Zinc and copper status in ewes supplemented with sulfate- and amino acid-complexed forms of zinc and copper

Thirty 6-yr-old Targhee ewes were randomly allotted to one of five supplemental treatments to evaluate supplementation effects on liver and fecal Zn and Cu concentrations and serum alkaline phosphatase activity: 1) control, 2) Zn complex, 3) Zn and Cu (ZnCu) complex, 4) Zn sulfate, and 5) ZnCu sulfates. Supplements were administered daily in gelatin capsules for 56 d. Liver biopsies and serum samples were collected every 14 d starting on d 0. Supplemental Zn and Cu levels were formulated to provide 90 mg/kg Zn and 10 mg/kg Cu, respectively, on a daily dry matter intake basis. Form (complex vs sulfate) x type (Zn vs ZnCu) interactions were not detected (P > 0.35). Therefore, contrast statements were used to make the following treatment comparisons: 1) control vs supplement, 2) Zn vs ZnCu, and 3) complex vs sulfate. Ewe BW at the end of the study (P = 0.09) and ewe BW change from beginning to end of the study (P = 0.07) were greater for supplemented than control ewes. Body weight and BW change did not differ between sulfate and complex (P > 0.39) or Zn- and ZnCu- (P > 0.40) supplemented ewes. Liver Cu concentrations did not differ (P = 0.41) between control and supplemented ewes. Liver Cu concentrations were higher (P < 0.10) for ewes supplemented with ZnCu than Zn and complex than sulfate forms of supplement. Liver Zn concentration tended (P = 0.13) to be higher in ZnCu than Zn-supplemented ewes. Liver and fecal Zn concentration were higher (P < 0.06) in ewes fed complex than sulfate supplements. However, serum alkaline phosphatase activity tended (P = 0.12) to be greater in ewes fed sulfate than complex supplements. Supplementing mature ewes with complexed minerals resulted in higher concentrations of Zn and Cu in the liver. In addition, supplemental Cu tended to increase concentrations of Zn in the livers of ewes; however, high levels of supplemental Zn did not negatively impact liver Cu concentrations.     

Performance of light vs heavy steers grazing Plains Old World bluestem at three stocking rates

Live weight gains of light and heavy calves grazing Plains Old World bluestem at three stocking rates were evaluated during the summers of 1997 and 1998. Initial weights of mixed-breed light-weight steers (LHT) were 141 SD = 17 kg (n = 214) in 1997 and 160 SD = 23 kg (n = 193) in 1998. Initial weights of mixed-breed heavy steers (HWT) were 265 SD = 17 kg (n = 115) in 1997 and 248 SD = 13 kg (n = 126) in 1998. Initial stocking rates for both sizes of steers were as follows: light, 392 kg of live weight/ha; moderate, 504 kg of live weight/ha (increased to 616 kg live weight/ha in 1998); and heavy, 840 kg of live weight/ ha. Averaged gain and gain/hectare are reported as stocking rate by steer type within year. Heavy steers had greater ADG than LHT steers during both years. Forage intake, expressed as a percentage of BW, was greater (P = 0.05) for LHT (3.1%) than for HWT (2.8%) calves. Grazing time (min/d; 1998 only) was greater (P = 0.05) for LHT (665) than for HWT (624) steers. Forage CP and in vivo digestible organic matter (DOM) were slightly greater (P < 0.05) in pastures grazed by HWT vs LHT cattle. Gain/hectare was greater (P < 0.05) for LHT than for HWT calves at all three stocking rates during both years. A linear decline in ADG was observed (P < 0.07) as stocking rates increased for HWT steers in 1997 and LHT steers in 1998. However, ADG did not decline with increasing stocking rate for LHT calves during 1997 or HWT calves during 1998. Forage intake was not different among stocking rates in either 1997 or 1998. Grazing time was greatest (P < 0.05) for steers in the moderate and heavy stocking rates. Forage in vivo DOM decreased (P < 0.05) as stocking rate increased. Both LHT and HWT steers had lower (P < 0.05) ADG at all three stocking rates during 1998 compared with 1997. Despite lower ADG, LHT steers had greater gain/hectare than HWT steers during both 1997 and 1998.     

An alternative pathway electrosurgical unit injury in a dog

Objective: To report esophageal perforation, caused by alternative current pathway from the use of a monopolar electrosurgery unit (ESU), during routine orthopedic surgery in a dog. Study Design: Clinical report. Animals: Two‐year‐old male Labrador retriever. Methods: Medial meniscectomy and lateral suture stabilization were performed on a healthy Labrador retriever with a ruptured cranial cruciate ligament. Monopolar electrosurgery was used during the procedure for hemostasis and tissue dissection. Anesthetic monitoring was augmented with an esophageal electrocardiogram (ECG) probe. The day after surgery, the dog appeared dehydrated. After intravenous fluid therapy, respiratory distress was noted and thoracic radiography and contrast fluoroscopy revealed an esophageal perforation. Results: Exploratory surgery was planned to repair the defect. Cardiac arrest occurred after induction. Gross necropsy findings and histopathologic examination revealed lesions consistent with thermal necrosis of the esophagus and myocardial degeneration. An internal investigation of this medical device accident revealed that multiple factors may have contributed to the injury. Conclusions: An alternative current pathway from the monopolar ESU to the esophageal ECG probe resulted in a full‐thickness esophageal thermal injury and cardiac failure.     

Neutrophil myeloperoxidase measurements in plasma, laminar tissue, and skin of horses given black walnut extract

OBJECTIVE: To compare measurements of myeloperoxidase (MPO) in plasma, laminar tissues, and skin obtained from control horses and horses given black walnut heartwood extract (BWHE). ANIMALS: 22 healthy 5- to 15-year-old horses. PROCEDURES: Horses were randomly assigned to 4 groups as follows: a control group given water (n = 5) and 3 experimental groups given BWHE (17) via nasogastric intubation. Experimental groups consisted of 5, 6, and 6 horses that received BWHE and were euthanatized at 1.5, 3, and 12 hours after intubation, respectively. Control horses were euthanatized at 12 hours after intubation. Plasma samples were obtained hourly for all horses. Laminar tissue and skin from the middle region of the neck were harvested at the time of euthanasia. Plasma and tissue MPO concentrations were determined via an ELISA; tissue MPO activity was measured by use of specific immunologic extraction followed by enzymatic detection. RESULTS: Tissues and plasma of horses receiving BWHE contained significantly higher concentrations of MPO beginning at hour 3. Laminar tissue and skin from horses in experimental groups contained significantly higher MPO activity than tissues from control horses. Concentrations and activities of MPO in skin and laminar tissues were similar over time. CONCLUSIONS AND CLINICAL RELEVANCE: In horses, BWHE administration causes increases in MPO concentration and activity in laminar tissue and skin and the time of increased MPO concentration correlates with emigration of WBCs from the vasculature. These findings support the hypothesis that activation of peripheral WBCs is an early step in the pathogenesis of acute laminitis.     

Reduced mitotic activity and increased apoptosis of fetal sertoli cells in rat hypogonadic (hgn/hgn) testes

Sterility in male hypogonadic (hgn/hgn) rats results from congenital testicular dysplasia caused by a single recessive gene hgn on rat chromosome 10. We recently identified an insertion mutation in the Spag5/astrin gene of hgn/hgn rats that may cause defective proliferation of immature Sertoli cells in the postnatal hgn/hgn testis. Since the pathological alterations were present in the testes at birth, we examined the involvement of defective mitosis and apoptotic cell death in embryonic development of hgn/hgn testes. Testicular hypoplasia was apparent at embryonic day (ED) 18.5. Immunostaining of hgn/hgn testes at ED 21.5 with antibody to GATA-4, which is specific for fetal Sertoli cells in the seminiferous cords, showed that the significant decrease in the number of fetal Sertoli cells was accompanied by a two fold increase in their mitotic index and abnormal mitosis and apoptosis. Prior to this, we observed a decrease in the number of BrdU-labeled cells, an increase in the number of TUNEL-positive apoptotic cells, and presence of MIS-positive apoptotic cells in hgn/hgn testes on ED 17.5 and 18.5. These results suggest that the Spag5 mutation may cause a reduction in mitotic activity and an increase in apoptosis of fetal Sertoli cells in hgn/hgn testes.     

Surgical advancement of the larynx (laryngeal tie-forward) as a treatment for dorsal displacement of the soft palate in horses: a prospective study 2001-2004

REASONS FOR PERFORMING STUDY: Correct placement of sutures ('laryngeal tie-forward') in experimentally created dorsal displacement of the soft palate (DDSP) has been observed to replace the function of the thyrohyoideus muscles and prevent DDSP. HYPOTHESIS: The 'laryngeal tie-forward' procedure would prevent or delay the occurrence of DDSP during exercise in horses with naturally occurring DDSP and therefore improve performance. METHODS: A clinical population (n = 116), mainly of racehorses was presented for treatment of naturally occurring exercise-induced DDSP. All horses underwent the 'laryngeal tie-forward' procedure. The relative position of the thyroid and cricoid cartilage in relation to the caudal aspect of the basihyoid bone was recorded; follow-up was obtained by telephone communication with trainers, owners and/or referring veterinarians. In addition, a performance index and earnings were determined using race records. RESULTS: Preoperatively, the median distance between the caudal aspect of the basihyoid bone and rostral aspect of the thyroid cartilage was 3.5 cm. Post operatively, the thyroid cartilage was moved a median distance of 4 cm rostrally and the larynx was shown to be in a position more rostral and dorsal than in preoperative radiographs. Of 98 horses for which follow-up was available, the performance of 87% was classified as improved, 12% as unchanged and 2% as worse. In 20 horses in which the diagnosis had been confirmed by treadmill videoendoscopy, 80% had a significantly increased performance index and earnings (P = 0.007). For the entire population, there was a significant improvement in performance index and earnings after surgery (82%) (P = 0.0001). CONCLUSIONS: Placing the larynx in a more rostral and dorsal position may have improved the performance in 80-82% of the horses affected with naturally-occurring DDSP. POTENTIAL RELEVANCE: 'Laryngeal tie-forward' is a surgical technique that has a measurable effect on the position of the larynx and offers an alternative therapy for treating horses affected with DDSP. More experience may be needed with this technique prior to its widespread use in horses with a clinical diagnosis of DDSP.