Effects of aerobic and anaerobic fluid collection on biochemical analysis of peritoneal fluid in healthy horses and horses with colic

Objective: To determine whether in healthy horses and those with colic, exposure of peritoneal fluid to room air affects values obtained on biochemical analysis. Study Design: Prospective study. Animals: Adult horses with a primary complaint of acute abdominal pain (n=29) and 12 healthy horses. Methods: Peritoneal fluid was aseptically collected under aerobic and anaerobic conditions. After collection, pH, PCO₂, PO₂, HCO₃^?, Na⁺, ionized Ca²⁺, K⁺, lactate, and glucose were immediately measured using a commercial blood gas analyzer. Biochemical variables were compared between aerobically and anaerobically obtained samples using a paired t‐test. Results: In healthy horses, peritoneal fluid samples collected under anaerobic conditions had higher PCO₂ and ionized Ca²⁺ and lower PO₂, HCO₃^?, and pH compared with samples exposed to air. No differences were observed for K⁺, Na⁺, glucose, and lactate. In horses with colic, samples collected anaerobically had higher PCO₂, ionized Ca²⁺, Na⁺, and glucose and lower PO₂, HCO₃^?, and pH value compared with samples exposed to air. No differences were observed for K⁺ and lactate. Conclusion: Exposure of peritoneal fluid to room air had a significant effect on pH, PCO₂, PO₂, and variables associated or dependent on changes in pH such as HCO₃^? and ionized Ca²⁺. Interpretation of biochemical analysis of peritoneal fluid may be influenced by sample collection method.     

The concentration of ionized magnesium in serum during the periparturient period of non-paretic dairy cows

Ion-selective electrodes have recently been designed for determining the ionized concentration of magnesium (Mg²⁺) in serum. This development may allow new insights into some metabolic diseases of cattle. For this report, the concentrations of Mg²⁺, total magnesium (Mg_tot), ionized calcium (Ca²⁺), total calcium (Ca_tot), and inorganic phosphate (P_i) were determined in sera from seventeen 3-to 16-year-old Brown Swiss and crossed Simmental/Red Holstein cows during the periparturient period. In each animal, a transient increase of Mg²⁺ and Mg_tot serum concentrations was observed in association with the transient decrease in serum concentrations of Ca²⁺, Ca_tot and P_i after parturition. On average, throughout the study, the serum Mg²⁺ concentrations were 68.5% of those of Mg_tot, whereas the serum Ca²⁺ concentrations were 52% of those of Ca_tot. The possible mechanisms involved in the transient increase of Mg²⁺ and Mg_tot serum concentrations are discussed.Abbreviations Ca²⁺ ionized calcium - Ca_tot total calcium - Mg²⁺ ionized magnesium - Mg_tot total magnesium - P_i inorganic phosphate - PTH parathyroid hormone - PTHrP parathyroid homrone related protein     

Arterial Acid-Base Measurements in 1–3 Days Old Piglets

A method of percutaneous arterial blood sampling in piglets has been developed and determinations of arterial pH, pCO₂, pCO2, BE, HGO3 , LA and Hb have been performed in 121 piglets 1–3 days of age. The validity of these measurements has been tested and proved valid for clinical practice with the exception of pO₂ and LA values. The correlations with age were statistically significant but poor and therefore the mean values are presented as reference values. These were: pH: 7.423±0.082, PCO₂: 4.98±0.74 kPa, BE: 0.4±4.1 mmol/1, HCO³_‒: 23.0+3.2 mmol/1 and Hb: 88±14 g/1.     

Prescribed Fire,Soil, and Plants: Burn Effects and Interactions in the Central Great Basin

Pinyon and juniper expansion into sagebrush ecosystems results in decreased cover and biomass of perennial grasses and forbs. We examine the effectiveness of spring prescribed fire on restoration of sagebrush ecosystems by documenting burn effects on soil nutrients, herbaceous aboveground biomass, and tissue nutrient concentrations. This study was conducted in a central Nevada woodland and included control and burn treatment plots sampled before and after a prescribed fire. Six native understory plant species (Crepis acuminata, Eriogonum umbellatum, Eriogonum elatum, Poa secunda secunda, Festuca idahoensis, and Lupinus argenteus) important for native sagebrush obligate foragers were chosen to represent the understory plant community. L. argenteus is also important for system nutrient cycling and nitrogen fixation. Plants were collected from three microsites (under tree canopy, under shrub canopy, and interspace) common in transitional woodlands during peak growth the summer before a spring prescribed burn and each of two summers following the burn. Soils were collected from corresponding locations at two depth intervals (0–8 and 8–52 cm) to determine the relationships between soil and plant nutrients following fire. Microsite affected soil nutrients but did not influence plant tissue concentrations with the exception of F. idahoensis. Burning resulted in increases in soil surface NH+4, NO₃⁻, inorganic N, Ca²⁺, Mn²⁺, and Zn²⁺. Increases in NO₃⁻, inorganic N, and Zn²⁺ were also observed in deeper horizons. Burning did not affect aboveground plant biomass or nutrient concentrations in the first year with the exception of F. idahoensis, which had increased tissue P. By the second year, all species had statistically significant responses to burning. The most common response was for increased aboveground plant weight and tissue N concentrations. Plant response to burning appeared to be related to the burn treatment and the soil variables surface K⁺, NO₃⁻, and inorganic N.     

Effects of dietary cation-anion balance on blood PH, acid base parameters, serum and urine mineral levels, and parathyroidhormone (PTH) in weanling horses.

This study demonstrated that the feeding of treatment diets with calculated dietary cation-anion balances (DCAB) of +370.43 (H) and -25.69 (L) did not have significant effects on blood pH, pCO₂, and HCO₃-. Serum Ca²⁺, P, Na⁺, and Cl^- as well as plasma PTH did not differ (P > .05) between the two treatment groups. Serum K⁺ was higher (P< .05) in horses fed diet H rather than diet L. The DCAB of the diet significantly affected urinary Ca²⁺, P, Na⁺, K⁺, and Cl^- excretion in the young growing horse. Urine Ca²⁺ and Cl- levels were higher (P < .01) in horses fed diet H versus diet L. Furthermore, levels of P, Na⁺, and K⁺ in the urine were higher (P < .01) in horses on diet H as opposed to diet L. Results of this study indicate that horses were able to maintain acid-base status regardless of diet. However, these data imply that growing horses consuming diets low in DCAB may be predisposed to abnormal bone mineralization due to the increase in calcium excretion which could lead to a weakening of the skeletal system.     

Environmental Exposures and Airway Inflammation in Young Thoroughbred Horses

Background

Inflammatory airway disease (IAD) in horses is a widespread, performance‐limiting syndrome believed to develop in response to inhaled irritants in the barn environment.

Objectives

To evaluate changes in bronchoalveolar lavage fluid (BALF) cytology and exposure to particulates, endotoxin, and ammonia during horses'' first month in training.

Animals

Forty‐nine client‐owned 12‐ to 36‐month‐old Thoroughbred horses entering race training.

Methods

In this prospective cohort study, a convenience sample of horses was assigned to be fed hay from a net (n = 16), whereas the remaining horses were fed hay from the ground (n = 33). BALF was collected at enrollment and after 14 and 28 days in training. Respirable particulate, inhalable particulate, respirable endotoxin, and ammonia concentrations were measured at the breathing zone of each horse weekly.

Results

Median respirable particulates were significantly higher when horses were fed from hay nets than when fed hay from the ground (hay net 0.28 mg/m³, no hay net 0.055 mg/m³, P < .001). Likewise, inhalable particulate (hay net 8.3 mg/m³, no hay net 3.3 mg/m³, P = .0064) and respirable endotoxin (hay net 173.4 EU/m³, no hay net 59.2 EU/m³, P = .018) exposures were significantly higher when horses were fed from hay nets. Feeding hay from a net resulted in significantly higher BALF eosinophil proportions over time (P < .001). BALF eosinophils were significantly related to respirable particulate exposure (14 days in training r _s = 0.37, P = .012, 28 days in training, r _s = 0.38, P = .017).

Conclusions and Clinical Importance

Pulmonary eosinophilic inflammation develops in response to respirable particulate exposure in young Thoroughbreds, indicating a potential hypersensitivity to inhaled particulate allergens.     

Isoenzymes of lactate dehydrogenase in swine. Stability during storage at different temperatures and by heat treatment

The isoenzymes of lactate dehydrogenase (LDH) in serum from normal pigs were studied after separation by agar gel electrophoresis with subsequent staining with a tetrazolium salt.Experiment 1. The stability of isoenzymes was investigated for 5 successive days after storage at room temperature (22°C), in the refrigerator (4°G), and once after storage for 32 days in the deep-freezer (—20°C). Greatest loss of activity was seen after storage in the refrigerator, where LDH₂ and LDH₃ lost most of its activity after 5 days. In LDH₄ and LDH₅ no loss had occurred at this time. Also at room temperature great losses were seen in LDH₂ and LDH₃. After storage in the deep-freezer an increase in LDH₃ activity was recorded.Experiment 2. Serum samples were kept in water baths for 30 min. at 50, 53, and 56°C. A simultaneous and increasing loss in activity of LDH₃, LDH₄, and LDH₅ was seen from 50° to 56°C. At 56° no activity was left in LDH₃, LDH₄, or LDH₅, and only about 15 % of the original activity was present in LDH₂. LDH₁ showed no loss at 56°, but all activity was lost at 65°.A close correlation was found between total lactate dehydrogenase and α-hydroxybutyrate dehydrogenase activity in both experiments.     

Analytical sensitivity of air samplers based on uniform point-source exposure to airborne Porcine reproductive and respiratory syndrome virus and swine influenza virus

Research and surveillance activities involving airborne pathogens rely on the capture and enumeration of pathogens suspended in aerosols. The objective of this study was to estimate the analytical sensitivity (detection threshold) of each of 4 air samplers for Porcine reproductive and respiratory syndrome virus (PRRSV) and swine influenza virus (SIV). In a 5-min sampling period under controlled conditions, the analytical sensitivity of the AGI-30 (Ace Glass, Vineland, New Jersey, USA), AGI-4 (Ace Glass), SKC BioSampler (SKC, Eighty Four, Pennsylvania, USA), and Midwest Micro-Tek sampler (Midwest Micro-Tek, Brookings, South Dakota, USA) was calculated at 1 × 10^1.1, 1 × 10^1.3, 1 × 10^1.1, and 1 × 10^1.2 median tissue culture infectious dose (TCID₅₀) equivalents for PRRSV and 1 × 10^1.4, 1 × 10^1.1, 1 × 10^1.6, and 1 × 10^1.2 TCID₅₀ equivalents for SIV [per 60 L (5-min sampling period)]. Despite marked differences in sampler design, no statistically significant difference in analytical sensitivity was detected between the samplers for collection of artificially produced aerosols containing cell-culture-propagated PRRSV or SIV.     

Investigation into the durability of washed rice straw for equine bedding and the repetitive use of washing water

The present experiment investigated durability during the repetitive use of washed rice straw, as bedding material, and washing water as a model study. Residual nitrogen levels, elasticity, and water suction rates for washed rice straw‐adhered urea were measured. In addition, outflow levels of nitrogen and mineral ions (Na⁺, NO₂^‐ + NO₃^‐, SO₄^2?, PO₄^3?, Cl^‐) for washing water were measured to determine durability. Nitrogen levels of rice straw significantly (P < 0.05) decreased after two washings. There was no significant change in elasticity of repetitively used rice straw. Suction rates of rice straw after the second and third washings increased significantly (P < 0.05) compared to the first time. With regard to the number of washings, the mineral ion outflow level in the washing water for nitrogen, Na⁺, NO₂^‐ + NO₃^‐ and PO₄^3? after each washing was not significant. However, nitrogen outflow level tended to decrease after the third washing. SO₄^‐ and Cl^‐ did significantly decrease (P < 0.05) with the number of washings. In this study, it was considered that rice straw and washing water could be used repetitively three times. Furthermore, in order to maintain effluent standards, washing water from the first washing needs to be processed in a septic tank.     

Cardiopulmonary and analgesic effects of caudal epidurally administered ropivacaine in cattle

ObjectiveTo assess cardiopulmonary and analgesic effects after administration of ropivacaine into the caudal epidural space of cattle.Study designProspective, single-dose trial.AnimalsEight healthy mixed breed cows aged 8 ± 5 years and weighing 507 ± 112 kg.MethodsCaudal epidural anesthesia was produced in cows with 0.75% ropivacaine (0.11 mg kg^?1). Onset time, duration and cranial spread of analgesia were recorded. Heart rate (HR), respiratory rate (f_R), rectal temperature (RT), and mean arterial blood pressure (MAP) were measured prior to epidural administration (T₀) and at 15, 30, 60, 120, 180 and 240 minutes after epidural administration (T₁₅, T₃₀, T₆₀, T₁₂₀, T₁₈₀ and T₂₄₀). Arterial blood acid-base balance (pH, standard bicarbonate and base excess), gas tension (PaO₂, PaCO₂, SaO₂) and electrolytes (Na⁺, K⁺, iCa²⁺,Cl^?) were recorded at T₀, T₃₀, T₆₀, T₁₂₀, T₁₈₀ and T_240. Ataxia was evaluated at T₀, T₃₀, T₆₀, T₁₂₀, T₁₈₀ and T₂₄₀ and at 1 hour intervals thereafter until analgesia was no longer present in each animal.ResultsEpidurally administered ropivacaine induced variable analgesia extending bilaterally from the coccyx to S3. Time to onset of analgesia and mean duration in the perineal area were 15 ± 4 and 359 ± 90 minutes, respectively. Respiratory rate and RT increased from T₁₂₀ to T₂₄₀ when compared to the value at T₀. Ionized calcium and chloride concentrations increased at T₁₈₀ and T₂₄₀ when compared to T₀. The other variables were not significantly different from baseline values (p> 0.05). Four animals were mildly ataxic.Conclusion and clinical relevanceRopivacaine (0.75%, 0.11 mg kg^?1) can be administered by caudal epidural injection to produce prolonged bilateral perineal analgesia with minimal ataxia and cardiopulmonary changes in standing cattle.     

No effect of exogenous melatonin on development of cryopreserved metaphase II oocytes in mouse

Background

This study was conducted to investigate effect of exogenous melatonin on the development of mouse mature oocytes after cryopreservation.

Results

First, mouse metaphase II (MII) oocytes were vitrified in the open-pulled straws (OPS). After warming, they were cultured for 1 h in M₂ medium containing melatonin at different concentrations (0, 10⁻⁹, 10⁻⁷, 10⁻⁵, 10⁻³ mol/L). Then the oocytes were used to detect reactive oxygen species (ROS) and glutathione (GSH) levels (fluorescence microscopy), and the developmental potential after parthenogenetic activation. The experimental results showed that the ROS level and cleavage rate in 10⁻³ mol/L melatonin group was significantly lower than that in melatonin-free group (control). The GSH levels and blastocyst rates in all melatonin-treated groups were similar to that in control. Based on the above results, we detected the expression of gene Hsp90aa1, Hsf1, Hspa1b, Nrf2 and Bcl-x1 with qRT-PCR in oocytes treated with 10⁻⁷, or 10⁻³ mol/L melatonin and untreated control. After warming and culture for 1 h, the oocytes showed higher Hsp90aa1 expression in 10⁻⁷ mol/L melatonin-treated group than in the control (P < 0.05); the Hsf1, Hsp90aa1 and Bcl-x1 expression were significantly decreased in 10⁻³ mol/L melatonin-treated group when compared to the control. Based on the above results and previous research, we detected the development of vitrified-warmed oocytes treated with either 10⁻⁷ or 0 mol/L melatonin by in vitro fertilization. No difference was observed between them.

Conclusions

Our results indicate that the supplementation of melatonin (10⁻⁹ to 10⁻³ mol/L) in culture medium and incubation for 1 h did not improve the subsequent developmental potential of vitrified-warmed mouse MII oocytes, even if there were alteration in gene expression.     

Mechanisms involved in the cytosolic calcium ion elevation induced by activating factors in chicken and rat phagocytes

The aim of the present study was to determine the mechanism of cytosolic calcium ion concentration [Ca²⁺]_i elevation in chicken and rat phagocytes stimulated with phorbol myristate acetate (PMA), leukotriene B₄ (LTB₄), formyl‐methionyl‐leucyl‐phenylananine (fMLP) and Saccaromyces cerevisiae culture supernatant (SCS). Pretreatment with EGTA completely suppressed the PMA‐induced [Ca²⁺]_i elevation in rat and chicken phagocytes, suggesting that all the [Ca²⁺]_i elevation induced in the PMA‐stimulated rat and chicken phagocytes was attributable to the influx of extracellular Ca²⁺. On the other hand, the elevation of LTB₄‐, FMLP‐ and SCS‐induced [Ca²⁺]_i was only partially suppressed by ethyleneglycol‐bis (β‐aminoethyl)‐N,N,N′,N′‐tetraacetic acid ethylene (EGTA) pretreatment of phagocytes. The results indicated that two pathways of [Ca²⁺]_i elevation, recruitment from the intracellular Ca²⁺ store and influx of extracellular Ca²⁺, are involved in the [Ca²⁺]_i elevation of LTB₄‐, fMLP‐ and SCS‐stimulated phagocytes. In fMLP‐stimulated rat neutrophils, [Ca²⁺]_i elevation showed a two‐phase pattern in which the time lag between the first and second phase was approximately 1 min. The EGTA treatment of the fMLP‐stimulated cells induced a reduction of the first phase level and a disappearance of the second phase. The reason for the special influence of EGTA observed in fMLP‐stimulated cells is unknown, but the disappearance of the second phase of the [Ca²⁺]_i may be elicited by the EGTA‐induced decrease of the first phase [Ca²⁺]_i elevation that depends on IP₃ and diacylglycerol induced by fMLP.     

pH-dependent modulation of intracellular free magnesium ions with ion-selective electrodes in papillary muscle of guinea pig

A change in pH can alter the intracellular concentration of electrolytes such as intracellular Ca²⁺ and Na⁺ ([Na⁺]_i) that are important for the cardiac function. For the determination of the role of pH in the cardiac magnesium homeostasis, the intracellular Mg²⁺ concentration ([Mg²⁺]_i), membrane potential and contraction in the papillary muscle of guinea pigs using ion-selective electrodes changing extracellular pH ([pH]_o) or intracellular pH ([pH]_i) were measured in this study. A high CO₂-induced low [pH]_o causes a significant increase in the [Mg²⁺]_i and [Na⁺]_i, which was accompanied by a decrease in the membrane potential and twitch force. The high [pH]_o had the opposite effect. These effects were reversible in both the beating and quiescent muscles. The low [pH]_o-induced increase in [Mg²⁺]_i occurred in the absence of [Mg²⁺]_o. The [Mg²⁺]_i was increased by the low [pH]_i induced by propionate. The [Mg²⁺]_i was increased by the low [pH]_i induced by NH₄Cl-prepulse and decreased by the recovery of [pH]_i induced by the removal of NH₄Cl. These results suggest that the pH can modulate [Mg²⁺]_i with a reverse relationship in heart, probably by affecting the intracellular Mg²⁺ homeostasis, but not by Mg²⁺ transport across the sarcolemma.     

The effect of intramuscularly administered vitamin D3 on serum vitamin D metabolites and electrolytes in vitamin D3 deficient dairy cows

The effect of intramuscular administration of vitamin D₃ (1×10⁶ IU D₃/100 kg bodyweight) to 3 different dairy breeds on the serum levels of vitamin D₃, 25-OH-D₂, 25-OH-D₃, Ca, inorganic P and Mg was studied.The vitamin metabolites and the electrolytes were analysed on 9 occasions during a 36-day period. Vitamin D₃ was analysed on 6 occasions during the same period. No significant breed differences were observed except for 25-OH-D₃ (P ≤ 0.05). The D₃ level rose in 1 day from < 2 ng/ml to 906 ng/ml and decreased to below 50 % of the peak level after 6 days. At the end of the experiment (day 36) vitamin D₃ was < 2 ng/ml. 25-OH-D₃ rose from < 2 ng/ml to 106 ng/ml in 6 days and stayed at this level during the whole experiment. 25-OH-D₂ decreased from 16 ng/ml to 5 ng/ml during the observation period.     

Calcium homeostasis and its relationship to superoxide production in blood and milk neutrophils of lactating goats

Polymorphonuclear neutrophils (PMN), which comprise over 70% of the somatic cells in goat milk, are a major cellular component of innate immunity in the goat mammary gland. However, the function of milk PMNs is modified after diapedesis compared to PMNs in blood. As many aspects of PMN activity depend directly on intracellular Ca²⁺ concentration ((Ca²⁺)_i), the present study aimed to determine the changes in Ca²⁺ homeostasis of milk PMNs from lactating goats compared to autologous blood PMNs, and to examine the significance of these variations to the immuno-competency of milk PMNs. The intracellular Ca²⁺ store of freshly prepared milk cells was estimated from the elevation of (Ca²⁺)_i after ionomycin treatment, which was found to be significantly less than blood PMNs. Replenishment of the intracellular Ca²⁺ store in milk cells after intracellular Ca²⁺ depletion by Bapta-AM followed by spiking with 2.5 mM Ca²⁺ for 20 min was also compared to that of blood PMNs, showing that after depletion/spiking the intracellular Ca²⁺ store in milk cells was much less than blood PMNs. The production of superoxide anion (O₂^?) in vitro in response to (Ca²⁺)_i-dependent or (Ca²⁺)_i-independent modulators was used to evaluate the relevance of altered Ca²⁺ homeostasis on the immuno-competency of milk cells compared to blood PMNs. The results indicated that milk cells produced similarly low levels of O₂^? as blood PMNs when treated with ionomycin. However, the amount of O₂^? produced by milk cells in response to phorbol 12-myristate 13-acetate (PMA) stimulation, although greater than ionomycin treatment, was significantly less than that of blood PMNs. The capacity for O₂^? production by both cell types in response to PMA reverted to the resting state with use of the protein kinase C (PKC) inhibitor, staurosporine. In conclusion, the current study demonstrated an irreversible shortage of intracellular Ca²⁺ in the milk PMNs of lactating goats compared to blood PMNs. It also showed that preliminary O₂^–production, primed by ionomycin treatment, remained unchanged in milk PMNs, despite the shortage in intracellular Ca²⁺, but decreased O₂^? production capacity, mediated via the PKC pathway, in milk PMN. It is suggested that the defects in Ca²⁺ homeostasis in milk PMNs of lactating goats is partially attributable for the post-diapedesis functionality modifications.     

Influence of copper sulphate on the water and electrolyte balance of the freshwater snail Bulinus (Bulinus) tropicus

The water and electrolyte balance of Bulinus (Bulinus) tropicus, a freshwater pulmonate, was determined when subjected to different sublethal concentrations of copper sulphate. It was found that the lethal dose (LD₅₀), which is the dose lethal to 50% of the snails, is 1,0 ppm in water of pH 8,5. Increasing dosages disturb the ionic and water balance. Haemolymph concentrations of Na ⁺ , Ca²⁺ and Cl^- decrease markedly. The rates of ion influx and efflux for Ca²⁺ , Na ⁺ , Cl^- and ³H₂0, measured With their corresponding radioisotopes, were drastically changed. The results indicate that the physiological effects of copper are not limited to particular organs or tissues but probably occur throughout the snail body. The possible effect of copper sulphate on the in- tegumental exchange mechanisms for Ca²⁺, HCO3^-, Na⁺ , K⁺ and Cl^- are discussed.     

Cellular mechanisms by which oxytocin mediates uterine prostaglandin F2α synthesis in bovine endometrium: role of calcium

The objective of these experiments was to determine the role of Ca²⁺ during oxytocin-stimulated prostaglandin (PG) F_2α release from bovine endometrial tissue in vitro. Uteri were collected from dairy cows on the day after spontaneous luteal regression. Caruncular endometrial explants were dissected and incubated in vitro to determine phospholipase C activity or PGF_2α release. A23187 (a calcium ionophore) and maitotoxin (an activator of voltage-gated L-type calcium channels) stimulated release of PGF_2α in a concentration-dependent manner (P < 0.05). Thapsigargin (induces accumulation of Ca²⁺ in the cytoplasm by inhibiting endoplasmic reticulum Ca²⁺/ATPase pumps) stimulated release of PGF_2α in a concentration-dependent manner as well (P < 0.13). Oxytocin (10⁻⁶ M), AlF₄⁻ (a nonspecific activator of G-proteins; 10⁻⁵ M), A23187 (10⁻⁵ M), and melittin (a stimulator of phospholipase A₂; 10⁻⁴ M) stimulated PGF_2α release when explants were incubated in Ca²⁺-free medium (P < 0.10); however, oxytocin, A23187, or melittin were unable to stimulate PGF_2α release when explants were incubated in Ca²⁺-free medium containing the calcium chelator EGTA (P < 0.10). This treatment did not prevent oxytocin or AlF₄⁻ from stimulating phospholipase C activity (P < 0.08). CoCl₂ (a nonspecific Ca²⁺ channel blocker) and methoxyverapamil (a specific voltage-gated L-type Ca²⁺ channel blocker) prevented oxytocin from stimulating PGF_2α release (P < 0.05). Our results suggest that both extracellular and intracellular Ca²⁺ may be required for oxytocin to stimulate PGF_2α secretion in bovine endometrial tissue.     

Performance of a new carbon dioxide absorbent,Yabashi lime? as compared to conventional carbon dioxide absorbent during sevoflurane anesthesia in dogs

In the present study, we compare a new carbon dioxide (CO₂) absorbent, Yabashi lime^® with a conventional CO₂ absorbent, Sodasorb^® as a control CO₂ absorbent for Compound A (CA) and Carbon monoxide (CO) productions. Four dogs were anesthetized with sevoflurane. Each dog was anesthetized with four preparations, Yabashi lime^® with high or low-flow rate of oxygen and control CO₂ absorbent with high or low-flow rate. CA and CO concentrations in the anesthetic circuit, canister temperature and carbooxyhemoglobin (COHb) concentration in the blood were measured. Yabashi lime^® did not produce CA. Control CO₂ absorbent generated CA, and its concentration was significantly higher in low-flow rate than a high-flow rate. CO was generated only in low-flow rate groups, but there was no significance between Yabashi lime^® groups and control CO₂ absorbent groups. However, the CO concentration in the circuit could not be detected (≤5ppm), and no change was found in COHb level. Canister temperature was significantly higher in low-flow rate groups than high-flow rate groups. Furthermore, in low-flow rate groups, the lower layer of canister temperature in control CO₂ absorbent group was significantly higher than Yabashi lime^® group. CA and CO productions are thought to be related to the composition of CO₂ absorbent, flow rate and canister temperature. Though CO concentration is equal, it might be safer to use Yabashi lime^® with sevoflurane anesthesia in dogs than conventional CO₂ absorbent at the point of CA production.     

Characteristics of ammonia and carbon dioxide releases from layer hen manure

1.?Ammonia (NH₃) is an important gaseous pollutant generated from manure in commercial poultry farms and has been an environmental, ecological, and health concern. Poultry manure also releases carbon dioxide (CO₂), which is a greenhouse gas and is often used as a tracer gas to calculate building ventilation.

2.?A 38-d laboratory study was conducted to evaluate the characteristics of NH₃ and CO₂ releases from layer hen manure using 4 manure reactors (122 cm tall, 38 cm internal diameter), which were initially filled with 66 cm deep manure followed by weekly additions of 5 cm to simulate manure accumulation in commercial layer houses.

3.?The average daily mean (ADM) NH₃ and CO₂ release fluxes for the 4 reactors during the entire study were 161?5 ± 21?1 µg/s.m² (ADM ± 95% confidence interval) and 10?0 ± 0?3 mg/s.m², respectively. The daily mean NH₃ and CO₂ releases in individual reactors varied from 35?2 to 679?1 µg/s.m² and from 6?6 to 20?5 mg/s.m², respectively.

4.?The ADM NH₃ release flux was within the range of those obtained in 4 high-rise layer houses by Liang et al. (2005 Liang, Y, Xin, H, Wheeler, EF, Gates, RS, Li, H, Zajaczkowski, JS, Topper, PA, Casey, KD, Behrends, BR, Burnham, DJ and Zajaczkowski, FJ. 2005. Ammonia emissions from US laying hen houses in Iowa and Pennsylvania. Transactions of the ASAE, 48: 1927–1941. [Crossref] [Google Scholar], Transactions of the ASAE, 48). However, the CO₂ release flux in this study was about 10 to 13 times as high as the data reported by Liang et al. (2005 Liang, Y, Xin, H, Wheeler, EF, Gates, RS, Li, H, Zajaczkowski, JS, Topper, PA, Casey, KD, Behrends, BR, Burnham, DJ and Zajaczkowski, FJ. 2005. Ammonia emissions from US laying hen houses in Iowa and Pennsylvania. Transactions of the ASAE, 48: 1927–1941. [Crossref] [Google Scholar]). Fresh manure had greater NH₃ release potential than the manure in the reactors under continuous ventilation. Manure with higher contents of moisture, total nitrogen, and ammonium in the 4th weekly addition induced 11 times higher NH₃ and 75% higher CO₂ releases immediately after manure addition compared with pre-addition releases.     

Blood acid-base and plasma electrolyte values in healthy ostriches: The effect of age and sex

The effect of age and sex on blood acid-base and plasma electrolyte values was determined in venous blood samples from 45 clinically healthy ostriches (Struthio camelus) from 26 days to 6 years of age. Animals were divided by age into four groups and the group of adults was divided by sex into two subgroups. Blood samples were collected without sedation. There was a significant (P < 0.05) age difference in blood values of base excess (BE), plasma , total CO₂ (TCO₂), Na⁺, K⁺, Cl⁻ and anion gap (AG). The highest plasma concentrations of Na⁺, Cl⁻ and value of AG were found in adult ostriches with a steady decrease to chicks. A significant (P < 0.05) sex difference in adult animals with higher blood pH, lower blood values of pCO₂, BE, plasma concentrations of , TCO₂ and K⁺ was found in females. We concluded that blood acid-base values and plasma electrolyte concentrations in ostriches are affected by age and sex.