Total intravenous anesthesia with ketamine–medetomidine–propofol in horses

Propofol is a potentially useful intravenous anesthetic agent for total intravenous anesthesia (TIVA) in horses. The purpose of this study was to compare the anesthetic and cardiorespiratory effects of TIVA following the administration of propofol alone(P–TIVA) and ketamine–medetomidine–propofol (KM–P–TIVA) in adult horses. The carotid artery was translocated to a subcutaneous position during TIVA with P–TIVA (n = 6) or KM–P–TIVA (n = 6). All horses were premedicated with medetomidine [0.005 mg kg^–1, intravenously (IV)]. Anesthesia was induced with midazolam (0.04 mg kg^–1 IV) and ketamine (2.5 mg kg IV). All horses were orotracheally intubated and breathed 100% oxygen. The KM drug combination (ketamine 40 mg mL^–1 and medetomidine 0.05 mg mL^–1) was infused at a rate of 0.025 mL kg^–1 hour^–1. Subsequently, a loading dose of propofol (0.5 mg kg^–1, bolus IV) was administered to all horses; surgical anesthesia (determined by horse response to incision and surgical manipulation, positive response being purposeful or spontaneous movement of limbs or head) was maintained by varying the propofol infusion rate as needed. Arterial blood pressure and HR were also monitored. Both methods of producing TIVA provided excellent general anesthesia for the surgical procedure. Anesthesia time was 115 ± 17 (mean ± SD) and 112 ± 11 minutes in horses anesthetized with KM–P–TIVA and P–TIVA, respectively. The infusion rate of propofol required to maintain surgical anesthesia with KM–P–TIVA was significantly less than for P–TIVA (mean infusion rate of propofol during anesthesia; KM–P–TIVA 0.15 0.02 P–TIVA 0.23 ± 0.03 mg kg^–1 minute^–1, p = 0.004). Apnea occurred in all horses lasting 1–2 minutes and intermittent positive pressure ventilation was started. Cardiovascular function was maintained during both methods of producing TIVA. There were no differences in the time to standing after the cessation of anesthesia (KM–P–TIVA 62 ± 10 minutes versus P–TIVA 87 ± 36 minutes, p = 0.150). The quality of recovery was good in KM–P–TIVA and satisfactory in P–TIVA. KM–P–TIVA and P–TIVA produced clinically useful general anesthesia with minimum cardiovascular depression. Positive pressure ventilation was required to treat respiratory depression. Respiratory depression and apnea must be considered prior to the use of propofol in the horse.     

Astaxanthin Normalizes Epigenetic Modifications of Bovine Somatic Cell Cloned Embryos and Decreases the Generation of Lipid Peroxidation

Astaxanthin is an extremely common antioxidant scavenging reactive oxygen species (ROS) and blocking lipid peroxidation. This study was conducted to investigate the effects of astaxanthin supplementation on oocyte maturation, and development of bovine somatic cell nuclear transfer (SCNT) embryos. Cumulus–oocyte complexes were cultured in maturation medium with astaxanthin (0, 0.5, 1.0, or 1.5 mg/l), respectively. We found that 0.5 mg/l astaxanthin supplementation significantly increased the proportion of oocyte maturation. Oocytes cultured in 0.5 mg/l astaxanthin supplementation were used to construct SCNT embryos and further cultured with 0, 0.5, 1.0 or 1.5 mg/l astaxanthin. The results showed that the supplementation of 0.5 mg/l astaxanthin significantly improved the proportions of cleavage and blastulation, as well as the total cell number in blastocysts compared with the control group, yet this influence was not concentration dependent. Chromosomal analyses revealed that more blastomeres showed a normal chromosomal complement in 0.5 mg/l astaxanthin treatment group, which was similar to that in IVF embryos. The methylation levels located on the exon 1 of the imprinted gene H19 and IGF2, pluripotent gene OCT4 were normalized, and global DNA methylation, H3K9 and H4K12 acetylation were also improved significantly, which was comparable to that in vitro fertilization (IVF) embryos. Moreover, we also found that astaxanthin supplementation significantly decreased the level of lipid peroxidation. Our findings showed that the supplementation of 0.5 mg/l astaxanthin to oocyte maturation medium and embryo culture medium improved oocyte maturation, SCNT embryo development, increased chromosomal stability and normalized the epigenetic modifications, as well as inhibited overproduction of lipid peroxidation.     

The hawaii to tahiti shuttle experiment

The Shuttle Experiment conducted between Hawaii and Tahiti from January 1979 to June 1980 was designed to observe the changing equatorial ocean structure and circulation, to study the variations and interactions of the four major equatorial ocean currents, and to develop a scientific basis for their monitoring by simple observations of thermal structure and sea level. Preliminary analyses of the results show that the equatorial thermal structure remains intact during a normal year and that only the positions and intensities of the currents are subject to change. The water transport of the equatorial undercurrent varied from 25 x 10(6) cubic meters per second in January to 51 x 10(6) cubic meters per second in July, but also exhibited strong short-term pulsations. The equatorial surface flow responded strongly to the winds at periods of 1 month and longer. An array of drifter buoys in the equatoral countercurrent was subject to very little dispersion while traveling over 4500 kilometers in 4 months. Low-frequency fluctuations in the North Equatorial Countercurrent can be monitored by means of the difference in sea level between Fanning and Majuro.     

Power analysis based on spatial effects mixed models: A tool for comparing design and analysis strategies in the presence of spatial variability

Spatial variability among experimental units is known to exist in many designed experiments. Agronomic field trials are a particularly well-known example, but there are others. Historically, spatial variability has been dealt with in one of two ways: either though design, by blocking to account for spatial effects, or though analysis, by nearest neighbor adjustment. More recently, mixed models with spatial covariance structures such as those used in geostatistics have been proposed. These mixed model procedures have tempted some to conclude—to the dismay of many consulting statisticians—that design principles may be bypassed, since spatial covariance models can recover any lost information. Although design principles clearly should not be ignored, spatial procedures do raise questions. Are traditional notions of appropriate design affected? If so, how? How do spatial effects mixed models compare to conventional analysis of variance used in conjunction with blocked designs? This article presents mixed model methods to assess power and precision of proposed designs in the presence of spatial variability and to compare competing design and analysis strategies. The main conclusion is that, if anything, spatial models reinforce the need for sound design principles, particularly the use of incomplete block designs.     

Cyclic variation in cattle feed intake data: characterization and implications for experimental design

Feed intake data were collected every 6 h in a 140-d feeding trial involving two pens of 15 bull calves, each using one Pinpointer single-animal feeding stall per pen. Spectral analysis of these data revealed strong cyclic patterns of feed intake. These patterns were unique to each animal and consisted of two or more cycle lengths, some up to 28 d, for each animal. Feed intake behavior is an important factor in many forms of animal experimentation. Animal researchers frequently use row-column designs, where columns represent animals and rows represent periods. Latin squares and crossover designs are common examples. Standard analysis of variance procedures are appropriate for these experiments only if certain assumptions are met; one is that if cyclic variation is present, it is identical for all animals, i.e., there is no row X column interaction. If this assumption is not satisfied, standard analysis of variance procedures will result in upward bias of the mean square error and may result in serious distortion of treatment effect estimates. This occurred using the data from the feeding trial reported in this paper. Time-series analysis of covariance greatly improved the accuracy and efficiency of estimates of treatment effects. Consideration of variations in cyclic behavior should be part of the design process in experiments using feed intake data. Guidelines for the design of experiments to take advantage of time-series methodology are given.     

Effects of oral administration of controlled-ileal-release budesonide and assessment of pituitary-adrenocortical axis suppression in clinically normal dogs

OBJECTIVE: To evaluate the effects of oral administration of controlled-ileal-release (CIR) budesonide on the pituitary-adrenal axis in dogs with a normal gastrointestinal mucosal barrier. ANIMALS: 10 healthy dogs. PROCEDURES: 5 dogs received CIR budesonide orally once daily for days 1 through 28, and 5 dogs received placebo. Treatment group dogs that weighed < 18 kg received 2 mg of CIR budesonide; treatment group dogs that weighed > or = 18 kg received 3 mg of CIR budesonide. In the treatment and placebo groups, there were 3 and 2 dogs, respectively, that weighed > 18 kg. Plasma cortisol concentration before and after ACTH stimulation, basal plasma endogenous ACTH concentration, and body weight were measured on days 0, 7, 14, 21, 28, and 35. Serum biochemical analysis, CBC determination, and urinalysis were performed on days 0, 28, and 35. On days 7, 14, and 21, serum ALP and ALT activities, serum glucose concentration, and urine specific gravity were obtained in lieu of a full hematologic evaluation and urinalysis. RESULTS: Basal and post-ACTH stimulation plasma cortisol concentrations and plasma endogenous ACTH concentration were significantly suppressed by treatment. No other variables were altered over the course of the study. CONCLUSIONS AND CLINICAL RELEVANCE: Budesonide suppresses pituitary-adrenal function in dogs with normal gastrointestinal integrity, whereas other variables often affected by glucocorticoids were not altered by a 4-week treatment course. Budesonide may be a good alternative to traditional cortico-steroids if used short-term for acute exacerbations of inflammatory bowel disease.     

Clinical evaluation of balanced anesthesia using infusion of midazolam–ketamine–medetomidine in combination with inhalation of sevoflurane (MKM–OS anesthesia) in horses

MKM–OS anesthesia provides general anesthesia with minimum cardiovascular depression in experimental horses. The purpose of this study was to evaluate the effect of MKM–OS anesthesia in clinical cases. Sixty‐eight horses were anesthetized with MKM–OS anesthesia for selective or emergency surgery. The horse physical status was categorized based upon the American Society of Anesthesiologists (ASA) classification scheme. Forty‐four horses were classified as ASA I or II (low‐risk; 30 soft tissue, eight ophthalmic, and six orthopedic surgeries) and 24 horses were classified as ASA III to V (high‐risk; 24 emergency colic surgeries). All horses were administered medetomidine (0.005 mg kg^–1 IV) as premedication and anesthetized with ketamine (2.5 mg kg^–1 IV) and midazolam (0.04 mg kg^–1 IV). The horses were orotracheally intubated and connected to a large animal breathing circuit that delivered oxygen‐sevoflurane and administered the midazolam (0.8 mg mL^–1)‐ketamine (40 mg mL^–1)‐medetomidine (0.05 mg mL^–1) drug combination at a rate of 0.025 mL kg^–1 hour^–1. Surgical anesthesia was maintained by controlling the dial setting of the sevoflurane vaporizer and achieved by delivering 1.6–1.8% of end‐tidal sevoflurane concentration. All horses were mechanically ventilated during anesthesia. Hypercapnia and hypoxia were not sufficiently improved in high‐risk horses (PaCO₂; low‐risk 45–53 mm Hg versus high‐risk 56–60 mm Hg, p < 0.01: PaO₂ low‐risk 248–388 mm Hg versus high‐risk 95–180 mm Hg, p < 0.01). Heart rate was significantly higher in high‐risk horses (low‐risk 37–42 bpm versus high‐risk 44–73 bpm, p < 0.01). Dobutamine infusion was required in five low‐risk (11%) and 17 high‐risk horses (68%) to maintain mean arterial blood pressure >70 mm Hg. Eleven high‐risk horses died during the perioperative period (three euthanized during surgery, two died during recovery, six died after recovery). The quality of recovery was good in low‐risk horses and good to satisfactory in high‐risk horses. MKM–OS anesthesia provided excellent surgical anesthesia with minimal to mild cardiovascular depression in low risk‐horses and mild to moderate cardiovascular depression in high risk‐horses. The possibility of preserve cardiovascular function could be the advantage of MKM–OS anesthesia in high‐risk horses.     

Long Chain Fatty Acids of Diet as Factors Influencing Reproduction in Cattle

Cattle are fed moderate amounts of long chain fatty acids (FA) with the objective to enhance lactation and growth; however, recent interest on lipid feeding to cows has focused on reproduction, immunity and health. Increasing the caloric density of the ration by fat feeding has generally improved measures of cow reproduction, but when milk yield and body weight losses were increased by fat supplementation, positive effects on reproduction were not always observed. Feeding fat has influenced reproduction by altering the size of the dominant follicle, hastening the interval to first postpartum ovulation in beef cows, increasing progesterone concentrations during the luteal phase of the oestrous cycle, modulating uterine prostaglandin (PG) synthesis, and improving oocyte and embryo quality and developmental competence. Some of these effects were altered by the type of FA fed. The polyunsaturated FA of the n-6 and n-3 families seem to have the most remarkable effects on reproductive responses of cattle, but it is not completely clear whether these effects are mediated only by them or by other potential intermediates produced during rumen biohydrogenation. Generally, feeding fat sources rich in n-6 FA during late gestation and early lactation enhanced follicle growth, uterine PG secretion, embryo quality and pregnancy in cows. Similarly, feeding n-3 FA during lactation suppressed uterine PG release, and improved embryo quality and maintenance of pregnancy. Future research ought to focus on methods to improve the delivery of specific FA and adequately powered studies should be designed to critically evaluate their effects on establishment and maintenance of pregnancy in cattle.     

Production‐level risk factors for syncytial hepatitis in farmed tilapia (Oreochromis niloticus L)

Syncytial hepatitis (SHT) is an emerging viral disease of tilapia characterized by significant morbidity and mortality. This study aimed to establish the production‐level risk factors associated with presence and severity of SHT. Production factors were analysed during multiple outbreaks of SHT that occurred between 2011 and 2013 on a single tilapia farm in Ecuador and compared with the year 2010 before the SHT outbreaks. Relative risks, t tests, modified Poisson and forward stepwise linear regression analyses were performed using EPIINFO?. Compared to other strains, Chitralada had an elevated risk of SHT [RR = 2.1 (95%CI 1.8–2.4)]. Excessive mortality associated with the presence (and severity) of SHT increased by 611 (365), 6,814 (5,768) and 388 (340) deaths per 100,000 fry when stocking density, dissolved oxygen and pond production cycles were raised by 1 fish/m², 1 mg/L and 1 cycle, respectively. Excessive mortality associated with the presence (and severity) of SHT decreased by 337 (258) and 1,354 (1,025) deaths per 100,000 when stocking weight and water temperature increased by 1 g and 1°C, respectively. Time (season and stocking year) was not significantly associated with SHT. This study shows that some production factors increase the risk incidence and severity of SHTon a farm.