The development and integrity of equine pre‐antral follicles cultured in vitro with follicle‐stimulating hormone (FSH) supplementation

This study investigated the effects of different concentrations of FSH (10, 50, 100 and 200 ng/ml) in supplemented MEM+ on the development of equine pre‐antral follicles that were cultured in vitro for 2 or 6 days. The ovaries (n = 5) from mares in seasonal anoestrus were collected from a local abattoir. Ten ovarian tissue fragments of approximately 3 × 3 × 1 mm were obtained from each animal. The fragments were cultured in situ for 2 days (D2) or 6 days (D6) in MEM+ or MEM+ supplemented with FSH at four different concentrations, establishing the following 11 groups: control (D0); MEM + (D2); MEM + (D6); MEM + 10 ng/ml of FSH (D2); MEM + 10 ng/ml of FSH (D6); MEM + 50 ng/ml of FSH (D2); MEM + 50 ng/ml of FSH (D6); MEM + 100 ng/ml of FSH (D2); MEM + 100 ng/ml of FSH (D6); MEM + 200 ng/ml of FSH (D2); and MEM + 200 ng/ml of FSH (D6). Follicles were observed in only 9.65% (388 of 4,018) of the histological sections. Of the 861 follicles evaluated, 488 were in the primordial stage, and 373 were in various developmental stages; 59.7% were morphologically normal. Regarding the integrity of the pre‐antral follicles, the groups with 100 ng/ml FSH of 2‐days culture as well as 50, 100 and 200 ng/ml FSH of 6‐days culture provided the best results. In conclusion, the in vitro culture of abattoir‐derived equine ovarian fragments presented better morphological integrity when supplemented with FSH for 6 days, in comparison with the MEM culture group. However, no clear effects were observed with FSH regarding the promotion of activation from a primordial to a developing follicle.     

Ultrasonography and progesterone concentration at a single time point for the detection of puberty in dairy heifers

Data were available from 1657 heifers across 48 dairy farms which were visited once, on average 9 days (± 5.2) prior to the mating start date (23 April, ± 12.6). Blood samples were collected via coccygeal venepuncture for progesterone (P4) analysis, and animals were scanned for the presence or absence of corpora lutea (CL), to determine the luteal status. A comparison of luteal status between ultrasound (CL identified) and P4 (≥ 1 ng/ml), based on a single measurement point, showed poor agreement (K = 0.32). The majority of animals were classified as luteal (76%) using both ultrasonography and P4. There was excellent agreement between luteal status detected by ultrasonography alone and luteal status assigned by a combination of ultrasonography and P4 (K = 0.93). The agreement between luteal status assigned by P4 and luteal status assigned by the combination of ultrasonography and P4 was poor (K = 0.37). These results indicate that at a single examination, ultrasonography is the preferred modality to determine the luteal status of maiden heifers.     

Floods,drying, habitat connectivity,and fish occupancy dynamics in restored and unrestored oxbows of West Central Iowa,USA

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Meta-analysis of pharmacokinetic data of veterinary drugs using the Food Animal Residue Avoidance Databank: oxytetracycline and procaine penicillin G

Investigators frequently face the quandary of how to interpret the often times disparate pharmacokinetic parameter values reported in the literature. Combining of data from multiple studies (meta-analysis) is a useful tool in pharmacokinetics. Few studies have explored the use of meta-analysis for veterinary species. Even fewer studies have explored the potential strengths and weaknesses of the various methods of performing a meta-analysis. Therefore, in this study we performed a meta-analysis for oxytetracycline (OTC) and procaine penicillin G (PPG) given intramuscularly to cattle. The analysis included 28 individual data sets from 18 published papers for PPG (288 data points), and 41 individual data sets from 25 published papers for OTC (489 data points). Three methods were used to calculate the parameters. The first was a simple statistical analysis of the parameter values reported in each paper. The second method was a standard Two-Stage Method (TSM) using the mean concentration vs. time data extracted from each paper. The third method was the use of nonlinear mixed effect modeling (NMEM) of the concentration vs. time data reported in the various papers, treating the mean data as if each set came from an individual animal. The results of this evaluation indicate that all three methods generate comparable mean parameter estimates for OTC and PPG. The only significant difference noted was for OTC absorption half-lives taken from the published literature, a difference attributable to the use of an alternative method of parameter calculation. The NMEM procedure offers the possibility of including covariates such as dose, age, and weight. In this study the covariates did not influence the derived parameters. A combination approach to meta-analysis of published mean data is recommended, where the TSM is the first step, followed by the NMEM approach.     

Disseminated mycobacteriosis in a cat (abstract)

A 12-year-old, FIV-positive domestic cat from rural Northland presented with diffuse and slowly progressive swellings of the vulva, tail base, head, and distal limbs. Fine needle aspirate biopsy of the subcutis revealed large numbers of pleomorphic acid fast bacteria. At necropsy, the dermis and subcutis in the affected areas were expanded by a pale yellow opaque infiltrate. Large ulcerated cutaneous swellings were present in the left maxillary area and bilaterally at the point of the jaw corresponding to the submandibular lymph nodes. Cutaneous nodules were present in the pre-auricular area. The skin of the carpi and tarsi was thickened and there was extensive hair loss, also evident over the tail base. The internal organs were normal in appearance. Histopathologically, the cutaneous swellings consisted of sheets of large foamy macrophages, macrophages, containing yellow/brown pigment and large numbers of acid-fast bacilli, that extended from the superficial dermis to the subcutis and fascia. Infiltrates of acid fast-laden macrophages were present in the liver, lung, spleen, and lymph nodes. Infection by a novel saprophytic Mycobacterium spp was considered most likely.     

Multivariate meta-analysis of pharmacokinetic studies of ampicillin trihydrate in cattle

OBJECTIVE: To investigate the feasibility of using multivariate cluster analysis to meta-analyze pharmacokinetic data obtained from studies of pharmacokinetics of ampicillin trihydrate in cattle and identify factors that could account for variability in pharmacokinetic parameters among studies. SAMPLE POPULATION: Data from original studies of the pharmacokinetics of ampicillin trihydrate in cattle in the database of the Food Animal Residue Avoidance Databank. PROCEDURE: Mean plasma or serum ampicillin concentration versus time data and potential factors that may have affected the pharmacokinetics of ampicillin trihydrate were obtained from each study. Noncompartmental pharmacokinetic analyses were performed, and values of pharmacokinetic parameters were clustered by use of multivariate cluster analysis. Practical importance of the clusters was evaluated by comparing the frequency of factors that may have affected the pharmacokinetics of ampicillin trihydrate among clusters. RESULTS: A single cluster with lower mean values for clearance and volume of distribution of ampicillin trihydrate administered PO, compared with other clusters, was identified. This cluster included studies that used preruminant calves in which feeding was withheld overnight and calves to which probenecid had been administered concurrently. CONCLUSIONS AND CLINICAL RELEVANCE: Meta-analysis was successful in detecting a potential subpopulation of cattle for which factors that explained differences in pharmacokinetic parameters could be identified. Accurate estimates of pharmacokinetic parameters are important for the calculation of dosages and extended withdrawal intervals after extralabel drug administration.