Effect of season and superstimulatory treatment on in vivo and in vitro embryo production in wood bison (Bison bison athabascae)

Two experiments were done using a two-by-two design to determine the effects of season and superstimulatory protocol on embryo production in wood bison. In Experiment 1 (in vivo-derived embryos), ovarian superstimulation was induced in female bison during the ovulatory and anovulatory seasons with either two or three doses of FSH given every-other-day (FSH × 2 vs. FSH × 3, respectively). Bison were given hCG to induce ovulation, inseminated 12 and 24 hr after hCG, and embryos were collected 8 days after hCG (n = 10 bison/group). In Experiment 2 (in vitro embryo production), ovarian superstimulation was induced in female bison during the ovulatory and anovulatory seasons with two doses of FSH, and in vivo maturation of the cumulus–oocyte complexes (COC) was induced with hCG at either 48 or 72 hr after the last dose of FSH. COC were collected 34 hr after hCG, and expanded COC were used for in vitro fertilization and culture. In Experiment 1, the number of follicles ≥9 mm, the proportion of follicles that ovulated, the number of CL, and the total number of ova/embryos collected did not differ between seasons or treatment groups, but the number of transferable embryos was greater (p < .05) in the ovulatory season. In Experiment 2, no differences were detected between seasons or treatment groups for any end point. The number of transferable embryos produced per bison was greatest (p < .05) using in vitro fertilization and was unaffected by season (1.5 ± 0.2 and 1.1 ± 0.3 during anovulatory and ovulatory seasons, respectively), in contrast to in vivo embryo production which was affected by season (0.1 ± 0.01 and 0.7 ± 0.2 during anovulatory and ovulatory seasons, respectively). Results demonstrate that transferable embryos can be produced throughout the year in wood bison by both in vivo and in vitro techniques, but the efficiency of embryo production of in vivo-derived embryos is significantly lower during the anovulatory season.     

A review of current timed-AI (TAI) programs for beef and dairy cattle

This is a review of the physiology and endocrinology of the estrous cycle and how ovarian physiology can be manipulated and controlled for timed artificial insemination (TAI) in beef and dairy cattle. Estrus detection is required for artificial insemination (AI), but it is done poorly in dairy cattle and it is difficult in beef cattle. Protocols that synchronize follicle growth, corpus luteum regression and ovulation, allowing for TAI, result in improved reproductive performance, because all animals are inseminated whether they show estrus or not. As result, TAI programs have become an integral part of reproductive management in many dairy herds and offer beef producers the opportunity to incorporate AI into their herds. Gonadotropin-releasing hormone-based protocols are commonly used in North America for estrus synchronization as part of a TAI program. Protocols that increase pregnancy rates in lactating dairy cows and suckling beef cows have been developed. Protocols that improve pregnancy rates in heifers, acyclic beef cows, and resynchronized lactating dairy cows are also discussed.     

Clinical findings in 10 horses diagnosed with monorchidism following exploratory laparotomy or standing laparoscopic surgery

Monorchidism describes the complete absence of one testis and is rare in horses. This study reports the clinical findings in 10 horses diagnosed as monorchids by standing laparoscopy or exploratory laparotomy. Hospital records for all horses undergoing cryptorchidectomy (2000–2016) in four centres were reviewed from which horses diagnosed with monorchidism were identified. Surgery was by either standing flank laparoscopy or an inguinal exploration and subsequent exploratory laparotomy under general anaesthesia. Ten horses were diagnosed as monorchids, five by laparoscopy (one bilateral laparoscopy) and five by laparotomy. Nine horses had a normally descended scrotal testicle, which was also removed at surgery. The right testicle was absent in three horses, and the left testicle was absent in seven horses. Anatomical findings were recorded in each case; the vaginal process was present in all horses, ductus deferens and epididymis were present in 80% of horses and the ligament of the tail of the epididymis and testicular vessels were present in 50% of horses. Laparoscopy allowed easy identification of spermatic structures enabling a prompt diagnosis of monorchidism. In conclusion, when monorchidism occurs, most other associated spermatic structures are likely to be present. A diagnosis of true monorchidism is reliant on hormonal testing and absence of testicular tissue on histopathology and so some of these horses may strictly be somewhere on the spectrum of testicular degeneration. This information is particularly useful in the surgical situation when it is not clear whether the testicle is present or not.     

Soil sensitised generation of singlet oxygen in the photodegradation of bioresmethrin

The ability of soil samples of pH 4·2, 5·5 and 7·2 to generate gaseous singlet oxygen was investigated using a separated-surface-sensitised reactor. It was found that the soil samples can act as sensitisers for the production of singlet oxygen in a similar fashion to the well known sensitisers chlorophyll and Rose Bengal. The reaction of singlet oxygen so produced with the pyrethroid insecticide, bioresmethrin, has been investigated.     

Optical coherence tomography as a novel tool for non-destructive measurement of the hull thickness of lupin seeds

Hull thickness is an important component of seed quality, which effects dehulling ability, feed or food nutritional aspects and cooking times. A breeding objective in Lupinus angustifolius crop improvement is to reduce hull thickness and a rapid screening method is needed to efficiently screen genotypes. Optical coherence tomography (OCT) imaging using infrared illumination at 980 nm was used to compare hull thickness of genotypes of four lupin species. OCT‐derived hull layer thickness correlated highly with actual hull thickness determined by environmental scanning electron microscopy (r = 0.90) and allowed reliable distinction between mutant (thin‐hulled) and parent genotypes of L. angustifolius. The imaging could clearly penetrate lupin seed to a depth of approximately 200 μm. The use of OCT to measure hull thickness has the advantage that it is rapid and non‐destructive and should be very useful in selecting thin hull lines of lupins and other species on a single seed basis in germplasm or progeny from crosses.     

Nitrogen,phosphorus, and potassium effects on pre‐ and post‐transplant growth of salvia and vinca seedlings

Pre‐ and post‐transplant growth of bedding plants is affected by seedling nutrition. However, there is little information available on how seedling nutrition affects the growth of ornamental bedding plants. In this study, we quantified the effects of nitrogen (N) (8 to 32 mM) and phosphorus (P) and potassium (K) concentration (0.25 to 1 mM) of the seedling fertilizer on pre‐ and post‐transplant growth and nutrient element content of salvia (Salvia splendens F. Sellow ex Roem. & Schult.) and vinca (Catharanthus roseus L.) seedlings. Shoot growth of salvia and vinca increased with increasing concentrations of N in the pre‐transplant fertilizer and these differences lasted until the end of the study at 15 days after transplanting. Pre‐transplant root dry mass of these species was not affected by the N concentration of the fertilizer, but root dry mass at 12 days after transplanting was positively correlated with the N concentration of the pre‐transplant fertilizer. Increasing N concentrations in the seedling fertilizer increased tissue N levels of salvia and decreased tissue K level of vinca at transplanting. Increasing P and K concentrations in the pre‐transplant fertilizer increased tissue P level of salvia and P and K levels of vinca, but had little effect on seedling growth. Leaf area and root dry mass at transplanting decreased slightly with increasing P and K concentration in the fertilizer. There were no lasting effects of pre‐transplant P and K concentration of the fertilizer. These results indicate that salvia and vinca seedlings can benefit from high concentrations of N (up to 32 mM) in the fertilizer, while only low concentrations of P and K (0.25 mM) are needed.     

Sequence homology and morphologic similarity of HTLV-III and visna virus, a pathogenic lentivirus

A study was conducted of the genetic relation between human T-cell lymphotropic retroviruses and visna virus. The human T-cell lymphotropic viruses include those associated with T-cell malignancies (HTLV-I and HTLV-II) as well as the etiologic agent of the acquired immune deficiency syndrome (HTLV-III). Visna virus, a slowly replicating and pathogenic but nononcogenic retrovirus of sheep, is a member of the subfamily Lentivirinae. Results obtained by molecular hybridization and heteroduplex analysis indicated that a greater extent of nucleotide sequence homology exists between HTLV-III and visna virus than between HTLV-III and any of the other viruses. The homology observed under conditions of low stringency spanned the entire genome, but was strongest in the gag/pol region. The morphogenesis and fine structure of HTLV-III and visna virus also demonstrated striking similarities. The data provide strong evidence for a close taxonomic and thus evolutionary relation between HTLV-III and the Lentivirinae subfamily.     

Kinematic analysis of the gait of 10 labrador retrievers during treadmill locomotion

The trotting gait of 10 sound, adult labrador retrievers was analysed using kinematic gait analysis on a purpose-built treadmill using video-based motion analysis software. The maximal angular displacement, minimal angular displacement, average angular displacement, and the maximal positive and negative angular velocities of the right elbow and right stifle were measured over five gait cycles at defined time points during each of five two-minute sessions. The dogs' trotting gait was not repeatable, either for individual dogs during the first session or between sessions, or between dogs at the same time points during a session.