Cooled Storage of Canine Semen: in vitro Effects of Different Concentrations of an Antibiotic Combination on Growth of Mollicutes

The aim of this study was to examine effects of an antibiotic combination at different concentrations on growth of mycoplasma and ureaplasma during cooled storage of canine semen (n = 20). Semen aliquots were diluted with Tris–citric acid–fructose–egg yolk extender containing either 1.0 g/l streptomycin and 0.6 g/l benzylpenicillin (control) or a combination of gentamycin, tylosin, lincomycin and spectinomycin (GTLS‐1: 0.25, 0.05, 0.15 and 0.3; GTLS‐2: 0.5, 0.1, 0.3 and 0.6; GTLS‐3: 1.0, 0.2, 0.6 and 1.2 g/l). Samples were assessed for motility and membrane integrity by computer‐assisted sperm analysis immediately after dilution and at 24, 48 and 72 h of cooled storage. Morphologically, normal spermatozoa were determined, and bacterial culture was performed at 24 and 72 h. Mycoplasma spp. were detected in 14 of 20 ejaculates (70%) with severe growth in 12 samples. A reduction but not total elimination of mycoplasma growth occurred in all GTLS extenders with the most pronounced reduction in group GTLS‐3 (control vs GTLS‐1 and GTLS‐2 p < 0.05, control vs GTLS‐3 p < 0.001). Ureaplasmas were detected in four ejaculates, and growth was reduced to the same extent in GTLS and control extender. Progressive motility in all groups, total motility in groups GTLS 1–3 and percentage of membrane‐intact spermatozoa in groups GTLS 2 and 3 decreased slightly (p < 0.05) over time. In conclusion, dilution of canine semen with GTLS extender has no major detrimental effects on spermatozoa during cooled storage. It reduced the growth but did not totally eliminate mycoplasmas and ureaplasmas from cooled‐stored dog semen.     

Quantitative characteristics of anesthetic induction with and recovery from isoflurane and sevoflurane in cats

Isoflurane (ISO) is the most commonly administered feline inhalant anesthetic in North America. A newer agent, sevoflurane (SEVO), may provide faster induction and recovery from anesthesia based on its physical characteristics. Accordingly, we compared some induction and recovery characteristics of ISO and SEVO in healthy cats. Six female DSH cats (17.9 ± 9.0 (mean ± SD) months, 3.7 ± 0.3 kg) received four randomly assigned treatments: ISO for 1 hour (IS), SEVO for 1 hour (SS), ISO for 5 hours (IL), and SEVO for 5 hours (SL). Anesthesia was induced in a chamber into which ISO or SEVO was delivered at 2.7 times the individual's MAC (determined previously) in 6 L minute^?1 O₂. Measured (Rascal II, Ohmeda) anesthetic concentration was reported after correction using a multiple gas, standard‐defined calibration curve. For induction, time (seconds) from introduction of inhalant to onset of incoordinated movement (IM), recumbency with movement (RM), recumbency without movement, loss of pedal reflex (PD), and intubation (ET) were recorded. Following intubation, anesthesia was maintained for the required time at 1.25 times the individual's MAC. For recovery, time (seconds) from discontinuation of the inhalant (with continuation of O₂) to first movement, extubation (EXT), start of incoordinated movement, head‐lift, sternal recumbency (SR), crawl, stand/walk with incoordination, and jump without incoordination were recorded. Esophageal normothermia was maintained. Data were analyzed by paired t‐test (induction) or One‐way Repeated Measures anova followed, when appropriate, by Tukey's test (recovery). p < 0.05 was regarded as significant. For induction, IM was not significantly different between ISO and SEVO (118 ± 28 seconds vs. 104 ± 28 seconds). All other induction times were significantly shorter with SEVO vs. ISO, e.g. RM (181 ± 31 seconds vs. 213 ± 31 seconds), PD (426 ± 68 seconds vs. 504 ± 70 seconds), and ET (434 ± 66 seconds vs. 515 ± 69 seconds). For recovery, there were no differences between ISO and SEVO for any stage of recovery, e.g. EXT (IS 588 ± 163 seconds vs. SS 425 ± 109 seconds), SR (IS 735 ± 215 seconds vs. SS 655 ± 337 seconds), and IL (710 ± 658 seconds vs. SL 807 ± 465 seconds). We concluded that quantitative recovery characteristics did not depend on whether cats are anesthetized with equipotent amounts of SEVO or ISO, but some induction end‐points were reached more quickly with SEVO.     

Mechanisms of Infertility Associated with Clinical and Subclinical Endometritis in High Producing Dairy Cattle

Clinical and subclinical endometritis are common causes of infertility and subfertility in high producing dairy cattle, delaying the onset of ovarian cyclic activity after parturition, extending luteal phases and reducing conception rates. Escherichia coli and Arcanobacterium pyogenes cause endometrial damage and inflammation. Components of microbes, such as lipopolysaccharide (LPS), are detected by Toll-like receptors on endometrial cells, leading to secretion of cytokines, chemokines and antimicrobial peptides. Long luteal phases associated with endometritis are probably caused by a switch in endometrial prostaglandin production from prostaglandin F_2a (PGF) to prostaglandin E₂. In addition, LPS impairs the function of the hypothalamus and pituitary, and directly perturbs ovarian granulosa cells steroidogenesis, providing mechanisms to explain the association between uterine disease and anovulatory anoestrus. Cows with uterine disease that ovulate have lower peripheral plasma progesterone concentrations that may further reduce the chance of conception associated with endometritis.     

Oxidized dietary fat,alkaline phosphatase concentrations and performance in racing greyhounds

Racing dogs are often fed raw meat. Raw meat may become oxidized because it contains no preservatives but few studies have examined the effect of feeding oxidized food to dogs. This study was originally designed to determine the effect of different concentrations of dietary fat on greyhound performance. After the experiment had been completed, however, it was discovered that the peroxide values (PV) of both diets were elevated indicating that fat oxidation had been present. This study was considered to have value, therefore, because it compared performance and blood parameters in eight trained Greyhounds fed either a high fat moderately oxidized (HFMO) diet (43%ME fat with PV of 44 mEq/kg) or a medium fat highly oxidized (MFHO) diet (31%ME fat with PV of 211 mEq/kg) for 8 weeks per diet in a randomized cross‐over design. Dogs were raced over 500 m twice weekly. Race times over the last 4 weeks of each diet period and blood parameters before racing during the last week of each diet period were compared. Dogs fed the MFHO food ran 0.04 m/s slower (p = 0.06) and serum alkaline phosphatase concentrations were higher (149 vs. 56 U/L; p < 0.0001) than in dogs fed the HFMO diet. Further evaluation is needed to determine whether lower dietary fat or increased oxidation was responsible for the altered performance but oxidation of the food should be considered as one possible explanation for an increase in serum alkaline phosphatase during a diet trial.