P<0.001). There were no mortalities of lambs fed either diet. Loose faeces (mild scours), pink eye and navel infections were observed in both M and NM lambs. These findings may allow refinement of lamb-rearing practices by adjustments to the provision of meal to lambs since no adverse behavioural or health effects were observed in lambs without meal access

The nutrition and growth of lambs reared artificially with or without meal : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Animal Science at Massey University, Manawatu, New Zealand.

Content removed from thesis due to copyright reasons: figure 1.1 (page 14). FAO (2011) Rearing young ruminants on milk replacers and starter feeds, Rome, FAO Animal Production and Health Manual No. 13. http://www.fao.org/docrep/014/i2439e/i2439e00.pdf ; figure 1.2 (page 24). Lane, M., Baldwin, R. L. & Jesse, B. (2000) Sheep rumen metabolic development in response to age and dietary treatments. Journal of Animal Science, 78, 1990-1996. https://www.animalsciencepublications.org/publications/jas/articles/78/7/1990 ; figure 1.3 (page 34). Bimczok, D., Rohl, F. W. & Ganter, M. (2005) Evaluation of lamb performance and costs in motherless rearing of German Grey Heath sheep under field conditions using automatic feeding systems. Small Ruminant Research, 60(3), 255-265. http://www.sciencedirect.com/science/article/pii/S0921448805000027Artificial rearing is routinely used in large-scale dairy sheep farms. One approach is to offer milk replacer (MR) and meal ad libitum to lambs. The aim was to evaluate the growth of female lambs in the first 12 weeks of rearing with (M) and without (NM) grain-based meal access (n=30/group) during four feeding periods. In period 1 (week 0-3), lambs were offered MR and meal ad libitum, and in period 2 (week 4-5) were transitioned outdoors onto pasture with continued access to MR and meal. Lambs were weaned off MR in period 3 (week 6-10), and meal in period 4 (week 10-12). The NM lambs received identical management, but meal was excluded. A treatment-by-time interaction was found whereby NM lambs had lower average daily gain (ADG) (P0.05), and higher ADG in period 4 (157±18 vs. -55±18 g/d, P<0.05) than M lambs. These results indicate that when lambs fed MR ad libitum are offered unrestricted access to good-quality pasture before weaning, meal may not be required to achieve a similar live weight at 12 weeks of age. Data from the aforementioned experiment were further investigated by week to allow investigations of the relationship between nutrient intake and growth, describe variation in ADG in relation to environmental and feeding transitions, and to estimate pasture intakes, which were not measured. The different feeding transitions, nutrient intakes, and feeds were most likely causing the differences in ADG that occurred between treatment groups and weeks. The greatest variation in ADG of lambs occurred in the M lambs after meal weaning, which was likely due to a poor adaption to a pasture-only diet. Pasture intakes were estimated by calculating lamb requirements for maintenance and growth from actual ADG and live-weight measurements, assuming that pasture intake made up the difference between actual intakes and theoretical intakes. It was found there were significant differences in estimated pasture intakes between M and NM lambs (P<0.0001) and intakes changed over weeks. In weeks seven, eight, and nine, M lambs were estimated to not consume any pasture, due to a high intake of meal, to achieve the observed growth rates. However, NM lambs consumed pasture over these weeks as pasture was their only feed source. These results allow speculation that pasture intake was very low in M lambs before meal was removed. It has been previously reported that high meal intakes when combined with low roughage intake can negatively impact rumen health and development, and transitioning from high meal to high roughage diets requires alterations in the ruminal microbe population and fermentation. The estimated low pasture intake before meal weaning, combined with the high meal intake recorded, may have contributed to the growth check that occurred once meal was removed, as lambs required a period to adapt to the pasture diet, as their rumen underwent the changes associated with transitioning between these diets. Further investigation into differences in pasture intake between lambs reared with and without meal, and more evidence as to what caused the growth check after meal weaning may allow further optimisation of different lamb-rearing systems

Nutrient utilisation, growth and chemical body composition of pre-weaned lambs reared artificially : effects of feeding milk replacer and pellets : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science at Massey University, Palmerston North, Manawatū, New Zealand

Listed in 2016 Dean's List of Exceptional ThesesUnderstanding how nutrient supply controls lamb growth is important in improving the efficiency of nutrient utilisation. Estimation of metabolisable energy (ME) requirements for lamb maintenance and growth pre-weaning has been limited to milk-only fed lambs. This is due, at least in part, to the difficulty of measuring pasture intake in pre-weaned lambs, which restricts the determination of nutrient balances and nutrient use efficiencies. The aims of this thesis were to: 1) evaluate the effect of various milk and pellets combinations on lamb growth, organ development, body composition and utilisation of energy for maintenance and growth, 2) derive equations for predicting feed intake, and 3) develop a growth simulation model for use as a tool to develop feeding strategies for lambs. Lambs were offered various diet combinations from age one day until slaughter at 18 kg live weight (LW). Addition of solid feed to the milk diet of pre-weaned lambs improved their growth rates, efficiency of gain and enhanced rumen development. Increasing daily ME intake from 1.5 times maintenance to ad libitum at a constant protein to energy ratio did not alter the total chemical body composition of the lambs fed to a fixed LW. Increasing the crude protein content of milk replacer, and therefore the corresponding protein to energy ratio, increased average daily gain and efficiency of gain in lambs. Further, the protein content in the empty bodies of lambs increased whilst fat content decreased. Growth and body composition of lambs were unaffected by altered pellet protein content. The study also showed that lambs fed in excess of their protein and energy requirements reached maximum potential protein deposition rates. Based on a model developed, overestimating the maintenance energy requirements of milk-only fed lambs underestimated their daily fat deposition rates and underestimating the maintenance requirements of lamb offered milk and ad libitum access to pellets over estimated their daily fat deposition. A greater percentage increase in fat deposited in gain increased the energy requirements for gain in the lambs. This study has contributed to the knowledge on rearing lambs artificially with various combinations of milk and pellets. The findings will provide a useful platform for future studies aiming to develop feeding strategies to improve pre-weaning lamb growth

Sarda female lambs bred at pasture: growth rate from weaning to reproductive activity

The traditional dairy sheep system in Sardinia presents 2 lambing seasons: in November-December for mature ewes and in February-March for primiparous. Replacement (20-25% of female lambs) usually came from mature ewes whereas all lambs born in January-February are slaughtered when their market price is low. These lambs could represent part of flock replacement that can integrate the traditional lamb breeding system, and also a flock replacement of ewes that are planned to lamb in late winter to have a continuous milk production all over the year. The aim of the present work, that represent an aspect of a wider trial, was to determine the suitability to breed this lambs under grazing condition monitoring their growth rate from weaning to the beginning of reproductive activity. At the “Bonassai” research farm an experiment was carried out from March 2004 to May 2005. 51 female Sarda lambs born from 19/01/2004 to 07/02/2004 (live weight 3.24±0.51 kg; mean±standard deviation) were weaned on average of 45 days (live weight 12.02±1.52 kg) and weighted monthly. After weaning feeding regimen was based on grazed forage crops (Lolium multiflorum Lam., Hedysarum coronarium L. and Cichorium intybus L.) and on natural pasture with an average stocking rate of 5.5 head/ha. The supplementation ranged between 0 - 1200 g/head/d of Lucerne and Italian ryegrass hay and 0 - 400 g/head/d of commercial concentrate, depending on herbage on offer. The amount of hay and concentrate offered during the trial represented 51% of total energetic requirements of lambs. Average lamb daily gain (ADG) during the experimental period resulted 74±11 g head/day. The ADG pattern showed a maximum value 30 days after weaning (139±33 g head/day) and a minimum value in January when herbage availability was low. At the beginning of reproductive activity lambs weighed on average 40.5±3.5 kg and their average body condition score was 3.03±0.12. The trial showed that is possible to breed lambs born in late winter at pasture. However an economic and technical evaluation of differences of these lambs compared to those bred in the traditional system is under evaluation

The use of the stable oxygen isotope (18O) to trace the distribution and uptake of water in riparian woodlands

Streamside vegetation forming narrow "corridors" in temperate regions, is typically dominated by deciduous tree species reflecting strong influences by human activities. Riparian woodlands depend on hydrological resources and have to adapt to rapid changes in water levels and soil moisture conditions. Three main water sources are typically present in the riparian zone: river water originating in the mountains, ground water and rainfall. Stable isotopes, such as oxygen-18, are useful tools which allow for water movement to be traced within the riparian zone and which help to identify water sources utilised by the trees growing in these areas