排序方式： 共有93条查询结果，搜索用时 15 毫秒
81.
Endogenous Progesterone Concentrations Affect Progesterone Release from Intravaginal Devices Used for Oestrous Synchronization in Cattle 
下载免费PDF全文
下载免费PDF全文 HL Neri MP Palhao DS Costa JHM Viana CAC Fernandes 《Reproduction in domestic animals》2015,50(4):692-695
Intravaginal progesterone‐releasing devices are largely used both as contraceptives in humans and as a component of oestrous synchronization protocols in cattle. To reduce costs in large‐scale timed artificial insemination, the reuse of these releasing devices is common. Passive hormone diffusion, however, depends on the concentration gradient, which could affect the amount of residual progesterone present in these devices after a first use. To evaluate the effect of the presence of a corpus luteum in the release of progesterone from intravaginal devices, three synchronization protocols were designed to simulate the effects of inserting the device in the early dioestrus, late dioestrus or anoestrus. Holstein‐Zebu cross‐bred heifers were randomly allocated into one of these three treatments, and a series of blood samples was taken to evaluate the plasma progesterone concentrations. After 8 days, the intravaginal devices were removed and underwent a previously validated alcoholic extraction technique to measure the residual progesterone. Non‐used devices were used as controls. As expected, the simultaneous presence of the intravaginal device and a corpus luteum resulted in increased plasma progesterone concentrations. Conversely, the amount of residual progesterone in the devices after use was inversely proportional to the plasma progesterone concentration. These results demonstrate that the release rate of progesterone from intravaginal devices is affected by the endogenous concentration of this hormone; consequently, the strategy for reuse should account for the category and expected luteal cyclic activity of the animals undergoing synchronization protocols. 相似文献
82.
83.
MP HEGARTY WR KELLY D. McEWAN OJ WILLIAM R. CAMERON 《Australian veterinary journal》1988,65(11):337-340
SUMMARY: An outbreak of liver disease which killed more than 30 dogs at Alice Springs was associated with feeding meat from horses, some of which had developed Indigofera linnaei poisoning (Birdsville horse disease). Affected livers were small, nodular and yellow. There was associated jaundice, ascites, elevation of alanine aminotransferase levels in serum, a tendency to bleed, and signs of hepatic encephalopathy. Histologically, livers showed periacinar necrosis, collapse and haemorrhage, with severe swelling, vacuolation and cholestasis in remaining hepatocytes. Indospicine, a toxic amino acid found in the genus Indigofera, was detected in samples of suspect horsemeat. Experimental feeding of horsemeat containing 16 mg indospicine/kg for 32 days produced periacinar necrosis and hepatocellular swelling in 2 dogs, although neither died nor showed clinical illness. In another experiment, intakes of as little as 0.13 mg indospicine/kg bodyweightlday for 70 days produced periacinar liver lesions, and indospicine concentrations in serum, muscle and liver rose during this period to 3.9, 7.9 and 17.5 mg/kg, respectively. It was concluded that meat from horses grazing l. linnael can be hepatotoxic for dogs, and that this toxicity may be related to its indospicine content. 相似文献
84.
85.
C Cortell JS Vicente E Mocé F Marco-Jiménez MP Viudes De Castro 《Reproduction in domestic animals》2010,45(1):155-159
This study aims to assess the efficiency of in vivo oocyte and embryo recovery after a recombinant human FSH (rhFSH) treatment in rabbit does. Females were distributed in two experimental groups: donor does were treated with rhFSH (superovulation group) for 3 days prior to artificial insemination (embryo recovery) or ovulation induction (oocyte recovery) and does without treatment remained as the control group. Mature oocytes or embryos were collected with the laparoscopy technique 16 h after ovulation induction (oocytes) or 72 h after artificial insemination (embryos). Up to four recoveries were performed with each doe. Recovery efficiencies differed significantly between embryos (84%) and oocytes (58%). Yet, the recovery rates for the superovulation and control groups did not differ. The rhFSH group was associated with a significant increase (p < 0.05) in the number of oocytes and embryos recovered in comparison with the control group (10.2 ± 1.0 and 14.3 ± 1.2 vs 6.0 ± 2.7 and 8.4 ± 2.3 for oocytes and embryos, respectively). Results from this study indicate that repeated in vivo oocyte and embryo recovery from rhFSH superovulated does maximizes the number of oocytes or embryos collected from the same female. 相似文献
86.
IA Zervos SN Lavrentiadou MP Tsantarliotou MP Georgiadis NA Kokolis IA Taitzoglou 《Reproduction in domestic animals》2010,45(6):e440-e446
Plasminogen activators (PA) are proteolytic enzymes present in the spermatozoa and seminal plasma of various species. They play a role in the binding of the spermatozoon and its penetration through the layers surrounding the oocyte. Plasminogen activator activity (PAA) is modulated by hormones that have a seasonal variation, such as testosterone and melatonin. The present study investigates the seasonal variation of PA activity in sperm extracts and seminal plasma of four farm animal species: boar, buck, bull and stallion. Semen samples were collected every second week during a 12‐month period and PAA was determined. With respect to sperm enzyme activity, the boar showed a peak from late January until the beginning of April, whereas the activity in the bull was at the highest levels from April until October and gradually declined during autumn and winter period. Plasminogen activator activity of stallion spermatozoa peaked during March and April, and remained low throughout the rest of the year, whereas in the buck sperm, PAA increased from late October until the end of January. No biologically significant variation was detected regarding the seminal PAA activity in any of the species studied. While seasonality of reproduction is typically studied from the female perspective, the present data provide compelling information about a factor that may affect the reproductive ability of the male. 相似文献
87.
88.
89.
Effects of Serum Deprivation and Cycloheximide on Cell Cycle of Low and High Passage Porcine Fetal Fibroblasts 总被引：1，自引：0，他引：1
MD Goissis HVA Caetano MG Marques FRO de Barros WB Feitosa MP Milazzotto M Binelli MEOA Assumpção JA Visintin 《Reproduction in domestic animals》2007,42(6):660-663
Arrest of cells in G0/G1 cell cycle phase is desired for nuclear transfer procedures. Serum starvation and cell cycle inhibitors are different ways to induce synchronization of the cell cycle. This study investigated the effects of serum starvation and cycloheximide (CHX) on the cell cycle of low (5th) and high (15th) passages fetal porcine fibroblasts. Cell cycle phases were determined using fluorescent activated cell sorting. Fifth passage fibroblast cultures had higher (p < 0.05) proportion of cells in G0/G1 only after 72 h of serum starvation (77.60 ± 0.65) when compared with non‐starved cells (71.44 ± 1.88). Serum starvation for all periods tested induced an increase (p < 0.05) on proportion of cells in G0/G1 on the 15th passage. No significant differences were observed on the 5th passage cultures exposed to CHX, although, on the 15th passage an increase on proportion of cells was observed after all periods of exposure (p < 0.05). These data indicates that high passage cells in vitro are more susceptible to serum starvation and CHX G0/G1 synchronization. 相似文献
90.
M Rodriguez F Marco-Jiménez JS Vicente MP Viudes-de-Castro 《Reproduction in domestic animals》2006,41(S2):105-105
In extensive systems, beef cows should be continuously with their calves to optimise pasture use but this practice can lengthen post-partum interval (PPI). A study was conducted to determine the influence of suckling frequency on Parda de Montaña cow-calf performance when cows are fed 70% energy requirements during lactation (outdoor winter conditions simulation). Thirty-six autumn-calving cows with similar body condition at calving (2.57) were assigned to three suckling systems [ ad libitum (AL), twice (2D) or once daily (1D) for 30 min]. Blood samples were collected twice a week to analyse progesterone concentrations by RIA. Cows lost similar weight until start of mating period (day 52 post-partum; −0.583, –0.513, –0.520 kg/day in AL, 2D and 1D). Standard milk yield was higher in AL than the rest (8.9, 6.2, 7.0 kg; p < 0.05), which was reflected on greater calf gain (0.895, 0.752, 0.676 kg/day; p < 0.05) and larger cow weight loss within 90 days post-partum in this treatment (–0.345, –0.188, –0.083 kg/day; p < 0.05). Suckling system did not affect either PPI (69.6, 89.1, 65.5 days) or cows cycling within 90 days post-partum (55, 46, 58%), which may compromise the target calving interval. In Parda de Montaña breed fed moderately pre-calving and undernourished during lactation, restricted suckling did not favour ovarian activity resumption, but post-partum subnutrition delayed about 40 days PPI observed in similar body condition at calving and calf management (Sanz et al., 2003; Anim Reprod Sci 79: 57–69) 相似文献