Stenting of a partially obstructed nasolacrimal duct using a steerable angle-tipped hydrophilic guidewire in a cat.

OBJECTIVE: This case report describes the successful correction of partial obstruction of the NL duct in a cat by means of a modified retrograde NL duct cannulation using a steerable angle-tipped hydrophilic guidewire (AH guidewire) following a paranasal incision. ANIMAL STUDIED: A 2-year-old neutered male American domestic shorthair cat was referred to the Purdue University Veterinary Hospital (PUVH) for chronic epiphora suspected secondary to nasolacrimal (NL) system obstruction. PROCEDURES: At the first visit, the cat had epiphora OD and facial dermatitis but no other abnormalities on physical and ophthalmic examinations. Computed tomography (CT)-dacryocystorhinography revealed partial obstruction of the NL duct secondary to stenosis near the distal root of the right maxillary third premolar (107). A digital three-dimensional (3D) model of the right maxilla and NL duct was created for inspection and virtual cannulation of the NL. The model was 3D printed and cannulation of the NL duct was rehearsed with various stent materials. Retrograde NL stenting with the guidance of a steerable angle-tipped hydrophilic guidewire was conducted following a paranasal incision. A urethral catheter was cannulated over the guidewire and maintained for 44 days. RESULTS: The epiphora resolved immediately after stenting. At 21 days post-stenting, the cat developed acute bullous keratopathy secondary to self-trauma which was treated with a third eyelid flap. On the final follow-up communication with the owner at 210 days post-stenting, no epiphora or any other concerns were reported. CONCLUSION: To the authors' knowledge, this is the first report of successful NL stenting and resolution of epiphora in a cat with a partial NL system obstruction.

Outcomes and Complications Associated With Caudal Thoracic and Abdominal Air Sac Cannulation in 68 Birds.

Air sac cannulation is used both as an emergency procedure in avian patients with severe upper respiratory compromise, as well as a means of routine ventilation for surgery of the head and neck. The objective of this retrospective study was to describe and quantify the complications associated with air sac cannulation in birds. Medical records were retrieved for all patients that underwent caudal thoracic or abdominal air sac cannulation at a single center between August 2004 and October 2020. Patient signalment, indication for air sac cannulation, location of air sac cannula (ASC) placement, occurrence and category of complications encountered, and survival data were recorded. Eighty-four ASCs were placed in 68 birds across 6 orders; 95.2% (80/84) of cases survived general anesthesia for initial ASC placement. The side and position of ASC placement were known in 33.3% (28/84) and 21.4% (18/84) of cases, respectively. Survival to ASC removal was known in 91.3% (73/80) of cases; 43 (58.9%) of these 73 cases survived to ASC removal. Complications were observed in 32.5% (26/80) of cases, and 11.5% (3/26) of cases died as a direct result of the complication. The most common reported ASC complication was loss of patency in 23.8% (19/80) of cases. Increased likelihoods for complications were seen in cases where exercise intolerance (P = 0.04) or abnormal respiratory sounds (P = 0.04) were reported at presentation. Increased likelihoods for survival to ASC removal were seen with intercostal placements (P = 0.049) and peri-interventional antibiotic therapy (P = 0.005). Decreased likelihood for survival to ASC removal was seen in cases where voice change was reported at presentation (P = 0.02). This study demonstrates a moderate risk of ASC complication, with a guarded overall prognosis for survival to ASC removal.

Laparoscopy assisted abomasal cannulation in cadavers of bovine fetuses.

BACKGROUND: Due to the complexity of ruminant digestion, cannulation of organs of the digestive tract has been carried out in order to advance the understanding of digestive physiology, nutrient degradability, gastrointestinal diseases and biotechnological research. The abomasal cannulation is interesting for nutritional studies, especially in suckling calves, to obtain fluid and abomasal content, evaluation of abomasal flow and function, and infusion of nutrients and drugs when it is intended to reach high concentrations in the organ. Conventionally, access and cannulation of digestive organs of ruminants has been performed by laparotomy, a method often criticized and classified as cruel by some sectors related to ethics and animal welfare. The aim of this present study is to describe and standardize a minimally invasive by laparoscopy assisted abomasal cannulation in bovine fetuses (cadavers), which had been previously slaughtered by accident and would be discarded in local slaughterhouses. RESULTS: The abomasal cannulation technique was feasible, simple and did not present major difficulties. The surgical time for cannulation of the abomasum, from the insertion of the trocars to the completion of the technique with fixation of the organ to the abdominal wall, ranged from 9 to 27 min, with an average of 15.5 ± 6.62 min. CONCLUSIONS: The Laproscopic assisted abomasal cannulation in bovine fetuses was feasible and safe with minimal tissue injury to the abdominal wall and with short surgical time. More studies in the clinical routine related to minimally invasive abomasal content collection, abomasopexy and abomasotomy are required in order to demonstrate its impact and importance in bovine clinic.

Treatment of acute traumatic nasopharyngeal stenosis with balloon dilation in two dogs.

CASE HISTORY: Two dogs were referred to Veterinary Specialists Aotearoa for evaluation and treatment after sustaining significant head trauma. Case 1 was a 7-month-old, female Staffordshire Bull Terrier who was hit by a car at low speed. Case 2 was a 2-year old, male neutered German Shepherd who sustained a gunshot wound to the head whilst on duty for the New Zealand Police Dog Unit. CLINICAL FINDINGS: The dog in Case 1 suffered numerous facial fractures which caused collapse of the ventral nasal meatus and dorsal nasopharyngeal wall. The dog in Case 2 had extensive osseous and soft tissue damage to the nose, nasopharynx and cervical region with severe narrowing of the ventral meatuses, nasopharyngeal meatus and rostral nasopharynx due to multiple fracture fragments and shrapnel pieces. A diagnosis of traumatic nasopharyngeal stenosis was made in each case by computed tomography. Mechanical balloon dilation was used to treat the stenosis in both dogs. The balloon dilations were performed using a 12-mm balloon dilation catheter inserted in an antegrade fashion. In the first dog, the procedure was performed blind and was repeated three times with 5- and 9-day intervals between dilations. In the second dog, the procedure was performed under endoscopic guidance and again, was repeated three times with a 7-day interval between dilations. Clinical success was reported in both patients following treatment and the second dog also underwent a follow-up computed tomography scan which confirmed resolution of the stenosis. DIAGNOSIS: Traumatic nasopharyngeal stenosis that was successfully treated with balloon dilation. CLINICAL RELEVANCE: Findings suggest that balloon dilation may be an effective technique for the treatment of traumatic nasopharyngeal stenosis in dogs. Multiple dilation procedures are likely required, but the procedure can ultimately result in long term clinical resolution.Abbreviations: CT: Computed tomography; VSA: Veterinary Specialists Aotearoa.

No size-dependent net particle retention in the hindgut of horses.

Sieve analyses of hindgut contents of horses as well as observations in horses where plastic markers had been applied to a caecal cannula suggested that there may be a discrimination by particle size in the passage or retention of digesta. Here, we performed a similar experiment with five caecum-cannulated horses (562 ± 31 kg) fed a constant amount (6.81 kg dry matter/day) of grass hay. Passage markers representing the liquid (Co-EDTA) as well as the particulate digesta phase (Yb-undefined; Cr mordanted fibre 1-2 mm; Ce-mordanted fibre 8 mm) were given as a pulse-dose into the cannula to measure their mean retention times (MRT). The MRTs were compared by repeated-measurements analysis of variance. The MRT in the hindgut was 22.2 ± 2.4 h for Co, 25.0 ± 3.4 h for Yb, 26.2 ± 1.6 h for Cr and 26.3 ± 1.5 h for Ce. Whereas differences between the particle marker MRTs were not significant (padj. > 0.05), significant differences were observed between the solute marker Co and each of the particle markers Cr and Ce (padj. < 0.009). The results confirm the well-known significant, albeit small, difference in MRT in horses between the fluid and the particle digesta phase, and corroborate another recent study that used a combination of whole, marked hay and individual marker analysis in different particle size fractions of the faeces, which also did not detect a selective retention of any particle size class.

Evaluation of totally implantable catheters in healthy horses.

BACKGROUND: For horses requiring prolonged daily cephalic intravenous regional limb perfusion (IVRLP), the use of a totally implantable catheter (TIC) could be indicated to reduce complications associated with frequent venipuncture or external catheterization. This study aims to evaluate the implantation technique of the TIC in the cephalic vein of horses for IVRLP, describe the complications associated with the device's placement and use, and assess its viability up to 60 days after implantation. Totally implantable catheters, cut to 15 cm (n = 5) and 46 cm (n = 5) in length, were implanted into one cephalic vein in ten adult horses (n = 10). Twenty-four hours following placement, IVRLP with contrast was performed via the TIC and evaluated with radiography. Physical examinations, lameness evaluation, hematologic assessment, and the catheter patency tests were performed at scheduled intervals for the duration of catheterization (7-60 days). RESULTS: Catheters were implanted without difficulty and allowed for IVRLP 24 h post implantation. Complications resulted in removal of the catheters, with four maintained for 7 days, three in place for 15 days, and three catheters maintained for 60 days. Complications included lameness, limb swelling, catheter kinking, and venous thrombosis. CONCLUSIONS: The implantation technique of the TIC in the cephalic vein of horses is feasible and requires minimal technical effort. Although TIC allows venous access without the need for repeated venipuncture, its long-term use presents complications. For horses requiring prolonged daily cephalic IVRLP, the use of a TIC could be indicated. However, the high incidence of venous thrombosis may limit clinical application.

Influence of two rumen cannulation techniques on postoperative recovery in sheep.

OBJECTIVE: To determine the influence of two methods of rumen cannulation on postoperative animal welfare. STUDY DESIGN: Experimental study. ANIMALS: Twelve commercial wethers (n = 6 per group). METHODS: Group 1 wethers underwent a one-step procedure to place a cannula immediately after fistulation of the rumen to the skin. Group 2 wethers underwent a two-step procedure in which a portion of the rumen was externalized and held with a clamp for 9 days, after which the cannula was placed into the fistula created by removal of the clamped rumen tissue. Feed intake and vital signs were monitored daily for 24 days postoperatively. Plasma fibrinogen and serum cortisol were measured daily for 14 days postoperatively to estimate inflammatory and stress responses, respectively. Change in body weight was also assessed. RESULTS: Cannulation method did not affect (P > .05) body weight, temperature, heart rate, respiratory rate, fibrinogen level, or cumulative cortisol level. Feed intake was lower (0.82 vs 1.2 kg/d; P < .0001), and mean cortisol level was greater (124.2 vs 121.5 ng/mL; P = .038) in group 2 compared with group 1. CONCLUSION: Although both cannulation methods mostly elicited similar physiological responses, animals seemed to experience more discomfort and stress when undergoing the two-step procedure. CLINICAL SIGNIFICANCE: Rumen cannulation performed in one step is recommended to improve postoperative welfare.

Influence of normograde versus retrograde catheterization of bile ducts in dogs treated for gallbladder mucocele.

OBJECTIVE: To determine the influence of normograde (NG) versus retrograde (RG) catheterization of the cystic duct and common bile duct (CBD) in dogs with gallbladder mucoceles (GBM) treated with open cholecystectomy. STUDY DESIGN: Retrospective study. ANIMALS: Dogs (n = 117) with GBM. METHODS: Medical records were reviewed for signalment, history, clinical laboratory and diagnostic imaging findings, details of surgery including catheterization method, complications, and outcome. Long-term follow-up data were obtained by telephone or electronic communication. Relationships between catheterization method and clinical variables and outcome were evaluated. RESULTS: Dogs catheterized RG were more likely to experience any postoperative complication (p = .0004) including persistence of gastrointestinal signs (p = .0003). Survival to discharge and long-term survival did not differ by group (p = .23 and p = .49). Total bilirubin (TB) decreased by 70.3% after NG catheterization compared to 39.1% after RG catheterization (p = .03) and increased in 14.9% dogs catheterized NG and 38.0% dogs catheterized RG (p = .004). The presence of a diplomate surgeon at surgery resulted in decreased incidences of any perioperative or postoperative complication (p = .003 and p = .05). CONCLUSION: Retrograde catheterization was associated with more postoperative concerns than NG catheterization, but similar survival times. Surgery should be performed by diplomates experienced in biliary surgery to minimize complications. CLINICAL SIGNIFICANCE: Although both NG and RG techniques to catheterize the cystic duct and CBD are options for treatment of GBM with low mortality, results of this study provide some evidence to recommend NG over RG catheterization.

Association between biliary tree manipulation and outcome in dogs undergoing cholecystectomy for gallbladder mucocele: A multi-institutional retrospective study.

OBJECTIVE: To determine whether catheterization of the common bile duct (CBD) is associated with outcome in dogs undergoing cholecystectomy for gallbladder mucocele and to determine whether this association is modified by the catheterization method. STUDY DESIGN: Multi-institutional retrospective cohort study. ANIMALS: Dogs (n = 252) that underwent cholecystectomy for gallbladder mucocele. METHODS: Dogs were identified via electronic medical record review at four veterinary teaching hospitals. Baseline dog characteristics, surgical findings, and methods including normograde vs retrograde CBD catheterization, intraoperative outcomes, and postoperative outcomes and complications were recorded. Variables were compared between dogs with and without catheterization. RESULTS: Catheterized dogs had higher American Society of Anesthesiologists scores (P = .04), higher total bilirubin (P = .01), and were more likely to have dilated CBD at the time of surgery (P < .01). Incidence of major and minor intraoperative complications was similar between the two groups. Surgical time was longer for the catheterized group (P = .01). The overall incidence of postoperative complications was similar between the groups; however, postoperative pancreatitis was associated with performing CBD catheterization (P = .01). This association was retained as an independent association in a multivariable model that addressed baseline group differences (P = .04). Likelihood of developing postoperative pancreatitis was not different between normograde and retrograde catheterization (P = .57). CONCLUSION: Catheterization of the CBD was associated with development of postoperative pancreatitis. This was not influenced by the method of catheterization. CLINICAL SIGNIFICANCE: The requirement for catheterization of the CBD during open cholecystectomy in dogs should be carefully considered, particularly in dogs without evidence of biliary obstruction because the procedure may induce postoperative pancreatitis.

Design and Validation of a Simulator for Feline Cephalic Vein Cannulation-A Pilot Study.

In recent years there has been an increased use of alternative methods for teaching veterinary clinical skills, since ethical considerations preclude the use of live animals for demonstration or practice of many procedures. Skills training on cats (i.e., feline venipuncture) is a particularly challenging area. This study aimed to develop a simulator for cephalic venipuncture in cats and to validate this simulator using questionnaires answered by undergraduate students and experienced veterinarians. The simulator was developed to provide an experience that was close to reality, including an artificial blood system that flows through the catheter when venipuncture is correctly performed, while at the same time using simple methodology and accessible materials so that it could be reproduced in other universities. The experienced vets agreed (44.4%) or strongly agreed (55.6%) that the simulator was good for venipuncture training, and the most useful feature was the experience of catheter manipulation and fixation on the cat's limb. All the students agreed that the practical class with the simulator was important for learning this skill. Both groups (students and experienced veterinarians) unanimously agreed that it is important to train using a simulator before trying the procedure on a live cat. This simulator offers undergraduate students an alternative way to learn and practice venipuncture in cats helping to reduce the use of live animals in practical classes.

Technical note: Evaluation of the ororuminal FLORA sampling device for rumen fluid sampling in intact cattle.

The objectives of this study were to evaluate the actual intraruminal sampling site of the ororuminal FLORA sampling device (Profs Products, Wittibreut, Germany), and to compare pH and volatile fatty acid (VFA) data obtained using FLORA and those obtained using a suction strainer introduced to the ventral ruminal sac via a rumen cannula. Five lactating multiparous Danish Holstein cows fitted with ruminal cannulas were used. All cows were fed the same diet once daily, and the diet was allowed ad libitum. Samples of rumen fluid and recordings were obtained 6 h after feeding at 3 occasions. Rumen fluid samples were taken using 2 devices: (1) the ororuminal FLORA sampling device and (2) a suction strainer inserted through the rumen cannula to the ventral ruminal sac and a 60-mL syringe for suction. Both sampling devices were inserted concomitantly, and samples of rumen fluid were obtained simultaneously with both devices. After sampling rumen fluid, the actual intraruminal placement of the FLORA sampling cup was manually assessed as being in either the cranial sac, the dorsal sac, the medial layer, or the ventral sac. Only VFA proportions, and not pH and VFA concentrations, were similar between rumen fluid samples obtained using FLORA and those obtained directly through the rumen cannula. The observed intraruminal sampling site of the FLORA sampling cup indicates that firm rumen digesta hampers the ability of the FLORA device to reach the ventral sac and impedes filling of the sampling cup and, consequently, increases the risk of saliva contamination of samples.

Short communication: A pilot study to describe duodenal and ileal flows of nutrients and to estimate small intestine endogenous protein losses in weaned calves.

The aims of this pilot study were (1) to evaluate the effect of an ileal and duodenal cannulation surgery on body weight and dry matter intake, (2) to estimate endogenous losses of crude protein (CP) and AA in the small intestine, and (3) to describe duodenal and ileal flows of nutrients in weaned dairy calves. Three Holstein male calves were fitted at 7 wk of life with a T-cannula at the terminal ileum and another cannula at the proximal duodenum. On wk 14 of life, calves were randomly assigned to a single 3 × 3 Latin square with 10-d periods. The 3 diets were fed ad libitum and consisted of a control calf starter (CS) with conventional soybean meal (SBM) as the main source of protein (CTRL), an isonitrogenous (20% CP) CS with an enzyme-treated SBM as the main source of protein (ENZT), and a CS with low content of CP (10%) and no soy protein (LOCP). Flows and digestibilities of nutrients were compared between the soy-based high-protein diets (HICP) and LOCP, and between CTRL and ENZT. Final data were only available from 2 calves per diet (n = 2) because cannulas from 1 calf became inoperative after the first collection period. Duodenal flows of CP, total AA, nonprotein nitrogen, microbial N, and fatty acids, as well as apparent duodenal digestibility of starch, were greater for HICP than for LOCP, indicating a greater foregut microbial activity and digestion. The apparent ileal digestibility (AID) of organic matter, CP, and total AA were greater for HICP than for LOCP. Duodenal net flow of CP was greater for ENZT than for CTRL, but flow of AA was not different. On the other hand, duodenal flow of microbial N was greater, and flows of nonprotein N and starch were lower for the ENZT diet, suggesting a more efficient microbial activity in the rumen. Even though CTRL had a greater AID when compared with ENZT, the AID of CP and AA were greater for enzyme-treated SBM than for SBM. Endogenous losses in the small intestine per kilogram of duodenal dry matter flow were 47 ± 15 and 37 ± 12 g/d, and the true ileal digestibilities for the HICP diets were 86 ± 0.1 and 87 ± 0.1% for CP and AA, respectively. An optimal supply of CP and the inclusion of an enzyme-treated SBM improved the efficiency of microbial digestion and increased AA absorption. Although further research with greater biological replication is needed, our results indicate that there is potential to improve digestion and absorption of proteins through dietary strategies in young weaned calves.

Intrasinus bolstering of traumatic maxillary sinus fractures by using Foley catheter balloons in two foals.

OBJECTIVE: To describe the repair of unstable facial fractures by using Foley catheter balloons as intrasinus bolsters. STUDY DESIGN: Case report ANIMALS: Two weanling foals with unilateral fractures of the sinus and orbit secondary to kick injuries. Preoperative imaging that included positive contrast dacrocystorhinography and computed tomography confirmed severe comminution of facial fractures and nasolacrimal duct disruption in both foals. METHODS: Small bone fragments were surgically removed, and large fragments were retained even when denuded of periosteum. Repair procedures included nasolacrimal canaliculosinusotomy and suturing fracture fragments together with polydioxanone sutures. After fixation, the fracture fragments could be depressed into the sinus with manual pressure, so two intrasinus Foley catheters were placed to bolster the sinus wall, with the tubing exiting through a frontal sinus trephine. The skin was completely closed over the fractures. Catheters and nasolacrimal stenting were maintained in place during fracture healing. RESULTS: One foal prematurely dislodged catheters and nasolacrimal stent 11 days after fixation. The catheters and stenting were removed as planned 4 weeks after surgery in the second foal. Wound, fracture healing, and overall cosmesis was good in both foals, and epiphora resolved. Surgical site infection, sinusitis, and sequestration did not occur. Both foals became high-level performance horses with acceptable cosmetic outcome and good bilateral nasal airflow. CONCLUSION: Foley catheter balloons supported sinus fracture repair and maintained stability of the surgical reconstruction during convalescence. CLINICAL SIGNIFICANCE: Suture repair of comminuted sinus fractures can be supported by using Foley catheters, which are readily available.

Development of a surgical technique for long-term catheterisation of bovine fetuses.

The aim of this study was to further develop and extensively describe a surgical technique in order to realise long-term fetal blood sampling in the bovine species. Eleven Holstein-Friesian 6- to 8-month pregnant cows (4-10 years old) were used for this study. Gestational age on the day of surgery varied from approximately 180 days (n = 1) to 240 days (minimum: 232 days, maximum 252 days; n = 10). The fetal medial tarsal artery was catheterised in pregnant cows with a polyvinyl catheter in dorsal recumbency under general anaesthesia. Although 5 out of 11 operations (45.5%) performed between 232 and 252 days of gestation were lost due to different causes mainly associated with peritonitis and septicaemia, the mean interval between operations and calvings was 42.5 days (between 27 and 95 days). It is important to emphasise that a well-trained surgical team is needed for bovine fetal cannulation in order to be able to decrease the risk factors during the operations. Due to the fact that after 5 unsuccessful cases none of the pregnancies were lost, this skill can be reached, and our technique can enable bovine fetal blood sampling for long-term endocrinological and physiological investigations before and during parturition.

Technical note: Establishment of an ileal cannulation technique in preweaning calves and use of a piecewise regression approach to evaluate effects on growth and pH fluctuation of ileal digesta.

Digestibilities of nutrients, especially protein, are crucial characteristics of milk replacers in a calf-rearing program. Endogenous synthesis of proteins and microbial fermentation in the large intestine alter apparent total-tract digestibility of AA. Therefore, collection of digesta samples at the end of the ileum is the only method to estimate true small intestinal digestibility of AA. The aim of this work was to evaluate the effectiveness of inserting a T-cannula into the distal ileum of preweaning calves for use in digestibility studies. A second objective was to evaluate the use of a "broken-line" statistical model to compare treatment effects on calf growth and digesta pH. A T-cannula was surgically installed in the terminal ileum of 2 calves approximately 5 cm anterior to the ileocecal junction at 15 d of age, and 2 paired noncannulated calves were used as controls. Cannulation did not affect mean body weight (BW), average daily gain, milk and water intakes, and body frame dimensions. However, final BW (89.2 vs. 94.6 kg) was lower and starter intake (0.06 vs. 0.21 kg/d) tended to be decreased in cannulated calves compared with control calves. No effects on health scores, rectal temperature, or the odds of incurring diarrhea or being medicated were observed. Flow of digesta (46.4 ± 0.04 g/h) increased linearly after feeding, whereas there was a quadratic effect of time on digesta pH, with the nadir at approximately 8.5 h postfeeding. The broken-line model successfully fitted daily fluctuations of pH and allowed us to detect differences in growth slopes between cannulated and control calves. Despite the expected negative effect on BW, we conclude that this technique permitted sampling of representative ileal digesta while allowing satisfactory growth and health of the calves.

Effects of rumen cannulation on dissolved gases and methanogen community in dairy cows.

Rumen cannulation is a widely employed technique in ruminant nutrition research. However, the gap between skin and rumen cannula can cause leakage of fermentation gases and influx of atmospheric air, which may adversely affect the anaerobic environment in the rumen. The present study was designed to investigate the effects of rumen cannulation on headspace gases, dissolved gases, fermentation end products, and methanogen community in the rumen of dairy cows. Eight Holstein cows were used in the experiment. Four cows were surgically fitted with rumen cannulas, whereas the other 4 intact cows were used as control. Rumen cannulation decreased gaseous hydrogen and methane concentrations, dissolved carbon dioxide concentration, and relative abundances of Methanosphaera, and increased the saturation factor of dissolved hydrogen and dissolved methane, dissolved methane concentration, volatile fatty acid concentration, 16S ribosomal RNA gene copies of methanogens, and Simpson index of methanogen community. In summary, rumen cannulation causes a reduction in headspace gaseous hydrogen and gaseous methane, which may not decrease dissolved gas concentrations due to an increase in saturation factors. Furthermore, rumen cannulation alters methanogen community with increased methanogen population and decreased relative abundances of Methanosphaera.

Technical note: Infusion, sampling, and vacuum-assisted collection devices for use in ruminally cannulated calves.

Calves can be ruminally cannulated at young ages, but equipment size limitations preclude use of an infusion and sampling device in these small animals. Likewise, a procedure to easily evacuate rumen contents in young calves has not been described. Overcoming these technical complications related to assessment of ruminal passage kinetics, nutrient digestion, and volatile fatty acid absorption would aid in future studies advancing our knowledge of dairy calf nutrition. The first objective was to design and fabricate 2 devices (one device for infusion and sampling, and another for vacuum-assisted collection) suitable for use in young ruminally cannulated dairy calves. The second objective was to test the utility of these tools when performing procedures commonly used in ruminant nutrition research. A single weaned 62-d-old ruminally cannulated calf was used to evaluate the ability to infuse a solution of LiCoEDTA and sample rumen contents through the cannula cap over a period of 2 h to assess the rumen liquid passage rate (procedure 1). The device was capable of infusing the LiCoEDTA and sampling the rumen fluid, as evidenced by the presence of elevated Co concentrations in the sampled rumen fluid. Using the fluid samples obtained, liquid passage rate within the calf was estimated to be 40.2% of ruminal fluid/h. The second procedure tested the vacuum-assisted collection device and consisted of evacuating and weighing the rumen contents, which is considered a key preparatory step in washed reticulorumen technique experiments that aim to measure nutrient absorption. In agreement with existing literature, evacuated rumen contents represented approximately 4% of the calf's body weight. In conclusion, custom-built devices for infusion, sampling, and vacuum-assisted collection were efficacious when tested in a 62-d-old ruminally cannulated calf fed a diet of 100% texturized starter (18% crude protein, as-fed). Fellow scientists may employ and further modify these techniques to suit their needs when assessing passage kinetics, nutrient digestion, and volatile fatty acid absorption in calves.

Effect of supplemental concentrate during the dry period or early lactation on rumen epithelium gene and protein expression in dairy cattle during the transition period.

We previously reported 2 experiments with rumen-cannulated Holstein-Friesian dairy cows showing that during the transition period, rumen papillae surface area, and fractional absorption rate of volatile fatty acids (VFA) increase after calving. However, supplemental concentrate during the dry period and rate of increase of concentrate allowance during lactation affected papillae surface area, but not VFA absorption. Here we report the changes in gene and protein expression in rumen papillae related to tissue growth and VFA utilization. The lactation experiment treatment consisted of a rapid [RAP; 1.0 kg of dry matter (DM)/d; n = 6] or gradual (GRAD; 0.25 kg of DM/d; n = 6) increase of concentrate allowance (up to 10.9 kg of DM/d), starting at 4 d postpartum (pp). The dry period experiment treatment consisted of 3.0 kg of DM/d of concentrate (n = 4) or no concentrate (n = 5) during the last 28 d of the dry period. Real-time quantitative PCR analysis of rumen papillae showed that the expression of apoptosis-related genes was neither affected by day nor its interaction with treatment for both experiments. Expression of epithelial transporter genes was not affected by day or treatment in the lactation experiment, except for NBC1. In the dry period experiment, expression of MCT1, NBC1, DRA, NHE2, NHE3, and UT-B generally decreased after calving. A day and treatment interaction was observed for ATP1A1 in the dry period experiment, with greater expression at 18 and 8 d antepartum for concentrate than no concentrate. Generally, expression of VFA metabolism-related genes was not affected by day or its interaction with treatment. In the lactation experiment, immunoblotting of 5 selected genes showed that protein expression of DRA and PCCA was greater at 16 d pp compared with 3 and 44 d pp. Expression of NHE2 was greater, and that of ATP1A1 lower, at 16 and 44 d pp compared with 3 d pp, suggesting alterations in intracellular pH regulation and sodium homeostasis. Both MCT1 and PCCA protein were upregulated by RAP from 3 to 16 d pp, indicating modulations in VFA metabolism. Our data suggests that VFA absorption and metabolic capacity changed little per unit of surface area during the transition period, and suggests that a change in mitosis rate rather than apoptosis rate is associated with the increased ruminal VFA production, resulting in tissue growth. A significant but weak correlation between the examined gene and protein expression levels was observed only for PCCA, indicating that care must be taken when interpreting results obtained at either level.

Modified technique for common carotid artery transposition in standing horses.

OBJECTIVE: To describe a modified technique for permanent translocation of the common carotid artery (CCA) to a subcutaneous position in standing horses. STUDY DESIGN: Experimental study. ANIMALS: Healthy adult Standardbred and Warmblood horses (n = 8). METHODS: Surgery was performed with the horses standing under sedation and with local anesthesia. A combination of previously described techniques was used modifying the approach and closure of the incision. The right CCA was approached through a linear skin incision dorsal and parallel to the jugular vein and through the brachiocephalicus and omohyoideus muscles. The artery was dissected free of its sheath and elevated to the skin incision with Penrose drains. The brachiocephalicus muscle was sutured in two layers underneath the artery leaving it in a subcutaneous position. The horses were allowed to heal for 3 weeks prior to catheterization of the artery. RESULTS: The transposed CCA was successfully used for repeated catheterization in six of eight horses for a period of 10 weeks. None of the horses had intraoperative complications. Two horses developed mild peri-incisional edema that resolved spontaneously. Right-sided laryngeal hemiplegia was observed endoscopically in two horses postoperatively. Two horses developed complications (surgical site infection and excessive periarterial fibrosis) that compromised the patency of the CCA and precluded catheterization. CONCLUSION: Permanent translocation of the CCA in standing horses was successful in six out of eight horses. Upper airway endoscopy postoperatively may be warranted as laryngeal hemiplegia may ensue.