Effect of Temporary Meiotic Attenuation of Oocytes with Butyrolactone I and Roscovitine in Resistance to Bovine Embryos on Vitrification

This study aimed to produce in vitro bovine embryos by the addition of two drugs, which is responsible for oocyte meiosis inhibition: roscovitine (ROS) and butyrolactone I (BL‐I). Oocytes were recovered from slaughtered cows and matured in a commercial medium and maintained in a 5% CO₂ atmosphere. Oocytes were maintained for 6 h in an in vitro maturation (IVM) medium containing ROS (12.5 μm ), BL‐I (50 μm ) and association of drugs (ROS 6.25 μm and BL‐I 25 μm ). Oocytes were cultured for 18 h in an agent‐free medium for the resumption of meiosis. After 24 h of maturation, oocytes were inseminated in the commercial in vitro fertilization (IVF) medium. Presumptive zygotes were cultured in SOFaa medium in a 5% CO₂ atmosphere. On day 3, rate of cleavage was evaluated and on days 6 and 7, rate of blastocyst formation. BL‐I and its association with the ROS increased the rates of cleavage and blastocyst formation (p < 0.05). The ROS alone was inefficient, impairing embryonic development, with low rates of blastocyst formation when compared to the control group and other treatments (p < 0.05). The embryos from BL‐I and ROS+BL‐I groups presented higher number of cells and lower rates of cellular apoptosis compared to other groups, either for the fresh or for post‐thawing embryos. Embryos from ROS+BL‐I group showed to be more resistant to the vitrification process, presenting a higher rate of embryonic re‐expansion (p < 0.05). In conclusion, block of meiosis using BL‐I or its association with ROS increased the rate of blastocyst formation, and the association of ROS+BL‐I resulted in a better resistance to the embryo cryopreservation process.     

农场动物痛苦的科学评价

动物所经历的情感状态中,疼痛无疑是非常特殊的.故意引起疼痛被认为是最令人厌恶的1种社会行为.同样地,在动物身上出现的疼痛会引起公众对动物福利的关注.     

Herd and within-herd BoHV-1 prevalence among Irish beef herds submitting bulls for entry to a performance testing station

Infectious bovine rhinotracheitis (IBR), caused by bovine herpes virus 1 (BoHV-1), may result in various clinical consequences, including severe respiratory disease and conjunctivitis, venereal disease and reduced reproductive performance and abortion. This paper presents the serosurveillance findings from an intake of bulls into a performance testing station in Ireland during November 2007. The herd and within-herd BoHV-1 prevalence in 53 Irish beef herds and the risk factors for infection in these herds were determined, among bulls entering a beef performance testing station in Ireland. BoHV-1 status was determined for 41 herds, of which 30 (73.2%) herds were infected and the mean within-herd BoHV-1 prevalence was 28 (± 20)%. Multivariate exact logistic modelling revealed increasing numbers of contiguous herds and decreasing percentage of males within the herd as significant risk factors associated with infected herds. These findings highlight the high prevalence of BoHV-1 infection in those Irish beef herds that submitted bulls to this performance testing station, and raise concerns regarding IBR control nationally.     

Endometrial Explant Culture to Study the Response of Equine Endometrium to Insemination

Mating‐induced endometritis (MIE) is ubiquitous in the horse after natural mating and artificial insemination with frozen/thawed semen causing the most aggressive response. The majority of mares eliminate MIE 24–48 h after insemination. An endometrial explant culture was tested as a potential in vitro exemplar for sperm‐induced MIE. Endometrial prostaglandin F_2α (PGF_2α) secretion and expression of interleukin‐8 (IL‐8) were used as markers of inflammation. Endometrial explants were cultured from uteri collected from follicular phase mares. Explants were challenged with 1 or 10 × 10⁶ sperm/ml frozen/thawed semen, chilled semen, washed sperm or seminal plasma. Medium was collected 24 and 72 h after challenge and assayed for PGF_2α by radioimmunoassay. Treatment of endometrial explants with frozen/thawed, chilled semen or washed sperm did not change the secretion of PGF_2α compared with untreated controls. However, 24 h after challenge cultured explants expressed IL‐8. The in vitro endometrial explant system did not represent the in vivo response to semen when PGF_2α was used as a marker of inflammation, yet the use of gene expression as an inflammatory marker warrants further investigation.     

The relationship of training milestones with racing success in a population of Standardbred horses in New Zealand

AIM: To gather information on the repeatability of a faecal nematode egg count (FEC) reduction (FECR) test (FECRT), evaluating both different methods of calculating efficacy and variations within a method, in order to supply veterinarians and other advisors with sufficient information to apply some level of confidence around a diagnosis of anthelmintic resistance based on FECRT results.

METHODS: Two commercial sheep farms were selected on the basis of having previously recorded FECR <95% after treatment with ivermectin (Farm 1) or albendazole (Farm 2). On each farm at least 250 lambs, managed as a single mob, were individually ear-tagged and sampled for FEC. The resulting counts were used, 3—4 days later, to sort the lambs into 24 groups of 10. First, the animals were split into three groups of 80, having high, medium or low FEC. Second, within each of these groups the 80 animals were further divided into four replicate mobs of 20 (each with the same mean count). Third, each of these replicates was further split into two groups of 10: those that would be drenched and those that would remain as untreated controls. All animals were again faecal-sampled and those in the drenched groups were dosed, using a syringe, to their individual liveweight, with ivermectin (Farm 1) or albendazole (Farm 2). Ten days after treatment all animals were individually faecal- sampled again. FEC and larval cultures were undertaken for all 24 groups from both pre- and post-treatment samples. Ef- ficacy (FECR) of the undifferentiated FECRT was calculated using three different equations, and efficacy by genus was also calculated.

RESULTS: Calculated efficacies differed between equations, and the equation which did not utilise an untreated control yielded significantly lower efficacy estimates on both farms. Faecal cultures varied considerably in the proportions of parasite genera recovered. In general, this did not differ between FEC groups, except on Farm 1 where Haemonchus spp were more common and Cooperia spp less common in high-FEC samples. Estimated efficacies against individual genera varied considerably or very little, depending on the level of resistance. On both farms, differing proportions of tests against some genera passed or failed FECRTs based on a threshold pass mark of ≥95% FECR.

CONCLUSION: There was considerable variability in the outcomes of FECRTs and in larval culture results. Caution is warranted in interpreting the results of FECRTs when efficacy values fall into the 90—95% range. Further, the possibility of a test returning a false-negative result is raised, indicating that even an efficacy estimated ≥95% may not guarantee the absence of resistant parasites.