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61.
María Sofía Larroulet Estela Noemí Hepper Mónica Patricia Álvarez Redondo Valeria Belmonte Ana María Urioste 《Arid Land Research and Management》2016,30(1):105-119
Before and after a prescribed burning, the upper 2.5 cm of soil in patches of forage, nonforage, and shrub vegetation were sampled. Then, bulk density, gravimetric moisture, pH in water, available phosphorus, exchangeable cations, cationic exchange capacity, total nitrogen, total, particulate, and mineral organic carbon contents were determined. Maximum temperature ranges reached over the ground during burning were measured and the highest values were registered in shrubs. Results showed that total, particulate, and mineral organic carbon and total nitrogen contents and percent base saturation increased in all soils after burning, without detecting differential effects between vegetation patches. After burning, available phosphorus content increased both for forage and shrub patches. A Na+ content decrease was observed for all soils in the different patches while Mg2+ content increased. No changes in the other analyzed variables were observed. Prescribed burning, as studied in the present work, might improve the Caldenal soils’ chemical fertility, mainly due to an increase in labile organic matter and some nutrients essential for plant growth. 相似文献
62.
Jaroslav Matoušek Rajen J. J. Piernikarczyk Petr Dědič Josef Mertelík Kateřina Uhlířová Ganesh S. Duraisamy Lidmila Orctová Kateřina Kloudová Jiří Ptáček Gerhard Steger 《European journal of plant pathology / European Foundation for Plant Pathology》2014,138(1):93-101
We analyzed the spreading and persistence of PSTVd variants in several ornamentals in the territory of the Czech Republic. The pool of PSTVd variants detected in Solanum jasminoides, S. muricatum, Datura sp. and Brugmansia sp. was biolistically transferred to Matricaria chamomilla, Argyranthemum frutescens and Diascia sp., species which we found as sensitive hosts for PSTVd from ornamentals. The PSTVd pool showed sequence changes and increased variation after its transfer to potato, suggesting a wide adaptation potential of PSTVd in this crop. Potato exhibited genotype-dependent leaf and spindle tuber symptoms, when inoculated with the sap from S. jasminoides infected with the predominant and sequence-stable PSTVd-S1. 相似文献
63.
JR Rodriguez-Sosa JD Silvertown RA Foster JA Medin A Hahnel 《Reproduction in domestic animals》2009,44(4):612-620
Spermatogonial transplantation will provide a new way to study spermatogenesis in domestic animals, disseminate male genetics and produce transgenic animals, if efficiency can be improved. We evaluated a 'surgical' method for transplanting donor cells into testes of ram lambs, where the head of the epididymis is reflected, and a catheter introduced into the extra-testicular rete testis. We also tested transduction of ram spermatogonia with a lentiviral (LV) vector as a means to identify permanent colonization, and introduce genes into donor cells. Eight ram lambs, 11- to 13-week olds, were the recipients: in five, spermatogonia were injected into one testis, and the contralateral testis was an un-manipulated control: in two, spermatogonia were injected into one testis and the contralateral was sham-injected: in one, both testes were injected. Six lambs received spermatogonia labelled with a cell-tracking dye and these were collected 1 or 2 weeks after transplantation; three lambs received spermatogonia transduced with a LV vector driving the expression of enhanced Green Fluorescence Protein and these were collected after 2 months. Donor cells were detected by immunohistochemistry in tubules of seven of nine recipient testes. Approximately 22% of tubule cross-sections contained donor cells immediately after transplantation, and 0.2% contained virally transduced cells 2 months after transplantation. The onset of spermatogenesis was delayed, and there were lesions in both injected and sham-injected testes. Despite the effects of the surgery, elongated spermatids were present in one recipient testis 2 months after surgery. The results suggest that, after modifying the surgical and transduction techniques, this approach will be a means to produce good colonization by donor spermatogonia in sheep testes. 相似文献
64.
Equine amnionitis and fetal loss: The case definition for an unrecognised cause of abortion in mares
KH Todhunter NR Perkins RM Wylie C Chicken AJ Blishen DJ Racklyeft G Muscatello MC Wilson PL Adams JR Gilkerson WL Bryden AP Begg 《Australian veterinary journal》2009,87(1-2):35-38
A series of abortions occurred in mares in New South Wales during 2004 that involved similar and unusual findings on post mortem examination of aborted fetuses and fetal membranes. The term Equine Amnionitis and Fetal Loss (EAFL) was developed to describe the condition. This form of abortion had not been previously recognised in Australia. The pathology alone is not specific for EAFL and diagnosis requires demonstration of a combination of certain pathological and bacteriological features. The purpose of this paper is to describe patterns considered consistent with EAFL cases as a working case definition for use by veterinarians and veterinary pathologists in identifying future cases of EAFL. More detailed papers are in preparation to fully describe the epidemiological, histopathological, and microbiological aspects of EAFL. 相似文献
65.
Since 1980, over 20,000 Irish landowners have afforested land, for the first time, as part of an afforestation programme subsidised
by the Government and the EU. A survey of 99 private forest owners was conducted to determine their knowledge of broad aspects
of forest management. Key questions were scored so as to test whether respondents had passed or failed a forestry knowledge
test. Over two-thirds of private forest owners passed the test. Success in this test was shown to be related to whether respondents
had (a) attended extension field days; (b) been active in forest operations in the early stages of the forest cycle and (c)
been members of farming and/or forestry groups. Younger respondents (i.e., ≤50 years) were more likely to pass the knowledge
test than older respondents. 相似文献
66.
Growth and survival of 0+ perch were studied in 4 ponds with the topmouth gudgeon (Pseudorasbora parva) and without it. In the end of April, all ponds were stocked by free-swimming perch larvae (120,000 ind ha?1). In June, topmouth gudgeon was introduced as forage fish (40 kg ha?1) into two of the experimental ponds. Topmouth gudgeon significantly influenced neither the total abundance of zooplankton nor the abundance of its groups (Rotifera, Cladocera, Copepoda). The most important food item for perch (TL > 29 mm) was macroinvertebrates (especially Chironomidae). In the ponds with topmouth gudgeon, copepods and cladocerans were more important than in ponds without it. Specific growth rate of perch was 0.01 mm day?1 in all ponds. Final mean total length (TL ± SD) of perch was 73 ± 13 and 70 ± 6 mm in the ponds with topmouth gudgeon and without it, respectively. Only 1 % of the perch reached higher TL than that recorded in the ponds without the topmouth gudgeon. Survival rate of perch varied from 12 to 36 % depending on ponds. Piscivory was recorded in all ponds from the age of 57 days (post-stocking); however, perch siblings were preferred to topmouth gudgeon. The highest asymptotic growth (L∞ = 88 mm) was calculated in the pond stocked with topmouth gudgeon. This corresponded with the highest cannibalism and lowest survival rate (12 %). Perch growth rate increased till 42–53 days of perch age and then started to decrease. There was no significant influence of potential prey fish (topmouth gudgeon) on the growth of 0+ perch; however, two size cohorts were found in the ponds with the topmouth gudgeon. Presence or absence of littoral macrophytes seems to be more substantial for rearing perch in ponds than stocking with the prey fish. 相似文献
67.
Abstract Depredation can have economic, social and ecological impacts by decreasing fishery landings and threatening marine predator populations through increased risk of entanglement. This investigation quantified the loss of landings attributed to harbour seal, Phoca vitulina L., and spiny dogfish, Squalus acanthias L., depredation in the Georges Bank, Massachusetts, USA gillnet fishery. Approximately 1361 kg (2.38%) of fish was discarded from a total possible catch weight of nearly 57 300 kg because it was unsalable following depredation. Spiny dogfish accounted for 1134 kg (1.98%), and harbour seal accounted for 227 kg (0.40%) of discards. This represented an estimated US$2250 loss in profits from a total possible catch value of almost US$61 800, signifying a 3.64% market‐value loss during the assessment period. These results suggest that discarding due to harbour seal and spiny dogfish depredation results in a relatively small market loss to fishers, although additional information and research is needed before this can be confirmed. This study is the first on this subject in the fishery and provides baseline information on depredation rates that could be useful if harbour seal and spiny dogfish populations continue to increase. 相似文献
68.
Organogenesis and foetal haemodynamics during the normal gestation of healthy black‐rumped agoutis (Dasyprocta prymnolopha,Wagler, 1831) bred in captivity 下载免费PDF全文
FCA Sousa GT Pessoa LS Moura JR Araújo RPS Rodrigues MAPS Barbosa AN Diniz AB Souza EG Silva LU Lucena MP Sanches OF Silva‐Filho PC Guerra JM Sousa WC Neves FR Alves 《Reproduction in domestic animals》2017,52(1):60-66
The objective of this study was to define the patterns of organogenesis and foetal haemodynamics during the normal gestation of healthy agoutis (Dasyprocta prymnolopha) kept in captivity. Thirty pregnant agoutis that ranged in size from small to medium and weighed between 2.5 and 3 kg underwent B‐mode and Doppler ultrasonography for the biometric evaluation of the foetal organs. The foetal aortic blood flow proved to be predominantly systolic, and the measured flow velocity was 78.89 ± 2.95 cm/s, with a maximum pressure gradient of 2.12 ± 0.27 mmHg. The liver was characterized by its large volume, occupying the entire cranial aspect of the abdominal cavity, and it was associated cranially with the diaphragm and caudally with the stomach. The flow velocity in the portal vein was estimated to equal 12.17 ± 2.37 cm/s, with a resistivity index of 0.82 ± 0.05. The gallbladder was centrally located and protruded cranially towards the diaphragm. The spleen was visualized as an elongated structure with tapered cranial and caudal extremities, and the foetal kidneys were visualized bilaterally in the retroperitoneal region, with the right kidney positioned slightly more cranially than the left. The morphological characterization and hemodynamic analysis of the foetal organs of black‐rumped agoutis via B‐mode and Doppler ultrasonography allow determination of the vascular network and of reference values for the blood flow required for perfusing the anatomical elements essential for maintaining the viability of foetuses at different gestational ages. 相似文献
69.
Effect of exogenous progesterone administration on luteal sensitivity to PGF during the early development of the corpus luteum in mares and cows 下载免费PDF全文
A Garcia‐Muñoz X Valldecabres‐Torres JR Newcombe J Cuervo‐Arango E Garcia‐Rosello 《Reproduction in domestic animals》2017,52(6):1074-1080
The objective of this study was to determine the effect of exogenous progesterone administration at ovulation and during the early development of the CL, on its future sensitivity to a single administration of PGF2a in mares and cows. Horse Retrospective reproductive data from an equine clinic in the UK during three breeding seasons were used. Mares were divided into: control group, cycles with single ovulations; double ovulation group cycles with asynchronous double ovulations; and PRID group: cycles with single ovulations and treatment with intravaginal progesterone device (CIDR) immediately after the ovulation. All mares were treated with d‐cloprostenol (PGF) at either: (i) 88 hr; (ii) 96 hr; (iii) 104 hr; or (iv) 112 hr after the last ovulation. Cattle A total of nine non‐lactating Holstein cows were used. All cows were administered PGF14 d apart and allocated to one of two groups control group GnRH was administered 56 hr after the second PGF administration. CIDR group CIDR was inserted at the same time of GnRH administration. All cows were administered PGF at 120 hr post‐ovulation. The complete luteolysis rate of mares with double ovulation (66.7%) and those treated with exogenous progesterone (68.4%) was significantly higher than the rate of mares with single ovulation (35.6%) at 104 hr. In the cow, however, the treatment with CIDR did not increase the luteolytic response in cows treated at 120 hr post‐ovulation. In conclusion, the degree of complete luteolysis can be influenced by increasing the concentration of progesterone during the early luteal development in mares. 相似文献
70.
The expression and concentration of follistatin and activin change during oestrous cycle suggesting their involvement in the regulation of follicular development. The aim of this study was to determine the level, source and potential role of follistatin in the sheep ovary. Follistatin in ovarian venous blood, measured by radioimmunoassay, remained at its low level from follicular phase (day ?1 and 0) to mid‐luteal phase (days 11–13) phase but were significantly elevated during the late luteal phase (days 14 and 15) when corpora lutea underwent regression. Western blot analyses of follicular fluid at day 15 of the cycle showed two strong bands at 42 and 45 kDa and weakly stained bands at 39 and 31 kDa. At day 0, these bands became weaker and the 39 kDa band became undetectable. However, there were no differences in follistatin concentrations between ovaries with and without functional corpus luteum (CL) during the whole luteal phase. In addition, although the ovaries of Booroola ewes normally contain more corpora lutea than those of normal merino ewes, follistatin concentrations in both jugular and ovarian venous blood were similar in Booroola and normal merino ewes. It is concluded that the secretion of follistatin from the ovary is not related to the formation of CL or high ovulation rate of Booroola ewes. The elevation in follistatin concentration in follicular fluid and ovarian blood during late luteal phase may indicate a dual role of follistatin in the luteolysis of existing CL and development of new follicle cohort. 相似文献