Key Factors Affecting Reproductive Success of Thoroughbred Mares and Stallions on a Commercial Stud Farm          下载免费PDF全文

EA Lane  MLJ Bijnen  M Osborne  SJ More  ISF Henderson  P Duffy  MA Crowe 《Reproduction in domestic animals》2016,51(2):181-187

To evaluate factors contributing to fertility of thoroughbred mares, data from 3743 oestrous periods of 2385 mares were collected on a large thoroughbred farm in Ireland. Fourteen stallions (mean age 8.3 years; range 4–15 years) had bred 2385 mares (mean age 9.4 years; range 3–24 years). Maiden mares accounted for 12%, mares with a foal at foot for 64%, and barren, slipped or rested mares for 24% of the total. The mean pregnancy rate per cycle was 67.8% (68.6% in year 1 and 66.9% in year 2). Backward stepwise multivariable logistic regression analysis was utilized to develop two models to evaluate mare factors, including mare age, reproductive status, month of foaling, dystocia, month of cover, foal heat, cycle number, treatments, walk‐in status and stallion factors including stallion identity, stallion age, shuttle status, time elapsed between covers and high stallion usage on the per cycle pregnancy rate and pregnancy loss. Old age (p < 0.001) and cover within 20 days post‐partum (p < 0.003) were associated with lowered pregnancy rates. High mare age (p < 0.05) and barren, slipped or rested reproductive status (p = 0.05) increased the likelihood of pregnancy loss. Uterine inflammation or infection, if appropriately treated, did not affect fertility. Only high usage of stallions (used more than 21 times in previous week) was associated with lowered (p = 0.009) pregnancy rates. However, shuttle stallions were more likely to have increased (p = 0.035) pregnancy survival, perhaps reflecting a bias in stallion selection. In conclusion, mare age exerted the greatest influence on fertility; nonetheless, thoroughbreds can be effectively managed to achieve high reproductive performance in a commercial setting.  相似文献   

Chemisch-mineralogische und mikromorphologische untersuchung einer eutrophen (Ramann-) braunerde des Budapester Hügellandes     

F. Scheffer  H. Gebhardt 《Geoderma》1977,17(2):145-163

In spite of the fact that Ramann's concept of Braunerde was extensively used throughout the world, some pedogenic processes and soil properties which are important for the formation and existence of Brown Forest Soils (eutrophic brown earths) are still not well known. Hence, a soil was investigated which was classified as a “Braunerde” by Ramann in 1909. The main question was, whether there might be soil constituents such as inorganic amorphous substances (allophanes) which are able to stabilize the brown-earth fabric, or to inhibit clay migration. From chemical data as well as from the magnitude of the pH-dependent CEC, it was deduced that there are no appreciable amounts of allophanes within the soil. The fabric, however, seems to be stabilized by colloid-chemical flocculation of the clay particles caused by large amounts of carbonates and silicates deposited with the parent material (loess). The decalcified solum is still rich in silicates, especially sand and coarse-silt-sized micas and feldspars (60–200 and 20–60 μm fractions, respectively). Since - in comparison - loesses and loess-derived soils of the Central German mountain region contain less silicates, mainly in fine and medium silt fractions (2–6 and 6–20 μm diameter, respectively), the coarser-grained silicates were assumed to be important for maintaining the Ca²⁺ and Mg²⁺ saturation of the soil by continuous weathering and thus stabilizing the brown-earth fabric.Although the soil is saturated predominantly with Ca²⁺ and Mg²⁺ ions, clay migration proceeds within the upper horizons. This was shown by calculation of the amounts of clay formed by breakdown of micas originally present in the parent material (“clay formation balance”), as well as by micromorphological studies. Furthermore, micromorphological studies and x-ray diffraction data gave some evidence for the migration of preferably finest grained montmorillonitic clays (smectites) penetrated by organic substances (humus). This kind of “selective clay migration” was assumed to be caused by high Ca²⁺ (or Mg²⁺) concentrations in soil solution required for flocculation of humus-penetrated (humus-coated) smectites. From the occurrence of these “humus-smectites” the possibility was assumed that the soil studied has been developed from a former Chernozem type.Quantitatively, clay migration does not reach the amounts of clay formation (breakdown of micas) accompanied by precipitation of iron oxides on mineral surfaces (“Verbraunung”). Thus, the soil profile visually and macromorphologically clearly exhibits the features of brown earths. On the other hand, however, some clay migration was observed. Hence, the soil was classified as a “brown earth with some clay migration” (“schwach durchschlämmte Braunerde”).Judging from the results of the “clay formation balance” an appreciable pedogenic (autigenic) clay formation from weathering products of feldspars was excluded for the soil studied.  相似文献   

Induced resistance in tomato plants against Fusarium wilt invoked by Fusarium oxysporum f.sp. dianthi     

B. A. M. Kroon  R. J. Scheffer  D. M. Elgersma 《European journal of plant pathology / European Foundation for Plant Pathology》1991,97(6):401-408

Tomato plants, susceptible toFusarium oxysporum f. sp.lycopersici, were inoculated by immersing the roots in a conidial suspension ofF. oxysporum f. sp.lycopersici race 1,F. oxysporum f. sp.dianthi race 2 or a mixture of both fungi. Plants inoculated withF. oxysporum f. sp.lycopersici showed disease symptoms after 2 weeks, whereas plants inoculated withF. oxysporum f. sp.dianthi or a mixture of both fungi remained symptomless for over 7 weeks, the duration of the experiment. In another experiment root systems of plants were split and each half was separately inoculated. One half was firstly inoculated withF. oxysporum f. sp.dianthi or treated with water, followed after a week by a second inoculation of the other half withF. oxysporum f. sp.lycopersici or by a water treatment. The disease symptoms in the half firstly inoculated withF. oxysporum f. sp.dianthi were significantly delayed, compared to plants of which that half had been treated with water. BecauseF. oxysporum f. sp.dianthi reduced disease symptoms caused byF. oxysporum f. sp.lycopersici without any direct interaction with this pathogen, it is concluded thatF. oxysporum f. sp.dianthi is able to induce resistance againstF. oxysporum f. sp.lycopersici in tomato plants.  相似文献   

The effects of vaccination of Merino ewes with an attenuated Australian bluetongue virus serotype 23 at different stages of gestation   总被引：1，自引：0，他引：1  

M. FLANAGAN  SJ JOHNSON 《Australian veterinary journal》1995,72(12):455-457

SUMMARY A cell culture attenuated Australian bluetongue virus serotype 23 (BLU23) prototype vaccine was assessed for its effects on pregnant Merino sheep. Seventy-six ewes were vaccinated at 5 different stages of gestation, and the failure to lamb at term was as follows: 35 to 43 days of gestation, 20/36 (56%); 57 to 64 days of gestation, 3/10 (30%); 81 to 88 days of gestation, 3/10 (30%); 109 to 116 days of gestation, 0/10 (0%); 130 to 137 days of gestation, 0/10 (0%). Of 30 ewes vaccinated with a cell culture supernatant fluid control between 35 and 43 days of gestation, 6.7% (2/30) failed to lamb at term. Two ewes vaccinated with BLU23 vaccine between 35 and 43 days of gestation had lambs with hydranencephaly. All other lambs born were clinically normal. Three ewes vaccinated with BLU23 aborted. Two of these were vaccinated between 35 and 43 days of gestation, the 3rd between 81 and 88 days of gestation. Five lambs were born with BLU group antibody. Four of these were from ewes vaccinated between 35 and 43 days of gestation, and 2 of these had hydranencephaly. The fifth was from a ewe vaccinated between 57 and 64 days of gestation. The vaccine did not produce disease in adult sheep, but was a potent cause of early foetal death and to a much lesser extent foetal malformation.  相似文献   

Gram-negative Mastitis in Early Lactation May Interfere with Ovarian and Certain Endocrine Functions and Metabolism in Dairy Cows   总被引：1，自引：0，他引：1  

G Huszenicza  S Jánosi  M Kulcsár  P Kóródi  SJ Dieleman  J Bartyik  P Rudas  P Ribiczei-Szabó 《Reproduction in domestic animals》1998,33(3-4):147-153

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Effects of crushed conspecifics on growth and survival of Penaeus monodon Fabricius post larvae     

Bui Tui Nga  Miquel Lürling  Edwin Peeters  Rudil Roijackers  Marten Scheffer  & Truong Trong Nghia 《Aquaculture Research》2006,37(3):224-232

In the present study, the hypothesis tested was that Penaeus monodon post‐larvae (PL) experience lower growth when exposed to crushed conspecifics, which was achieved by exposing individual P. monodon PL with abundant food for 4 weeks to a gradient from 0 to 100 crushed conspecific PL L^?1. Both dry weight (48.5±7.2 mg) and body size (28.0±1.3 mm) of animals exposed to 1 macerated PL L^?1 were significantly (P≤0.011) higher than those of animals in treatments with 0, 5 and 10 crushed PL L^?1 (average over treatments: 25.6±3.2 mg; 23.4±0.5 mm). All animals died within 1 week when exposed to 70 and 100 crushed PL L^?1, and within 3–4 weeks when exposed to 50 and 30 crushed PL L^?1. Exposure time affected mortality and it appeared that LC₅₀ values decreased from 60 to 13 crushed PL L^?1 from 1 to 4 weeks' exposure. Survival of P. monodon PL was negatively correlated to pH, biological oxygen demand, ammonia and nitrate. In conclusion, low dose of crushed conspecifics has a stimulatory effect on P. monodon PL, as larvae were heavier and larger, while high doses cause high mortality.  相似文献   

Die Phosphatmobilität im Hochmoorboden in Abhängigkeit von der Düngung     

H. Kuntze  B. Scheffer 《植物养料与土壤学杂志》1979,142(2):155-168

Phosphate mobility in relation to fertilizing effects in raised-bog peat The phosphate solubility of raised-bog peat soils is very different from the phosphate solubility of mineral soils. Compared to mineral soils the losses of phosphates by leaching are 10 to 20 times higher. This mobility of phosphates is destined by the quantity, kind and time of fertilizing, land use (grassland or arable land) and fertilizing technique. Field and lysimeter trials with raised-bog peat soils show: 1. Water soluble phosphates are quickly translocated and leached. 2. Water insoluble phosphates are quickly solved and leached in raised-bog peat soils. The mobility of the phosphates decreases with increasing pH-value of the top soil and topdressing. At a pH-value of 4,O nearly 80% of Thomasphosphat and nearly 70% of Hyperphos phosphates are leached in lysimeter trials; at pH-value of 4 3 only 17 % of Thomasphosphat and 15 % of Hyperphos phosphates are leached. 3. To minimize leaching losses phosphate fertilizingin spring is recommended to reduce the phosphate leaching. 4. The phosphate leaching in grassland is twice or thrice less than in arable land.  相似文献   

Imaging of intermittency in ripple-wave turbulence     

WB Wright  R Budakian  DJ Pine  SJ Putterman 《Science (New York, N.Y.)》1997,278(5343):1609-1612

The dynamics of a fluid surface filled with high-amplitude ripples were studied with a technique (diffusing light photography) that resolves the height at all locations instantaneously. Even when nonlinearities are strong enough to generate a (Kolmogorov) cascade from long wavelength (where energy is input) to shorter wavelength, the resulting turbulent state contains large coherent spatial structures. The appearance of these structures in a thermal equilibrium state (with the same average energy) would be highly improbable.  相似文献   

Evaluation of a regimen using a progesterone releasing intravaginal device (CIDR) and PMSG as a treatment for post partum anoestrus in dairy cattle     

TF. JUBB  P. BRIGHTLING  J. MALMO†  MT. LARCOMBE  GA. ANDERSON  SJ. HIDES‡ 《Australian veterinary journal》1989,66(10):334-336

Anoestrous dairy cows in seasonally calving herds in the Macalister Irrigation District of Gippsland, Victoria were treated at the start of the mating period with a progesterone releasing intravaginal device (CIDR). The CIDR was inserted for 7 days and 400 IU of PMSG was injected intramuscularly at removal. There was no clinically useful difference among cows receiving the CIDR, a placebo and untreated cows in the interval from treatment to either first oestrus or conception, the conception rate to first service or percent pregnant by the end of mating. Analyses of data from 2-year-old cows, older cattle, cows calved at least 45 days or cows calved at least 55 days and cows treated 3 weeks after the start of mating did not show improved reproductive performance following treatment with the CIDR.  相似文献   

An attempt to prevent acute toxoplasmosis in macropods by vaccination with Hammondia hammondi     

GL REDDACLIFF  SJ PARKER  JP DUBEY  PJ NICHOLLS  AM JOHNSON  DW COOPER 《Australian veterinary journal》1993,70(1):33-35

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