Environment and food of the budgerigar Melopsittacus undulatus

The effects of stocking rate, calving season and post-weaning growth were investigated over 3 years for Angus cattle on annual pastures. Angus cows, mated to Angus bulls for 8 weeks to start calving early summer (ES), early autumn (EA) or early winter (EW), were stocked at 0.6, 0.8 and 1.0 cows/ha and calves/ha until their fourth calving ended. Weaning, at average age 10.5 months, was at the end of October, January or April. Some calves were slaughtered at weaning and others after a year at 1.4 calves/ha. Late autumn-winter pasture growth [2500-3500 kg dry matter (DM)/ha] was below average in 2 of the 3 years of the study, and spring growth did not vary (overall mean 4400 kg DM/ha). Unseasonable pasture growth during late summer-early autumn occurred between weaning in EA and EW for years 2 and 3. Milk consumption was an overall average of 4.8 kg/ca1f.day. The only variation was a higher value in EW in year 2 than in years 1 and 3. Winter calf growth in ES and EA was sometimes affected by year and stocking rate, and overall average spring growth was 1.23, 1.33 and 1.13 kg/calf.day in ES, EA and EW, respectively. Weaning weight occasionally differed with stocking rate in ES and EA, and tended to differ between years in EW in proportion to the level of unseasonable pasture growth. Overall, carcasses tended to be slightly heavier and fatter in ES but otherwise followed the weaning weight patterns. Minimum cow weight tended to vary with stocking rate in years 2 and 3 and overall increased from ES to EW. Maximum weight also differed in these years. Yearly treatment means for average daily weight change during mating were -1.47 to +1.45 kg/cow. Weight gain declined from ES to EW except for reversal of the ES and EA situations in year 3 when poor winter pasture conditions followed unseasonable pasture growth. Average mating weight was greater with the lightest stocking rate in year 3 and with EW in years 1 and 2. Condition score generally followed weight patterns. In the 3 years, calf birth weight tended to be higher in EW, except for increased birth weight in EA in a year of unseasonable pasture growth. Average calving percentage and interval between successive calvings were 87% and 365 days, respectively, with no clear treatment trends. Overall average gross margins/ha ($A) for the lightest to heaviest stocking rates, respectively, were 126, 141 and 142 in ES, 93,109 and 118 in EA, and 54, 70 and 84 in EW. In general, ES enabled mainly heavier carcasses to be sold at seasonally favourable prices but resulted in some calf scours. Relative to ES and EA, EW calving tended to result in less cow stress in most years but heavier birth weights, more dystocia and lighter weaning weights if prolonged unseasonable pasture growth did not occur. Calf response to pasture conditions was generally proportional to calf age, and spring growth was probably affected by the level of milk consumption and calf growth potential relative to age. Post-weaning calf growth did not differ consistently with calving season. The relationship between animal performance and pasture condition may be useful for assessing different calving seasons in other environments.

Cattle under the effect of heat stress have reduced fertility, with negative effects on the oocyte observed at the morphological, biochemical, transcriptional and developmental levels. There are no studies evaluating the effect of heat stress on the epigenetic profile of bovine oocytes, which plays a fundamental role in the regulation of gamete development. The objective of this study was to evaluate the effect of in vivo heat stress during the spring to summer transition on DNA methylation and DNA hydroxymethylation of bovine oocytes at the germinal vesicle (GV) and metaphase II (MII) stages. Ten Bos taurus crossbred nonlactating beef cows located at Saint Gabriel, Louisiana, USA (30°16′11.1″ N, 91°06′12.1″ W), were used for oocyte collection once monthly from April to August. Dominant follicle removal was performed 5-7 days before oocyte collection. Cumulus-oocyte complexes were collected through ovum pick-up from follicles >2mm. Germinal vesicle (GV)-stage oocytes (50% of total obtained per cow) were subjected to a standard bovine in vitro maturation protocol to obtain metaphase II (MII) stage oocytes. The DNA methylation and DNA hydroxymethylation of GV and MII oocytes was assessed by fluorescence immunohistochemistry utilising primary antibodies against 5′-methylcytosine and 5′-hydromethylcytosine. Secondary antibodies utilised were Alexa Fluor 488 goat anti-mouse IgG and Alexa Fluor 546 donkey anti-rabbit IgG. Oocytes were visualised utilising a fluorescence deconvolution microscope and immunofluorescence data were expressed as corrected relative fluorescence per nucleus. The polar body was not included for fluorescence quantification when evaluating MII stage oocytes. Results (least squares means±standard error) were evaluated as cold months (April and May) and hot months (June, July, and August). Results were analysed by the type III test of fixed effects and Tukey media separation utilising Proc Glimmix of SAS 9.4 (P<0.05; SAS Institute Inc., Cary, NC, USA). Maturation rates and percent of grade 1, grade 2, and grade 3 oocytes were square root arcsine transformed for statistical analysis. The number of total oocytes obtained per cow was higher in cold compared to hot months (21.88±2.34 and 14.23±2.17, respectively). Percent of grade-1 oocytes was higher in cold compared to hot months (38.25±3.69 and 27.59±3.09, respectively). There was no difference in percent of grade-2 oocytes between cold and hot months (21.80±2.44 and 22.60±2.20, respectively). There was a lower percent of grade-3 oocytes in cold compared to hot months (39.82±4.54 and 55.87±3.98, respectively). Maturation rate (in vitro maturation) was not different between cold and hot months (81.92±4.04 and 91.11±3.36, respectively). There was no difference between cold and hot months in DNA methylation (417,218.90±71,793.86 and 313,819.88±55,528.01, respectively) and DNA hydroxymethylation (444,931.10±67,920.78 and 352,254.68±56,425.96, respectively) of GV-stage oocytes. There was no difference between cold and hot months in DNA methylation (87,122.36±14,449.47 and 89,807.26±11,303.72 AU, respectively) and DNA hydroxymethylation (102,933.83±15,517.70 and 137,622.45±11,826.86 AU, respectively) of MII-stage oocytes.

Maintaining pasture quality in late spring and early summer is a challenge in many hill country farming systems where pasture growth often exceeds animal demand. One possible management tool is to defer grazing on a portion of the farm to enable the desired grazing management and animal performance on the remainder. This study aimed to evaluate the effect of timing and duration of deferred grazing in mid-spring to early-summer on subsequent pasture accumulation rates, composition and quality, from mid-spring through to the following winter. A factorial design (3 durations x 3 closing times) in eight replicates compared withholding grazing (nil, 1 or 3 grazings), in three closing periods, mid spring, late spring, and early summer. Grazing pasture when covers reached 2500 - 3000 kg DM/ha to a residual of 1500 kg DM/ha was the standard grazing regimen used. Grazing after the exclusion period aimed to achieve the same residual as in the control treatment based on a feed budget. Short early closures resulted in little, or no change in pasture quality and quantity for the remainder of the season. Longer closure periods reduced pasture quality due to increases in the proportions of dead and reproductive stem. This effect was reduced with later closings. The control (nil deferred grazings) and mid-spring closings had a net loss of dead matter (-1000 and -420 kg DM/ ha, respectively), while the late -spring and earlysummer closings accumulated 60 and 180 kg DM/ha, respectively. These differences in dead matter were the major driver of the differences of net herbage accumulations (P=0.018), with net accumulations from 7990 kg DM/ha for the control (Nil) closings to 9660 kg DM/ha for the December (late) closings. Deferred grazing can be used to alter feed availability and utilisation while maintaining net pasture production over spring, summer and autumn. Keywords: grazing management, pasture quality, deferred grazing, net pasture accumulation, dead matter, reproductive tillers, metabolisable energy

The present state of reindeer winter and summer pastures in northern Finland has been mapped using field sampling, remote sensing, and GIS. The winter pasture inventory was made during 1995-96 and the summer pasture inventory during 1997-98. Winter pastures can be divided into ground lichen and arboreal lichen pastures. Autumn pastures, including pastures with grasses, dwarf shrubs, and mushrooms, were also mapped and added to the inventory of winter pastures. Summer and winter pastures partly overlap, but the main pasture areas are clearly distinct from each other. Major summer feeding areas are marshes, mires and river meadows, and mountain birch woodland. Biomass data were obtained by volumetric calculations of lichens and standard samples of the green parts of summer fodder plants. The results show that the most abundant lichen resources are found in the northern part of the management area, while the most abundant summer pasture resources prevail in the middle and southern parts. The overall accuracy of the winter pasture mosaic is 88%, with a Kappa coefficient of 0.84. The overall accuracy of the summer pasture mosaic is 84%, with a Kappa coefficient of 0.81.

The effect of gonadotropin releasing hormone (GnRH) analogue on the ovulatory response of oestrual follicle during cold and hotter months of the year was studied. A total of 120 crossbred cows brought for insemination with oestrus signs during colder months (December 2022 –January 2023; n=52) and hotter months (April – May 2023; n=68) to the Gynaecology Unit of Veterinary Clinical Complex, Veterinary College and Research Institute, Orathanadu were utilized for the study. Oestrus (Day 0) was confirmed by gynaeco-clinical and ultrasound examination and animals were inseminated with (n =33) or without (n = 87) GnRH (Buserelin acetate 10 mcg; im). The biometry of oestrual follicle (OF) and regressing corpus luteum (RCL) were measured ultrasonographically on Day 0 and the OF was observed every 24 hours until ovulation. The diameter of the OF on Day 0 was non-significantly (P > 0.05) larger during hotter months (12.19 ± 0.21 mm) than colder months (11.58 ± 0.32 mm). There were no significant (P > 0.05) differences in the diameter of RCL between the two periods (9.63 ± 0.21 and 9.56 ± 0.22 mm respectively). OFs were observed majorly in the right ovary during the hotter (60.76%) and colder (54.17%) months. Ovulations occurred on the mean days of 1.00 and 1.37 ± 0.18 in GnRH group during hotter (H-Gn) and colder months (C-Gn) respectively. The respective mean days in non-GnRH group were 1.14 ± 0.05 and 1.33 ± 0.08 during hotter (H-O) and colder months (C-O). In H-Gn group all the animals (100%) ovulated on Day 1, when compared to C-Gn animals (62.50%). On perusing the possible effect of RCL on ovulation, significantly increased percentages of ovulations were observed in OFs on the contralateral ovary to the ovary having the RCL in GnRH group and viceversa in non-GnRH group. It could be assumed that GnRH administration on the day of insemination may be beneficial during the hotter months of the year.

1 Growth and survival of juvenile Armadillidium vulgare (Latrielle) in the laboratory were greatest on a diet of an excess of freshly fallen leaves from dicotyledonous plants but decreased with decreasing supply of this food, even though alternative lower quality foods were provided in excess. Growth in the laboratory was positively related to temperature but mortality was not clearly related to temperature over the range observed in the field. 2 Growth and survivorship of a field population on a Breckland grass heath are described for a 2-year period during which density declined from 673m-2 to 102 m-2. The demand for high-quality food by the field population peaked during a period of rapid growth in spring and early summer when supply of leaf litter from dicotyledonous plants was at a minimum. Litter production peaked in autumn after isopods had finished breeding and when low temperatures reduced their consumption rates. 3 Competition for high-quality food in spring and early summer during this period could have reduced growth and survivorship sufficiently to account for the observed decline in population density. 4 A simulation model, based on laboratory observations, closely predicted the observed decline in the field population. Further simulations also predicted the higher population densities observed in the field before this study and also the lower equilibrium densities found on the site since the study. Key-words: Population dynamics, competition, food quality, woodlouse, Armadillidium vulgare, densitydependence, growth, survivorship, consumption * Present address: Dr S.P. Rushton, Department of Agricultural Biology, The University, Newcastle-uponTyne NEl 7RU, UK. Introduction The role of food quality in the population dynamics of herbivores has been intensively studied and its importance in limiting populations widely recognized (Lawton & McNeil, 1979; Crawley, 1983; Dempster, 1983). In contrast, the influence of food quality on the population dynamics of decomposers has received little attention. As most decomposers have a broad range of diet and dead organic material is relatively abundant in most ecosystems, it is often assumed that detrivores are surrounded by an abundance of suitable food. For this reason Warburg, Linsenmair & Bercovitz (1984), in a comprehensive review, suggest that food is not important in influencing population fluctuations of terrestrial isopods; instead they propose that the dynamics of isopod populations are primarily controlled by climatic variables, such as temperature and humidity, since these strongly affect growth, survivorship and reproduction of isopods. Growth and survivorship are also importantly influenced by food quality, as demonstrated for Armadillidium vulgare (Latreille) by Cromack (1967) and Merriam (1971). The quality of isopod foods in the field shows much variation (Hassall & Rushton, 1984) but this would not limit isopod populations if optimal quality foods were always present in excess. However, populations could be adversely affected by either a shortage of the best quality foods or by a temporal separation in supply and demand of optimal food as is the case for herbivores in the African savannah (Sinclair,

In the last years a large number of weather driven extreme events has occurred worldwide with unprecedented socio-economic impacts and are expected to increase, in both frequency and intensity, under future global-warming conditions. In this context early identification and predictability of such events are paramount as they mostly affect several socio-economic activities. Despite the effort in monitoring and evaluation of these extreme events, a quantitative assessment of their interaction is still a challenge. We propose to analyze if the occurrence of extremely hot days/nights in the summer is preceded by drought events in spring and early summer throughout the Mediterranean area. This was investigated by correlating the number of hot days and nights in the regions hottest months with a drought indicator on the prior months. Drought characterization was performed using both the Standardized Precipitation Evaporation Index (SPEI) and the Standardized Precipitation Index (SPI) for the 3-, 6- and 9-months time scales, considering the period 1980–2014 with a spatial resolution of 0.5°. The number of hot days and nights per month (NHD and NHN, respectively) is determined for the same period and spatial resolution. Results show that the most frequent hottest months for the Mediterranean region occur in July and August. Most regions exhibit statistically significant negative correlations, i.e. high (low) NHD/NHN following negative (positive) SPEI/SPI values, and thus a potential for NHD/NHN early warning. This analysis allowed to identify the Iberian Peninsula, northern Italy, northern Africa and the Balkans as the main hotspots of predictability of extreme hot temperatures in the summer preceded by the occurrence of drought events in the spring or early summer.

A dairy farmer's experiences in managing various levels of fertiliser nitrogen (N) inputs over the 1991-95 seasons is discussed and compared to previous years when very little N fertiliser was used. N requirements were assessed by regular herbage tests. Fertiliser N increased pasture growth in spring, early summer and autumn. Animal intakes were greater on N-boosted pasture. Higher rates of N fertilisers (450 kgN/ha/yr) generated large spring surpluses which were harvested as silage. Several changes in management were required to maintain pasture quality and effectively utilise these surpluses. Feed costs vs milk returns are compared for a number of seasons. Moderate fertiliser N usage (200- 300 kg N/ha/yr) is considered likely to give the most profitable balance. Keywords: clover, dairying, grazing management, milksolids, nitrogen, pasture growth, pasture quality

Understanding the relationship between alfalfa (Medicago sativa L.) yield and nutritive value throughout the growing season will permit optimum timing of harvest. Our objective was to determine the rate at which alfalfa yield and fiber components change during each of four harvest periods. In spring, early summer, late summer, and fall of 2004 and 2005 at Pennsylvania, Wisconsin, and Idaho, primary growth of three alfalfa cultivars was initially harvested at late vegetative stage and every 5 d thereafter for 20 d. Forage dry matter (DM) yield, neutral detergent fiber (NDF), and in vitro neutral detergent fiber digestibility (NDFD) were measured at each harvest. Rate of DM production of all cultivars was greatest both years during the spring at Pennsylvania (222.5 and 702.2 kg ha−1 d−1, respectively) and early summer at Wisconsin (83.4 and 278.8 kg ha−1 d−1, respectively), and in early and late summer at Idaho (198.4 and 194.4 kg DM ha−1 d−1, respectively, in 2005 only). The rate of increase in NDF was generally greatest during spring at Pennsylvania and Wisconsin, and during early summer at Idaho, while the rate of decrease in NDFD was generally greatest during early summer at all locations. The results suggest that the negative association between yield and nutritive value has greatest impact on timing of harvests made in spring and early summer in humid environments, and in early and late summer in more arid regions.

Variability of soybean phenology response to temperature, daylength and rate of change in daylength

The profitable production of lamb from pasture-based systems is dependent on high levels of pasture production being efficiently utilised by sheep of superior genetic merit. Pastures that can extend the pasture-growing season and provide high quality feed in late spring and summer have the potential to increase production efficiency and the proportion of lambs that meet market specifications. In this paper we tested the hypothesis that arrowleaf clover (cv. Arrotas), a cultivar selected for late maturity, would supply feed of higher nutritive value than conventional annual legumes and perennial ryegrass mixtures during December and January and this would improve lamb growth rates over this period. Two experiments were conducted to compare the nutritive value of pasture and growth rates of lambs grazing arrowleaf clover, subterranean clover (cv. Leura) or subterranean clover/perennial ryegrass mixtures at different stocking rates during late spring and early summer in south-west Victoria. In the second experiment an arrowleaf clover/perennial ryegrass treatment was also included. Lambs were removed from the plots when they could no longer maintain liveweight. Arrowleaf clover extended the growing season by 4–6 weeks and provided feed of significantly higher digestibility than subterranean clover during December and January. The digestibility of arrowleaf and perennial ryegrass was comparable, but arrowleaf had significantly higher crude protein content during this period. Lambs grazing arrowleaf clover at stocking rates up to 24 lambs/ha grew at or above 100 g/day until the end of January, whereas lambs grazing subterranean clover and perennial ryegrass mixed pastures could not maintain weight by mid-to-late December in both years and were removed from the pastures. At the highest stocking rates total lamb production from arrowleaf clover monoculture pastures in late spring and early summer was ~400 kg liveweight/ha, and was more than double that achieved from the subterranean clover and perennial ryegrass/subterranean clover mixed pastures. The perennial ryegrass/arrowleaf clover mixed pastures in the second experiment produced a similar quantity of lamb per hectare as the arrowleaf clover monoculture pastures at the same stocking rate. In this paper we demonstrated that late-maturing arrowleaf clover can be a profitable, special purpose lamb-finishing pasture. Arrowleaf clover was most suited to more elevated parts of the landscape where estimated carrying capacity was 20 to 40% greater than that from lower lying parts of the landscape that were more subject to water logging and weed infestation. The risks of including arrowleaf clover pastures into the farming system could be reduced by direct drilling arrowleaf clover, which has relatively poor winter production, into existing perennial ryegrass pastures.

In situ mini-lysimeters with ion exchange resin traps were used to measure the effect of dung and urine return on pasture growth and pasture uptake and leaching losses of sulfur (S), nitrogen (N) and potassium (K) in hill pastures grazed by sheep.Single dung or urine events in winter boosted pasture production by 37% and pasture uptake of S, N and K by up to 35%, 55% and 57%, respectively, during the following year. Whereas the late summer single superphosphate application increased late spring and mid summer pasture growth of the following year only, dung or urine return increased pasture growth in every season of the following year. Despite the addition of 11.5, 4.7 and 376 kg of readily available S, N and K ha-1 in a single dung event and 14.5, 28.5 and 146 kg of S, N and K ha-1 in a urine event, accelerated leaching of S, N and K did not occur from dung or urine affected soil. Less than 3 kg S, 0.5 kg N and 2 kg K ha-1 were lost by leaching from dung or urine affected soil. The majority of S, N and K from excreta remained in the soil, either immobilized in soil organic matter and/or adsorbed on to soil sesquioxide surfaces and cation exchange sites with the equivalent of only 1.6% of S, 4.4% of N and 9.0% of K from dung and 29% of S, 18.7% of N and 31% of K from urine being recovered in increased pasture uptake over a period of one year. Under the climatic conditions that prevailed after the winter deposition of excreta, immediate loss of excreta-derived nutrients was negligible but urine deposition markedly accelerated the leaching losses of native soil calcium and magnesium (8 kg Ca and 2.9 kg Mg ha-1 from urine and 6.4 kg Ca and 2.4 kg Mg from dung, respectively). Quantitative information of this kind is important for determining the long-term sustainability of soil fertility in grazed pastures before a comprehensive understanding of pasture nutrient cycles is complete.

Age and growth of the common goby, Pomatoschistus microps, on the south coast of England

Accurate representation of mesoscale scale convective systems (MCSs) in climate models is of vital importance to understanding global energy, water cycles, and extreme weather. In this study, we evaluate the simulated MCS features over the United States from the newly developed GFDL global high-resolution (∼50 km) AM4 model by comparing them with the observations during spring to early summer (April–June) and late summer (July–August). The results show that the spatial distribution and seasonality of occurrence and genesis frequency of MCSs are reasonably simulated over the central United States in both seasons. The model reliably reproduces the observed features of MCS duration, translation speed, and size over the central United States, as well as the favorable large-scale circulation pattern associated with MCS development over the central United States during spring and early summer. However, the model misrepresents the amplitude and the phase of the diurnal cycle of MCSs during both seasons. In addition, the spatial distribution of occurrence and genesis frequency of MCSs over the eastern United States is substantially overestimated, with larger biases in early spring and summer. Furthermore, while large-scale circulation patterns are reasonably simulated in spring and early summer, they are misrepresented in the model during summer. Finally, we examine MCS-related precipitation, finding that the model overestimates MCS-related precipitation during spring and early summer, but this bias is insufficient to explain the significant dry bias observed in total precipitation over the central United States. Nonetheless, the dry biases in MCS-associated precipitation during late summer likely contribute to the overall precipitation deficit in the model.

Exploring future trends of precipitation and runoff in arid regions under different scenarios based on a bias-corrected CMIP6 model