The application of biotechnology to the control of foot-and-mouth disease virus.

Biotechnology, which less than 10 years ago was heralded as an alternative to epidemiology in providing the answers to the control of foot-and-mouth disease (FMD), has not fulfilled its initial promise. Instead it is now complementing epidemiology by providing extremely sensitive and specific tools for identifying and characterizing strains of FMD virus in diagnostic material. Considerable advances in our understanding of the evolution of the virus in different field situations has been made possible by the development and application of polymerase chain reaction and nucleotide sequencing techniques. The individual genes of FMD virus can now be cloned into a number of vectors and separately expressed and studied in isolation from the other viral proteins. Biotechnology has not provided a safe and effective vaccine to replace the conventional tissue culture derived vaccine that would have made FMD a disease of the past. FMD remains the most economically significant animal disease having a major influence on the international trade of animals and their products. The world distribution of FMD has remained almost unchanged over the last 20 years and a balance has been maintained between improved surveillance and diagnostic technology and the ever increasing legal and illegal international movement of animals and reduction in veterinary resources. Research continues on peptide, recombinant and vector expressed virus protein vaccines which could at any time yield a breakthrough, not only for FMD control but, using similar technology, for control of other viral diseases, human and animal. Until this occurs, control and eradication of FMD still relies on classical epidemiological techniques, making use of new biotechnological methods.     

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.     

Influence of signalment on developing cranial cruciate rupture in dogs in the UK

Objectives : To investigate risk factors associated with cranial cruciate ligament rupture in dogs. Methods : Retrospective case‐control study: medical records of a first‐opinion veterinary practice were searched for dogs diagnosed with cranial cruciate ligament rupture (1995 to 2007). For each case, six unaffected dogs were randomly selected from all dogs presenting that day for comparison. Multi‐variable binary logistic regression was performed to assess the association of variables on likelihood of cruciate rupture. Results : Frequency of cranial cruciate ligament rupture was 1·19% [95% confidence interval (CI) 1·02 to 1.36%]. West Highland white terriers (n=17), Yorkshire terriers (n=14) and Rottweilers (n=11) were at significantly increased risk of cranial cruciate ligament rupture (P≤0·002). Rottweilers were at five times greater risk compared with other pure breeds (OR 5·12, 95% CI 2·281 to 11·494, P<0·001), obesity quadrupled the risk of cranial cruciate ligament rupture (OR 3·756, 95% CI 1·659 to 8·502, P=0·001) and females were twice as likely to suffer cranial cruciate ligament failure compared to males (OR 2·054, 95% CI 1·467 to 2·877, P<0·001). Dogs less than two years old were statistically less likely to sustain cranial cruciate ligament rupture than dogs older than eight years (OR 0·246, 95% CI 0·127 to 0·477, P<0·001). There was no significant difference in median weights (in kilograms) of neutered dogs, compared to their entire counterparts in either the case group (P=0·994) or in the control group (P=0·630). There was also no significant difference in body condition (‐underweight/normal weight/overweight/obese) of neutered versus entire dogs among the cases (P=0·243), or the controls (P=0·211). Clinical Significance : Cranial cruciate ligament rupture is more likely in Rottweilers and in female dogs, older dogs and obese dogs. Following multi‐variable analysis, it was established that neutering was not associated with increased risk of cranial cruciate ligament rupture.     

Genetic analysis of Anisakis typica (Nematoda: Anisakidae) from cetaceans of the northeast coast of Brazil: new data on its definitive hosts

Prevalence and seasonal variations of helminth infections and their association with morbidity parameters were studied in traditionally reared Cambodian cattle. Four villages in two provinces of West Cambodia were visited on monthly intervals over a period of 11 months, during which 2391 animals were faecal and blood sampled for parasitological and haematological examinations. The body condition score (BCS), faecal consistency (diarrhoea score, DS), colour of the ocular conjunctivae (FAMACHA(?)) and packed cell volume were determined for each individual animal. The overall proportion of samples that was positive for gastrointestinal nematodes was 52%, 44% and 37% in calves (from 1 to 6 months), young animals (6 to 24 months) and adults (over 24 months), respectively, while geometric mean faecal egg counts (FECs) for each of these age categories were 125, 66 and 15 eggs per gram, respectively. Six genera of strongyles were found in the faecal cultures, i.e. in descending order of occurrence, Cooperia, Oesophagostomum, Haemonchus, Trichostrongylus, Mecistocirrus and Bunostomum. The prevalences of Fasciola and Paramphistomum, estimated by coprological examination, varied between 5-20% and 45-95%, respectively. Logistic mixed models were used to investigate associations of morbidity markers with the presence of parasite infection. A low BCS was associated with gastrointestinal nematode and liver fluke infections, and soft faecal consistency with Paramphistomum infections. However, other factors such as nutritional deficiencies and intercurrent diseases are likely to enhance the effects of parasites and should therefore be considered when using these morbidity parameters as indicators of parasitism.     

Mitochondrial dysfunction influences apoptosis and autophagy in porcine parthenotes developing in vitro

Mitochondria are important regulators of both apoptosis and autophagy. One of the triggers for mitochondrial-mediated apoptosis is the production of reactive oxygen species (ROS), which include hydrogen peroxide, superoxide, hydroxyl radical, nitric oxide and peroxynitrite. Recently, several studies have indicated that ROS may also be involved in the induction of autophagy. In the present study, we used H(2)O(2) to induce mitochondrial stress, examined apoptotic- and autophagic-related gene expression and observed LC3 protein (autophagosome presence marker) expression in porcine parthenotes developing in vitro. In porcine four-cell parthenotes cultured for 5 days in NCSU37 medium containing 0.4% BSA, the developmental rate and mitochondrial distribution did not differ from that of the group supplemented with 100 μM H(2)O(2) but was significantly decreased in the group supplemented with 500 μM H(2)O(2) (P<0.05). Transmission electron microscopy (TEM) indicated that whereas normal shaped mitochondria were observed in blastocysts from the control group, abnormal mitochondria (mitophagy) and autophagic vacuoles were observed in blastocysts from the group that received 500 μM H(2)O(2). Furthermore, addition of H(2)O(2) (100 μM and 500 μM) decreased cell numbers (P<0.05) and increased both apoptosis (P<0.05) and LC3 protein expression in the blastocysts. Real-time RT-PCR showed that H(2)O(2) significantly decreased mRNA expression of anti-apoptotic gene Bcl-xL but increased pro-apoptotic genes, Caspase 3 (Casp3) and Bak, and autophagy-related genes, microtubule-associated protein 1 light chain 3 (Map1lc3b) and lysosomal-associated membrane protein 2 (Lamp2). However, the addition of H(2)O(2) had no effect on mRNA expression levels in nuclear DNA-encoded mitochondrial-related genes, cytochrome oxidase (Cox) 5a, Cox5b and Cox6b1, in blastocysts. These results suggest that H(2)O(2) leads to mitochondrial dysfunction that results in apoptosis and autophagy, which is possibly related to porcine early embryo development.     

Dose and release pattern of anabolic implants affects growth of finishing beef steers across days on feed

Four experiments evaluated the effect of implant dose and release pattern on performance and carcass traits of crossbred beef steers. In Exp. 1, steers (4 to 7 pens/treatment; initial BW = 315 kg) were fed an average of 174 d. Treatments were 1) no implant (NI); 2) Revalor-S [120 mg of trenbolone acetate (TBA) and 24 mg of estradiol 17β (E(2)); REV-S]; 3) Revalor-IS followed by REV-S (cumulatively 200 mg of TBA and 40 mg of E(2); reimplanted at 68 to 74 d; REV-IS/S); and 4) Revalor-XS (200 mg of TBA and 40 mg of E(2); REV-X). Carcass-adjusted final BW was greater (P < 0.05) for REV-X and REV-IS/S than for REV-S (610, 609, and 598 kg, respectively). Daily DMI did not differ (P > 0.10) among the 3 implants, but carcass-adjusted G:F was greater (P < 0.05) for REV-X and REV-IS/S than for REV-S (0.197 and 0.195 vs. 0.188). Both HCW and LM area were greater (P < 0.05) for REV-X and REV-IS/S than for REV-S. Marbling scores were greatest (P < 0.05) for REV-S and least (P < 0.05) for REV-IS/S; REV-X was intermediate to NI and REV-IS/S. In Exp. 2, steers (10 pens/treatment; initial BW = 391 kg) were fed 131 d, with treatments of REV-S, REV-IS/S (reimplanted at 44 to 47 d), and REV-X. Carcass-adjusted final BW (598 kg), ADG (1.6 kg), DMI (9.4 kg), G:F (0.17), and HCW did not differ (P > 0.10) among treatments. The percentage of Choice was less (P < 0.05) and percentage of Select greater (P < 0.05) for REV-IS/S than for REV-S and REV-X. In Exp. 3, steers (10 pens/treatment; initial BW = 277 kg) were fed 197 d and received either REV-IS/S (reimplanted at 90 to 103 d) or REV-X. Carcass-adjusted final BW (625 vs. 633 kg) and ADG (1.81 vs. 1.76 kg) were greater (P < 0.05) for REV-X-implanted steers. Daily DMI did not differ, but G:F tended (P < 0.10) to be increased and HCW was greater (P < 0.05) for REV-X than for REV-IS/S. In Exp. 4, steers (8 pens/treatment; initial BW = 238 kg) were fed 243 d and received either REV-IS/S (reimplanted at 68 to 71 d) or REV-X. Carcass-adjusted final BW (612 kg), ADG (1.54 kg), DMI (7.55), and G:F (0.21) did not differ (P > 0.10) for REV-IS/S and REV-X-implanted steers. Carcass traits did not differ among implants, but the percentage of Choice carcasses was greater (P < 0.05) and percentage of Select was less (P < 0.05) for REV-X than for REV-IS/S. These data indicate that when TBA/E(2) dose is equal, the altered release rate of REV-X can improve performance and quality grade, but these effects depend on duration of the feeding period and timing of initial and terminal implants.     

The influence of gamete co-incubation length on the in vitro fertility and sex ratio of bovine bulls with different penetration speed

The objectives of this work were to evaluate whether the sperm penetration speed is correlated to the in vitro fertility and whether adapting the gamete co-incubation length to the kinetics of the bull improves in vitro fertility and affects the sex ratio. In vitro matured oocytes were co-incubated with spermatozoa from four different bulls (A-D). At various post-insemination (p.i.) times (4, 8, 12, 16 and 20 h), samples of oocytes were fixed and stained with DAPI for nuclei examination, while the remaining ones were transferred into culture to evaluate embryo development. The blastocysts produced were sexed by PCR. Two bulls (A and B) had faster kinetics than the others (C and D), as shown by the higher penetration rates recorded at 4 h p.i. (43%, 30%, 11% and 6%, respectively for bulls A, B, C and D; p<0.01). The differences in the kinetics among bulls did not reflect their in vitro fertility. The incidence of polyspermy was higher for faster penetrating bulls (36%, 24%, 16% and 4%, respectively for bulls A, B, C and D; p<0.01) and at longer co-incubation times (0%, 16%, 19%, 30% and 34%, respectively at 4, 8, 12, 16 and 20 h p.i.; p<0.01). The fertilizing ability of individual bulls may be improved by adapting the co-incubation length to their penetration speed. A sperm-oocyte co-incubation length of 8 h ensured the greatest blastocyst yields for the two faster penetrating bulls. On the contrary, 16 h co-incubation was required to increase (p<0.01) cleavage rate of the two slower bulls. Bulls with a faster kinetics did not alter the embryo sex ratio towards males. The female/male (F/M) ratios recorded were 2.1, 1.4, 1.2, 1.3 and 1.6, respectively at 4, 8, 12, 16 and 20 h p.i.