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1.
KC Silva‐Santos LS Siloto GMG Santos F Morotti TN Marcantonio MM Seneda 《Reproduction in domestic animals》2014,49(1):48-51
The objective was to compare populations of antral and pre‐antral ovarian follicles in Bos indicus and Bos indicus‐taurus cows with high and low antral follicle counts. Nelore (Bos indicus, n = 20) and Nelore X Angus (1/2 Bos indicus‐taurus, n = 20) cows were subjected to follicular aspiration without regard to the stage of their oestrous cycle (day of aspiration = D0) to remove all follicles ≥3 mm and induce growth of a new follicular wave. Ovaries were examined by ultrasonography on D4, D19, D34, D49 and D64, and antral follicles ≥3 mm were counted. Thereafter, cows were assigned to one of two groups: high or low antral follicular count (AFC, ≥30 and ≤15 antral follicles, respectively). After D64, ovaries were collected after slaughter and processed for histological evaluation. There was high repeatability in the numbers of antral follicles for all groups (range 0.77–0.96). The mean (±SD) numbers of antral follicles were 35 ± 9 (Bos indicus) and 38 ± 6 (Bos indicus‐taurus) for the high AFC group and 10 ± 3 (Bos indicus) and 12 ± 2 (Bos indicus‐taurus) follicles for the low AFC. The mean number of preantral follicles in the ovaries of Bos indicus‐taurus cows with high AFC (116 226 ± 83 156 follicles) was greater (p < 0.05) than that of Bos indicus cows (63 032 ± 58 705 follicles) with high AFC. However, there was no significant correlation between numbers of antral and preantral follicles. 相似文献
2.
KC Silva‐Santos CR Ferreira GMG Santos MN Eberlin LS Siloto CO Rosa TN Marcantonio MM Seneda 《Reproduction in domestic animals》2014,49(5):711-718
The aim of the present study was to compare the lipid profile in oocytes of indicus and 1/2 indicus × taurus cows with high and low antral follicle count (AFC)/oocyte yields. After an OPU procedure (D0), antral follicles ≥3 mm were counted by ultrasonography (D4, 19, 34, 49, 64), and cows were assigned to groups with either high AFC (≥30 follicles; indicus, NH group; 1/2 indicus × taurus, AH group) or low AFC (≤15 antral follicles; indicus, NL group; 1/2 indicus × taurus, AL group). The lipid profiles of the oocytes were determined by MALDI‐MS. For GI, GII and GIII oocytes, the indicus samples tend to cluster separately from the 1/2 indicus × taurus samples. The lipid species [PC (P‐38:5) + H]+ and/or [PC (P‐36:2) + Na]+, [PC (38:2) + H]+, [PC (38:5) + Na]+ and [TAG (60:8) + NH4]+ were more abundant in indicus (NH and NL groups) than 1/2 indicus × taurus. The higher lipid content in the indicus oocytes likely reflects differences in the rate of lipid metabolism and may contribute to oocyte competence and embryo development. 相似文献
3.
Larionov G. A. Gorobets A. V. Dobrovolskaya N. G. Kiryukhina Z. P. Krasnov S. F. Litvin L. F. 《Eurasian Soil Science》2019,52(10):1306-1309
Eurasian Soil Science - It has been experimentally shown that there are two ranges of water flow velocities, at which the erodibility of a monofractional soil (of aggregates 1–2 mm) sharply... 相似文献
4.
KC Silva‐Santos GMG Santos C Koetz Júnior F Morotti LS Siloto TN Marcantonio MR Urbano RL Oliveira DCM Lima MM Seneda 《Reproduction in domestic animals》2014,49(2):228-232
Interest in indicus–taurus cattle has been increasing, as these animals are likely to present the best characteristics of Zebu and European bovine breeds. The aim of this study was to compare the embryo production of indicus–taurus donors with high vs low antral follicle counts obtained by ovum pickup/in vitro production (OPU/IVP) and superovulation (SOV)/embryo collection. Braford females at weaning age (3/8 Nelore × 5/8 Hereford, n = 137, 9 ± 1 month old) were subjected to six serial ovarian ultrasonographs and were assigned to two groups according to the number of antral follicles ≥3 mm as follows: G‐High antral follicular count (AFC, n = 20, mean ≥40 follicles) and G‐Low AFC (n = 20, mean ≤10 follicles). When the females (n = 40) reached 24 months of age, they were subjected to both OPU/IVP and SOV/embryo collection. The average number of follicles remained highly stable throughout all of the ultrasound evaluations (range 0.90–0.92). The mean number of COCs recovered (36.90 ± 13.68 vs 5.80 ± 3.40) was higher (p < 0.05) for females with high AFC, resulting in higher (p < 0.05) numbers of total embryos among females with high vs low AFC (6.10 ± 4.51 vs 0.55 ± 0.83). The mean number of embryos per collection was also higher (p < 0.05) for G‐High vs G‐Low (6.95 ± 5.34 vs 1.9 ± 2.13). We conclude that a single ultrasound performed at pre‐pubertal ages to count antral follicles can be used as a predictor of embryo production following IVP and SOV/embryo collection in indicus–taurus females. 相似文献
5.
L. F. Litvin Z. P. Kiryukhina S. F. Krasnov N. G. Dobrovol’skaya 《Eurasian Soil Science》2017,50(11):1344-1353
Socioeconomic transformation together with climate change in recent decades significantly affected the geography of agricultural erosion in European Russia. Calculations of erosion rate and soil loss from slopes using logical-mathematical erosion models within different landscape zones and administrative regions revealed spatial-temporal regularities in the dynamics of these parameters and made it possible to assess the role of changes in the main natural and anthropogenic factors of erosion. A universal significant reduction in the mass of soil material washed from tilled slopes is revealed on the background of multidirectional changes in erosion rate. 相似文献
6.
G. A. Larionov O. G. Bushueva N. G. Dobrovol’skaya Z. P. Kiryukhina S. F. Krasnov L. F. Litvin R. R. Murataev 《Eurasian Soil Science》2010,43(4):453-458
The rates of the soil loss were studied in a wide range of flow velocities from 0.41 to 1.64 m/s. The results confirmed the
main implications of the hydrophysical model: (1) the rate of the soil loss in the region of flow velocities exceeding the
threshold value by 1.2–1.5 times and more is proportional to the cubic flow velocity; (2) the detachment of particles in the
pre-threshold region is probable in nature, and the relationship between the soil loss and flow velocity is S-shaped. On this
basis, a procedure was developed for the experimental determination of the soil erosion parameters: the erodibility, the threshold
flow velocity, and the coefficient characterizing the variance of the particles’ resistance to detachment. 相似文献
7.
Destruction of soil aggregates in slope flows 总被引:1,自引:0,他引:1
G. A. Larionov O. G. Bushueva N. G. Dobrovol’skaya Z. P. Kiryukhina L. F. Litvin I. A. Maksimova 《Eurasian Soil Science》2007,40(10):1128-1134
Field studies and model experiments, as well as theoretical considerations, suggest that bed sediments represented by soil aggregates in overland flows on slopes exert a considerable influence on the intensity of erosion processes. In this context, one of the key problems in the development of adequate erosion models is the problem of the rate of destruction of such aggregates in the flows. The results of experimental studies of the destruction of aggregates of chernozemic soils are analyzed. It is found that the destruction of soil aggregates in the flow proceeds in two stages. During the first stage, the aggregates are rapidly broken apart into smaller fragments. During the second stage, these fragments are subjected to abrasion. An equation describing the destruction of aggregates upon their movement in the flow in dependence on the aggregate size and the distance of aggregate transport is suggested. The effect of some groups of soil microorganisms on the aggregate resistance to the destruction is shown. 相似文献
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9.
G. A. Larionov O. G. Bushueva N. G. Dobrovol’skaya Z. P. Kiryukhina L. F. Litvin S. F. Krasnov 《Eurasian Soil Science》2016,49(5):546-550
It has been experimentally shown with monoaggregate model samples of chernozemic soil as an example that the weakening of cohesion between soil particles is due to the molecular interaction of soil particles with water as a dipole substance rather than to the hydraulic forces of the flow. Therefore, soil erosion should be considered as a two-stage process. First, the bonds between particles are weakened due to the interaction of soil particles with water; then, the particles that lost bonds with neighboring ones are entrapped by the flow. Thus, the erosion rate of a consolidated soil is determined by the destruction of bonds between particles during their interaction with water, rather than the flow velocity, although this factor also affects the erosion rate. 相似文献
10.
G. A. Larionov N. G. Dobrovol’skaya Z. P. Kiryukhina S. F. Krasnov L. F. Litvin A. V. Gorobets I. I. Sudnitsyn 《Eurasian Soil Science》2017,50(3):335-340
The effect of density of monofraction samples from the plow horizon of leached chernozem on the rupture rate of interaggregate bonds in water has been studied. The rupture rate of bonds has been determined in a hydraulic flume by alternating passive phases of 1–5 min in duration, during which the sample occurs under a nonmoving water layer, with short (15-s long) active phases with a water flow in the flume. Samples have also been tested for tensile strength and water infiltration rate. It has been shown that the rupture rate of interaggregate bonds is related by a hyperbolic law to the soil density and by an exponential law to the rate of water infiltration to the soil. The latter relationship varies within a year and, hence, can be used as reliable parameter for predicting the seasonal dynamics of soil erodibility. 相似文献