Effect of birthweight, total protein, serum IgG and packed cell volume on risk of neonatal diarrhea in calves on two California dairies.

The objective of the study was to determine if there was a relationship between hematological, immunological and physiological variables of newborn calves and risk of diarrhea during the neonatal period. Four hundred and seventeen heifer calves from two dairies (A and B) in the San Joaquin Valley of California were enrolled at birth and scored daily, to 28 days of age, for evidence and severity of diarrhea (0 to 3). Calves were weighted at birth and blood sampled at two to five days of age to determine packed cell volume (PCV), total protein (TP) and IgG serum concentration. The Cox proportional hazards model was used to determine if age at onset of the first diarrhea episode and length of the first episode were associated with the hypothesized variables (PCV, TP, IgG and birthweight). The IgG concentration was not associated with the age at onset of diarrhea (p = 0.6052, Dairy A; p = 0.4393, Dairy B) but a high IgG concentration was associated with a decreased length of episode (p = 0.0325, Dairy A; p = 0.0912, Dairy B), particularly for calves born in the winter on dairy A (p = 0.0211). For calves born in the winter, those with either a high or a low birthweight had diarrhea at a younger age (p = 0.0102, Dairy A; p = 0.0020, Dairy B). Associations were also found for PCV and TP with both the age at onset and length of the first episode of diarrhea. Results suggest that parameters measurable at, or shortly after birth may have important prognostic value in evaluating risk of calf diarrhea.     

Selectivity estimates for Amblygaster sirm (Clupeidae) in the small-meshed gill net fishery on the west coast of Sri Lanka

Selectivity of Amblygaster sirm by gill nets of seven mesh sizes ranging from 2.3 to 3.8 cm stretched mesh was studied for a period of 12 months in the coastal waters off Negombo on the west coast of Sri Lanka. The size range of fish caught was 9.0–22.0 cm. Selection by mesh sizes smaller than 3.0 cm was towards the lower end of the selection curve.

Estimated values for selection factors ranged from 5.11 to 6.03 and those for optimum selection lengths varied from 12.9 to 19.7 cm. The highest selection factor was observed for 2.9 cm mesh, probably due to wedging of larger individuals in this mesh.     

Aerosol therapy in the equine species

Inhalation therapy plays an increasing role in the management of equine respiratory disorders. Thisalternative to systematic treatment permits a high concentration of medication to act locally while minimizing side effects and residues. In human medicine, literature in this field is prolific and continuously renewed, whereas in veterinary medicine, applications of aerosol therapy are less extensive. This review considers the principles of action of the different types of devices used for inhalation, i.e., nebulization, metered-dose inhalation and dry powder inhalation, describes the technical and practical requirements for their use in the equine species and considers the advantages and disadvantages of each inhalation device. The pharmacological agents currently administered to horses by inhalation are also discussed. Perspectives of aerosol therapy in the equine species, including aerosols already used in human medicine and their potential applications for horses are described.     

Effect of Integration of Fertilizer and Green Manure Nitrogen on Yield Attributes, Nitrogen Uptake and Yield of Lowland Rice (Oryza sativa L.)

Field experiments were conducted at Tamil Nadu Rice Research Institute, Aduthurai, India, during the wet seasons of 1992 and 1993 to study the effect of full and partial substitution of fertiliser N with green manure N (Sesbania rostrata) on nitrogen uptake, yield attributes and yield of rice. The experiment consisted of eight treatments with two levels of N (100 and 200 kg ha⁻¹) and three sources of N application viz., fertilizer, integrated (1:1 fertilizer and green manure N) and green manure N compared to the recommended practice (150 kg fertilizer plus 6.25 t ha⁻¹ (72 kg N) green manure) and a no N control. Nitrogen application markedly increased the N uptake. Combined use of the two N sources at 200 and 222 kg N ha⁻¹ and of single fertilizer N at 200 kg N ha⁻¹ recorded the maximum N uptake, increased the yield attributes such as number of panicles per unit area, weight per panicle, number of total and filled grains per panicle and test weight. At 200 kg N ha⁻¹ full substitution of N by green manure reduced the grain yield but only partial substitution of N by green manure resulted in almost similar yield as single fertilizer N. Thus 200 kg N ha⁻¹ applied in equal proportions of fertilizer and green manure N can be recommended for medium duration rice cultivars.     

Does the induction agent affect the course of halothane anaesthesia in horses?

Four hundred and ninety horses were anaesthetised with halothane for clinical surgical or diagnostic procedures following induction with either detomidine/keta-mine, detomidine/thiopentone, xylazine/ketamine or guaiphenesin/thiopentone. Routine clinical monitoring was performed during anaesthesia. All horses developed hypotension (mean arterial pressures below 80 mm Hg) and respiratory depression (significant fall in respiratory rate and arterial carbon dioxide tension above 7 kPa (53 mm Hg)) consistent with the recognised effects of halothane. All anaesthetic procedures incorporating xylazine or detomidine resulted in lower pulse rates (28–35 per min) than after guaiphenesin/thiopentone (36–44 per min) and there was greater respiratory depression after techniques employing thiopentone rather than keta-mine. Development of hypotension was delayed after techniques using the α₂ adrenoceptor agonist agents (xylazine and detomidine), particularly detomidine. Prernedication with acepromazine did not affect any of the physiological variables measured after techniques employing detomidine. Recovery to standing was fastest after xylazine/ketamine (31±1 min) and slowest after detomidine/thiopentone (53±2 min). Recovery quality was best after detomidine/thiopentone and all techniques employing an α₂ adrenoceptor agonist agent resulted in smoother recovery than after guaiphenesin/thiopentone. This study demonstrates that most of the physiological effects of individual induction agents are overridden by the cardiovascular and respiratory depressant effects of halothane. The study also shows that detomidine is an acceptable sedative for use before general anaesthesia with halothane in horses.     

In vitro viability of cryopreserved equine embryos following different freezing protocols.

The main objective of this study was to evaluate two freezing protocols and the effect of agar embedding on survival of day 6.5 equine embryos. A total of 133 embryos were used, in one group (n = 51), embryos were first embedded in agar before the freezing protocol was started. A freezing protocol to -30 degrees C or -33 degrees C was used before plunging embryos into liquid nitrogen (LN2). The embryos were thawed in water at 37 degrees C, evaluated and placed in culture. After 24 h culture, the embryos were evaluated for their morphology and development. No differences were observed between embryos plunged at -30 degrees or at -33 degrees C in LN2. The analysis of the morphology and development after thawing showed that the diameter and developmental stage at freezing correlated with embryo survival. Morula and early blastocyst stages of development were associated with better quality after freezing and thawing and had a better potential to survive after in vitro culture (p < 0.05) compared to more advanced stages. The agar failed to protect embryos from zona pellucida damage, but a tendency to prevent rupture was observed in larger embedded embryos.     

Changes in some biochemical indicators of bone turnover after ultraviolet irradiation of dairy cows

The effect of ultraviolet irradiation on some biochemical indicators of bone turnover in dairy cows was determined. The irradiation was performed using a stationary system for two months and comprised a regimen of 10 days irradiation followed by 10 days rest. After ultraviolet irradiation, significant differences in the activities of serum alkaline phosphatase (P < 0.001) and bone alkaline phosphatase isoenzyme (P < 0.05) and concentration of osteocalcin (P < 0.01) were demonstrated. The results suggest that supplementary ultraviolet irradiation during winter could be used as a simple but reliable method of preventing the development of generalised metabolic bone disorders in dairy cows.     

Milk production, water consumption, and somatic cell count responses of cows subject to one to two volts of alternating current.

A dairy farm located in central New York was visited because of complaints of electrical shock in the farmhouse shower and the milk house sink. As much as 2 volts AC of potential difference was measured between the waterline and the cow platform (cow-contact voltage). Voltage was coming from the primary neutral wire. The farm's electrical service was modified so that the farmstead could be connected or disconnected from the primary neutral wire at 2-week intervals for 12 weeks. When connected to the primary neutral wire, voltage between waterline and floor ranged between 0 and 1.8 volts, producing estimated current flow through cows of 3.6 to 4.9 mA; when disconnected from primary neutral wire, voltage between waterline and floor was less than 0.1 volt. There was no difference in mean milk production, bulk tank milk somatic cell count, or water consumption among periods when cows were exposed or unexposed to voltage. Despite statistical nonsignificance, the values for somatic cell count were lower and water consumption was higher when cows were exposed to voltage than when they were not.     

Other new and potentially useful inhalational anesthetics.

Sevoflurane and desflurane are volatile inhaled anesthetics that are currently being investigated as possible improvements for the anesthetic management of human patients. Information to date suggests these agents have several advantages over existing clinical agents. For example, the blood/gas partition coefficient for both agents is lower than that of other halogenated anesthetics. Consistent with this physical characteristic is a more rapid induction of and emergence from anesthesia. Both cause a dose-related depression of cardiopulmonary function, which is comparable to isoflurane. Results of studies to date favor desflurane over sevoflurane because it is less soluble in blood, is stable in soda lime, is biodegraded the least of any volatile anesthetic, and is not toxic.