L.E. Evans

Selective metals determination with a photoreversible spirobenzopyran

The photoreversible metal-ion complexation behavior of nitroquinolinospiropyranindoline (NQSP) was studied in combination with the selective identification of six different transition-metal ions, Zn(2+), Co(2+), Hg(2+), Cu(2+), Cd(2+), and Ni(2+), in single- and binary-component mixtures via partial least squares discriminant (PLSD) analysis. The plasticizer, dicapryl phthalate, was chosen as the support medium for this study on the basis of (1) its enhancement of the photoreversibility and hypsochromic shifts seen in metal complexation and (2) its potential application to supported liquid membranes for eventual sensor applications. Complexation of divalent transition-metal ions by NQSP in dicapryl phthalate produced variable hypsochromic shifts in the absorption spectra (30-60 nm), requiring chemometric techniques in order to overcome the spectral overlaps. PLSD analysis was used to build classification analysis models to differentiate between the six divalent transition-metal ions. The feasibility of performing mixture analysis was studied using the concept of net analyte signal prior to experimental verification. Single- and binary-component mixtures of metals were identified with 100 and 97.4% accuracy, respectively, which included no false positives in either the training or prediction sets.

Effects of prolactin suppression with cabergoline on the pregnancy of the bitch

Abstract Twenty-one mated bitches were used, some of them repeatedly, to study the effect of an ergot alkaloid derivative, cabergoline (CAB), on ovarian endocrine function during early- to mid-luteal phase and late-luteal phase of gestation. In a blind trial, twelve bitches were bred three times; six of them received a daily dose of 5 mcg/kg body weight (BW) for 28 d, starting the day after the third breeding; the remaining six bitches received a placebo. In open trials, three bitches were given 15 mcg/kg CAB, and one bitch was given 5 mcg/kg daily for 5 d, around four wk of pregnancy (mid-luteal phase). Bight bitches were given 5 mcg/kg CAB once daily for 5 d, around 6 to 7 wk of pregnancy (late-luteal. phase). All dogs treated during the early- to mid-luteal phase maintained pregnancies. However, abortion resulted during or after CAB treatment during the late-luteal phase. Prolactin levels were determined in four bitches (late-luteal phase), and they showed a drop to baseline levels within 24 h after the first treatment with CAB. Progesterone blood levels always dropped in response to CAB treatment, but they reached baseline levels within 48 h only in bitches treated after mid pregnancy. These results indicate that CAB is not sufficiently luteolytic during the first half of pregnancy; however, it is fully luteolytic during the second half and can be used as an abortifacient during this period.

Effects of epidural administration of xylazine or lidocaine on bovine uterine motility and perineal analgesia.

The objective of this study was to evaluate and compare the effects of caudal epidural (sacral-coccygeal interspace) administration of xylazine or lidocaine on uterine motility and perineal analgesia in the cow. Six Holstein cows (7 d post estrus) were assigned to one of three treatment groups: control (5 ml saline); lidocaine (0.2 mg/kg, 2% solution); and xylazine (0.06 mg/kg suspended in 5 ml saline), with each cow randomly assigned to each treatment over a period of three estrous cycles. Uterine motility, perineal analgesia, electrocardiography, and overt signs of sedation were recorded. Data were collected at 10-min intervals starting 10 min before treatment and continuing until 60 min post treatment. At 60 min post treatment, oxytocin (20 USP units) was administered i.v. to serve as a positive control for uterine motility. In the xylazine group, uterine motility significantly (P < 0.05) increased at 20 min post treatment, peaked at 30 min, and gradually decreased to non-significant levels at 50 min post treatment when compared with the lidocaine and control groups. Additionally, xylazine produced a higher degree and longer duration of perineal analgesia than lidocaine. Systemically, epidural xylazine produced signs of sedation, salivation, vocalization and bradycardia. Ataxia was also observed in the xylazine-treated group which may have been induced through a local and/or systemic effect. The individual properties of xylazine and lidocaine should be taken into consideration when performing an obstetrical procedure requiring the use of an epidural analgesic agent, and they should be utilized to benefit the clinician in performing the procedure.

The effects of xylazine and alpha-adrenoreceptor antagonists on bovine uterine contractility in vitro.

The effects of alpha-adrenoreceptor antagonists prazosin (alpha-1), yohimbine (alpha-2), and idazoxan (alpha-2) on xylazine-induced bovine uterine contractility were tested in vitro. Uterine strips from proestrous/estrous and diestrous cows were mounted in tissue baths containing Tyrodes solution. Changes in uterine contractility were measured by strain gauge. The following results were observed: 1) Xylazine increased uterine contractility in a dose dependent manner (cumulative concentrations: 10(-8), 3x10(-8), 10(-7), 3x10(-7) and 10(-6)M). 2) Idazoxan (10(-8), 10(-7) and 10(-6)M) and yohimbine (10(-6), 10(-5) and 10(-4)M) antagonized uterine contractility induced by xylazine in a dose-dependent manner. Idazoxan was approximately 50 to 100 times more potent than yohimbine. 3) Prazosin (10(-5)M) did not alter the effect of xylazine on uterine contractility. These results suggested that xylazine-induced uterine contractility in the cyclic cow is directly mediated by myometrial alpha-2 adrenoreceptors.

Vaginal conductivity as an indicator for optimum breeding time in the sow after weaning

Abstract One hundred crossbreed multiparous sows were probed for vaginal mucosal conductivity using a conductivity meter (OVU-MATETM) to detect optimum time for breeding. The vaginal mucosal conductivity was measured once daily, starting the day of weaning until the sows were bred. According to the manufacturer, a 15 point increase in the OVU-MATE reading, when compared to that of the previous day, indicates the approach of estrus. After weaning the one hundred sows were randomly assigned to one (n = 20) of the five groups according to the following breeding schedules: sows were bred once at 0 h (Group 1), at 12 h (Group 2), at 24 h (Group 3) and at 36 h (Group 4) following a 15 point or higher increase in vaginal mucosal conductivity. Control sows (Group 5) were bred twice, 24 h apart, when estrus was detected by intact boars. All sows were bred naturally. The percentage of sows standing for the scheduled breeding, farrowing rate and litter size of each group were recorded. Only 60 and 50% of the sows were mated at 0 and 12 h, respectively, after an increase in vaginal mucosal conductivity, while all the sows in the other groups were mated. Sows in the control group and sows bred at 24 and 36 h after the vaginal mucosal conductivity increase had a similar farrowing rate (85%). There was no significant difference for litter size between the treatment groups when compared with those of the controls (0 h:10.33; 12 h:10.8; 24 h:11.11, 36 h:9.76, and controls:10.29;). These results suggest that a single mating at 24 or 36 h after a 15-point or higher vaginal mucosal conductivity increase results in a farrowing rate and litter size which is comparable with twice-mated control sows.

Toxicity effects of latex gloves on boar spermatozoa

It is known that several materials used in semen collection have been found to be detrimental to spermatozoal motility. In this study, examinations for toxic effects of latex and vinyl gloves, used with and without talcum powder on boar spermatozoa, were performed. Ten boars of known fertility with >/=80% sperm motility were divided into two groups (n = 5 boars each) for in vitro and in vivo studies. In the in vitro study, semen was collected from each of the five boars and was divided into five separate aliquots (5 ml each). One aliquot from each of the boars remained as the control, while the remaining aliquots were divided into individual treatments exposing the semen to a l cm(2) piece of latex or vinyl glove with or without talcum powder. In the in vivo experiment, semen from each of the five boars was collected using a gloved hand. During collection, the first half of the sperm-rich fraction was collected into a filtered sterile container, while the second half of the fraction was allowed to run through the palm of either a latex or vinyl powdered glove prior to collection in the container. In both experiments, semen sample motility was assessed by two independent observers at 1 minute after exposure. Results of both experiments consistently showed a significant (P<0.05) effect of latex gloves (with or without talcum powder) on boar semen when compared with the control semen. Motility was at or near 0% at 1 min after exposure to latex. No significant difference (P>0.05) in motility was observed between the control semen and the semen exposed to talcum powdered vinyl gloves. These results show that latex gloves are detrimental to boar spermatozoa. Therefore, it is suggested that when collecting boar semen vinyl gloves should be used.

Farrowing induction with cloprostenol-xylazine combination.

Eighty crossbred, multiparous sows, weighing between 190 and 320 kg, were randomly assigned to the following four treatment groups of 20 sows each: 1) saline-saline, 2) cloprostenol-saline, 3) saline-xylazine and 4) cloprostenol-xylazine. The mean gestation length of each multiparous sow was calculated. Cloprostenol (250 ug/sow, i.m.) or saline was given 3 d prior to the calculated due date at 11:30 a.m. Xylazine (2 mg/kg, i.m.) or saline was given 20 h after either the cloprostenol or previous saline treatment. Cloprostenol-xylazine treated sows had the shortest mean farrowing interval (1.5 +/- 0.3 h) when compared with the rest of the treatment groups (saline-saline:66.0 +/- 8.1, cloprostenol-saline:10.5 +/- 1.9, saline-xylazine:60.6 +/- 5.6 h). Farrowing time, percentage of stillbirths, average birth weight, d-5 and d-21 postbirth weights, number of pigs born, number of pigs born alive, and number of pigs surviving at 5 and 21 d afterbirth were not significantly different among the four groups. This study demonstrated that cloprostenol-xylazine treatment decreases the time to onset of farrowing with less variation than cloprostenol or xylazine alone. Therefore, the use of a cloprostenol-xylazine combination is suggested as an alternative method for inducing farrowing.

A Simple Technique for the Purification of Plasma Membranes from Ejaculated Boar Spermatozoa

Spermatozoa were initially separated from fresh boar ejaculates using a 1.0 M sucrose density gradient. Spermatozoa (1 x 10(8) cells/ml) were subjected to gas cavitation (650 psi, 10 minutes), followed by a 4-step centrifugation technique to yield the final plasma membrane preparation. Purity of the plasma membrane isolate was determined using microscopic techniques (i.e. differential interference contrast and transmission electron microscopy) and marker enzymes for biochemical characterization. Plasma membranes were found to be removed primarily from the periacrosomal region of the sperm. Acrosomes appeared to remain intact on the cavitated spermatozoa. Transmission electron microscopy yielded a homogenous population of 100-200 microns unilamellar vesicles. Enzyme markers specific for plasma, acrosome and mitochondrial membranes substantial the purity observed under visual examination.

Multiple congenital defects in a female calf: A case report

This case report describes a female calf with arthogryposis, an extra set of incision teeth, ventral abdominal hernia, tibial hemimelia and the nonunion of mullerian ducts. This is possibly the first occurrence of these anomalies in one animal. The cause of these anomalies may have been genetic in origin due to the close relationship between the dam and the sire and the negative history for such various tetragenic factors.

Termination of midterm pregnancy in mares using intra-allantoic dexamethasone

Abstract Elective termination of midterm pregnancy was successful in four mares using a single intra-allantoic infusion of dexamethasone solution. Duration of gestation in the experimental animals ranged from 167 to 174 d. All mares responded within 72 h, with a mean of 53.5 h from treatment to abortion. Fetal death occurred in utero probably 24 h before abortion. All mares exhibited estrus by Day 16 post treatment and were bred with three mares conceiving at this estrus.