Sperm output in rainbow trout (Salmo gairdneri) — Effect of age,timing and frequency of stripping and presence of females     

S. Büyükhatipoglu  W. Holtz 《Aquaculture (Amsterdam, Netherlands)》1984,37(1):63-71

An experiment was conducted to investigate the sperm production of rainbow trout. Eighty-four first-spawners were allocated randomly to three groups to be stripped at weekly, 2-weekly or 4-weekly intervals, respectively. Half of each group were exposed to females. The trial extended over two successive spawning seasons.First-season spawners were modest sperm producers. Depending on the collection frequency they produced mean stripped semen volumes of 1.17 to 1.48 ml containing 7.7 × 10⁹ to 16.8 × 10⁹ sperm. The corresponding means for the second spawning season were 3.54 to 4.59 ml and 22.2 to 35.4 × 10⁹. The spawning season extended from October to April. Production and motility increased from the beginning to mid-season, followed by a gradual decline. The effect of the presence of females was not very evident. With increased frequency of stripping, more sperm/male were obtained. Total semen volume and number of sperm/spawner obtained during the first season with weekly, 2-weekly or 4-weekly collection amounted to 24.6 ml and 160.9 × 10⁹ sperm, 13.4 ml and 135.8 × 10⁹ sperm and 8.9 ml and 101.1 × 10⁹ sperm, respectively. The corresponding values for the second season were 88.9 ml and 546.1 × 10⁹ sperm, 50.3 ml and 377.5 × 10⁹ sperm and 32.1 ml and 247.9 × 10⁹ sperm.From a practical point of view, weekly collection is feasible in second-season spawners, but a maximum of one stripping every 2 weeks appears appropriate for first-season spawners.  相似文献   

Digestive Tract Anatomy of Norwegian Sheep: Difference Between Breeds     

Geir Stenheim  La Nordheim  Rb Weladji  Ø Holand  T Ådnøy 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(3):155-158

Data on 216,428 Danish Red, 798,152 Danish Friesian and 232,953 Danish Jersey cows were used to estimate phenotypic and genetic parameters for actual and production‐corrected survival traits and for milk production. Genetic effects of imported breeds were also estimated. Phenotypic trends in days in milk were similar for Danish Red and Danish Friesian, and showed influences of the milk quota system, whereas Danish Jersey showed a continuous downwards trend. Significant additive and non‐additive effects due to imported breeds were found. Heritabilities differed between breeds, ranging from 0.072 to 0.122 for actual continuous lifetime traits, and from 0.048 to 0.076 for production‐corrected continuous lifetime traits. Binary stayability traits showed lower heritability. Genetic correlations between milk production and actual or production‐corrected days in milk were 0.63 and 0.31 respectively. Genetic correlations between binary stayabilities and continuous lifetime traits were high (>0.78), which indicates that stayabilities can be used as early predictors of the lifetime traits.  相似文献   

Indications of breed by environment interaction for lamb weights in Norwegian sheep breeds     

G. Steinheim  T. Ådnøy  T. Meuwissen  G. Klemetsdal 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(4):193-196

With high variation in environmental conditions, especially during the extensive grazing season, genotype by environment interaction is potentially important to lamb production in Norway. Using breed as an indicator of genotype, the interaction between breed and environment, i.e. production level of farm and year calculated as solutions of a random farm*year variable, on 52 farms keeping both long-tailed Dala and short-tailed Spæl during 1989–98 was studied. The dataset included 48,946 Dala lambs and 38,299 Spæl lambs. The breed by environment interaction affected lamb autumn weights, and though Dala lambs were always heavier, the difference was substantially smaller at lower than at higher production levels: 1 kg increase in production level was related to Dala lambs’ weights increasing 0.09 kg more than the Spæl lambs’ weights. The results indicate that breed by environment interaction may be of importance, and potential bias in the data and need for further research is discussed.  相似文献   

Effects of concentrate feeding systems,genotype and sex on productive performance and meat quality of Norwegian lambs     

D. E. Mushi  O. S⊘rheim  T. Ådn⊘y 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(1):23-30

Abstract

Two factorial experiments, I and II, were carried out in this study using 84 lambs (140±1.24 days old, 40.00±0.75 kg live weight) divided into six groups. Two levels of concentrate supplementation; restricted (0.4 kg concentrate/lamb/day) or ad libitum, two breed types; Norwegian White lamb or Nor-X and two sex types; ram or ewe lambs, were investigated. In experiment I, a 2×2×2 factorial arrangement of treatments (level of supplementation, sex, and breed) was imposed whereas a 2×2 arrangement of treatments (level of supplementation and breeds) was studied in Experiment II. Each of the two experiments lasted for four weeks. Lambs on ad libitum access to concentrate grew at 231 g d^–1 and 125 g d^–1 faster than those on restricted access in Experiment I and II, respectively. Moreover, ram lambs grew at 64 g d^–1 faster than ewe lambs. Lambs on ad libitum access to concentrate had about 5 kg heavier carcasses than that on restricted access. Ewe and ram lambs on ad libitum allowance to concentrate had 4.2 kg and 5.6 kg, respectively, higher carcass weight than those on restricted allowance. The two levels of concentrate supplementation had limited effects on the meat sensory qualities. Meat taste intensity increased with level of concentrate supplementation. Difference in meat tenderness between ram and ewe lambs was only evidenced on ad libitum concentrate feeding. Irrespective of stage of growth (Experiment I vs. II) and concentrate supplementation level, Nor-X lambs were superior to Norwegian White lambs with respect to carcass conformation scores. Based on results from sensory assessments of meat, ram lambs should be slaughtered before October to avoid off-flavour on meat.  相似文献   

Differences in choice of diet between sheep breeds grazing mountain pastures in Norway     

G. Steinheim  L.A. Nordheim  R.B. Weladji  I.J. Gordon  T. Ådnøy  Ø. Holand 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(1):16-20

In the present study, the foraging behaviour of ewes from three common Norwegian sheep breeds; the long-tailed Dala sheep, and the two short-tailed breeds Spæl sheep and Norwegian Fur sheep was studied. Based on difference in body size and digestive anatomy, we expected the lighter short-tailed ewes to browse more on woody plants than the Dala ewes. The experiments were conducted during two consecutive summers within the flocks’ usual grazing areas, and we sampled the proportion of grazing time that ewes spent feeding on woody plant species. We tested the hypothesis by applying generalized linear mixed models to the feeding behaviour data. As predicted, the short-tailed ewes spent substantially more of their grazing time browsing on trees, bushes and heather compared to the Dala ewes. We discuss the results in the context of maintaining the, now threatened, pastoral landscapes of mountainous regions of Norway; short-tailed breeds should be more effective than the Dala breed in reducing tree and bush encroachment, but more detailed studies are needed to quantify the breed differences in this respect.  相似文献   

Variation in quantity and quality of native forages and grazing behavior of cattle and goats in Tanzania     

Ismail Saidi Selemani  Lars Olav Eik  Øystein Holand  Tormod Ådnøy  Ephraim Mtengeti  Daniel Mushi 《Livestock Science》2013,157(1):173-183

The study was conducted to assess the effects of seasonal variation in the quality and quantity of pasture and management of livestock exclosures (ngitili) on the grazing behavior of cattle and goats. The study was 2×2×2 factorial design with three independent variables: season (Dry or Rainy), ngitili management (Private or Communal) and animal species (Cattle or Goats). Focal and scan observation methods were used to record different behavioral activities. Vegetation attributes from the study areas were measured in two consecutive seasons. Most key forage species had significant higher crude protein (CP) content and in vitro organic matter digestibility (INVOMD) in rainy than in dry season (P<0.05), but Neutral Detergent Fiber (NDF) and Acid Detergent Fiber (ADF) did not vary significantly with season (P>0.05). ADF and NDF were significantly higher in species from communal ngitili than those from private ngitili (P<0.05). Above-ground herbaceous biomass and bulk density (BD) were significantly higher in the rainy season and in the private ngitili than in the dry season and in the communal ngitili respectively. Cattle and goats spent considerably more time grazing and browsing respectively in the rainy season than in the dry season (P<0.05). Cattle foraging activities did not vary significantly (P>0.05) with ngitili management, but goats found to spend considerably more time browsing in the communal ngitili and more time grazing in the private ngitili (P<0.05). Despite the merits of stocking cattle and goats together in the heterogeneous pasture, seasonal variation in forage resources requires investigation of other strategies such as use of multipurpose trees and treatment of crop residues to improve livestock production.  相似文献   

粗山羊草苗期抗叶锈性离体鉴定及抗叶锈基因推导     

魏学军  张海涛  张娜  胡亚亚  谢欢  赵丽娟  杨文香 《麦类作物学报》2013,33(5):907-911

为明确来自加拿大的17份粗山羊草含有的苗期抗叶锈病基因,选用15个小麦叶锈菌菌株和42个小麦叶锈病近等基因系,采用苗期离体叶片对其抗叶锈性进行鉴定和抗叶锈基因推导。结果表明,17份粗山羊草材料中,30942对15个菌株均表现免疫,30941对13个菌株表现免疫,说明这两个材料抗锈谱广,含有效的抗叶锈基因。经基因推导,这些粗山羊草材料中可能含有Lr1、LrB、Lr2b、Lr18、Lr21、Lr32、Lr33及未知抗叶锈基因。  相似文献   

Simulating the production potential and net energy yield of maize-ethanol in the southeastern USA     

Tomas Persson  Axel Garcia y Garcia  Joel O. Paz  Brenda V. Ortiz  Gerrit Hoogenboom 《European Journal of Agronomy》2010,32(4):272-279

The interest in producing ethanol from maize has increased during recent years. However, the potential for maize-ethanol production is restricted to the extent of the feedstock production and the feedstock collection radius around an ethanol processing plant. The harvested acreage of maize in Alabama, Florida and Georgia has varied from 115,000 ha to 1.4 million ha during the last 50 years. One basic criterion for a sustainable production of renewable bio-ethanol is a positive net energy yield (NEY), i.e. more energy must be produced than the non-renewable energy that is used in the energy production chain, including the feedstock production and transportation and the biofuel processing. The goal of this study was to evaluate the potential to produce renewable energy the form of maize-ethanol in a region with typical southeastern USA maize cropping conditions. Two maize production acreages, which represent current and historical large acreages, and two feedstock collection radii of 100 and 200 km around an ethanol plant in southwest Georgia were evaluated. Maize growth and yield were simulated with the Cropping System Model (CSM)-CERES-Maize model to account for climate and soil variability. The simulations included weather data for 68 years. The potential ethanol production and NEY were calculated based on the simulated yields and energy requirements for the production. The ethanol production potential was 30–40 times greater for the large production acreage than for the small acreage. The average NEY across all simulated years was positive for all evaluated production acreages and collection radii. However, it was negative for the large production acreage under certain weather conditions. This study showed the potential to provide for an increase in renewable ethanol production from maize in the southeastern USA to meet the demand of the ethanol processing infrastructure.  相似文献   

Nutritional and physicochemical variation in Turkish kabuli chickpea (<Emphasis Type="Italic">Cicer arietinum</Emphasis> L.) landraces     

Sertaç Özer  Tolga Karaköy  Faruk Toklu  Faheem S. Baloch  Benjamin Kilian  Hakan Özkan 《Euphytica》2010,175(2):237-249

We examined the physical, physicochemical, and cooking properties of 91 kabuli chickpea landraces from Turkey, using two cultivars (İnci and İzmir-92) as controls. All landraces were grown under the same agroclimatic conditions to eliminate variance caused by genotype × environment interactions. There was high diversity among the landraces in the contents of protein (17.55–23.31%), fat (4.45–6.11%), ash (2.54–3.41%), fiber (2.03–4.18%), starch (41.76–49.07%), moisture (6.39–10.57%), 100-seed weight (25.03–51.67 g), hydration capacity (0.2585–0.6169 g/ml), swelling index (0.7207–1.1859), swelling capacity (0.15–0.32 ml seed⁻¹), cooking time (33–72 min), and seed density (0.8450–1.4800 g/ml). Regional analysis of landraces showed significant differences with respect to nutritional characteristics and cooking parameters. There were also significant relationships between various seed quality and cooking parameters. Together, our results provide an initial step toward identification of chickpea landraces that may be useful for development of high-quality chickpea cultivars.  相似文献   

Protection of winter wheat against orange wheat blossom midge,Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae): efficacy of insecticides and cultivar resistance          下载免费PDF全文

Sandrine Chavalle  Florence Censier  Gilles San Martin y Gomez  Michel De Proft 《Pest management science》2015,71(5):783-790

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