The rabbit corpus luteum becomes an estradiol-dependent tissue by day 6 of gestation, and adequate estrogen is critical to avoid pregnancy failure. The aim of this study was to investigate the effect of parity (primiparous or multiparous), day of mating (11 or 21 d postpartum), and suckling status (suckling or nonsuckling) on various reproductive traits in hybrid rabbit does (n = 96). Ovarian structures on day 6 after coitus were evaluated by means of ultrasonography. Blood samples were collected that day, and the serum was analyzed for estradiol-17β by radioimmunoassay (RIA). Parity and suckling had significant effects on mating rate (P < 0.01 and P < 0.05, respectively). More does accepted the male on day 11 than on day 21 (P < 0.05). Ovulation frequency was significantly affected by parity (P < 0.05), day of mating (P < 0.01), and suckling (P < 0.01). Fewer ovarian large follicles and lower estradiol-17β levels were detected in suckling compared with nonsuckling rabbits (P < 0.01). Since estrogen concentrations are commonly used to assess follicular growth and steroidogenic capacity, the lower hormonal levels in the suckling rabbits may reveal poorer ovarian activity, which could result in reduced reproductive efficiency. Our observations confirm the existence of a partial antagonism between lactation and reproduction in rabbits. Further research is needed to elucidate these phenomena, including when artificial insemination is done. Ultrasonography could represent a noninvasive and reliable method for studying several reproductive functions and dysfunctions in rabbits.

Objective—To evaluate with CT the efficacy of various combinations of firearms and ammunitions to penetrate and disrupt the brain tissue of cadaveric heads of feedlot steers. Sample—42 fresh cadaveric heads of 12- to 18-month-old Bos taurus steers. Procedures—For each of 7 combinations of firearms and ammunitions (.22-caliber rifle firing a long rifle 30-grain plated lead solid- or hollow-point round, .223-caliber carbine firing a 50-grain ballistic-tip round, 9-mm pistol firing a 124-grain total metal jacket round, .45-caliber automatic Colt pistol [ACP] firing a 230-grain full metal jacket round, and 12-gauge shotgun firing a 2.75-inch 1.25-ounce No. 4 birdshot shell or a 1-ounce rifled slug), 6 cadaveric heads were shot at an identical distance (3 m), angle, and anatomic location. Heads were scanned with third-generation CT, and images were evaluated to determine extent of penetration, projectile fragmentation, cranial fracture, and likelihood of instantaneous death (≥ 30% destruction of brain tissue or a brainstem lesion). Results—41 of 42 skulls were penetrated by the projectile. Instantaneous death was considered a likely consequence for 83% (25/30) of heads shot with a rifle-fired .22-caliber solid-point round, pistol-fired .45-caliber ACP round, carbine-fired .223-caliber round, and shotgun-fired birdshot and slug. Of the 18 heads shot with pistol-fired 9-mm and .45-caliber ACP rounds and rifle-fired .22-caliber hollow-point rounds, only 6 had brainstem lesions. Conclusions and Clinical Relevance—Results suggested that gunshots delivered by all firearm-ammunition combinations except rifle-fired .22-caliber hollow-point rounds and pistol-fired 9-mm rounds were viable options for euthanasia of feedlot cattle.

Objective-To assess dual-energy x-ray absorptiometry (DXA) for evaluating effects of diet and environment on bone mineral density in Hermann's tortoises (Testudo hermanni). Animals-26 Hermann's tortoises within 1 month after hatching. Procedures-Group 1 was housed in an artificial setting and fed naturally growing vegetation. Group 2 was housed in an artificial setting and fed vegetables grown for human consumption. Group 3 was maintained in an outside enclosure and fed naturally growing vegetation. After 10 months, pyramidal growth, body weight, and adverse conditions were assessed. Bone mineral density (BMD) of the axial and appendicular skeleton, shell, vertebral column, and pelvis was measured via DXA. Results-Group 2 had the highest mean +/- SD body weight (65.42 +/- 30.85 g), followed by group 1 (51.08 +/- 22.92 g) and group 3 (35.74 +/- 7.13 g). Mean BMD of the shell varied significantly among groups (group 1, 0.05 +/- 0.03 g/cm2•m; group 2, 0.09 +/- 0.15 g/cm2•m; and group 3, undetectable). The BMD of the axial and appendicular skeleton, vertebral column, and pelvis did not differ significantly among groups. Pyramidal growth was highest in group 1 and not evident in group 3. Conclusions and Clinical Relevance-Tortoises raised in artificial conditions did not have deficits in BMD, compared with results for outdoor-housed hibernating tortoises. Supplemental calcium was apparently not necessary when an adequate photothermal habitat and plant-based diet were provided. Higher BMD of captive-raised tortoises was morphologically associated with a higher incidence of pyramidal growth in captive-raised groups.

Objective: To assess inhibitory effects of orally administered anti-inflammatory medications on paracentesis-induced intraocular inflammation in clinically normal cats. Animals: 30 clinically normal domestic shorthair cats. Procedures: Cats were randomly assigned to a control group and 4 treatment groups. Cats in the treatment groups received an anti-inflammatory medication orally once daily at 7 am (acetylsalicylic acid [40.5 mg/cat], meloxicam [0.1 mg/kg], prednisone [5 mg/cat], or prednisolone [5 mg/cat]) for 5 days beginning 2 days before paracentesis-induced breakdown of the blood-aqueous barrier (BAB) and continuing until 2 days after paracentesis. Paracentesis of the anterior chamber was performed in 1 randomly selected eye of each cat. Fluorophotometry was performed in both eyes of each cat immediately before (time 0) and 6, 24, and 48 hours after paracentesis. Results: At 24 and 48 hours after paracentesis, fluorescein concentration in the eye subjected to paracentesis in the cats receiving prednisolone was decreased, compared with that in the control cats. At 48 hours, a decrease in the fluorescein concentration was also apparent in the eye subjected to paracentesis in the cats receiving meloxicam, compared with that in the control cats. There was no evidence of treatment effects for acetylsalicylic acid or prednisone. There was no evidence of treatment effects in eyes not subjected to paracentesis. Conclusions and Clinical Relevance: Orally administered prednisolone and meloxicam significantly decreased intraocular inflammation in clinically normal cats with paracentesis-induced BAB breakdown. Oral administration of prednisolone or meloxicam may be an effective treatment for cats with uveitis.

Objective: To determine the pharmacokinetics of meloxicam after IV and PO administration to 6 healthy sheep. Animals: 6 healthy adult Dorset cross sheep (5 males and 1 female). Procedures: Meloxicam (0.5 mg/kg, IV, or 1.0 mg/kg, PO) was administered in a randomized crossover design with a 10-day washout period. Blood samples were collected at predetermined times over 96 hours. Serum drug concentrations were determined by high-pressure liquid chromatography with mass spectrometry. Computer software was used to estimate values of pharmacokinetic parameters through noncompartmental methods. Results: Following IV administration (n = 5), the geometric mean (range) elimination half-life was 14.0 hours (10.5 to 17.0 hours), volume of distribution was 0.204 L/kg (0.171 to 0.272 L/kg), and clearance was 0.17 mL/min/kg (0.12 to 0.27 mL/min/kg). Following oral administration (n = 6), maximum serum concentration was 1.72 μg/mL (1.45 to 1.93 μg/mL), time to maximum serum concentration was 19.0 hours (12.0 to 24.0 hours), clearance per bioavailability was 0.22 mL/min/kg (0.16 to 0.30 mL/min/kg), and terminal half-life was 15.4 hours (13.2 to 17.7 hours). Bioavailability of orally administered meloxicam was calculated as 72% (40% to 125%; n = 5). No adverse effects were evident following meloxicam administration via either route. Conclusions and Clinical Relevance: Meloxicam administered PO at 1.0 mg/kg has good bioavailability with slow elimination kinetics in sheep. These data suggested that meloxicam may be clinically useful, provided the safety and analgesic efficacy of meloxicam as well as feed-related influences on its pharmacokinetics are established in ruminants.

The current study tested the benefit of commercially available spray-dried bovine colostrum (The Saskatoon Colostrum Company, Saskatoon, Saskatchewan) in raising snatch-farrowed, porcine-colostrum-deprived (SF-pCD) pigs. In experiment 1, 12 SF-pCD pigs received a liquid diet composed mainly of bovine colostrum from birth to day 10; 6 remained on the same liquid diet (COL), and the other 6 were fed a diet composed mainly of milk replacer (RPL) until weaning. In experiment 2, 12 SF-pCD pigs were fed mainly bovine colostrum before weaning; after weaning, 6 were fed a starter diet containing 20% (w/w) bovine colostrum powder (STARTER-COL), and the other 6 were fed a starter diet without any bovine colostrum (STARTER-CTRL) until termination (day 42 or day 49). In experiment 1 the COL pigs had significantly fewer fever-days than did the RPL pigs. In experiment 2 diarrhea, typhlocolitis, and pancreatic degeneration developed in 4 of the STARTER-COL pigs after weaning. In both experiments all the pigs fed mainly bovine colostrum before weaning survived until termination. All pigs tested free of swine influenza virus H1N1 and H3N2, Porcine reproductive and respiratory syndrome virus, and Porcine parvovirus. In experiment 2 all the pigs tested free of Porcine circovirus type 2 (PCV2), but some in both groups tested positive for Torque teno virus genogroups 1 and 2. In conclusion, with the use of snatch-farrowing and bovine colostrum, pigs can be raised in the absence of porcine maternal antibodies with 100% survival and freedom from most porcine pathogens of biologic relevance. This model is potentially suitable for animal disease research.

Objective-To validate the use of a human enzyme immunoassay (EIA) kit for measurement of plasma antidiuretic hormone (ADH) concentration in dogs and evaluate plasma ADH concentrations in dogs with congestive heart failure (CHF) attributable to acquired cardiac disease, compared with findings in healthy dogs. Animals-6 healthy dogs and 12 dogs with CHF as a result of chronic degenerative valve disease or dilated cardiomyopathy. Procedures-Plasma samples from the 6 healthy dogs were pooled and used to validate the EIA kit for measurement of plasma ADH concentration in dogs by assessing intra-assay precision, dilutional linearity, and spiking recovery. Following validation, plasma ADH concentrations were measured in the 6 healthy dogs and in the 12 dogs with CHF for comparison. Results-The EIA kit measured ADH concentrations in canine plasma samples with acceptable intra-assay precision, dilutional linearity, and spiking recovery. The intra-assay coefficient of variation was 11%. By use of this assay, the median plasma concentration of ADH in dogs with CHF was 6.15 pg/mL (SD, 3.2 pg/mL; range, 4.18 to 15.47 pg/mL), which was significantly higher than the median concentration in healthy dogs (3.67 pg/mL [SD, 0.93 pg/mL; range, 3.49 to 5.45 pg/mL]). Conclusions and Clinical Relevance-Plasma ADH concentrations in dogs can be measured with the tested EIA kit. Plasma ADH concentrations were higher in dogs with CHF induced by acquired cardiac disease than in healthy dogs. This observation provides a basis for future studies evaluating circulating ADH concentrations in dogs with developing heart failure.

Objective-To determine the effect of biopsy collection depth on the postprandial activation of mammalian target of rapamycin (mTOR) signaling factors, particularly protein kinase B, ribosomal protein S6 kinase, ribosomal protein S6, and eukaryotic initiation factor 4E binding protein 1 in middle-aged horses. Animals-6 healthy Thoroughbred mares (mean +/- SD age, 13.4 +/- 3.4 years). Procedures-Horses were fed a high-protein feed at 3 g/kg. Sixty minutes after horses were fed, the percutaneous needle biopsy technique was used to collect biopsy specimens from the gluteus medius muscle at 6, 8, and 10 cm below the surface of the skin. Muscle specimens were analyzed for the activation of upstream and downstream mTOR signaling factors, myosin heavy chain (MHC) isoform composition, and amino acid concentrations. Results-A 21% increase in MHC IIA isoform expression and a 21% decrease in MHC IIX isoform expression were identified as biopsy depth increased from 8 to 10 cm below the surface of the skin; however, no significant change was evident in the degree of MHC I expression with muscle depth. Biopsy depth had no significant effect on the phosphorylation of any of the mTOR signaling factors evaluated. Conclusions and Clinical Relevance-Postprandial mTOR signaling could be compared between middle-aged horses when biopsy specimens were collected between 6 and 10 cm below the surface of the skin. Optimization of muscle biopsy techniques for evaluating mTOR signaling in horses will facilitate the design of future investigations into the factors that regulate muscle mass in horses.

Objective-To determine the degree of agreement between 2 analyzers for measurement of total CO2 concentration (ctCO2) in equine plasma. Animals-6 healthy untrained horses, 6 trained Standardbreds undergoing a simulated race protocol, and 135 trained Standardbreds at a racetrack. Procedures-Jugular venous blood samples were obtained from all horses. Two analyzers (commonly used analyzer A and less expensive analyzer B) were used to measure plasma ctCO2 in each sample. Validation of both analyzers was conducted in accordance with guidelines established by the Clinical and Laboratory Standards Institute and involved characterization of linearity, total analytic error, and bias estimation. Results-Total analytic error (instrument SD) was 0.58 mmol/L (coefficient of variation, 1.6%) and 0.49 mmol/L (coefficient of variation, 1.4%) for analyzers A and B, respectively, when measuring an aqueous standard containing 36.0 mmol of CO2/L. A 1 g/L decrease in plasma protein concentration corresponded to an increase in ctCO2 measured with analyzer B of 0.065 mmol/L. A difference plot indicated that analyzer B produced values 2.7% higher than analyzer A for 103 samples from the 6 trained and exercised Standardbreds (mean plasma protein concentration, 67 g/L). Conclusions and Clinical Relevance-Analyzer B provided adequate precision and linearity for measurement of ctCO2 from 5 to 40 mmol/L and was therefore suitable for measuring ctCO2 in equine plasma, provided allowances are made for changes in plasma protein concentration.

Objective: To compare the degree of mRNA expression for matrix metalloproteinases (MMPs), tissue inhibitors (TIMPs), and lysyl oxidase in myocardial samples from dogs with cardiac and systemic diseases and from healthy control dogs. Sample: Myocardial samples from the atria, ventricles, and septum of 8 control dogs, 6 dogs with systemic diseases, 4 dogs with dilated cardiomyopathy (DCM), and 5 dogs with other cardiac diseases. Procedures: Degrees of mRNA expression for MMP-1, -2, -3, -9, and -13; TIMP-1, -2, -3, and -4; and lysyl oxidase were measured via quantitative real-time PCR assay. Histologic examination of the hearts was performed to identify pathological changes. Results: In myocardial samples from control dogs, only TIMP-3 and TIMP-4 mRNA expression was detected, with a significantly higher degree in male versus female dogs. In dogs with systemic and cardiac diseases, all investigated markers were expressed, with a significantly higher degree of mRNA expression than in control dogs. Furthermore, the degree of expression for MMP-2, TIMP-1, and TIMP-2 was significantly higher in dogs with DCM than in dogs with systemic diseases and cardiac diseases other than DCM. Expression was generally greater in atrial than in ventricular tissue for MMP-2, MMP-13, and lysyl oxidase in samples from dogs with atrial fibrillation. Conclusions and Clinical Relevance: Degrees of myocardial MMP, TIMP, and lysyl oxidase mRNA expression were higher in dogs with cardiac and systemic diseases than in healthy dogs, suggesting that expression of these markers is a nonspecific consequence of end-stage diseases. Selective differences in the expression of some markers may reflect specific pathogenic mechanisms and may play a role in disease progression, morbidity and mortality rates, and treatment response.