Behavioral and stress responses to feeding time in pregnant sows under limit-fed regime

We investigated the effect of feeding time on behavior and stress responses in pregnant sows under isocaloric conditions. Twenty-four sows were balanced for parity and randomly assigned to 1 of 3 feeding times. Corn–soybean meal-based diet was fed once at: 0730 (Control, T1), 1130 (T2), and 1530 hours (T3). On average, sows received 7,062 kcal ME/d from 2.20 kg of diet formulated to contain SID Lys/ME of 1.71 g/Mcal. The study was conducted for 28 d (21 d acclimation to the feeding regime and 7 d data collection). Saliva samples were collected every 2 hr for 12 hr in stalls on day 52 of pregnancy. Behavior data were collected 24 hr for 7 d from day 53 of gestating by affixing a remote insights ear tag to each sow. Each sow had 120,960 data points categorized into: “Active,” “Feed,” or “Dormant”. Due to housing constraint, all sows were housed in individual stalls in the same barn presenting a potential limitation of the study. Data were analyzed using PROC MIXED and GLIMMIX procedures of SAS 9.4 for cortisol and behavior data, respectively. Sow was the experimental unit. The area under the curve (AUC) is quantitative evaluation of response as threshold varies over all possible values. A 12-hr cortisol total AUC for sows fed once daily at 1130 hours was reduced relative to sow group fed at 1530 hours (P = 0.046) but similar compared with the control sows (P = 0. 323). The control sows (0730 hours) had reduced total (P < 0.001) and feeding (P = 0.001) activity AUCs relative to sows on 1130 hours but did not differ compared with sows on 1530 hours feeding schedules (P > 0.100). Sows on 1130 hours feeding schedule had greater feed anticipatory activity, 24-hr total activity count, total (P < 0.001) and feeding (P < 0.001) activity AUC compared with sows fed daily at 1530 hours. In conclusion, feeding pregnant sows earlier in the morning (0730 hours) appears to minimize sows’ behavior but similar cortisol response. Sows on 1130 hours feeding schedule had greater activities but reduced cortisol concentration, suggesting that elevated sow activity might not necessarily indicate activation of hypothalamic–pituitary–adrenal axis.     

Evaluation of pheromone release from commercial mating disruption dispensers

Pome fruit growers and crop consultants have expressed concerns about the seasonal release performance of commercial codling moth mating disruption dispenser products. Because of these concerns, we developed a laboratory flow-through volatile collection system (VCS) for measuring the volatile release of the codling moth sex pheromone, codlemone, from commercially available hand-applied dispensers. Under controlled air-flow and temperature conditions, the released vapor was trapped onto a polyurethane foam adsorbent followed by solvent extraction, solvent reduction, and GC/MS determination. Method recovery and breakthrough validations were performed to demonstrate system reliability before determining codlemone release from commercial dispensers field-aged over 140 days. The volatile collection was carried out in a consistent manner among five dispenser types most commonly used by growers, so that direct comparison of performance could be made. The comparison showed differences in the amount of pheromone released and in the patterns of release throughout the season between dispenser types. The variation in release performance demonstrates the need for routine evaluation of commercially marketed mating disruption dispensers. We believe that the simple and cost-effective volatile collection system can assist pheromone dispenser manufacturers in determining seasonal dispenser performance before new products are introduced into the commercial market and in rapidly verifying dispenser release when field-aged dispenser efficacy is in question.     

Cost-Benefit Analysis and the Development of Acification Policy in Europe

Countries that will ratify the new Protocol to abate acidification, eutrophication and ground-level ozone, also known as the Göteborg-protocol, are committed to meet national emission ceilings for SO₂, NOx, VOCs and NH₃ in 2010. AEA Technology calculated impacts and monetised benefits for four scenarios used during the preparation of the new Protocol, each scenario compared with the situation 1990. The calculated benefits were compared with the costs calculated by the International Institute for Applied Systems Analysis (IIASA) using the RAINS model. The overall conclusion is that the benefits are likely to exceed the costs of implementing the scenarios considered in the study, by a factor of between two and three. Based on the principal set of assumptions followed in the study, it appeared that impacts on haity and materials were negligible. Impacts on ecosystems remained unquantified.     

Mapping genes for resistance to sprouting damage in wheat

A series of experiments to investigate the genetic basis of pre-harvest sprouting are reported. The results are combined with previously published studies in a composite genetic map for sprout resistance in hexaploid wheat. Different studies, using classical genetics, aneuploids, chromosome substitutions, or QTL mapping, have identified various regions of the A, B, and D genomes affecting dormancy. Comparisons between the available studies lead to the following conclusions: • Different studies often identify different genetic loci, in part reflecting different sampling from the available gene pool. This implies that many loci are involved in determining resistance, and that new loci may be discovered as the number of mapping studies increases.• There are, however, examples where similar map locations are implicated over different crosses. These may reflect the detection of key resistance genes. • Finally, (genotype × environment) interactions are frequently observed. The implications of these observations for crop improvement and research programmes are discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Relationship between weaning age and antibiotic usage on pig growth performance and mortality

A total of 2,184 pigs (DNA 600 × PIC L42) were used to evaluate the effects of weaning age and antibiotic (AB) use on pig performance from weaning to marketing in a commercial production system. Experimental treatments were arranged in a 3 × 2 factorial with main effects of weaning age (18.5, 21.5, or 24.5 d of age) and with the use of ABs or an antibiotic-free (NAE) program. At birth, pigs were ear tagged, and the date of birth and sex recorded. Pigs were weaned from a 4,000-sow farm over four consecutive weeks. Four weaning batches (one per week) of 546 pigs were used. Each weaning batch had one-third of pigs of each weaning age. Pigs were placed in pens by weaning age and then randomly assigned to an AB or NAE program. There were 14 replicate pens per treatment and 26 pigs per pen (13 barrows and 13 gilts). Pigs allocated to the AB program were fed a diet containing 441 mg/kg chlortetracycline (CTC) from day 8 to 21 postweaning. They were also administered 22 mg/kg of body weight (BW) of CTC via drinking water for five consecutive days after a porcine respiratory and reproductive syndrome outbreak during week 7 after weaning. In the first 42 d postweaning, increasing weaning age improved (linear, P < 0.001) BW at day 42, average daily gain (ADG), and average daily feed intake (ADFI). From weaning to 197 d of age, increasing weaning age increased (linear, P < 0.001) ADG and ADFI. Pigs on the AB program had greater (P = 0.031) ADG and ADFI compared with NAE pigs. An interaction (linear, P = 0.005) was observed for feed efficiency (G:F). When ABs were provided, increasing weaning age did not result in any change in G:F; however, in the NAE program, increasing weaning age increased G:F. Pigs on the AB program had lower (P < 0.001) total losses (mortality and removals) than those on the NAE program. Increasing weaning age marginally (linear, P = 0.097) decreased total losses. Increasing weaning age decreased (quadratic, P < 0.001) the number of pigs treated with an injectable AB but the AB program did not (P = 0.238). The weight sold (at 197 d of age) per pig weaned was increased (linear, P = 0.050) by increasing weaning age and by using AB in feed and water (P = 0.019). In summary, increasing weaning age linearly improved most of the pig performance criteria and relatively the short-term use of ABs reduced mortality and removals with both factors contributing to increased weight sold per pig weaned.     

Egg Quality Determinants in Finfish The Role of Overripening with Special Reference to the Timing of Stripping in the Atlantic Halibut Hippoglossus hippoglossus

Egg quality, those characteristics of the egg that determine its capacity to survive, is a significant problem for many species of fish currently being farmed. Little is known about the determinants of egg quality and there is little agreement regarding reliable methods for its assessment. To be of practical benefit, assessments should be simple to perform and should be carried out as early in development as is possible. Fertilization rates are often used as measures of quality. For the Atlantic halibut Hippoglossus hippoglossus, fertilization rate and assessments of cell symmetry at early cleavage stages provide reasonable indicators of quality. Regardless of assessment method, it is strongly recommended that performance data from all batches of each broodfish be examined when surveying the overall quality of a stock. The misleading effects of pooling such information are demonstrated for a rainbow trout Oncorhynchus mykiss broodstock. Although a large number of factors have been implicated as possible determinants of egg quality, only 1) bacterial colonization of the eggs, 2) nutritional status of the broodfish and, 3) overripening, the process of aging that occurs when eggs are retained within the broodfish after ovulation, have been clearly shown to affect egg quality. The effect of overripening on fish egg quality is discussed in detail. Species-specific differences in the time scale of overripening are pointed out and related to spawning strategy and water temperature. Rainbow trout eggs and those of other salmonids should be fertilized within approximately one week of ovulation. Overripening proceeds much more rapidly in warm water species, e.g., tilapia eggs must be fertilized within an hour or so of ovulation. Egg viability also decreases rapidly for batch spawning species. Fertilization data are presented for Atlantic halibut demonstrating that egg quality decreases 4–6 h after ovulation. The rate of overripening was comparable for eggs held in vitro in ovarian fluid to those retained within the ovarian lumen. These halibut data, combined with information from other marine and freshwater fish, indicate that overripening is a significant determinant of egg quality for many if not all fish.     

Diurnal patterns of water use in Eucalyptus victrix indicate pronounced desiccation-rehydration cycles despite unlimited water supply

Knowledge about nocturnal transpiration (E(night)) of trees is increasing and its impact on regional water and carbon balance has been recognized. Most of this knowledge has been generated in temperate or equatorial regions. Yet, little is known about E(night) and tree water use (Q) in semi-arid regions. We investigated the influence of atmospheric conditions on daytime (Q(day)) and nighttime water transport (Q(night)) of Eucalyptus victrix L.A.S. Johnson & K.D. Hill growing over shallow groundwater (not >1.5 m in depth) in semi-arid tropical Australia. We recorded Q(day) and Q(night) at different tree heights in conjunction with measurements of stomatal conductance (g(s)) and partitioned E(night) from refilling processes. Q of average-sized trees (200-400 mm diameter) was 1000-3000 l month(-1), but increased exponentially with diameter such that large trees (>500 mm diameter) used up to 8000 l month(-1). Q was remarkably stable across seasons. Water flux densities (J(s)) varied significantly at different tree heights during day and night. We show that g(s) remained significantly different from zero and E(night) was always greater than zero due to vapor pressure deficits (D) that remained >1.5 kPa at night throughout the year. Q(night) reached a maximum of 50% of Q(day) and was >0.03 mm h(-1) averaged across seasons. Refilling began during afternoon hours and continued well into the night. Q(night) eventually stabilized and closely tracked D(night). Coupling of Q(night) and D(night) was particularly strong during the wet season (R2?=?0.95). We suggest that these trees have developed the capacity to withstand a pronounced desiccation-rehydration cycle in a semi-arid environment. Such a cycle has important implications for local and regional hydrological budgets of semi-arid landscapes, as large nighttime water fluxes must be included in any accounting.     

Semiochemicals of the common bed bug,Cimex lectularius L. (Hemiptera: Cimicidae), and their potential for use in monitoring and control

The recent resurgence of the common bed bug, Cimex lectularius L., has driven an increase in research into the biology and behaviour of this pest. Current control is reliant on the application of insecticides, but, owing to the development of insecticide resistance, there is a need for new tools and techniques. Semiochemicals (behaviour‐ and physiology‐modifying chemicals) could be exploited for management of bed bugs. The aim of this review was to evaluate studies undertaken in bed bug chemical ecology to date, with particular reference to how the research could be exploited for monitoring and control. Bed bugs, like many other insects, have a complex olfactory system. Recent studies have characterised the olfactory sensilla, located on the terminal segment of the antennae, to functional classes by electrophysiological screening. Behavioural studies have revealed the presence of an alarm pheromone and potential airborne aggregation semiochemicals, but it is not yet understood if bed bugs use a sex pheromone during mating. Host location cues have been investigated, and carbon dioxide has been found to be highly attractive both in laboratory and in field studies. Recent field trials have tested blends of other potential kairomones, which have been shown to have an additive effect when used in a heated bed bug trap with carbon dioxide. The trap, which combines heat and kairomones, is the only trap currently available with proven efficacy in the field. In order for semiochemicals to be useful for bed bug management, an increased knowledge and understanding of the biology, behaviour and chemical ecology of this insect is essential. Copyright © 2010 Society of Chemical Industry