Absorption by sheep of dieldrin from contaminated soil

Objective To study the accumulation of dieldrin residues in sheep from ingestion of contaminated soils was studied in two experiments.
Design A controlled feeding study of sheep fed contaminated soils of different type at varying intervals.
Animals and procedure Thirty-four 2-years-old wethers were divided into four groups (one control sheep only) and fed water-soluble dieldrin or soil contaminated with aldrin and dieldrin at varying intervals in the first study. In a second study 34 similar sheep were divided into four treatments with one being a control. Sheep were fed sandy, high clay or high organic matter soils with similar dieldrin and aldrin concentrations.
Results In the first study the concentration of dieldrin in the body fat of sheep dosed with dieldrin-contaminated soil was about half that in the body fat of sheep dosed with an equivalent amount of water-soluble dieldrin. The concentration of dieldrin was almost the same in sheep fed 500 μg of total dieldrin per day as it was in sheep fed 5000 μg every tenth day, over a 50-day period. In the second experiment sheep accumu-lated nearly three times as much pesticide from a soil with a high organic matter content, and about four times as much from a soil with a high clay content, as from a sandy soil with the same dieldrin content, over a 100-day period. The half-life of dieldrin in the fat of all sheep varied between 96 and 116 days after sheep ceased ingesting contaminated soil.
Conclusions Dieldrin concentrations in the fat of sheep that consume dieldrin contaminated soil fall within 10 days of removal from the source of contamination. However, dieidrin accumulates in the wool of sheep that consume dieldrin-contaminated soil.     

Short-term anaesthesia in piglets using a liquid injection, rebreathing, inhaler device

An economical anaesthetic technique of short duration that can be administered to piglets in the field is desirable for humanitarian reasons, for castration, tail docking or other brief procedures. Using the principles of anaesthetic uptake and distribution, an inhaler was developed to vaporize and administer isoflurane to piglets. The inhaler design consisted of a mask, vaporization chamber and a rebreathing bag. A stopcock provided access for injection of liquid isoflurane onto a wick contained in the vaporization chamber. Inspiratory and expiratory flow of air over the wick enhanced anaesthetic vaporization. The amount of liquid isoflurane required for induction and 2–3 minutes of surgical anaesthesia was calculated using the square root of time model proposed by Lowe & Ernst (1981) for liquid injection, closed circuit anaesthesia in people. Calculations were based on an assumed MAC of 1.4% and the achievement of a target alveolar concentration of 1.3 MAC to provide a surgical plane of anaesthesia. The appropriate isoflurane concentrations in the mask, inhaler, rebreathing bag and the piglet's FRC and tissues were calculated. Original calculations were based on metabolic size (BW^0.75) and then converted to weight (kg). Based on the piglet's scale weight, the total microliters of liquid isoflurane required were formulated into a table for field use. Isoflurane was injected into the inhaler stopcock followed by oxygen to fill the rebreathing bag and initiate vaporization. After the mask was placed over the piglet's nose a slide switch was activated to allow gases to move in and out of the inhaler and rebreathing bag. Fifty‐seven male piglets weighing (mean ± SD 3.0 ± 0.7 kg) and aged 7.7 ± 1.0 days were randomly selected to receive anaesthesia prior to castration. Remaining littermates served as controls for assessing morbidity or mortality. The time to induction, recovery and total anaesthetic time were measured. The Pe ′CO₂ was measured at the piglet's nostril immediately after the mask was removed at the end of the surgical procedure. Data were analysed in SAS using the Proc Mixed procedure. Inductions were rapid, 47 ± 9 seconds, generally with minimal or no resistance. The duration of surgery was 1–2 minutes. Anaesthesia was adequate and recovery was rapid, 122 ± 44 seconds. Total time from start to standing was 260 ± 51 seconds. The Pe ′CO₂ was 5.2 ± 1.1 kPa (39.4 ± 8.4 mm Hg). There was no morbidity or mortality associated with either group of piglets. After piglets were standing and mobile, they were returned to the sow and other littermates, where they immediately started nursing and were indistinguishable from littermates except by determination of ear notch number. This technique provides safe, rapid anaesthesia and recovery that is appropriate for use by veterinarians for brief field procedures.     

Response of Navel Lane Late citrus trees to regulated deficit irrigation: yield components and fruit composition

The effects of mid-summer regulated deficit irrigation (RDI) treatments were investigated on Navel Lane Late citrus trees over four seasons. Water restrictions applied from July until mid-September were compared with irrigation at full crop evapotranspiration (ETc). Two degrees of water restrictions were imposed: (1) RDI-1, irrigated at around 50% ETc and, (2) RDI-2, irrigated at 30–40% ETc. In addition, threshold values of midday stem water potential (Ψs) of ?1.3 to ?1.5 MPa for RDI-1 and of ?1.5 to ?1.7 MPa for RDI-2 were also taken into account. Results showed that Navel Lane Late is a citrus cultivar sensitive to water deficit since both RDI strategies reduced fruit size every year and water use efficiency in RDI trees was similar to control trees. However, the RDI-1 strategy allowed water savings up to 19% without reduction in yield when the water stress integral did not surpass 70 MPa day. RDI improved fruit quality, increasing total soluble solids and titratable acidity, while the fruit maturity was delayed. In conclusion, we suggest that RDI-1 strategy since it did not significantly impair the economic return can be applied in commercial orchards in case of water scarcity. Nevertheless, Navel Lane Late fruit is sensitive to water deficit and the fruit weight can be detrimentally affected.     

Addition of Recombinant Human Growth Hormone to In Vitro Maturation Medium of Bovine Oocytes

The aim of this study was to increase the bovine embryonic development rate, adding recombinant human growth hormone (rhGH) to maturation medium of bovine oocytes. Oocytes were matured for 24 h in TCM 199 Earle's salts and five treatments were developed: T1, 0.01 IU/ml of recombinant human follicle stimulating hormone (rhFSH); T2, 0.01 IU/ml of rhFSH + 100 ng/ml of rhGH; T3, 0.01 IU/ml of rhFSH + 1000 ng/ml of rhGH; T4, 100 ng/ml of rhGH; and T5, 1000 ng/ml of rhGH at 39 degrees C and 5% of CO(2) in air and saturated humidity. In vitro fertilization from cumulus-oocyte complexes was conducted in TALP-Fert medium (18-22 h) and spermatozoa were selected by Percoll gradient. Zygotes were incubated in SOFaaci medium in 5% of CO(2) in air, 5% of O(2) at 39 degrees C and saturated humidity for 11 days. There was no statistical difference in cleavage rate and embryo production on day 7 and day 9 among treatments. However, the hatching rate increased significantly in the T4 and T5 treatments (11.0 and 12.8%, respectively), compared with the T1 treatment (4.6%) (p < 0.05). Therefore, the rhGH addition to the oocyte maturation medium showed beneficial effects on the hatching rate of in vitro-produced bovine embryos.     

Buffalo (Bubalus bubali) Late Embryo and Foetus Development: A Morphological Analysis

Many researches describe the embryonic developmental features in domestic animals; however, in farm animals, they are scarce. Most farm animal studies are related to assisted reproduction and embryos transfer techniques. But, morphological features and size measure to estimate the age gestation are rarely reported in literature. Thus, in this study, we described the developmental changes in the bubaline (Bubalus bubali) concepts from 21 to 60 days of gestation. Our results revealed that buffalo embryos similar morphological characteristics similar to other mammalian species. Also, similarities between bovine and bubaline persist; except on foetal stages when buffalos have a faster development than bovine. Therefore, buffalo's gestation period exhibits some varieties and accurate embryo age is more difficult. Yet, when we use a combination of the crown–rump, macroscopic analysis and alizarin red, it is possible to describe better the whole embryogenesis stages of the buffalo and which can contribute for future reproduction researches and applications in veterinary practice.     

Crop load affects maximum daily trunk shrinkage of plum trees

We studied the effects of low fruit load (3-4 fruits cm(-2) of trunk cross-sectional area (TCSA), and high fruit load (6-7 fruits cm(-2) TCSA) on maximum daily trunk shrinkage (MDS) and trunk growth rates (TGR) over two seasons in plum (Prunus salicina Lindell) trees receiving full irrigation or deficit irrigation. Seasonal changes in MDS and TGR were compared with those in midday stem water potential (Psi(s)) and leaf stomatal conductance (g (s)). Crop load increased g (s) in fully irrigated trees approaching harvest. Although crop load did not affect plant water status in either watering regime, there were considerable differences in both MDS and TGR as a function of crop load. Compared with low-cropping [corrected] trees, MDS was 34% higher and TGR was 48% lower in high-cropping [corrected] trees. The differential responses of MDS and Psi(s) to crop load were a consequence of a higher MDS for a given Psi(s) in the high-cropping trees compared with the low-cropping trees. There was a linear increase in MDS with crop load, with a slope of 15.2 microm MPa(-1) per unit increment of crop load. In the fully irrigated trees, day-to-day variations in MDS were related to evaporative demand; however, the slope of the relationship between MDS and evaporative demand increased with crop load, indicating that different reference equations must be used to adjust for tree crop load when using MDS to determine plant water status and irrigation requirements.     

Nutritional response of Zea mays L. seedlings to “on plant demand” fertilizer: A vector analysis approach

Glass matrix based fertilizers (GMF) are new mineral fertilizers, able to release nutrients on the basis of plant demand: they are soluble only in metal complexing solutions, such as those exuded by plant roots. Moreover, nutrient release could be increased by mixing the glass-matrix fertilizer to different organic biomasses, such as leather meal, digested vine vinasse, etc. A greenhouse pot experiment was conducted for assessing the effect of an organo-mineral fertilizer, obtained by mixing GMF with increasing percentages of digested vine vinasse [DVV, at 5% (GMF95), 20% (GMF80) and 50% (GMF50) w/w], on the root and shoot biomass and nutritional status of Zea mays L. seedlings. Among tested fertilizers, the formulations GMF80 and GMF50 gave the best results as shoot/root ratio. The treatments with GMF, GMF95 and GMF80 gave rise to a significant increase of both shoot and root biomass and a tendency to increase the macro and micronutrients availability.