Impact of temperature, feeding preference and vaccination on Schmallenberg virus transmission in Scotland

First identified in 2011, Schmallenberg virus (SBV) is principally transmitted by Culicoides midges and affects ruminants. Clinical presentation is typified by foetal abnormalities, but despite very high infection rates, relatively few animals present with clinical signs. In this paper we further develop a previously published stochastic mathematical model of SBV spread to investigate the optimal deployment of a vaccine for SBV in Scotland, a country that has experienced only sporadic and isolated cases of SBV.We consider the use of the vaccine under different temperatures and explore the effects of a vector preference for feeding on cattle. We demonstrate that vaccine impact is optimised by targeting it at the high risk areas in the south of Scotland, or vaccinating only cattle. At higher than average temperatures, and hence increased transmission potential, the relative impact of vaccination is considerably enhanced. Vaccine impact is also enhanced if vectors feed preferentially on cattle. These findings are of considerable importance when planning control strategies for SBV and also have important implications for management of other arboviruses such as Bluetongue virus. Environmental determinants and feeding preferences should be researched further to inform development of effective control strategies

Multiobjective Output Feedback Control of a Class of Stochastic Hybrid Systems with State-Dependent Noise

This paper deals with dynamic output feedback control of continuous-time active fault tolerant control systems with Markovian parameters (AFTCSMP) and state-dependent noise. The main contribution is to formulate conditions for multiperformance design, related to this class of stochastic hybrid systems, that take into account the problematic resulting from the fact that the controller only depends on the fault detection and isolation (FDI) process. The specifications and objectives under consideration include stochastic stability, ℋ2 and ℋ∞ (or more generally, stochastic integral quadratic constraints) performances. Results are formulated as matrix inequalities. The theoretical results are illustrated using a classical example from literature

1974-2014 : quelle place pour l’embryon à l’ère de la génomique chez les ruminants ?

National audienceOver the last ten years, international trade in embryos has doubled. Embryo transfer remains one of the safest ways to exchange genetic material. Optimizing reproductive technologies has become a strategic priority in the era of genomics: the increase of genetic gain may be accelerated through a combined use of in vivo embryo recovery, superovulation, embryo transfer (ET) together with oocyte puncture followed by in vitro embryo development. After 40 years of development, one of the major challenges for reproductive biotechnologies is the possibility of a pre- implantation diagnosis from a small number of cells in the embryo, which opens new perspectives. Since the opening of genotyping service to French breeders in dairy cattle in 2011, genomic selection is now largely used in the Montbeliarde, Holstein, Pie Rouge, Normande, and Brown Swiss breeds. Through the genotyping of females, new perspectives are open to embryo biotechnologies, like prediction of the potential response of donor cows, adaptation of treatment protocols and optimization of breeding strategies (choice of mode of reproduction and / or use of sexed semen). These techniques integrate the concept of sustainable breeding practices, both at collective and individual levels and should continue to evolve with the continuous improvement of genotyping tools and reproductive phenotypesAu cours des dix dernières années, les échanges internationaux d’embryons ont doublé. Le transfert embryonnaire reste un des moyens les plus sûrs pour échanger du matériel génétique. Optimiser les techniques de reproduction est devenu un axe stratégique à l’ère de la génomique : l’amélioration du progrès génétique peut être accélérée grâce à l’utilisation combinée de la production d’embryons, de la superovulation, du transfert d’embryon (TE) et de la ponction d’ovocytes associée au développement embryonnaire in vitro. Après 40 ans de développement, un des défis majeurs des biotechnologies de la reproduction est la réalisation d’un diagnostic pré-implantatoire, à partir d’un petit nombre de cellules prélevées chez l’embryon, qui ouvre de nouvelles perspectives. Depuis l’ouverture du service de génotypage aux éleveurs bovins laitiers français en 2011, la sélection génomique s’installe à grand pas au sein des élevages des races Montbéliarde, Prim’Holstein, Pie Rouge, Normande et Brune. Grâce au génotypage des femelles, de nouvelles perspectives s’ouvrent au biotechnologies de l’embryon, permettant de prédire le potentiel des donneuses, d’adapter les protocoles de traitement et d’anticiper les plans d’accouplement (choix du mode de reproduction et/ou utilisation de semence sexée). Ces techniques de reproduction servent les pratiques d’élevage et de sélection durables, au niveau collectif autant qu’individuel et devraient encore évoluer avec l’amélioration continue des outils de génotypage et des phénotypes de reproduction

Dietary propylene glycol and in vitro embryo production after ovum pick-up in heifers with different anti-Müllerian hormone profiles

Rapid genetic improvement in cattle requires the production of high numbers of embryos of excellent quality. Increasing circulating insulin and/or glucose concentrations improves ovarian follicular growth, which may improve the response to superovulation. The measurement of anti-Müllerian hormone (AMH) can help predict an animal’s response to superovulation treatment. The aim of the present study was to investigate whether increasing circulating insulin concentrations, through propylene glycol (PG) drenches, could improve in vitro embryo production in oestrus-synchronised superovulated heifers with different AMH profiles. Holstein heifers were grouped according to pre-experimental AMH concentrations as low (L) or high (H). The PG drench increased circulating insulin and glucose concentrations and reduced β-hydroxybutyrate and urea concentrations compared with the control group. AMH was a good predictor of follicle and oocyte numbers at ovum pick-up (OPU), and of oocyte and embryo quality (AMH H > AMH L). PG in the AMH H group increased the number of follicles and blastocyst quality above that in the control group, but did not improve these parameters in the AMH L group. These results indicate that short-term oral PG supplementation modifies an animal’s metabolic milieu and is effective in improving in vitro embryo production, after superovulation–OPU, more markedly in heifers with high rather than low AMH concentrations

Ocular biocompatibility of a poly(ortho ester) characterized by autocatalyzed degradation.

The biocompatibility of autocatalyzed poly(ortho ester) (POE(70)LA(30)), a viscous, hydrophobic, bioerodible polymer, was investigated. POE(70)LA(30) was synthesized, sterilized by gamma irradiation, and injected in rabbit eyes at adequate volumes through subconjunctival, intracameral, intravitreal, and suprachoroidal routes. Clinical examinations were performed postoperatively at regular time points for 6 mo, and histopathologic analysis was carried out to confirm tissular biocompatibility. After subconjunctival injection, the polymer was well tolerated and persisted in the subconjunctival space for about 5 weeks. In the case of intracameral injections, polymer biocompatibility was good; the POE(70)LA(30) bubble was still present in the anterior chamber for up to 6 mo after injection. No major histopathologic anomalies were detected, with the exception of a localized Descemet membrane thickening. After intravitreal administration, POE(70)LA(30) biocompatibility was excellent, and no inflammatory reaction could be detected during the observation period. The polymer was degraded in approximately 3 mo. Suprachoroidal injections of POE(70)LA(30) were reproducible and well tolerated. POE(70)LA(30) triggered a slight elevation of the retina and choroid upon clinical observation. The polymer was detectable in the suprachoroidal space for about 6 mo. No inflammatory reaction and no major retinal anomalies could be detected by histology. In conclusion, POE(70)LA(30) appears to be a promising biomaterial for intraocular application, potentially providing sustained drug delivery over an extended period of time, with a good tolerance

Short term dietary propylene glycol supplementation affects circulating metabolic hormones, progesterone concentrations and follicular growth in dairy heifers

This study was designed to determine the effects of dietary propylene glycol (PG; Propypact®, DIFAGRI, France) on blood metabolites, metabolic and reproductive hormones and follicular growth in 10 dairy heifers. Treatments consisted of (1) 1.1 kg of sugar beet pulp (Control), (2) 150 g PG (PG150) and (3) 300 g PG (PG300). Each heifer received the three treatments in different randomized orders. A standard hay/concentrate diet, formulated to allow a daily liveweight gain of 900 g/day, was given at 8:00 and the dietary treatments were given at 16:00 from Days 1 to 13 of the oestrous cycle following induced oestrus (Day 0). Oestrus induction treatment consisted of a subcutaneous 3 mg norgestomet implant inserted for 9 days combined with GnRH treatment (i.m.) at implant insertion. Two days before implant removal, 500 µg cloprostenol was administered i.m. Blood samples were collected by jugular venipuncture every 2 h for 24 h on Days 0 and 13 to measure plasma insulin, glucose, β-hydroxybutyrate (BHB) and urea concentrations. Blood samples were also collected to measure insulin-like growth factor-1 (IGF-1), oestradiol, progesterone concentrations on Days 2, 6, 9 and 12 and AMH (Anti-Müllerian hormone) on Days 0, 2, 6, 9 and 12. On Days 2, 6, 9 and 12 ovarian follicular growth was evaluated; the total number of follicles and their diameters were recorded and classed (2-3 mm, 4-7 mm, and >8 mm). Results were analysed by repeated-measures ANOVA. There were no treatment, day and interaction effects on average urea concentrations while there were some differences between Days 0 and 13 for insulin, glucose and BHB. Insulin and glucose concentrations were higher on Day 13 compared to Day 0 and the opposite was observed for BHB. There were treatment, time and interaction effects on glucose and BHB concentrations measured over 24 h on Day 13; glucose concentrations were higher (P<0.05) at 4:00, 8:00, 12:00, 16:00 and 20:00 h, whereas BHB concentrations were lower (P<0.05) at 20:00 and 22:00 h in the PG300 group compared to the control and PG150 groups. There were treatment, day and interaction effects on IGF-1 and progesterone concentrations, and the number of small follicles. PG150 resulted in higher progesterone concentrations on Days 9 and 12, and more small follicles on Day 2 compared to Control. AMH concentrations were unaffected by day of oestrous cycle and dietary treatment. However a negative correlation was observed between pre-PG distribution insulin and AMH (r=−0.47, P<0.05). These results indicate that short-term dietary PG supplementation affects circulating concentrations of metabolites and metabolic hormones, increases progesterone concentrations and the number of small follicles. Propylene glycol supplementation may be effective in improving oocyte production when combined with hormonal treatments to stimulate follicular growth for superovulation or ovum-pick up