Influence of Superovulatory Protocols on In Vitro Production of Nellore (Bos indicus) Embryos

There are indications in the literature that delaying the period between ovarian superestimulation and ovum pick up (OPU) would induce follicles to a condition of initial atresia, which could be beneficial to oocyte development. In this work, we compared three protocols for OPU and in vitro production (IVP) of embryos, in Nellore cattle. Nellore cows (n = 18) were randomly allocated in three groups: Group 1 (OPU), Group 2 [Follicle stimulating hormone (FSH) and OPU] and Group 3 (FSH deprivation and OPU). Three OPUs were performed, and the animals were switched to a different group each time (crossover), in such a way that at the end of the experiment all cows received the 3 protocols. At random stage of the oestrous cycle (D‐2), all follicles ≥ 6 mm were aspirated to induce a new follicular wave 2 days afterwards (D0). In Group 1, OPU was performed on D2 and oocytes were processed to IVP. In Group 2, starting on D0, cows were superstimulated (FSH, Folltropin^®, 30 mg administered daily, i.m., during three consecutive days, total dose = 180 mg), and 6 h after the last FSH dose, they received exogenous luteinizing hormone (LH) (12.5 mg, i.m., Lutropin^®, D3). The OPU was performed 6 h after LH administration, i.e. 12 h after the last dose of FSH. Animals in Group 3 received the same treatment as those in Group 2, except that LH was administered 42 h after the last dose of FSH, and OPU occurred 6 h later. Therefore, in this group, follicles were deprived of FSH at 48 h. Both cleavage and blastocyst rates were similar (p > 0.05, anova ) among oocytes from Groups 1, 2 and 3, respectively: 77.4% (144/185) and 42.70% (79/185); 75.54% (105/139) and 31.65% (44/139); 63.52% (101/159) and 33.33% (53/159). However, hatched blastocyst rate was higher (p < 0.01) in Group 1 (30.27%, 56/185) when compared with Group 2 (11.51%, 16/139) or 3 (15.72%, 25/159). It is concluded that, contrary to previous work on European breeds (Bos taurus), ovarian superstimulation associated with deprivation of FSH and OPU (Group 3) did not increase IVP of Nellore embryos (Bos indicus). On the contrary, the highest hatched blastocyst rates were observed in oocytes from non‐superstimulated cows.     

Re: Use of polymerase chain reaction for the differentiation of Group A bovine rotavirus G6, G8, and G10 genotypes in the North Island of New Zealand

Extract

In the paper by L Howe, H Sugiarto and RA Squires published in the New Zealand Veterinary Journal 56, 218–221, 2008, entitled, “Use of polymerase chain reaction for the differentiation of Group A bovine rotavirus G6, G8, and G10 genotypes in the North Island of New Zealand”, the authors concluded that “Currently, the rotavirus vaccine available in New Zealand contains only the G6 strain, and may not provide optimal protection for animals infected with G10 rotavirus. … This information may be of assistance in the development and optimisation of vaccines, and enhancement of effective control strategies.”     

Survival of Escherichia coli,Enterococci and Campylobacter jejuni in Canada Goose Faeces on Pasture

Freshly excreted Canada goose faeces pose a public health risk as they contain pathogenic microorganisms. Accordingly, a study was carried out on the growth and survival of resident indicator bacteria (enterococci and Escherichia coli) and inoculated Campylobacter jejuni in freshly excreted faeces over summer and winter. Canada goose faeces were collected, mixed thoroughly and inoculated with 10⁸ g^?1C. jejuni. The faeces were mixed again before making the Canada goose dropping. The simulated goose droppings (N = 70) were placed on pasture, and the concentrations of E. coli, enterococci and the pathogen, C. jejuni, were monitored. In summer only, the molecular marker of E. coli LacZ and the avian‐associated bacteria E2 was also monitored. Results of the survival study indicated that significant growth of enterococci and E. coli occurred in summer, before concentrations decreased to less than 15% of the original concentration (day 77) for enterococci and 0.01% for E. coli. LacZ followed a similar pattern to E. coli, while the E2 marker dropped to below 0.1% of the original concentration within 4 days. In winter, enterococci grew slightly, while no growth of E. coli occurred. In both summer and winter, C. jejuni was rapidly inactivated. This research highlights the ability of bacterial indicators to replicate and survive in the environment when harboured by avian faeces, and the limited risk aged Canada goose faeces pose as an environmental source of Campylobacter spp.     

MEASUREMENT OF NORMAL MIDDLE EAR CAVITY VOLUME IN MESATICEPHALIC DOGS

Water-filling and serial computed tomographic (CT) imaging techniques were used to measure normal middle ear cavity volume (MECV) in 18 dogs (10 live dogs, eight cadavers; 36 ears in total). The specific aims of this study were to (1) compare MECV measurements by water-filling and CT techniques and (2) define a model of MECV vs. body weight (BW) from CT values. There was a significant difference between the two techniques (P = 0.02). The volume obtained by water filling was consistently greater than that obtained by computed tomography. MECV (expressed in ml) increased with BW (expressed in kg) according to the following formula: MECV = -0.612 + 0.757 (In BW) (P<0.01, R2 = 0.74).