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1.
Based on mark-recapture data, we studied the postnatal development of morphological features and vocalization of the pomona leaf-nosed bat (Hipposideros pomona). Morphological changes indicated that body mass and length of forearm followed a linear pattern of growth until 13 days of age at mean growth rates of 0.14 g/day and 1.08 mm/day, respectively, and thereafter, growth rates slowed. The length of the total epiphyseal gap of the fourth metacarpal–phalangeal joint showed a linear increase for up to 10 days, followed by a linear decrease until day 40 at a mean rate of 0.09 mm/day. Together, two equations permitted estimation of the age of H. pomona pups between 1 and 40 days. The logistic equation provided the best fit to the empirical curves for body mass and length of forearm. Studies of vocal development showed that the precursors of echolocation calls were not emitted until day 7 after birth. As the pups grew, the dominant frequency (DF) of isolation calls increased and number of harmonics (NH) decreased, whereas the duration remained relatively stable. The DF and BFM2 (the bandwidth of the terminal frequency-modulated sweep from the second harmonic) of the early echolocation calls increased; however, the NH and duration decreased.  相似文献   

2.
Avoiding the innervation zone (IZ) is important when collecting surface electromyographic data. The purposes of this study were threefold: (1) to examine the precision of two different techniques for expressing IZ location for the biceps brachii, (2) to compare these locations between men and women, and (3) to determine if IZ movement with changes in elbow joint angle is related to different anthropometric measures. Twenty-four subjects (mean ± SD ages = 21.8 ± 3.5 yr) performed isometric contractions of the right forearm flexors at each of three separate elbow joint angles (90°, 120°, and 150° between the arm and forearm). During each contraction, the location of the IZ for the biceps brachii was visually identified using a linear electrode array. These IZ locations were expressed in both absolute (i.e. as a distance (mm) from the acromion process) and relative (i.e. as a percentage of humerus length) terms. The results suggested that the estimations of IZ location were more precise when expressed in relative versus absolute terms, and were generally different for men and women. The shift in IZ location with changes in elbow joint angle was not, owever, related to height, weight, or humerus length.  相似文献   

3.
1997 年5 ~9 月,采用标志重捕法对中华山蝠的生长发育进行研究,共观察幼蝠388 只次(雄性184 只次,雌性204 只次),结果显示:中华山蝠幼蝠20 d 前体重和前臂长均呈直线增长,日平均生长率分别为0.57 g/d 与1.36 mm/d, 回归方程为:体重=3.05 + 0.57×日龄, 前臂长= 15.49+1.36×日龄。20 d后增长减慢, 大约5 周龄后开始飞行,初飞幼蝠与成体的体重差异显著,前臂长与成蝠差异不显著。中华山蝠幼体生长与Logistic、Von Bertalanffy 及Compertz 3 种生长曲线模型的拟合度均较高, R2 值超过0.93。前臂长的增长用Logistic曲线拟合最合适,体重的增长用Von Bertalanffy 曲线拟合最合适。根据前臂长以及第四掌骨与指骨间软骨的发育模式,得到出生后1 ~ 76 d幼蝠的年龄鉴定方程式。当前臂长≤43.32 mm时,日龄= -10.77 +0.71 × 前臂长;当前臂长> 43.32 mm时, 日龄= 71.10 - 9.89 ×第四掌骨与指骨间软骨长。   相似文献   

4.
《Theriogenology》2009,71(9):1489-1497
The Catalonian donkey breed is in danger of extinction, and much needs to be learned about the reproductive features of its females if breeding and conservation programmes are to be successful. This study reports the oestrous behaviour, oestrus cycle characteristics and dynamic ovarian events witnessed during 50 oestrous cycles (involving 106 ovulations) in 10 Catalonian jennies between March 2002 and January 2005. These jennies were teased, palpated transrectally and examined by ultrasound using a 5 MHz linear transducer—daily during oestrus and every other day during dioestrus. Predictors of ovulation were sought among the variables recorded.The most evident signs of oestrus were mouth clapping (the frequent vertical opening and closing of the mouth with ears depressed against the extended neck) and occasional urinating and winking of the vulval lips (homotypical behaviour). Interactions between jennies in oestrus were also recorded, including mounting, herding/chasing, the Flehmen response, and vocalization (heterotypical behaviour).Nine jennies ovulated regularly throughout the year; one had two anovulatory periods (54 and 35 days). The length of the oestrus cycle was 24.90 ± 0.26 days, with oestrus itself lasting 5.64 ± 0.20 days (mean ± S.E.M.) and dioestrus 19.83 ± 0.36 days. The incidence of single, double and triple ovulations was 55.66% (n = 59), 42.45% (n = 45) and 1.89% (n = 2), respectively. No significant difference was seen in the number of ovulations involving the left and right ovaries (52.63% [n = 70] compared to 47.37% [n = 63] respectively; P > 0.05). The mean interval between double ovulation was 1.44 ± 3.98 days. The mean diameter of the preovulatory follicle at day −1 was 44.9 ± 0.5 mm; the mean growth rate over the 5 days before ovulation was 3.7 mm/day.Data on preovulatory changes in oestrous behaviour, follicle size, follicle texture, the echographic appearance of the follicle and uterus, and uterine tone were subjected to stepwise logistic regression analysis to detect predictors of ovulation. The logit function showed the best predictors to be follicle size, follicular texture and oestrous behaviour. Certain combinations of these three variables allow the prediction of ovulation within 24 h with a probability of >75%.  相似文献   

5.
Effect of wearing gloves on timely muscle reaction to stabilize handle perturbation was investigated. Thirteen adults gripped a horizontal overhead handle to which an upward force was applied at a random time. Muscle reaction time, integrated EMGs for eight muscles, and handle displacement were compared among three glove conditions affecting the coefficient of friction (COF = 0.32, 0.50, and 0.74 for the polyester glove, bare hand, and latex glove, respectively). Lower COF increased the integrated EMGs and handle displacement until stabilization of the perturbed handle. The low-friction glove resulted in 16% (p = .01) greater muscular effort and 20% (p = .002) greater handle displacement, compared to the high-friction glove. Muscle reaction time was not influenced by glove condition. Cutaneous sensation and reflex eliciting forearm muscle activity appear to play an important role in detecting and responding to the perturbation initially, while the forearm and latissimus dorsi muscles primarily contribute to stabilizing the perturbed handle compared to other shoulder and upper arm muscles. Therefore, low-friction gloves, cutaneous sensory dysfunction, and weakened forearm and latissimus dorsi muscles may jeopardize persons’ ability to stabilize a grip of a handle after perturbation.  相似文献   

6.
A coordinated activation of distal forearm muscles allows the hand and fingers to be shaped during movement and grasp. However, little is known about how the muscle activation patterns are reflected in multi-channel mechanomyogram (MMG) signals. The purpose of this study is to determine if multi-site MMG signals exhibit distinctive patterns of forearm muscle activity. MMG signals were recorded from forearm muscle sites of nine able-bodied participants during hand movement. By using 14 features selected by a genetic algorithm and classified by a linear discriminant analysis classifier (LDA), we show that MMG patterns are specific and consistent enough to identify 7 ± 1 hand movements with an accuracy of 90 ± 4%. MMG-based movement recognition required a minimum of three recording sites. Further, by classifying five classes of contraction patterns with 98 ± 3% accuracy from MMG signals recorded from the residual limb of an amputee participant, we demonstrate that MMG shows pattern-specificity even in the absence of typical musculature. Multi-site monitoring of the RMS of MMG signals is suggested as a method of estimating the relative contributions of muscles to motor tasks. The patterns in MMG facilitate our understanding of the mechanical activity of muscles during movement.  相似文献   

7.
We studied the postnatal development of wing morphology and echolocation calls during flight in a free-ranging population of the big-footed bat, Myotis macrodactylus, using the mark-recapture methodology. Young bats were reluctant to move until 7 days of age and started fluttering at a mean age of 10 days. The wingspan and wing area of pups followed a linear pattern of growth until 22 days of age, by which time the young bats exhibited flapping flight, with mean growth rates of 0.62 mm/day and 3.15 mm2/day, for wingspan and area, respectively, after which growth rates decreased. Pups achieved sustained flight at 40 days of age. Of the three nonlinear growth models (logistic, Gompertz, and von Bertalanffy), the logistic equation provided the best fit to the empirical curves for wingspan and wing area. Neonates emitted long echolocation calls with multiple harmonics. The duration of calls decreased significantly between flutter (19 days) and flight (22 days) stages. The peak and start frequency of calls increased significantly over the 3-week period of development, but the terminal frequency did not change significantly over the development period.  相似文献   

8.
Background and objectivesTreatment of hypothyroid pregnant women is usually calculated based on weight (1 μg/kg/day) and TSH levels. This study assessed the usefulness of treating these women with a fixed dose of 75 μg/day.Patients and methodsAll women with pregnancy diagnosed from January to August 2012 in the Vigo Health Area (Spain) without previous diagnosis of thyroid disease or thyroxine treatment and with TSH levels over 4,5 mUI/ml were enrolled by consecutive sampling. All 116 women in the sample were treated with a fixed daily dose of thyroxine 75 μg-thyroxine levels were measured at two, four, and six months, and thyroxine dose was modified if TSH level was lower than 0.3 or higher than 4.5 mUI/ml.ResultsA woman had a TSH level less than 0.3 mUI/ml in a test; reduction of thyroxine dose to 50 μg/day allowed for maintaining TSH level within the desired range until delivery. Six women had TSH levels over 4.5 mUI/ml in one test; in all of them, increase in thyroxine dose to 100 μg/day allowed for maintaining the level within the desired range until delivery.ConclusionsFixed daily doses of thyroxine 75 μg allowed for achieving goal TSH levels in most of our pregnant women with subclinical hypothyroidism, irrespective of their weight and baseline TSH level.  相似文献   

9.
Maternal nutrient intake during gestation can alter fetal growth. Whilst this has been studied extensively in the sheep, less is known about effects in the bovine. Composite-breed beef heifers were allocated to either a high (H/? = 76 MJ metabolisable energy (ME) and 1.4 kg crude protein (CP)) or low (L/? = 62 MJ ME and 0.4 kg CP daily) nutritional treatment at artificial insemination. Half of each nutritional group changed to an opposite nutritional group at the end of the first trimester (?/H = 82 MJ ME and 1.4 kg CP; ?/L = 62 MJ ME and 0.4 kg CP daily), resulting in 4 treatment groups: HH (n = 16); HL (n = 19); LH (n = 17); LL (n = 19). During the third trimester all heifers were fed the same diets. Fetuses were measured at 4-weekly intervals beginning at day 39 of gestation. Calves were also measured at birth for physical body variables. Low maternal nutrient intake was associated with decreased crown-rump length at day 39 (P < 0.01) and increased thoracic diameter at day 95 (P < 0.01). Umbilical cord diameter was reduced in L/? fetuses in the first trimester (P < 0.05) but was greater in ?/L fetuses in the second trimester compared to their respective H counterparts (P < 0.05). Calf birth weight was decreased in association with ?/L maternal diets (P < 0.05). In conclusion, fetal development of cattle may be affected by maternal nutrition as early as day 39 of gestation. This may be followed by either compensatory fetal growth, or alternatively, preferential fetal tissue growth that is dependant upon maternal nutrition. Clearly, calf birth weight may be altered by maternal nutrition during mid-gestation.  相似文献   

10.
Static, B-mode ultrasound is the most common method of measuring fascicle length in vivo. However, most forearm muscles have fascicles that are longer than the field-of-view of traditional ultrasound (T-US). As such, little work has been done to quantify in vivo forearm muscle architecture. The extended field-of-view ultrasound (EFOV-US) method, which fits together a sequence of B-mode images taken from a continuous ultrasound scan, facilitates direct measurements of longer, curved fascicles. Here, we test the validity and reliability of the EFOV-US method for obtaining fascicle lengths in the extensor carpi ulnaris (ECU). Fascicle lengths from images of the ECU captured in vivo with EFOV-US were compared to lengths from a well-established method, T-US. Images were collected in a joint posture that shortens the ECU such that entire fascicle lengths were captured within a single T-US image. Resulting measurements were not significantly different (p = 0.18); a Bland-Altman test demonstrated their agreement. A novice sonographer implemented EFOV-US in a phantom and in vivo on the ECU. The novice sonographer’s measurements from the ultrasound phantom indicate that the combined imaging and analysis method is valid (average error = 2.2 ± 1.3 mm) and the in vivo fascicle length measurements demonstrate excellent reliability (ICC = 0.97). To our knowledge, this is the first study to quantify in vivo fascicle lengths of the ECU using any method. The ability to define a muscle’s architecture in vivo using EFOV-US could lead to improvements in diagnosis, model development, surgery guidance, and rehabilitation techniques.  相似文献   

11.
The feasibility of using Verano stylo (Stylosanthes hamata cv. Verano) and Guinea grass (Panicum maximum cv. Ntchisi) hays and their replacement values in concentrate diets for rabbits were determined. The intake and growth of the rabbits were monitored over a 7-week growth study following a 2-week adaptation period, while nutrient digestibility was determined over a 5-day period during the eighth week of the study. The DM intakes of the rabbits during the growth study were 53.1 g/day of the grass + concentrate (50 : 50) diet, 56.0 g/day of the all-concentrate diet and 64.8 g/day for the Verano stylo + concentrate (50 : 50) diet. The respective weight gains were 5.13, 8.44 and 8.35 g/day. Lower DM intake and consistent losses in weight of the animals were recorded on Verano stylo or Guinea grass alone. Verano stylo hay was better than Guinea grass hay. Thus, concentrate supplementation of forage diets is necessary for rabbits. Replacement of 0.50 of the concentrate with Verano stylo hay gave a similar performance to that for the all-concentrate diet. It is, therefore, possible to reduce the use of concentrates in the diets for growing rabbits in the dry season by replacing part of the diet with Verano stylo hay.  相似文献   

12.
《Zoologischer Anzeiger》2009,248(4):273-283
The limbs of the three-toed skink Chalcides chalcides are reduced to such a degree that the three digits are too small for skeletochronology. This study, performed on animals collected near Isernia (central Italy), describes the structure of the caudal vertebrae, which are often naturally lost due to autotomy, in order to determine whether they can be used to obtain data on age and growth with skeletochronological techniques. The reliability of the autotomous caudal vertebrae for skeletochronology was verified by performing skeletochronological analyses also on femora. Although the identification of the lines of arrested growth (LAGs) was easier in femora than in autotomous caudal vertebrae, a high correspondence of the LAG count between the two bones was observed. Females were larger and lived longer than males (4 and 3 years, respectively). For both sexes, the snout vent length (SVL) was significantly correlated with age. For both sexes, sexual maturity was attained after two hibernations from birth, beginning at the 20th month of age. At first reproduction, males had an SVL of 91–106 mm and females one of 111–150 mm. Von Bertalanffy growth curves of age versus SVL showed that females had slower growth rates than males for attaining their asymptotic SVL (females: 197 mm; males: 143 mm). The results provide the first data on age and growth of C. chalcide, and show that autotomous caudal vertebrae are reliable alternatives for obtaining such data for limb-reduced reptiles, avoiding the need to sacrifice or disable animals, as occurs when long bones are used.  相似文献   

13.
Acoustic signals that emanate from ecosystems are an important ecological variable which can provide evidence of current ecological condition as well as ecological change over time. The Terrestrial Ecosystem Research Network (TERN) established protocols to record sounds in ten SuperSites distributed throughout Australia with the objective of characterizing the soundscape in a representative landscape in different regions of Australia. This acoustic monitoring system enables a comparison of the soundscapes within and between Australian regions to determine similarities and differences in these landscapes and regions.This research quantifies the soundscape patterns in one of these SuperSites, Samford Ecological Research Facility (TERN-SERF), which is part of the South-East Queensland Peri-Urban SuperSite. An analysis and visualization of patterns in the soundscape was conducted using a continuous acoustic recording collected at TERN-SERF. The recording was made using a Song Meter (SM2) in a representative wooded habitat at TERN-SERF from 1 August to 30 September 2013. The recording was made in 16-bit stereo at 44 kHz and stored in wav file format. The recording was split into 1-minute-long recordings comprising 86,196 records and then sub-sampled at a 30-minute interval, providing 2878 one-minute-long recordings every 1/2 h. Soundscape metrics were computed for each of the two recording intervals. Soundscape power values were computed for each of ten frequency intervals (1–11 kHz) for both the 1-minute and the 30-minute interval recordings. In addition, six acoustic indices were computed from each recording.The acoustics metrics derived from the two sets of recordings (1-minute and 30-minute recording intervals) were examined to determine if they revealed different patterns. Several soundscape metrics were calculated for each recording including ten soundscape power values at 1 kHz frequency intervals and six acoustics indices. The soundscape shows a dynamic but consistent pattern over time of day during the monitoring period, depending on the metric examined. The metrics revealed different soundscape patterns. All soundscape power values at 1 kHz frequency intervals defined the dawn and dusk chorus, some more distinctly than others. Three of six acoustic indices also changed abruptly at the dawn chorus. No significant difference was found when soundscape metrics were compared between the 1-minute (high resolution) and 30-minute (lower resolution) recording intervals. A t-test was used to compare the mean values of ten soundscape power frequency intervals (p = 0.44) and the mean values of six acoustics indices (p = 0.41).Sounds were identified in 180 recordings made at 0530 h, 0600 h and 0630 h in the 1-minute long 30-minute interval recordings each day during the recording period (August and September). Sixty-seven species of birds were identified. Soundscape metrics were correlated with avian species counts and calls by all species using a correlation threshold of r > 0.7. This analysis revealed that soundscape power at the frequency interval 3–4 kHz was correlated with both the number of species (r =  0.927) and total calls (r =  0.996) over the three time periods. Three indices, the ADI (r = 0.953, r = 0.709), the AEI (r = 0.978, r = 0.774) and (H) (r = 0.795, r = 0.985) were similarly correlated as was an index derived soundscape power, the Shannon-Weaver Index (r =  0.997, r =  0.849). Other indices were correlated (r > 0.7) with only the number of avian species or only the number of calls.This methodology establishes an analysis protocol for analyzing large acoustic data sets, and demonstrates the effectiveness of using acoustic metrics for summarizing and interpreting long-term recordings.  相似文献   

14.
In this study, the effects of methyl jasmonate (MJ) and silver nitrate (SN) treatment on metabolic profiles and yields of phytosterols such as campesterol, stigmasterol, and β-sitosterol in whole plant cultures of Lemna paucicostata were investigated using gas chromatography–mass spectrometry coupled with multivariate statistical analysis. The MJ and SN treatments retarded the growth of L. paucicostata plants, while they enhanced the yields of three phytosterols, compared to control. Higher yields of phytosterols were attained at day 28 compared to day 42. Moreover, stigmasterol yield was the highest at 0.85 mg/g from day 28 plants grown under MJ + SN co-treated culture. Among the various metabolites, the levels of palmitic and stearic acids, which might participate in a defense mechanism, were higher in the MJ + SN condition than in control. To determine the optimal timing of MJ + SN addition, MJ + SN was added on days 21, 28, and 35 after inoculation. The total yield and productivity of phytosterol reached maximum levels when the MJ + SN was added at day 35. The highest productivity of stigmasterol (6.08 mg/L) was also achieved when MJ + SN was added on day 35.  相似文献   

15.
Many studies regarding growth in diameter at breast height (D) in trees suffer from several problems, including heteroscedasticity, temporal autocorrelation and very low statistical adjustments. In growth ring studies, growth models are sometimes omitted, presenting only a mean curve or smoothings, while studies that use models often do not address the above mentioned problems. For these reasons, this paper proposes a new approach to the classical modeling of D = f(t), where t is age (years), using the logarithmic transformation of the relative growth rate ln(1/D)(dD/dt) = ln f(D, A),where A is the asymptote of D based on the differential growth rate model of von Bertalanffy. High statistically significant adjustments for Cedrela odorata (ME = 65%, model efficiency, ME, an analogous to R2 but for non-linear regressions), and Juglans neotropica (ME = 78%) were obtained and met all regression assumptions. These equations were integrated to obtain D = f(t) for both species, followed by self and independent validation. Based on these equations, different life history and silviculture traits were calculated for both species. This procedure does not appear to have been previously used in the study of tree growth.  相似文献   

16.
《Aquatic Botany》2005,82(1):39-54
Meristematic growth and loss of distal tissue from blades of two ecologically important species in the south-east Pacific, Lessonia nigrescens and Lessonia trabeculata, was evaluated during 1 year. Comparative growth was determined by a hole-punch method, loss of distal tissue from the blades was determined by subtracting final blade length (with loss) from expected blade lengths (without loss); growth and tissue loss were transformed to fresh biomass units for calculation of inter-algae differences. The results showed that blade elongation rate increased at the beginning of spring, and declined towards the end of summer, with mean values between 0.40 and 0.08 cm day−1 for L. nigrescens, and 0.65–0.17 cm day−1 for L. trabeculata. Loss of distal tissue varied seasonally when examined as length units for both species; with mean values between 0.24 and 0.10 cm day−1 for L. nigrescens, and 0.51–0.25 cm day−1 for L. trabeculata. Variations in fresh biomass units were only observed in Lessonia trabeculata, increasing in spring, with mean values to 0.13 g (fresh weight) day−1. Annual growth and loss of distal tissue were higher in L. trabeculata (0.41 and 0.39 cm day−1, respectively) than in L nigrescens (0.19 and 0.15 cm day−1). When growth and tissue loss were considered as fresh biomass, monthly gains significantly outweighed loss of distal tissue in both species, but parallel results based on length data followed a different trend. L. trabeculata released about 50% of its growth biomass as particulate organic matter, while the comparative value for L. nigrescens was about 20%.  相似文献   

17.
《Small Ruminant Research》2000,35(2):133-139
Thirty-six Spanish goat wethers (196 ± 12.9 days of age and 17.5 ± 4.60 kg BW at experiment initiation) from a herd previously selected for cashmere growth were used to determine effects and interactions of ad libitum consumption of diets differing in concentrations of CP (10% and 15%) and ME (2.00, 2.35 and 2.70 Mcal/kg; DM basis) on growth and cashmere fiber production in an 84-day, fall-season experiment. DM intake was greater (P < 0.05) for diets with 15% vs. 10% CP (736 vs. 655 g/day) but similar among ME concentrations (P > 0.10). ADG was greater (P < 0.02) for 15% vs. 10% CP (79 vs. 53 g/day) and increased linearly (P < 0.10) as dietary ME level increased (58, 62 and 78 g/day for 2.00, 2.35 and 2.70 Mcal/kg ME, respectively). Total fleece weight at the end of the experiment was similar (P > 0.10) between CP levels but increased linearly (P < 0.03) as ME concentration in the diet increased (197, 239 and 227 g/day). Guard hair weight was not affected by dietary treatments (P > 0.10); cashmere length was similar among treatments (P > 0.10); and cashmere fiber diameter was not altered by dietary ME level (P > 0.10) but was greater (P < 0.05) for 15% vs. 10% CP (16.92 vs. 16.06 μm). Cashmere weight was influenced by an interaction between CP and ME levels (P < 0.05); cashmere fiber weight with 10% CP was 92, 82 and 95 g, and with 15% CP was 63, 115 and 99 g for 2.00, 2.35 and 2.70 Mcal ME/kg diets, respectively (SE = 10.2). However, the ranking of treatment means for initial cashmere fiber weight was similar to that at the end of the experiment, although differences at the beginning were non-significant and of lesser magnitude than at the end. In conclusion, further research with influences of concentrations of CP and ME in diets consumed ad libitum on cashmere fiber growth of growing US Spanish wether goats is required, and animal numbers and allocation to treatments deserve careful consideration in studies of cashmere fiber production.  相似文献   

18.
《Small Ruminant Research》2007,69(3):336-339
The aim of this study was to evaluate effects of two production systems (spring and winter), sex and birth type on growth performance in Norduz lambs. Data were collected using 103 and 140 lambs born during the winter and spring, respectively. Lambs born in the winter were heavier (P < 0.01) than those born in the spring at birth, 90 and 180 days of age by 0.5, 1.6 and 1.7 kg, respectively. Ram lambs were heavier (P < 0.01) than ewe lambs at birth, 90 and 180 days of age by 0.5, 1.0 and 2.3 kg, respectively, while lambs born as singles were heavier (P < 0.01) than lambs born as twins at birth, 90 and 180 days of age by 0.9, 1.6 and 2.3 kg, respectively. Lambs born in the winter recorded a higher (P < 0.01) pre-weaning ADG (15 g/day) than spring-born lambs, while ram lambs recorded a higher (P < 0.01) pre-weaning ADG (11 g/day) than ewe lambs. The effect of birth type was not significant on pre-weaning ADG. The influence of lambing season and sex were also not significant on post-weaning ADG. Lambs born as singles recorded a higher (P < 0.01) post-weaning ADG (16 g/day) than lambs born as twins. Results suggest the winter season to give rise to heavier lambs at weaning and post-weaning and suggest lambs born in different seasons to have distinctly different growth patterns. The data also confirm that the influence of sex and type of birth on growth to be very important and to be take into account sheep production.  相似文献   

19.
In this research, electromagnetic fields of strength gradient 48–115 kA/m were applied, and it was found that the increase in the field strength stimulated the regeneration and growth in the explants. The effect of a 10-min treatment of explants with a strength of 97 kA/m on the regeneration and growth was highest, and the number of the sprouts induced (17.2 ± 1.74) was 2.3 times greater than that in the control group (7.40 ± 0.51). The fresh weight, dry weight and height of the sprouts from the explants treated with a strength of 97 kA/m, in culture medium 2 (MS + 2.0 mg/L ZT + 0.2 mg/L IBA + 30 mg/L Vc), were higher than those in culture medium 1 (MS + 2.0 mg/L ZT + 0.2 mg/L NAA + 30 mg/L Vc) and the control group, and the mean number of the sprouts in culture medium 2 increased 5.2 times, but 3.1 times in culture medium 1. Root length of plantlets from explants treated with a strength of 97 kA/m and optimized rooting medium 1/2MS + 0.1 mg/L NAA + 0.1 mg/L IBA + 30 mg/L bovine serum albumin (BSA) was significantly larger, compared with the control. The average root length was 5.39 ± 0.68 cm. It was concluded that the optimization of culture medium and treatment of explants with a certain magnetic field strength could increase the number of regeneration sprouts and growth.  相似文献   

20.
《Small Ruminant Research》2010,91(1-3):150-152
Ghrelin, an endogenous gland for growth hormone secretagogue receptor, has been shown to stimulate food intake and control energy homeostasis and lipid metabolism. So, ghrelin precursor (GHRL) gene is a potential candidate gene for caprine growth traits. In this study, we detected the polymorphism of the caprine GHRL gene by PCR–SSCP and DNA sequencing methods in 459 individuals from four goat breeds. A novel single nucleotide polymorphism (SNP) (IVS2 + 147G > A) was detected. Frequencies of IVS2 + 147G allele varied from 0.842 to 1.000. The association of IVS2 + 147G > A with growth traits was analyzed and IVS2 + 147G > A was shown to be associated with growth traits. Individuals with genotype AG were significantly higher than those of individuals with genotype GG in circumference of chest and cannon and trunk index (P < 0.05 or P < 0.01). Moreover, there was a tendency that genotype AG individuals had better performance in other aspects such as body height and body length than genotype GG individuals although no significant differences appeared (P > 0.05). We suggested that IVS2 + 147G > A could be a perfect molecular marker in marker-assisted selection (MAS).  相似文献   

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