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1.
Totally 13575 ewes of two different breeds, Dala and Spel, were inseminated with semen, frozen in straws and thawed at 70°C for 8 sec. An insemination dose of 0.2 ml containing approx. 150 × 106 spermatozoa with at least 45 to 50% progressive motility was imerted 5 to 12 mm into the cervix. The insemination was performed once between 12 and 30 h after the onset of heat. The NR rate of the Dala ewes increased significantly during the season. The NR rate of the ewes inseminated before 15. November was 44.3%, from 15. to 20. November 52.2%. from 20. to 25. November 55.3% and from 25. November and later 61.4%. The corresponding values for the ewes of the Spel breed were 57.3, 58.7, 61.5 and 71.0% respectively, and only the difference between the two last values was statistically significant. The difference between the fertility of the two breeds was significant within each of the periods . 相似文献
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A A Andersen 《American journal of veterinary research》1978,39(4):603-606
Serum samples were obtained from 30 Hereford steers in an area known to be free of foot-and-mouth disease (FMD) viruses as follows: before shipment and 4 times during a 70-day period after shipment; the sera were tested for the presence of cross-reacting antibody to various viruses. Percentages of sera containing cross-reacting antibody to FMD virus detected by the plaque-reduction neutralization and the radial immunodiffusion techniques were higher for the FMD viruses Asia and SAT I5 than for the FMD viruses A5, O1, and C1. Cross-reacting antibody was usually of low titer and usually present in only 1 or 2 consecutive serum samples. The incidence of cross reactions increased after stress of shipping and thus an infective agent may be responsible. These results were compared with results from sera collected from Herefords and Holstein-Friesians in a 2nd area; results did not indicate that Herefords have an excess of cross reactions with FMD viruses. 相似文献
3.
Genetic resistance to race alpha of C. lindemuthianum in the nine varieties of beans studied can be accounted for by dominant alleles at either of two loci, which are unlinked and which behave as duplicate factor loci in the classical sense. A similar system of loci governs reaction to races beta and gamma, with evidence favoring multiple allelism and dominance of alleles conferring susceptibility in certain instances in the case of beta. In addition, for reaction to races beta and gamma, there are distinct systems of complementary factors, again with multiple allelism at the beta loci. Finally, there is genetic linkage between genes of the duplicate factor set governing reaction to gamma and genes of the duplicate factor set, and complementary factor set conditioning reaction to beta. The genes that are members of the set(s) pertaining to any one race alone are independent of each other in a linkage sense.Paper based on work conducted by the senior author in partial fulfilment of requirements for the Doctor of Philosophy degree at Michigan State University and supported by the Rockefeller Foundation.Formerly Rockefeller Foundation Student in Crop Science, now Director, Instituto Nacional de Investigaciones Agricolas, Veracruz, Mexico; Professor of Crop Science, Michigan State University; and Research Pathologist, Crops Research Division, Agricultural Research Service, USDA. 相似文献
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K. Th. Andersen 《Journal of pest science》1937,13(7):81-84
Ohne Zusammenfassung
Mit 5 Abbildungen. 相似文献
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Changes in phosphorus fractions in three tropical soils amended with corn cob and rice husk biochars
Joseph Osafo Eduah Mark Kofi Abekoe Mathias Neumann Andersen 《Communications in Soil Science and Plant Analysis》2020,51(10):1331-1340
ABSTRACT The formation of phosphorus (P) compounds including iron-P, aluminum-P and calcium-P in highly weathered tropical soils can be altered upon biochar addition. We investigated the effect of corn cob biochar (CC) and rice husk biochar (RH) pyrolyzed at three temperatures (300°C, 450°C and 650°C) on phosphorus (P) fractions of three contrasting soils. A 90d incubation study was conducted by mixing biochar with soil at a rate of 1% w/w and at 70% field capacity. Sequential P fraction was performed on biochar, soil and soil-biochar mixtures. Increase in most labile P (resin-Pi, NaHCO3-Pi) and organic P fraction (NaHCO3-Po + NaOH-Po) in CC and RH biochars were inversely related to increasing temperature. HCl-Pi and residual P increased with increasing temperature. Interaction of CC and RH with soils resulted in an increase in most labile P as well as moderately labile P (NaOH-Pi) fractions in the soils. CC increased most labile P in the soils more than RH. The increase in most labile P fraction in soils was more significant at relatively lower temperatures (300°C and 450°C) than 650°C. However, the increase in HCl-Pi and residual P of the soils was more predominant at high temperature (650°C). The study suggested that biochar pyrolyzed at 300–450°C could be used to increase P bioavailability in tropical soils. 相似文献
7.
Damgaard LH Korsgaard IR Simonsen J Dalsgaard O Andersen AH 《Journal of animal science》2006,84(6):1338-1350
The objective of this study was, by means of simulation, to quantify the effect of ignoring individual heterogeneity in Weibull sire frailty models on parameter estimates and to address the consequences for genetic inferences. Three simulation studies were evaluated, which included 3 levels of individual heterogeneity combined with 4 levels of censoring (0, 25, 50, or 75%). Data were simulated according to balanced half-sib designs using Weibull log-normal animal frailty models with a normally distributed residual effect on the log-frailty scale. The 12 data sets were analyzed with 2 models: the sire model, equivalent to the animal model used to generate the data (complete sire model), and a corresponding model in which individual heterogeneity in log-frailty was neglected (incomplete sire model). Parameter estimates were obtained from a Bayesian analysis using Gibbs sampling, and also from the software Survival Kit for the incomplete sire model. For the incomplete sire model, the Monte Carlo and Survival Kit parameter estimates were similar. This study established that when unobserved individual heterogeneity was ignored, the parameter estimates that included sire effects were biased toward zero by an amount that depended in magnitude on the level of censoring and the size of the ignored individual heterogeneity. Despite the biased parameter estimates, the ranking of sires, measured by the rank correlations between true and estimated sire effects, was unaffected. In comparison, parameter estimates obtained using complete sire models were consistent with the true values used to simulate the data. Thus, in this study, several issues of concern were demonstrated for the incomplete sire model. 相似文献
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Influence of Disease Process and Duration on Acute Phase Proteins in Serum and Peritoneal Fluid of Horses with Colic 下载免费PDF全文
T.H. Pihl E. Scheepers M. Sanz A. Goddard P. Page N. Toft P.H. Andersen S. Jacobsen 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2015,29(2):651-658