An intramammary device (IMD) was adapted for use in ewes; this device was made of abraded poly. ethylene material (1.7 mm in diameter, 47 mm long) and formed a 15-mm-diameter loop in the gland cistern. The IMD was inserted in 1 gland in each of 43 ewes. A significant (P < 0.0001) increase in milk somatic cell count (SCC) was observed in glands provided with an IMD. This increase was attributable to an increase in neutrophil numbers and was observed during the first 12 weeks after insertion. The IMD had a protective effect against experimentally induced staphylococcal mastitis (Staphylococcus aureus and S epidermidis), although different milk SCC were required for protection from each bacterial species in most ewes (10(6) and 2 X 10(5) cells/ml, respectively). Histologic studies revealed that the IMD induced local squamous metaplasia in the glandular part of the lactiferous sinus. Erythrocytes were found in milk from glands provided with an IMD throughout the studied period (35 days of the 45-day lactation) and, in some cases, blood clots were observed during the first 2 weeks of lactation. Glands with IMD also had lower milk production and quality at 30 and 32 days of lactation. Eight ewes with IMD were studied throughout a subsequent lactation. Milk from the IMD-containing glands had an increase in SCC, as in the previous lactation period; did not contain blood clots or erythrocytes; and had normal composition (similar to that in glands without the IMD).

OBJECTIVE To compare the mechanical properties of laryngeal tie-forward (LTF) constructs prepared with different suture materials and suture placement patterns during single load to failure testing. SAMPLE Larynges harvested from 50 horse cadavers and 5 intact horse cadavers. PROCEDURES In vitro LTF constructs were created by a standard technique with polyester sutures, a standard technique with polyethylene sutures, a modified technique with metallic implants and polyester sutures, a modified technique with metallic implants and polyethylene sutures, or a modified tie-off technique with polyester sutures (10 of each type of construct). Mechanical properties including maximal load (N) at failure and failure mode were compared among constructs. Also, maximal loads at failure of the in vitro LTF constructs were compared with the loads exerted on the sutures tightened to achieve rostral laryngeal advancement in intact cadavers. RESULTS Constructs prepared by a standard technique with polyethylene sutures had a significantly higher pull out strength than those prepared by a modified technique with metallic implants and either polyester or polyethylene sutures. For constructs prepared by a standard technique with polyethylene sutures or similarly placed polyester sutures, maximal load at failure did not differ but the failure mode did differ significantly. The load to failure for all in vitro constructs was higher than the maximal load measured during a range of motion test in intact horse cadavers. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that LTF procedures can be performed in live horses with any of the suture materials and techniques tested.

Objective- To compare the mechanical properties of laryngeal tie-forward (LTF) surrogate constructs prepared with steel fixtures and No. 5 braided polyester or braided polyethylene by use of a standard or a modified suture placement technique. Sample- 32 LTF surrogate constructs. Procedures- Surrogate constructs were prepared with steel fixtures and sutures (polyester or polyethylene) by use of a standard or modified suture placement technique. Constructs underwent single-load-to-failure testing. Maximal load at failure, elongation at failure, stiffness, and suture breakage sites were compared among constructs prepared with polyester sutures by means of the standard (n = 10) or modified (10) technique and those prepared with polyethylene sutures with the standard (6) or modified (6) technique. Results- Polyethylene suture constructs had higher stiffness, higher load at failure, and lower elongation at failure than did polyester suture constructs. Constructs prepared with the modified technique had higher load at failure than did those prepared with the standard technique for both suture materials. All sutures broke at the knot in constructs prepared with the standard technique. Sutures broke at a location away from the knot in 13 of 16 constructs prepared with the modified technique (3 such constructs with polyethylene sutures broke at the knot). Conclusions and Clinical Relevance- Results suggested LTF surrogate constructs prepared with polyethylene sutures or the modified technique were stronger than those prepared with polyester sutures or the standard technique.

Objective-To compare the diagnostic quality of bronchoalveolar lavage (BAL) fluid acquired from healthy dogs by manual aspiration via polyethylene tubing (MAPT) and via suction pump aspiration (SPA) with a suction trap connection. Animals-12 healthy adult Beagles. Procedures-BAL was performed with bronchoscopic guidance in anesthetized dogs. The MAPT was performed with a 35-mL syringe attached to polyethylene tubing wedged in a bronchus via the bronchoscope's biopsy channel. The SPA was performed with 5 kPa of negative pressure applied to the bronchoscope's suction valve via a suction trap. The MAPT and SPA techniques were performed in randomized order on opposite caudal lung lobes of each dog. Two 1 mL/kg lavages were performed per site. Samples of BAL fluid were analyzed on the basis of a semiquantitative quality scale, percentage of retrieved fluid, and total nucleated and differential cell counts. Results were compared with Wilcoxon signed rank tests. Results-Percentage of BAL fluid retrieved (median difference, 16.2%), surfactant score (median difference, 1), and neutrophil count (median difference, 74 cells/μL) were significantly higher for SPA than for MAPT. A higher BAL fluid epithelial cell score was obtained via MAPT, compared with that for samples obtained via SPA (median difference, 1). Conclusions and Clinical Relevance-Results indicated that in healthy dogs, SPA provided a higher percentage of BAL fluid retrieval than did MAPT. The SPA technique may improve the rate of diagnostic success for BAL in dogs, compared with that for MAPT. Further evaluation of these aspiration techniques in dogs with respiratory tract disease is required.

Objective-To compare effects of oxytocin, acepromazine maleate, xylazine hydrochloride-butorphanol tartrate, guaifenesin, and detomidine hydrochloride on esophageal manometric pressure in horses. Animals-8 healthy adult horses. Procedure-A nasogastric tube, modified with 3 polyethylene tubes that exited at the postpharyngeal area, thoracic inlet, and distal portion of the esophagus, was fitted for each horse. Amplitude, duration, and rate of propagation of pressure waveforms induced by swallows were measured at 5, 10, 20, 30, and 40 minutes after administration of oxytocin, detomidine, acepromazine, xylazine-butorphanol, guaifenesin, or saline (0.9% NaCl) solution. Number of spontaneous swallows, spontaneous events (contractions that occurred in the absence of a swallow stimulus), and high-pressure events (sustained increases in baseline pressure of > 10 mm Hg) were compared before and after drug administration. Results-At 5 minutes after administration, detomidine increased waveform amplitude and decreased waveform duration at the thoracic inlet. At 10 minutes after administration, detomidine increased waveform duration at the thoracic inlet. Acepromazine administration increased the number of spontaneous events at the thoracic inlet and distal portion of the esophagus. Acepromazine and detomidine administration increased the number of high-pressure events at the thoracic inlet. Guaifenesin administration increased the number of spontaneous events at the thoracic inlet. Xylazine-butorphanol, detomidine, acepromazine, and guaifenesin administration decreased the number of spontaneous swallows. Conclusions and Clinical Relevance-Detomidine, acepromazine, and a combination of xylazine butorphanol had the greatest effect on esophageal motility when evaluated manometrically. Reduction in spontaneous swallowing and changes in normal, coordinated peristaltic activity are the most clinically relevant effects.

OBJECTIVE To compare use of a 3-level self-locking suture (3LSLS) technique with use of a previously described modified 3-loop pulley (M3LP) technique to repair rupture of the proximal aspect of patellar tendons in limbs from canine cadavers. SAMPLE Paired hind limbs of 6 adult mixed-breed dogs. PROCEDURES A limb from each pair was randomly assigned to be repaired by the 3LSLS technique or M3LP technique with size-2 ultrahigh-molecular-weight polyethylene and size-0 monofilament polypropylene suture, respectively. Limbs were prepared, and each patellar tendon was transected at a site chosen to simulate rupture at the proximal aspect. Tendons were repaired with the assigned techniques and mechanically tested with a biaxial servohydraulic test system; the clamp was distracted until the repair failed. Force at 1 -mm gap formation, 3-mm gap formation, and repair failure and gap size at failure were measured and compared between methods. Mode of failure was recorded. RESULTS There was no significant difference between methods for the force required to produce a 1 - or 3-mm gap in the repair. The 3LSLS technique required a significantly higher load for complete failure; gap formation immediately before failure was significantly greater for this method than for the M3LP technique. Four of 6 repairs with the M3LP technique and 0 of 6 repairs with the 3LSLS technique failed by suture breakage. CONCLUSIONS AND CLINICAL RELEVANCE The 3LSLS technique with size-2 ultrahigh-molecular-weight polyethylene suture was as effective at resistance to 1 - and 3-mm gap formation as the M3LP with size-0 monofilament polypropylene suture.

Objective—To determine whether different suture configurations could improve the biomechanical performance of 3 suture materials used with bone anchors. Samples—3 suture materials (60-lb test nylon leader line, size 2 polyblend polyethylene composite suture, and 150-lb test ultrahigh–molecular weight spun polyethylene). Procedures—Each suture material was looped through the eyelet of a metallic bone anchor and constructs were evaluated by use of an acute uniaxial load. Three configurations were tested for each suture material: single stranded (SS), double stranded (DS), and single stranded plus plastic insert (SSP). Force at failure, extension at failure, force at 3 mm of extension, stiffness, and site of failure of the suture were recorded for each test. Results—For all sutures, the DS configuration was the stiffest and yielded significantly higher forces at failure and forces at 3 mm of extension. The SS configuration had the lowest forces at failure. The SSP configuration yielded greater forces at failure for all suture materials, compared with the SS configuration, with a comparable stiffness. All sutures failed at the eyelet in the SS and DS configurations. In the SSP configuration, 60-lb test nylon leader line and 150-lb test ultrahigh-molecular weight spun polyethylene failed at the eyelet less frequently than did the polyblend composite suture. Conclusions and Clinical Relevance—Among the tested constructs, a DS suture configuration used in combination with the metallic bone anchor gave the best biomechanical results for all suture materials. Considering that the SSP configuration yielded greater forces at failure, compared with the SS configuration, covering metallic edges in bone anchors with softer materials might protect sutures and result in increased forces at failure.

Objective: To compare effects of sterilization with hydrogen peroxide gas plasma (HPGP), ethylene oxide, and steam on bioadhesive properties of nylon and polyethylene lines used for stabilization of canine stifle joints. Sample: Samples of a 36.3-kg test nylon leader line, 57.8-kg test nylon fishing line, and 2-mm ultrahigh–molecular weight polyethylene (UHMWPE) were used. Procedures: In this in vitro study, samples of nylon leader line, fishing line, and UHMWPE sterilized by use of HPGP, ethylene oxide, and steam or unsterilized samples were used. Bacterial adherence on unsterilized and sterilized samples was tested with Staphylococcus epidermidis and Escherichia coli. Five samples were examined for each line type and sterilization condition, and final colony counts were obtained. Results: Bacterial adherence was significantly affected by method of sterilization for all 3 line types. For most of the samples, bacterial adherence was similar or lower when HPGP sterilization was used, compared with results for sterilization via ethylene oxide and steam, respectively. Bacterial adherence was significantly higher for UHMWPE, compared with adherence for the nylon line, regardless of the sterilization method used. Bacterial adherence was higher for nylon fishing line than for nylon leader line for S epidermidis after ethylene oxide sterilization and for E coli after HPGP and ethylene oxide sterilization. Conclusions and Clinical Relevance: Effects of HPGP sterilization on bioadhesive properties of nylon and polyethylene lines compared favorably with those for ethylene oxide and steam sterilization. Also, nylon line may be a more suitable material than UHMWPE for suture prostheses on the basis of bacterial adherence properties.

Objective: To determine mechanical properties of various prosthetic materials secured to cadaveric canine femurs via various methods and to compare results with those for isolated loops of prosthetic material. Sample: 80 femurs obtained from cadavers of skeletally mature large-breed dogs. Procedures: 10 femoral constructs in each of 8 groups (single circumfabellar loop of polyethylene cord, double loop of polyethylene tape secured via a bone anchor [BAPT], single or double circumfabellar loops of nylon leader material [CNL] or polyethylene tape [CPT], or single or double loops of polyethylene tape secured via a toggle placed through a bone tunnel [BTPT]) and 10 isolated loops of prosthetic material in each corresponding configuration were tested. Stress relaxation, creep, elongation, load at 3 mm of displacement, stiffness, and peak load at failure were determined. Results: 5 single CNL constructs failed before completion of testing. Double CNL and single circumfabellar polyethylene cord constructs had the lowest loads at 3 mm of displacement. Single and double CPT constructs had the highest stiffness. Double BTPT and CPT constructs had the highest peak loads at failure. Double BTPT, double CPT, and BAPT constructs were mechanically superior on the basis of lower creep and stress relaxation and higher stiffness and load at 3 mm of displacement versus other constructs. Stiffness of femoral constructs was 28% to 69% that of corresponding isolated prosthetic loops. Conclusions and Clinical Relevance: Double BTPT, double CPT, and BAPT constructs were mechanically superior to other constucts. Mechanical properties and methods of anchorage and securing of free ends of prostheses contributed to mechanical properties of constructs.

An intramammary device (IMD) was adapted for use in ewes; this device was made of abraded poly. ethylene material (1.7 mm in diameter, 47 mm long) and formed a 15-mm-diameter loop in the gland cistern. The IMD was inserted in 1 gland in each of 43 ewes. A significant (P < 0.0001) increase in milk somatic cell count (SCC) was observed in glands provided with an IMD. This increase was attributable to an increase in neutrophil numbers and was observed during the first 12 weeks after insertion. The IMD had a protective effect against experimentally induced staphylococcal mastitis (Staphylococcus aureus and S epidermidis), although different milk SCC were required for protection from each bacterial species in most ewes (10(6) and 2 X 10(5) cells/ml, respectively). Histologic studies revealed that the IMD induced local squamous metaplasia in the glandular part of the lactiferous sinus. Erythrocytes were found in milk from glands provided with an IMD throughout the studied period (35 days of the 45-day lactation) and, in some cases, blood clots were observed during the first 2 weeks of lactation. Glands with IMD also had lower milk production and quality at 30 and 32 days of lactation. Eight ewes with IMD were studied throughout a subsequent lactation. Milk from the IMD-containing glands had an increase in SCC, as in the previous lactation period; did not contain blood clots or erythrocytes; and had normal composition (similar to that in glands without the IMD).