Advantages and guidelines for using alpha-2 agonists as anesthetic adjuvants.

Xylazine and medetomidine produce reliable sedation, muscle relaxation, and analgesia in dogs and cats. In addition, alpha-2 agonists have proved very effective as sedative-analgesic adjuncts when coadministered with benzodiazepine or opioid agonists. Alpha-2 agonists should not be classified as monoanesthetics. They are excellent anesthetic adjuncts when combined with dissociatives and opioids. Because of the acute alterations in cardiopulmonary function commonly induced by alpha-2 agonists, it is suggested that their use be restricted to the young healthy patient undergoing routine surgical or diagnostic procedure. The development of more specific and selective alpha-2 agonists will continue to enhance the safety and reliability of this novel class of compounds. The unique spectrum of anesthetic properties induced by alpha-2 agonists has assured them of an increasingly prominent role in the development of new and sophisticated ways of achieving anesthesia.     

Thermographic Eye Temperature as an Index to Body Temperature in Ponies

Infrared thermography (IRT) is a passive, remote, and noninvasive method of measuring surface temperatures. Select surface locations, such as the eye, could indicate body temperature. To investigate whether thermographic eye temperatures were associated with body temperatures and could be used to detect febrile ponies, we measured IRT eye temperatures, rectal temperatures, and implanted thermal microchip temperatures from 24 male ponies daily for 3 consecutive days. Information regarding distance of the pony from the IRT device, presence of direct sunlight during the measurement period, and ambient temperature were also collected. A multivariate linear regression analysis indicated that 60.41% of the variance in IRT was accounted for by rectal temperature, sunlight, and distance between the camera and the pony, with rectal temperature being the major contributor to variance (46.23%). Using a rectal temperature of >38.6°C (101.5°F) as the indicator of febrile status, sensitivity and specificity of the IRT device used to detect the febrile ponies were found to be 74.6% and 92.3%, respectively, when using the maximum IRT eye temperature per pony per day. In conclusion, IRT eye temperature could be a preliminary screening tool to determine whether a more time-consuming, labor-intensive, and invasive method (e.g., rectal temperature) is warranted for fever validation.     

Adiposity and adiponectin in dogs: investigation of causes of discrepant results between two studies

Although one study showed lower adiponectin concentrations in obese dogs, other recent studies indicate that adiponectin might not be decreased in obese dogs, raising the possibility that the physiology of adiponectin is different in dogs than in humans. The aim of this study was to investigate possible causes of the discrepancy between the two largest studies to date that assessed the association between adiposity and adiponectin concentration in dogs, including the validity of the assay, laboratory error, and the effects of breed, sex, and neuter status on the relationship between adiposity and adiponectin concentrations. Adiponectin concentrations measured with a previously validated adiponectin ELISA were compared with those estimated by Western blotting analysis of reduced and denatured plasma samples. The possibility of laboratory error and the effect of EDTA anticoagulant and aprotinin were tested. Adiponectin concentration was measured by ELISA in 20 lean dogs (10 male and 10 female, 5 neutered in each sex). There was close correlation between adiponectin concentrations measured by ELISA and those estimated by Western blotting analysis (r = 0.90; P < 0.001). There was no substantial effect of EDTA, aprotinin, or laboratory error on the results. There was confounding by neuter status of the relationship between adiposity and adiponectin concentrations, but adiponectin concentrations were not significantly lower in male than in female lean dogs (females, 36 mg/L; males, 26 mg/L; P > 0.20) and were not significantly lower in intact than in neutered lean male dogs (intact, 28 mg/L; neutered, 23 mg/L; P = 0.49). We conclude that the adiponectin ELISA previously validated for use in dogs appears to be suitable for determination of canine adiponectin concentrations and that testosterone does not appear to have a strong effect on plasma adiponectin concentrations in dogs. Obesity might decrease adiponectin concentrations in intact but not in neutered dogs.     

Use of visible and near-infrared spectroscopy to predict pork longissimus lean color stability

This study evaluated the use of visible and near-infrared (VISNIR) spectroscopy to predict lean color stability in pork loin chops. Spectra were collected immediately after and approximately 1 h after rib removal on 1,208 loins. Loins were aged for 14 d before a 2.54-cm chop was placed in simulated retail display. Spectra were collected on aged loins immediately after removal from the vacuum package and on chops 10 min after cutting. Instrumental color measurements [L*, a*, b*, hue angle, chroma, and E (overall color change)] were determined on d 0, 1, 7, 11, and 14 of display. Principal components analysis of display d 0 and 14 values of these traits identified a factor (first principal component; PC1) explaining 67% of the variance that was related to color change. Partial least squares regression was used to develop 3 models to predict PC1 values by using VISNIR spectra collected in the plant, on aged loins, and on chops. Loins with predicted PC1 values less than 0 were classified as having a stable color, whereas values greater than 0 were classified as having a labile lean color. Loins classified as stable by the in-plant model had smaller (P < 0.05) L* values than those classified as labile. Hue angle and ΔE values were less (P < 0.05) and a* and chroma values were greater (P < 0.05) after d 7 of display in loins predicted to have a stable color than in loins predicted to have a labile lean color. Similarly, chops from loins classified as stable using the aged loin model had smaller (P < 0.05) L* values than those from loins classified as labile. Furthermore, loins predicted to be stable had smaller (P < 0.05) hue angle and ΔE values and greater (P < 0.05) a* and chroma values after d 7 of display than did loins predicted to be labile. Results for the chop model were similar to those from the 2 loin models. Chops predicted to have a stable lean color had smaller (P < 0.05) L* values than did those predicted to have a labile lean color. Chops classified as stable had smaller (P < 0.05) hue angle and ΔE values and greater (P < 0.05) a* and chroma values after d 7 of display compared with chops classified as labile. All 3 models effectively segregated chops based on color stability, particularly with regard to redness. Regardless of the model being used, d 14 display values for a*, hue angle, and ΔE in loins classified as stable were similar to the d 7 values of loins classified as labile. Thus, these results suggest that VISNIR spectroscopy would be an effective technology for sorting pork loins with regard to lean color stability.     

Physiology and endocrinology symposium: evidence that oviduct secretions influence sperm function: a retrospective view for livestock

The mammalian oviduct has long been recognized as an organ essential for successful reproduction. Bovine, ovine, porcine, and equine animal models have offered clear advantages for oviduct study related to gamete physiology, fertilization, and early embryonic development. Livestock species are amenable to surgical alteration of the reproductive tract, estrous cycle manipulation, gamete cryopreservation, and AI, as well as in vitro fertilization and embryo production. Although most reproductive technology developed for livestock was intended to benefit production animal agriculture, these techniques are a treasure trove of tools for researchers to better understand how the oviduct influences gamete function. Oviduct secretions obtained from in vitro tissue cultures or via indwelling oviduct catheters have been used for analyses to define the protein, lipid, carbohydrate, enzyme, and electrolyte compositions of the secretions during the estrous cycle or in response to hormone treatment. Oviduct secretions or components purified from them have also been used in in vitro assays to assess their ability to bind to sperm, influence sperm viability, motility, sperm capacitation, the acrosome reaction, sperm-egg binding, and egg penetration, as well as subsequent embryonic development. Compelling data have emerged which show that the composition of secretions differs during the estrous cycle and that their composition differs whether they originate from the ampullary or isthmic regions of the oviduct. These differences in composition are functionally relevant and associated with different responses by sperm. Evidence indicatess that oviduct-specific glycoproteins, glycosaminoglycans, carbohydrates, norepinepherine, catecholamines, heat-shock protein, and osteopontin are components of the oviductal milieu that have the capacity to modulate sperm function. Future research on the livestock oviduct will likely define the role that oviduct secretions have in modulating sperm function and how these modifications ultimately affect fertilization and embryo development.     

Disseminated hemangiosarcoma in a cow

An antemortem diagnosis of disseminated hemangiosarcoma with extensive hepatic and splenic involvement was made in a 9-year-old cow evaluated for lethargy, weight loss, regenerative anemia, thrombocytopenia, and elevated liver enzymes. This is the first report of hemangiosarcoma in a cow with a suspected primary location of the liver and/or spleen.