Use of progesterone in microspheres for maintenance of pregnancy in mares.

Administration of progesterone in poly(d-,l-lactide) microspheres was used to maintain pregnancy in mares after luteolysis was induced by treatment with prostaglandin F2 alpha at day 14 of pregnancy. Mares were given vehicle only (control, n = 6) or 0.75 g (n = 7), 1.5 g (n = 8), or 2.25 g (n = 5) of microencapsulated progesterone at days 12 and 22 of pregnancy. Serum progesterone concentrations were determined daily, and pregnancy was evaluated by transrectal ultrasonography on alternate days. Significantly (P less than 0.05) more mares given 1.5 or 2.25 g of progesterone (6 of 8 and 4 of 5 mares, respectively), but not those given 0.75 g (3 of 7 mares), maintained pregnancy through day 32, compared with control mares (0 of 6). Progesterone concentrations decreased significantly (P less than 0.025) in all groups after administration of prostaglandin F2 alpha at day 14, and significant (P less than 0.05) effects of time and treatment on progesterone concentrations were found between days 12 and 22, and 22 and 32. Although treatment with 1.5-g and 2.25-g doses of microencapsulated progesterone improved maintenance of pregnancy, compared with that of vehicle-treated controls, administration of 2.25 g of microencapsulated progesterone appeared to be most efficacious in maintenance of pregnancy during the study interval.     

Involvement of 20alpha-hydroxysteroid dehydrogenase in the maintenance of pregnancy in mice

The enzyme 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD) catabolizes progesterone into a biologically inactive steroid, 20alpha-dihydroprogesterone (20alpha-OHP). In the corpora lutea of rats and mice, 20alpha-HSD is considered to be involved in functional luteolysis. It is also distributed in other tissues including the placenta, endometrial epithelia and fetal skin, although the roles it plays in these tissues remain to be elucidated. In the present study, we investigated the role of 20alpha-HSD in the maintenance of pregnancy using mice with targeted disruption of the 20alpha-HSD gene. We first confirmed that the number of pups was significantly smaller in 20alpha-HSD-/- pairs than in 20alpha-HSD+/+ pairs. We then mated 20alpha-HSD+/- males and females so that each pregnant female produced 20alpha-HSD+/+, 20alpha-HSD+/- and 20alpha-HSD-/- offspring. The genotype ratio of the offspring did not match the Mendel's law of inheritance, and the numbers of 20alpha-HSD+/- and 20alpha-HSD-/- offspring were smaller than expected values. Although the genotype ratio of fetuses on days 13, 15 and 18 of pregnancy matched the Mendel's law, the total number of fetuses on day 18 was significantly smaller than that on day 13, suggesting that fetal loss occurred during late pregnancy. Next, we transferred 20alpha-HSD+/+ embryos to 20alpha-HSD+/+ or 20alpha-HSD-/- females and found that the number of offspring was significantly smaller in 20alpha-HSD-/- dams than in 20alpha-HSD+/+ dams. Expression of 20alpha-HSD mRNA in the fetus, placenta and uterus progressively increased from day 11 to 18 of pregnancy. In addition, concentrations of progesterone were significantly higher in the 20alpha-HSD-/- fetuses than in the 20alpha-HSD+/+ fetuses, while those of 20alpha-OHP were lower in the 20alpha-HSD-/- fetuses than in the 20alpha-HSD+/+ fetuses. These results suggest that both maternal and fetal 20alpha-HSD play a role in maintaining normal pregnancy at least partially by reducing progesterone concentrations in fetuses.     

Premature luteal regression in a pregnant mare and subsequent pregnancy maintenance with the use of oral altrenogest

Premature luteal demise or luteal insufficiency is not well characterised as a cause of pregnancy loss in domestic species, including horses. In this report, a mare inseminated with cooled‐transported semen at our facility returned for a routine pregnancy diagnosis at 15 days post ovulation. Ultrasonography per rectum revealed endometrial oedema and the absence of visual indication of a corpus luteum on either ovary. Nonetheless, an embryonic vesicle small for the gestational age was identified. Daily oral altrenogest treatment was implemented immediately. Serum progesterone concentration was 0.67 ng/ml, which is below the threshold considered adequate for pregnancy maintenance in the mare. Examinations were repeated at 17, 25, 30, 39, 49, 72 and 120 days post ovulation. At 25 days post ovulation the embryonic vesicle presented normal development for the gestational age. In addition, sequential blood samples were collected to measure progesterone, equine chorionic gonadotrophin and oestrone sulphate concentrations. Although progesterone concentration did not exceed 2 ng/ml until 72 days post ovulation, all other results were unremarkable and a healthy filly was born uneventfully at 344 days post ovulation.     

The effect of detomidine (Domosedan) on the maintenance of equine pregnancy and foetal development: ten cases

Detomidine was administered throughout 10 pregnancies in eight mares. An intravenous injection of 20 micrograms/kg body weight was given weekly from Day 14 to Day 60 of gestation and thereafter every four weeks until parturition. One mare suffered torsion of the large colon and was destroyed on Day 86; the foetus was normally developed. A further mare aborted at 167 days. The remaining eight pregnancies continued to full term. One foal was delivered by caesarean section because of torticollis and, of the seven foals born spontaneously, one had bilateral upward patellar fixation at one month old. Therefore, although only six of the 10 foals developed normally, the other four cases showed no pathological similarities to suggest a common cause. Although these data were based on a small number of mares, they did not suggest that the repeated administration of detomidine had specific adverse effects on the pregnancies.     

Effects of prostaglandin F2 alpha-analogue administration on luteal function, implantation of embryos and maintenance of pregnancy in bitches

The present experiment was carried out to clarify the effect of administration of the prostaglandin F2 alpha (PGF2 alpha)-analogue on the luteal function and the maintenance of pregnancy in bitches. Fifty-one bitches received a single inoculation of PGF2 alpha-analogue by intramuscular injection. The effect of this agent was observed by monitoring progesterone (P) levels and the state of the uterus by laparotomy, the occurrence of abortion, and the state of parturition. As a result, when bitches were administered with 100-400 micrograms at the beginning of the luteal phase, the decrease in the P level was temporary. In bitches inoculated with 100-800 micrograms of PGF2 alpha-analogue at the functional luteal stage, the P level began to decrease as early as on the following day after injection. In those treated with 100-200 micrograms of PGF2 alpha-analogue at 10-15 days of pregnancy, pregnancy was maintained in 3 of 5 bitches that had received the treatment at day 10, while in the remaining two, all embryos died after implantation. In those that had received the same treatment at day 15, only 2 of 7 maintained pregnancy. Pregnancy was interrupted in eight bitches treated with doses of 100-200 micrograms at days 25-45. In four bitches treated with doses of 100-200 micrograms at day 55, premature birth was induced after 30-44 hr. In conclusion, regression of the corpus luteum, abortion, and premature birth were induced in bitches treated with 100-200 micrograms at each stage, except the beginning of the luteal phase and of the pregnancy.     

Endometrial Expression of IFNAR‐1 and Oxytocin Receptor (OTR) is not Improved by Prostaglandin Analogues when Compared to Progestagens in Ewes

The objective of this study was to investigate differences on the endometrial immunoexpression of type I IFN receptor subunit 1 (IFNAR1) and oxytocin receptor (OTR) during the time of maternal recognition of pregnancy in sheep, when oestrus is synchronized with either prostaglandin analogues (group PG) or conventional progestagens (group P). Plasma progesterone was measured from day 0 to 21 post‐coitus (pc) (day 0 = day of oestrus). Immunohistochemistry was performed in samples of uterine horns from pregnant sheep on days 9pc, 13pc, 15pc, 17pc and 21pc to locate IFNAR1 and OTR expression in different endometrial compartments. Mean levels of plasma progesterone were different between treatments, obtaining higher levels in the PG group than in the P group (p < 0.05). Comparing days of pregnancy, IFNAR1 protein expression was different in the luminal epithelium (LE) (p < 0.05), while OTR was different in the LE and in the superficial glandular epithelium (SG) (p < 0.05). Temporal variation on the expression of both proteins from day 9pc to 21pc has been evidenced. IFNAR1 and OTR expression did not show significant differences between treatments. However, the response observed in the endometrium was highly inconsistent when prostaglandin analogues were used. Therefore, the protocol based on prostaglandin analogues still needs to be optimized before being considered as a better alternative to progestagens for oestrous synchronization in sheep.     

高尔夫球场草坪的养护管理

高尔夫球场的养护主要包括草坪的水肥管理、病虫害管理等方面.针对这些问题提出了具体的养护管理措施,并拟定了高尔夫球场的周年管理计划.     

高尔夫球场的草坪管理和维护

高尔夫球场的维护主要包括草坪的水肥管理，病虫害管理以及常见杂草的防除等方面。草坪的水肥管理主要包括草坪的土壤条件、草坪施肥的目的、种类及方法，草坪的病虫害管理主要包括高尔夫球场病虫害预测预报体系的建立以及高尔夫球场的草坪常见病虫害的发生特点及防治方法。     

高尔夫球场的草坪管理和维护

高尔夫球场的维护主要包括草坪的水肥管理、病虫害管理以及常见杂草的防除等方面.草坪的水肥管理主要包括草坪的土壤条件、草坪施肥的目的、种类及方法;草坪的病虫害管理主要包括高尔夫球场病虫害预测预报体系的建立以及高尔夫球场的草坪常见病虫害的发生特点及防治方法.     

Canine pregnancy and parturition

In contrast to the large variation in canine gestation lengths based on mating-to-whelping intervals (56 to 70 days), gestation length based on intervals from the preovulatory LH surge to whelping shows little variation (64 to 66 days). By considering the preovulatory LH surge as the central endocrine event of the fertile cycle, various events can be reasonably timed, including ovulation on day 2, oocyte maturation on day 4, reduced fertility after day 6, implantation around day 17, and development of fetal radiopacity after day 45. Throughout pregnancy, gestation is dependent on ovarian progesterone secretion and, thus, on pituitary LH and prolactin for luteotrophic support. Because prostaglandin F2 alpha is luteolytic in the bitch, it may be involved in the luteolysis observed immediately prepartum in association with rises in maternal cortisol and prolactin levels.     

Myosin: Formation and maintenance of thick filaments

Skeletal muscle consists of bundles of myofibers containing millions of myofibrils, each of which is formed of longitudinally aligned sarcomere structures. Sarcomeres are the minimum contractile unit, which mainly consists of four components: Z‐bands, thin filaments, thick filaments, and connectin/titin. The size and shape of the sarcomere component is strictly controlled. Surprisingly, skeletal muscle cells not only synthesize a series of myofibrillar proteins but also regulate the assembly of those proteins into the sarcomere structures. However, authentic sarcomere structures cannot be reconstituted by combining purified myofibrillar proteins in vitro, therefore there must be an elaborate mechanism ensuring the correct formation of myofibril structure in skeletal muscle cells. This review discusses the role of myosin, a main component of the thick filament, in thick filament formation and the dynamics of myosin in skeletal muscle cells. Changes in the number of myofibrils in myofibers can cause muscle hypertrophy or atrophy. Therefore, it is important to understand the fundamental mechanisms by which myofibers control myofibril formation at the molecular level to develop approaches that effectively enhance muscle growth in animals.     

颗粒饲料机械设备的选择、使用和维护

颗粒饲料是将混合后的全价配合饲料，经制粒机的压轴和压模的挤压，通过模孔成型，而后经过冷却、碎粒、分级、喷涂等工序加工而成。颗粒饲料生产在西方发达国家已有50多年的历史，近二十多年来，颗粒饲料在许多国家都有比较大的发展，在关、日、德等国家，颗粒饲料约占饲料总量的70％以上。颗粒饲料在我国是从20世纪70年代末发展起来的，近十几年迅速发展，特别是肉鸡、鱼虾和观赏动物颗粒饲料日益普及。颗粒饲料虽然加工成本高，但饲养效果明显优于粉状饲料，具有明显的经济效益。     

澳大利亚的动物健康维护体系

澳大利亚是畜牧业大国,也是世界上牲畜保健工作做得最好的国家之一,迄今尚未发生疯牛病等牲畜传染病.虽然地理条件有利于澳大利亚免受动物传染病的影响,但更重要的是,澳大利亚有一套完整的动物健康维护体系,这一体系是该国动物健康状况良好的根本保障,也是兽疫防控最根本的机制.……