Endoplasmic reticulum in rat renal interstitial cells: molecular rearrangement after water deprivation

Cylindrical bodies in renal interstitial cells of dehydrated rats are confluent with membranes of endoplasmic reticulum. The cylinder walls, composed of helically arranged pentagonal tubules, may represent a molecular rearrangement of the membrane structure. The cylinders may represent a morphologic expression of altered ergastoplasmic function possibly related to the production of concentrated urine.     

Enrichment of big-leaf mahogany (Swietenia macrophylla King) in logging gaps in Bolivia: The effects of planting method and silvicultural treatments on long-term seedling survival and growth

To insure adequate regeneration and future timber yields of mahogany (Swietenia macrophylla King), many logged forests will have to be restocked through enrichment planting and managed using silvicultural techniques that maintain this species’ long-term survival and growth. This study compared the effects of planting method and two silvicultural treatments on the survival and growth of mahogany seedlings in logging gaps in Bolivia. We tested the hypotheses that survival and growth will be higher among transplanted seedlings than seedlings established from sown seeds and higher in silvicultural treatments that reduce competing vegetation and increase light. The first silvicultural treatment consisted of gaps logged 6 months prior to planting, gaps logged just prior to planting, and gaps treated with herbicide prior to planting. The second treatment, applied 12 months after planting, consisted of manual vegetation cleaning around mahogany seedlings in half of the gaps. The first hypothesis was supported in terms of initial seedling growth but not survival, which was similar between planting methods during the 12-92 months after planting. Transplanted seedlings grew significantly faster than those established from sown seeds during the first year, but this growth advantage disappeared by the second year. Although transplants were 84 cm taller than seed-sown seedlings by the end of the study, this height gain was probably not worth the cost of growing and transplanting seedlings. The second hypothesis was supported in terms of both survival and growth. A significantly greater proportion of seedlings survived in herbicide (62%) compared to 6-month-old (46%) and recent gaps (18%) and in cleaned (51%) versus control gaps (39%). Seedlings initially grew faster in herbicide and recent gaps than in 6-month-old gaps. These differences among silvicultural treatments were largely explained by canopy cover, which, throughout the study, was at least 14% lower in herbicide gaps and 9% lower in cleaned gaps relative to their respective alternatives. By 64 months growth diminished to near zero and no longer differed among gap treatments, despite lower canopy cover in herbicide gaps. By 92 months, saplings in herbicide gaps were only 145 and 77 cm taller than those in recent and 6-month-old gaps, respectively. To maximize survival and growth of mahogany seedlings in logging gaps while minimizing costs, silvicultural strategies should focus on direct seed sowing and appropriately timed interventions (i.e. manual cleaning) to control competing vegetation.     

Evidence for the exposure of water ice on Titan's surface

The smoggy stratosphere of Saturn's largest moon, Titan, veils its surface from view, except at narrow wavelengths centered at 0.83, 0.94, 1.07, 1.28, 1.58, 2.0, 2.9, and 5.0 micrometers. We derived a spectrum of Titan's surface within these "windows" and detected features characteristic of water ice. Therefore, despite the hundreds of meters of organic liquids and solids hypothesized to exist on Titan's surface, its icy bedrock lies extensively exposed.     

Detection of daily clouds on Titan

We have discovered frequent variations in the near-infrared spectrum of Titan, Saturn's largest moon, which are indicative of the daily presence of sparse clouds covering less than 1% of the area of the satellite. The thermodynamics of Titan's atmosphere and the clouds' altitudes suggest that convection governs their evolutions. Their short lives point to the presence of rain. We propose that Titan's atmosphere resembles Earth's, with clouds, rain, and an active weather cycle, driven by latent heat release from the primary condensible species.     

Emerging technologies for identifying superior dairy cows in New Zealand

The performance of animals is determined by the interaction of their genes with environmental circumstances. Accordingly, animals exhibiting superior performance are not necessarily the animals with the best genes nor are they the best choice of parents. Statistical analyses of production records for repeated traits, e.g. lactation yields and reproductive performance, show that part of the variation in performance among animals in the same herd and year is due to genetic differences, and the remainder is due to so-called residual or environmental factors that are not passed on to offspring. These within-herd environmental factors can be partitioned into a component that affects performance throughout an animal's lifetime, and a part that is unique to each observation. The process of animal evaluation from pedigree and performance records partitions the superiority of each cow into these three components. Reliable assessment of the genetic merit of bulls has required progeny testing, and for cows has required observation of their own individual performance. Selection on the genetic or breeding value component has systematically improved animal performance over recent decades, but has been limited by the age at which assessments of genetic merit are available.

Emerging molecular technologies can read DNA sequences or measure RNA expression and have allowed the identification of a number of chromosome regions, and a few specific genes in those regions, that influence economic performance. This information allows better characterisation of the relationships between animals and more accurate predictions of genetic merit in bulls without progeny information and in cows that have yet to produce their own performance record. At some stage, enough genes responsible for variation in performance will be identified to allow faster genetic progress through selection of animals at young ages and therefore more rapid turnover of the generations. Mechanisms that modify gene expression have been identified and these may ultimately allow animals to be selected at an early age for lifetime productivity, accounting for processes that modify gene expression and lead to differences in performance that are not reflected by DNA sequence information. This review describes the status of these emerging technologies and their likely role in the improvement of dairy cattle.     

Components of electroencephalographic responses to slaughter in halothane-anaesthetised calves: Effects of cutting neck tissues compared with major blood vessels

AIM: To identify whether cutting neck tissues or cutting major blood vessels initiates the mechanisms responsible for electroencephalographic (EEG) responses to slaughter by ventral-neck incision without prior stunning in halothane-anaesthetised calves.

METHODS: Calves were assigned to two groups, viz transection of neck tissues with intact blood circulation through the brain (n=10), or transection of the major blood vessels of the neck but not most other neck tissues (n=7). They were minimally anaesthetised with halothane, using an established anaesthesia protocol. The animals in the neck-tissue transection group had their carotid arteries and jugular veins exposed and cannulated proximal and distal to the proposed site of subsequent ventral-neck incision; this diverted blood fl ow through these vessels so that cerebral perfusion and drainage were preserved. In animals in the blood-vessel transection group, the carotid arteries and jugular veins were exposed bilaterally by surgical dissection. They were then transected without further damage to the remaining structures of the neck. Changes in the median frequency (F50), 95% spectral edge frequency (F95), total power of the EEG (Ptot), and arterial blood pressure were compared within each group before and after neck-tissue or blood-vessel transection, and between groups following treatments.

RESULTS: Neck-tissue transection resulted in little overall change in the F50, an increase in the F95, and an initial increase in Ptot followed by a transient decrease and eventual return to pre-treatment values. There was between-animal variation in these EEG parameters. Transection of the major blood vessels of the neck resulted in a decrease in F50 in most animals; changes in F95 were highly variable, and there was a decrease in Ptot.

CONCLUSIONS: The EEG responses seen following necktissue and blood-vessel transection were qualitatively distinct, and suggested that cutting neck tissues caused greater noxious sensory input than transection of only the major blood vessels of the neck. These observations support the conclusion that the EEG responses seen after ventral-neck incision in intact animals are primarily due to noxious stimulation as a result of incision of ventral-neck tissues and not mainly as a result of loss of blood flow through the brain.     

Using the Five Domains Model to develop welfare assessment guidelines for Thoroughbred horses in New Zealand

ABSTRACT

This review outlines the processes followed by New Zealand Thoroughbred Racing (NZTR) when developing its Thoroughbred Welfare Assessment Guidelines. It accepted that guidance on welfare management must be based on up-to-date knowledge of how animal welfare is understood scientifically. NZTR established an expert panel to facilitate this process. First, major changes in animal welfare science thinking over the last 40 years were considered. For example, the separate biological function and affective state orientations were later accepted as dynamically interacting elements within the body operating as an integrated whole entity; conceptual problems with the Five Freedoms framework led to the formulation of the Five Provisions and Welfare Aims paradigm and development of the Five Domains Model for assessing nutritional, environmental, health, behavioural and mental facets of animal welfare; and the initial major focus on negative experiences evolved to include both negative and positive experiences. The Five Domains Model was very effective for illustrating up-to-date understanding of animal welfare and its use demonstrated how comprehensive animal welfare assessments may be conducted. The NZTR panel followed a sequential approach that included an update on animal welfare thinking and the Five Provisions and Welfare Aims paradigm; the generic Five Domains Model was refocused specifically on equids; a detailed model assessment of equine welfare practices was conducted; enhanced equine welfare practices were emphasised by comparing them to inadequate welfare practices; guidelines were framed in terms which provide domain-specific advice on provisions that achieve positive welfare; other domain-specific guidelines were focused on welfare-compromising consequences of inadequate provisions; and welfare-appropriate conditions were clarified for all stages of a Thoroughbred’s life cycle (in work and rest) to facilitate exercising a life-long duty of care. Finally, the guidelines were expressed in general terms to avoid them becoming overly detailed and unwieldy. They therefore do not address specific welfare issues such as use of whips, bits, spurs and tight nosebands, however the Five Domains Model may also be used for these specific purposes. The guidelines, and the way they were formulated, provide an example of one approach which other organisations may find immediately useful, or which may stimulate them to devise their own approaches when progressing such equine welfare initiatives.     

Leukotrienes are Auto‐/Paracrine Factors in the Bovine Corpus Luteum: An In Vitro Study

The aim of this study was to determine leukotrienes (LTs) functions in the bovine corpus luteum (BCL) during the oestrous cycle. In steroidogenic CL cells we examined the effect of luteotropic [LH, prostaglandin E₂ (PGE₂)] and luteolytic (PGF_2α, cytokines) factors on: the levels of LTB₄ and C₄, the expression of 5‐lipoxygenase (LO), LT receptors type I (LTR‐I) and LTR‐II, and the effects of LTB₄ and C₄ stimulations on the levels of progesterone (P4), PGE₂, F_2α and nitric oxide (NO) metabolites. Both luteolytic and luteotropic factors stimulated 5‐LO expression on days 2–4 and 17–19 of the cycle. Leukotriene receptors type I expression increased after PGE₂ and tumour necrosis factor α with interferon γ (TNF/IFN) stimulation on days 2–4 of the cycle. Leukotriene receptor type II expression increased after PGE_2α and TNF/IFN stimulation on days 2–4 and 17–19 of the cycle, and LTR‐II expression on days 8–10 of the cycle was unchanged after cell stimulation with any factor. Leukotriene B₄ level increased after BSC incubation with luteotropic factors during all examined days of the cycle and after cytokine stimulation at early‐ and mid‐luteal stages, whereas luteolytic factors stimulated LTC₄ secretion over the entire cycle. Leukotriene B₄ stimulated P4 secretion at the mid‐luteal stage and stimulated NO secretion during all examined phases. Leukotriene B₄ stimulated PGE₂ secretion at the early‐ and mid‐luteal stage. Leukotriene C₄ inhibited P4 secretion at the mid‐ and regressing‐luteal stage, stimulated NO (entire cycle) and PGF_2α at mid‐ and regressing‐luteal phases. Leukotrienes modulate steroidogenic cells functions, depending on the stage of the cycle. Leukotriene B₄ plays a luteotropic role stimulating P4 and PGE₂ secretions; LTC₄ stimulates the secretion of luteolytic factors and enhances the luteolytic cascade within BCL.     

Ingestion and excretion of nitrogen and phosphorus by beef cattle under contrasting grazing intensities

There is increased global interest in the environmental impacts of farming, including the need to prevent the contamination of soil, water and air with excessive amounts of nitrogen (N) and phosphorus (P) in grazed systems. Reduction in grazing intensity has frequently been recommended to meet biodiversity and production goals in sustainable grazing systems. The objective of this experiment was to measure N and P ingestion and excretion by beef cattle grazing semi‐natural pastures at two grazing intensities (Moderate or Lenient). The cattle grazing at Moderate grazing intensity had significantly more defaecations each day than those grazing at Lenient intensity (9·5 vs. 7·5) and tended to have more urinations (7·0 vs. 5·8). For the Moderate and Lenient treatments, respectively, 113 vs. 76 g N d^?1 was excreted compared with 136 vs. 94 g N d^?1 ingested; 12 vs. 8 g P d^?1 was excreted compared with 13 vs. 10 g P d^?1 ingested and urine N comprised 0·51 and 0·52 of the total N excreted each day. In improved, intensively managed grassland systems, urine N comprises a much higher proportion (approximately 0·70–0·85) of the daily total N excreted. The lower level found here is likely to impact on potential volatilization, denitrification and leaching losses, and these aspects should be examined further to see the extent to which semi‐improved grasslands containing increased plant diversity compared with improved grasslands can deliver higher resource protection, as well as enhanced grassland faunal diversity and abundance.