Evaluation of a liquid formulation of monensin to control bloat in pasture-fed milking cows

AIM: To evaluate the effectiveness of a liquid formulation of monensin in reducing bloat score in milking cows grazing pasture. METHODS: A Friesian x Jersey crossbred herd which had been genetically selected for high bloat susceptibility since 1973 was used in this study. Two trials were conducted, each involving two groups of 15 cows, randomly allocated to Treated or Control groups. Trial 1 involved twice-daily administration of a novel liquid formulation of monensin given to Treated cows at morning and afternoon milkings. Trial 2 involved once-daily administration of the same product to Treated cows at the morning milking only. Control cows received no preventative treatment. The total daily dose of monensin in each trial was 300 mg per cow, given in a total volume of 100 ml of liquid. Animals were scored for bloat twice-daily whilst grazing on white-clover/ryegrass or red-clover pastures. The scoring system used a scale of 0, 1, 1.5, 2, 2.5, or 3, representing scores of increasing bloat severity as assessed by palpation of abdominal pressure on the left and right sides of the cow. RESULTS: In Trial 1, severe bloat was recorded at 9 out of 23 scoring sessions. Twelve Control cows required therapeutic treatment for bloat on at least one day, compared to 3 cows in the Treated group (p=0.003). In Trial 2, severe bloat in 3 of 9 scoring sessions led to 8/15 Control animals requiring therapeutic treatment compared to 1/14 cows in the Treated group (p=0.02). CONCLUSIONS: Oral drenching with the liquid formulation of monensin tested was effective in reducing bloat score in milking cows grazed on pasture.     

Use of Cholesterol‐Loaded Cyclodextrin in Donkey Semen Cryopreservation Improves Sperm Viability but Results in Low Fertility in Mares

The use of cholesterol‐loaded cyclodextrin (CLC) on semen cryopreservation has been related with better sperm viability in several species; however, the effect on fertility is not known in donkey semen. Ejaculates (n = 25) from five donkeys were diluted in S‐MEDIUM with 0, 1, 2 or 3 mg of CLC/120 × 10⁶ spermatozoa. Semen was frozen, and thawed samples were evaluated by computer‐assisted sperm analyser system (CASA), supravital test, hyposmotic swelling test and fluorescent dyes to assess the integrity of sperm membranes. Mares (n = 60) were inseminated with frozen‐thawed semen treated with the doses of 0 or 1 mg CLC. Percentages of sperm with progressive motility and with functional plasma membrane were greater (p < 0.05) in the CLC‐treated groups than in the control. Percentages of intact plasma membrane and intact plasma membrane and acrosome detected by fluorescent dyes were also greater (p < 0.05) in CLC‐treated groups. Although no difference (p > 0.05) in conception rates was detected between groups (control, 3/30, 10%; CLC‐treated, 1/30, 3.3%), fertility was low for artificial insemination programs in mares. Therefore, we firstly demonstrated that frozen semen treated with CLC in S‐MEDIA extender before freezing improves the in vitro sperm viability, but semen treated or not with CLC in S‐MEDIUM extender results in a very low conception rate in mares inseminated with thawed donkey semen.     

Follicle Wave Growth in Cattle

Ovarian follicle growth in cattle culminates in the selection of a single dominant follicle which attains the ability for final maturation and ovulation once or twice during the luteal phase and at the end of the oestrous cycle, as well as during other reproductive states. This review will describe in detail the first follicle wave of the cycle leading to selection of the first wave dominant follicle, indicating the specific gonadotrophin dependencies of cohort and dominant follicles, and relating follicle fate to steroidogenesis. As a differential gonadotrophin response of growing antral follicles during the follies‐stimulating hormone (FSH) decline may determine which follicle becomes selected, first wave follicles are also characterized in relation to intrafollicular growth factors, which may modify the gonadotrophin response, such as inhibins and members of the insulin‐like growth factor (IGF) family. Subsequently, the follicular control of the transient FSH rise and decline so crucial to dominant follicle selection will be discussed. It is concluded that successful hormonal manipulation of follicle wave growth and dominant follicle selection will depend on our detailed understanding of the gonadotrophin requirements of differentiating wave follicles.     

Method evaluation and risk assessment: A framework for evaluating management strategies for data-limited fisheries

Fisheries managers are in need of quantitative tools to inform decisions regarding selection of robust management practices, prioritising research gaps and stocks to focus on, particularly where there are limited resources or data. To support these decisions, the use of Management Strategy Evaluation (MSE), that is, closed loop simulation-testing of management procedures, is widely regarded as best practice. However, applying MSE is time- and computationally intensive, and requires highly skilled expertise and processes for stakeholder input and peer review. For data- and capacity-limited fisheries, MSE may be particularly challenging to implement. Yet, these are the contexts where it is most critical to test assumptions, evaluate the implications of all sources of uncertainty and identify the most informative data sources. To facilitate wider use of MSE, the Method Evaluation and Risk Assessment (MERA) framework was developed as an accessible online interface, with quick processing time, focused on generic data-limited management procedures, but allowing progression to tailored and more data-rich methods. The framework links a quantitative questionnaire and data input standard to a flexible operating model with optional customisation via command line access to the back-end open-source R libraries. Here, we illustrate a case study application of MERA for the bocinegro (Pagrus pagrus, Sparidae) fishery in the Gulf of Cadiz, where in conjunction with fishery stakeholders, a custom management procedure was developed and tested and key research gaps and data collection priorities were identified. We discuss implications for wider use of MSE in various contexts, including eco-certification and fishery improvement projects.