Retinol, β-carotene and β-tocopherol concentrations in mare and foal plasma and in colostrum

Fat-soluble vitamins transfer poorly across the diffuse epitheliochorial placenta of the mare, so the neonatal foal is dependent on its supply via colostrum. Concentrations of retinol (RT), β-carotene (BC), and β-tocopherol (AT) were assayed in samples of plasma, colostrum and milk from nine mares of mixed light breeding and their foals at parturition and days 1, 2, and 4 postpartum. Samples were analyzed simultaneously for RT, BC, and AT using a new, less time-consuming reverse phase high-pressure liquid chromatography (HPLC) method. Feeds were analyzed, and mean daily intakes calculated. Mare plasma RT increased from day 1 to day 4 (P = .033), and plasma AT declined linearly from day 0 to day 4 (P = .006). Colostrum concentrations of all vitamins increased from parturition to day 1, and then declined rapidly over the 4 days. Foal plasma BC increased from parturition to day 4 (P = .080), and plasma AT increased from parturition to day 2 (P < .001), and 4 (P = .060). These observations suggest that three times the current recommendation of vitamin A is sufficient for pregnant mares, in keeping with previous studies of growth, pregnancy, and lactation. In contrast, the linear decrease in mare plasma AT suggests that 1.2 times the current recommendation of vitamin E may be less than optimal for pregnant mares.

Introduction

The diffuse epitheliochorial placenta of the mare does not allow fat-soluble vitamins to cross with ease to the fetus,[1] so their status in the neonatal foal is dependent on colostrum. This first milk contains these vitamins, which are necessary for many functions.Vitamin A is required for vision, reproduction, growth, development, and maintenance of epithelial cells, and osteoclast activity in bone formation. In addition, vitamin A deficiencies reduce resistance to disease, can cause neurological degeneration, and congenital defects.[2] Vitamin E, an antioxidant, prevents lipid peroxidation and cell membrane damage. Its deficiency in horses has been associated with a form of muscular dystrophy and impaired immune function. [3]Studies on the mare and foal have described blood concentrations of one or two of these vitamins,[4, 5 and 6] but only one involved all three. [7] In that study, vitamin concentrations were assayed in mare blood and milk, but only once in foal blood at parturition, so data during the periparturant period is incomplete.The objectives of this enumerative study were to determine concentrations of RT, BC, AT in plasma and colostrum, to evaluate colostral transfer of these vitamins, to assess the adequacy of vitamin intakes of mares, and to develop a time-saving single-run HPLC method.

Materials and methods

Animals

Nine healthy aged multiparous mares of mixed light breeding (13.6 ± 1.5 years, 592 ± 20 kg body mass) and their foals were sampled. The institutional animal care and use committee approved the protocol. Mares were kept on meager late-winter mixed grass pasture, with free access to round bale orchard and fescue grass hay, water, and trace mineral/vitamin salt. They were fed 2 kg of concentrate twice daily at 7:00 and 3:00 . The diet met or exceeded current recommendations for pregnant mares at 11 months gestation for energy.[8] Samples of hay and concentrate were submitted for partial proximate analysis to the Virginia Tech Forage Testing Laboratory where standard AOAC [9] methods are used ( Table 1). Samples of feeds were also taken for analysis of RT, BC, and AT ( Table 2).     

Comparison of anthelmintic activity of pyrantel, praziquantel, and nitazoxanide against Anoplocephala perfoliata in Horses

Three anthelmintics were compared for efficacy in reducing the egg production of Anoplocephala perfoliata in a herd of central Texas horses. Two trials were run, 1 in mares and the other in weanlings that were diagnosed as being infected with Anoplocephala by recovery of eggs in 5 g of feces with sugar centrifugation. Each animal was evaluated twice before treatment and again twice following treatment (at weeks 2 and 4 after treatment). The criteria for infection were the recovery of eggs on at least 1 occasion before treatment and the finding of eggs on 1 day following treatment. The mares were treated 1 time with either pyrantel pamoate at 13.2 mg/kg, nitazoxanide at 100 mg/kg, praziquantel at 1.23 mg/kg or remained as untreated controls. The weanlings were treated with pyrantel at 13.7 mg/kg nitazoxanide at 100 mg/kg or remained as untreated controls. The percentage reduction of patient infection in mares after treatment with pyrantel was 83%, with nitazoxanide was 78%, and with praziquantel was 83% and in controls was 17%. There was a 75% reduction of patient weanlings treated with pyrantel or nitazoxanide and a 17% reduction in untreated controls. The reduction of infection in all horses treated with any drug was significantly different from controls. All of the drugs were somewhat effective in the control of Anoplocephala, and there were no differences among the drugs in their effectiveness.

Introduction

Anoplocephala perfoliata, the lappeted tapeworm, is an inhabitant of the intestine of equids. Adult tapeworms attach to the intestinal mucosa at the ileocaecal valve and, when present in large numbers, cause edema and hypertrophy of the ileum. The disease manifest by this infection may be inapparent or may give rise to colic (abdominal pain) in the horse apparently from mechanical obstruction or intussusception of the small intestine into the caecocolon.^{1, 2, 3, 4, 5, 6, 7 and 8} The prevalence of infection is geographically variable^{9, 10, 11, 12 and 13} but appears to be increasing,¹⁴ with a much higher rate of infection found with necropsy as opposed to fecal observations. Horses become infected by the ingestion of infected orbatid mites in pastures. Orbatid mites, the intermediate hosts, are predatory and are found in decaying organic material, such as leaf litter. Horses of all ages are infected, but there are lower numbers of clinical cases in horses older than 4 years of age.⁴ The intensity of infection is highest in the late summer and autumn.^{8 and 12} Anthelmintics with reported efficacy against A perfoliata include pyrantel pamoate at 13.2 mg/kg,¹⁰ pyrantel tartrate at 2.6 mg/kg for 30 days,¹⁵ pyrantel embonate at 38 mg/kg,¹⁶ and praziquantel at 1 to 2 mg/kg.^{17 and 18} Nitazoxanide has not been evaluated for Anoplocephala but was included in the trial because of its effects against nematodes and tapeworms in humans.¹⁹ Because Anoplocephala infections may cause disease and there is a perception that current anthelmintics may not be as effective as in the past, a study was done to compare anthelmintics to lower the intensity of fecal egg counts in a herd of horses in central Texas.

Materials and methods

Quarter horse mares and weanlings from a single herd were evaluated with 5 g of feces with a sucrose double centrifugation test to determine whether eggs of Anoplocephala were present.²⁰ Feces from each individual horse were evaluated twice, once approximately 2 weeks before treatment and again on the day of treatment. If Anoplocephala eggs were found on either date, the horse was considered to have positive results. Within each group (mares or weanlings), the treatment selection was randomly allocated as the horses were restrained for treatment. Fecal samples were again evaluated at 14 and 28 days after treatment for the presence or absence of eggs on either day.The dose for each individual horse was determined by chest girth weight tape at the time of treatment. The treatments were as follows: pyrantel pamoate (Strongid-T, Pfizer Animal Health, Exton, Pa) at 13.7 mg/kg via nasogastric intubation (12 mares, 8 weanlings), nitazoxanide oral paste (Nitazoxanide, Idexx Laboratories, Westbrook, Me) at 100 mg/kg (9 mares, 8 weanlings), praziquantel (Droncet injectable, Bayer Corp, Shawnee Mission, Kan) at 1.23 mg/kg via nasogastric intubation (6 mares), and untreated controls (6 mares, 6 weanlings). A 1-tailed Fisher exact test was used to compare rates of infection before and after treatment. If a mare or foal did not have positive results before treatment, it was not evaluated in this study.

Results and discussion

No abnormal clinical signs were seen after treatment with any of the products. Treatment was administered to several additional animals with each product, but they were not included in the analysis if they did not have positive results on 1 of the 2 evaluations before treatment, hence, the different numbers of horses in treatment groups.None of the horses in the trial exhibited clinical signs associated with the infection of A perfoliata. However, before the trial, a mare from the infected herd exhibited signs of colic and Anoplocephala eggs were detected in the feces. Examination of the remainder of the herd gave impetus to the study.Mean egg counts before and after treatment are given in the Table.The presence of strongylate and Parascaris eggs in weanlings served as a control of the methodology of evaluation. The difficulty of finding Anoplocephala eggs has been recognized by several authors,^{5, 8, 13, 14 and 21} but the authors also recognize that when there were greater numbers of parasites there was increased egg production. Therefore, finding of eggs with fecal flotation indicated that there were 20 worms or more. However, there appears to be no correlation between the number of worms and egg counts once the detection threshold is reached,²² so the criterion for evaluation was the presence of eggs in the feces before treatment compared with after treatment. Although mean egg counts were not compared, the number of eggs in each infected horse was less after treatment in all groups compared with untreated controls (Table). The method of evaluation used in this study cannot be equated to those of critical^{10 and 16} or control¹⁴ studies in which horses are killed so that all worms are detected. However, the use of clinical studies to compare compounds is useful in detecting which anthelmintics are likely to be of value against geographically distinct populations of worms. Admittedly, more sampling may have increased the number of horses with positive results, both before and after treatment.     

Laparoscopic Cryptorchid Castration in Standing Horses

Objective — This article describes a new technique for laparoscopic cryptorchid castration in standing horses. Study Design — Prospective study. Animals or Sample Population — Eight horses aged 11 months to 3 years and weighing between 300 and 643 kg. Methods — Food was withheld for 24 to 36 hours, and then horses were sedated with detomidine HC1 (0.02 to 0.03 mg/kg) and butorphanol tartrate (0.02 mg/kg). The paralumbar fossa region was desensitized with 2% mepivacaine in an inverted “L” pattern and caudal epidural anesthesia was administered with either xylazine (0.18 mg/kg diluted to 10 to 15 mL with 0.9% sodium chloride) or a combination of 2% mepivacaine and xylazine (0.18 mg/kg). Initial laparoscopic exploration was performed from the left flank; in three horses, right flank laparoscopy was needed to complete the procedure. The spermatic cord was ligated within the abdomen with one or two sutures of 0 polydioxanone suture, and the testis or testes removed through a flank incision. Results — In five horses with no palpably descended testes, standing laparoscopy was the only procedure performed, whereas in two horses, the abdominal testis was removed laparoscopically, and the descended testis was removed under short acting anesthesia. In one horse, with nonpalpable testes, it was determined by laparoscopic observation that the testes were in the inguinal canal, and castration was performed under general anesthesia. No surgical or postoperative complications were noted. The right side of the abdomen, and especially the right vaginal ring, could be easily observed from the left side by passing the laparoscope through a small perforation in the mesocolon of the descending colon or by elevating the descending colon with an instrument or by use of an arm in the rectum. Conclusions — The standing laparoscopic approach combined with or without short-acting anesthesia to remove the descended testis is easily performed. Clinical Relevance — This approach will provide surgeons with another option to castrate cryptorchid stallions.     

Hepatic Lobe Torsion as a Cause of Colic in a Horse

A 14-year-old Arabian gelding was examined for colic. An exploratory celiotomy was subsequently performed and the left lobe of the liver was found to be twisted. The lobe was resected using a TA-90 surgical stapling instrument. Histologic examination of the resected liver indicated portal vein and sinusoid dilation and congestion with blood. There were focal areas of necrosis and bacterial cocci and rods throughout the section. The histologic findings were consistent with hepatic lobe torsion. After surgery, the horse was treated with broad spectrum antibiotics, anti-inflammatory drugs, heparin, and intravenous fluids. The horse recovered without complications, although serum liver enzymes remained elevated for more than 1 week after surgery. Seven months after surgery the horse showed no adverse affects from the disease.     

Effects of Thiopental, Ketamine, Diazepam, Xylazine, and Nitrous Oxide on EEG Spike Activity and Convulsive Behavior During Enflurane Anesthesia in Atropinized Cats Effect of Increasing Inhalant Concentrations

The effects of thiopental, ketamine, diazepam, xylazine, and nitrous oxide, and the combinations of thiopental-nitrous oxide and ketamine-nitrous oxide, on both enflurane-induced electroencephalographic (EEG) spike activity and convulsive behavior were measured quantitatively in atropinized cats receiving enflurane with controlled ventilation. Pretreatments with thiopental, ketamine, and diazepam reduced both EEG spike frequency and amplitude at 2.5% to 4.5% inspired enflurane but did not abolish spike activity. Nitrous oxide (66% of inspired gas) did not significantly alter spike frequency or amplitude during 2.5% to 4.5% inspired enflurane, but the combination of thiopental-nitrous oxide or ketamine-nitrous oxide reduced EEG spike activity during 2.5% inspired enflurane. Enflurane-induced convulsive score was markedly suppressed by thiopental and ketamine and was significantly reduced by diazepam, xylazine and nitrous oxide. The combinations of thiopental-nitrous oxide and ketamine-nitrous oxide greatly reduced behavioral-convulsive responses induced by 2.5% to 4.5% inspired enflurane.     

Controlled Cross Circulation in Dogs: Effects on Donor Hemodynamics

Controlled cross circulation (CCC) was performed in six pairs of dogs for 45 minutes with aortic cross clamping and cardioplegia. Data were collected in donor dogs at 10 minute intervals three times before, three times during, and three times after CCC and included arterial blood pressure, pulmonary capillary wedge pressure (PCWP), central venous pressure (CVP), cardiac index (CI), heart rate (HR), blood gas analysis, temperature, maximum rate of rise of left ventricular pressure dP/dt max/End diastolic volume (EDV), blood volume (BV), complete blood count (CBC) and activated clotting times (ACT). Pulse pressure (PP), systemic vascular resistance (SVR), oxygen delivery (Do₂), and left ventricular cardiac work (LVCW) were calculated. Arterial blood pressure, CVP, blood gas analysis, temperature, BV, CBC, and ACT were measured in recipient dogs. During CCC, donor hemodynamic changes resembled those observed in models of acute onset arteriovenous fistulas. Insidious BV shifts can occur despite the use of occlusive roller pumps. After CCC, donor hemodynamics resembled acute blood loss, characterized by decreases in mean arterial pressure (MAP), CVP, PCWP, and CI, and increases in SVR and dP/dt max/EDV. These changes were probably caused by pump imbalance and BV shift to the recipient dog.     

THE EFFECTS OF PATIENT POSITIONING AND SLICE SELECTION ON CANINE ACETABULAR ANGLE ASSESSMENT WITH COMPUTED TOMOGRAPHY

Acetabular angles (AAs) and dorsal acetabular rim angles acquired by computed tomographic (CT) imaging have been used to assess patient response to juvenile pubic symphysiodesis surgery. The purpose of this study was to evaluate the effects of patient positioning and slice selection on these angles, and an attempt was made to devise a repeatable method of measuring these angles that would eliminate positioning effects. We found significant variation in AAs with small differences in pelvic tilt and slice selection. Dorsal acetabular rim angles were not affected. As a result of positioning differences from one CT study to the next, every attempt should be made to standardize pelvic tilt, or eliminate its effect on AAs by standardizing gantry angle in relation to an anatomic landmark that will not change over time. The floor of the sacral vertebral canal may be a reasonable landmark for this purpose and deserves further study.     

Evaluation of chitosan and alginate immobilized Methylobacterium oryzae CBMB20 on tomato plant growth

Methylobacterium oryzae CBMB20, a promising plant growth promoting bacteria (PGPB) and a biocontrol agent, was immobilized in different formulations such as wet chitosan, dry chitosan, wet alginate and dry alginate and were tested for tomato plant growth promotion. Chitosan solution (1.5%) with pH 5.5–6.0 and 90 min contact time was found optimal for immobilization. The chitosan formulations showed better entrapment efficiency and good degradability resistance apart from slow release of cells under prolonged incubation. Survivability of bacteria (80%) was observed in wet chitosan formulation even after 90 days of storage at 4°C. The spermosphere survival of bacteria was high in both dry and wet chitosan formulations applied soils even after 21 days under greenhouse conditions. While the alginate formulation degraded fully, partial degradation of chitosan formulation was observed even after 30 days, indicating its ability to support the survival of M. oryzae CBMB20 in soil. Plants inoculated with wet chitosan formulation registered 1.3 fold increase in the shoot and root length and dry weight compared to other treatments. Hence, chitosan formulation supporting better plant growth compared to alginate will be a better carrier for taking bacteria to the plant rhizosphere and thereby promote plant growth.