bluuebunny/crossref_metadata_2025 huggingface dataset:
Strategic Position Taking and Presidential Influence in Congress
Authors: MARSHALL BRYAN W. , PRINS BRANDON C.
Published: March 2010

The rise and fall of presidential success in Congress remains a central puzzle in the literature. We model success as two interrelated processes: presidential position taking and Congress's decision to support or oppose the president. The analysis emphasizes the importance of strategic position taking in determining presidential success. We show that presidential approval significantly influences success, not only because it affects congressional behavior, but also because it shapes presidential decisions to take positions. Moreover, we explain that legislative success during the honeymoon period is driven by presidential position taking. Our findings highlight the role of a president's strategic decisions for theories explaining congressional‐executive relations.
The U.S. Congress and the Institutional Design of Agencies
Authors: MACDONALD JASON A.
Published: March 2010

Theories of agency design maintain that lawmakers impose requirements on how bureaucratic agencies make policy decisions, preventing those agencies from undermining lawmakers' political and policy goals. Empirical support for these theories is limited, however, by the difficulty of measuring critical variables hypothesized to influence the use of this tool of political control. For this study, I employed a methodology particularly well suited, but not previously employed, to study variance in the use of agency‐design provisions: interviews with congressional committee staff. Staffers' responses support several theories, cast doubt on one explanation, and point to nuances in other explanations of agency design.
Iraq Casualties and the 2006 Senate Elections
Authors: KRINER DOUGLAS L. , SHEN FRANCIS X.
Published: March 2010

Prior scholarship on the effects of war casualties on U.S. elections has focused on large‐scale conflicts. For this article, we examined whether or not the much‐smaller casualty totals incurred in Iraq had a similar influence on the 2006 Senate contests. We found that the change in vote share from 2000 to 2006 for Republican Senate candidates at both the state and county level was significantly and negatively related to local casualty tallies and rates. These results provide compelling evidence for the existence of a democratic brake on military adventurism, even in small‐scale wars, but one that is strongest in communities that have disproportionately shouldered a war's costs.
Building a Reputation on National Security: The Impact of Stereotypes Related To Gender and Military Experience
Authors: SWERS MICHELE
Published: March 2010

In a post‐9/11 world, all senators must establish their national security credentials with voters. Yet senators do not compete for leadership on an equal basis. Through an analysis of bill sponsorship, Sunday talk show appearances, and interviews with Senate staff, I demonstrate that defense policy is made in a partisan and gendered context. Gender stereotypes favoring male defense leadership create an additional hurdle for women, particularly Democratic women, as they seek to establish their reputations on security. By contrast, a record of military service facilitates senators' efforts to achieve action on their proposals and gain media attention for their views.
Communist Successor Parties And Coalition Formation In Eastern Europe
Authors: DRUCKMAN JAMES N. , ROBERTS ANDREW
Published: March 2010

One of the most distinctive features of new democracies is the presence of political parties associated with the old, repressive regime. This article investigates whether or not the Eastern European variant of these parties, which we call communist successor parties (CSPs), has affected coalition politics. It finds that CSPs do have significant effects on the dynamics of coalition formation. CSPs are less likely than other parties to be included in governing coalitions; coalitions that include CSPs are more likely to be oversized (that is, to include superfluous parties); and CSPs that make it into government are penalized, insofar as they receive less than their fair share of governing portfolios. We attribute these results to the salience of the regime divide—the affective dislike of many citizens for the legacies of communism. Our results extend research on coalition behavior to Eastern European contexts and show how affective dislike combined with vote‐seeking motivations can affect governing behavior.
Slavery, Partisanship, and Procedure in the U.S. House: The Gag Rule, 1836–1845
Authors: MEINKE SCOTT R.
Published: March 2010

From the 24th through the 28th Congresses, the House of Representatives operated under versions of a “gag rule” that blocked petitions dealing with abolition and related matters. This article presents the gag rule as not only a historically important window into slavery deliberations in Congress but also a case study in majority party restrictions of minority rights—and in the boundaries that constituency politics can place on majority power. Through analysis of vote choices and voting changes over time, I demonstrate that the gag rule's partisan origins gave way as northern members voted against party and with specific constituency pressures as well as general sectional sentiment. The gag rule shows the power of electoral considerations and constituency in the early U.S. House, and it also illustrates the force that constituency can have over majority procedural maneuvering.
War for the Floor: Partisan Theory and Agenda Control In the U.S. House of Representatives
Authors: FINOCCHIARO CHARLES J. , ROHDE DAVID W.
Published: March 2010

This article extends recent research on partisan agenda control in the U.S. House of Representatives to the issue of procedural control of the legislative agenda via special rules. In particular, we draw out a facet of cartel and conditional party government theories that has not been addressed in prior analyses: the simultaneous interrelationship between positive and negative agenda control. Using roll‐call data on two procedural matters—votes to order the previous question on a special rule and votes to adopt a special rule—over the 1953–2002 period, we found that, in the area of procedural control of the floor agenda, the majority party's amount of agenda control depends to a significant degree upon the party's homogeneity and power.
Third Parties, Elections, and Roll‐Call Votes: The Populist Party and the Late Nineteenth‐Century U.S. Congress
Authors: HIRANO SHIGEO
Published: March 2010

What effect do electorally successful third parties have on congressional roll‐call votes? There is widespread belief among scholars that third parties influence the policies of the major parties, but there is little systematic evidence of this influence. I exploit the unique historical context surrounding the Populist Party formation in 1892 to examine the effect of the Populist Party's electoral success on congressional roll‐call votes related to Populist issues. The results are consistent with two claims. First, co‐optation of the Populist Party's issues occurred even before the formation of the party. Second, the co‐optation of Populist policies does not appear to be correlated with the electoral success of the Populist candidates.
The Value of Majority Status: The Effect of Jeffords's Switch on Asset Prices of Republican and Democratic Firms
Authors: DEN HARTOG CHRIS , MONROE NATHAN W.
Published: March 2010

Using the change in party control of the Senate that resulted from Jim Jeffords's 2001 change in party affiliation, we compare competing partisan and partyless legislative theories. We offer a reconceptualization of agenda control that provides a new and promising basis for studying parties and policymaking in the Senate. Also, we present a novel methodology—an “event study”—to test partisan and partyless hypotheses. Our results show that, when Jeffords switched, the stock prices of Republican‐supported energy firms dropped and prices for Democrat‐supported firms rose, supporting the hypothesis that the majority party influences Senate decisions.
Agenda Power, Executive Decree Authority, and the Mixed Results of Reform in the Brazilian Congress
Authors: PEREIRA CARLOS , POWER TIMOTHY J. , RENNÓ LUCIO R.
Published: March 2010

This article examines how institutional change in the use of extraordinary legislation affects delegation of power and unilateral action in new democracies. From 1988 to 2001, Brazilian presidents were able to reissue decrees indefinitely and thus had substantial legislative power. In 2001, Congress amended the constitution so as to restrict the president to a single reissue of each lapsed decree. This reform has had mixed results: although it ended the practice of infinite reissues, it induced Presidents Cardoso and Lula to use more decrees than previous executives had. Presidential agenda power, rather than being reduced, has been sharpened. By analyzing patterns of presidential initiatives from 1995 to 2005, we demonstrate the mixed results of this constitutional reform.
The Consequences of Electoral Institutions for Careerism
Authors: HABEL PHILIP D.
Published: March 2010

Although electoral institutions have been shown to have a variety of effects, scholars have not investigated if certain voting rules enable politicians to enjoy longer legislative careers. I took advantage of a natural experiment—a sudden transition from a semiproportional voting rule to single‐member districts with plurality voting (SMDP)—to measure the effect of electoral institutions on careerism. My analysis revealed that voting rules have a profound influence on the dynamics of legislative careers: politicians elected under SMDP are far less likely to suffer electoral defeat or to retire than those elected via cumulative voting. The findings of this study not only provide additional insight into the seat safety of politicians elected in first‐past‐the‐post systems, but moreover offer new criteria by which to evaluate the choice of electoral institutions.
Legislative Voting Behavior, Seen and Unseen: A Theory of Roll‐Call Vote Selection
Authors: CARRUBBA CLIFFORD , GABEL MATTHEW , HUG SIMON
Published: March 2010

The empirical study of legislative behavior largely relies on roll‐call vote analysis, but roll‐call votes in many legislatures represent only a sample of legislative votes. We have good reasons to believe this sample is particularly poor for inferring party effects on legislative behavior. The selection of votes for roll call may be endogenous to exactly the characteristics of voting behavior (for instance, party cohesion) that we want to study. We must understand the roll‐call vote institution and account for its selection effects before we can draw inferences about legislative behavior from roll‐call results. This article develops a game‐theoretic model of roll‐call vote requests predicated on party leaders requesting votes to enforce party discipline. The model offers general and testable predictions about the selection process and how it affects observed and unobserved legislative voting behavior, particularly party cohesion.
Models of Nonresponse in Legislative Politics
Authors: ROSAS GUILLERMO , SHOMER YAEL
Published: March 2010

Tools dedicated to inferring the ideological leanings of legislators from observed votes—techniques such as NOMINATE (Poole and Rosenthal 1997) or the item‐response‐theory model of Clinton, Jackman, and Rivers (2004)—rest on the assumption that the political process that generates abstentions is ignorable, an assumption not always easy to justify. We extended the item‐response‐theory model to analyze abstention and voting processes simultaneously in situations where abstentions are suspected to be nonrandom. We applied this expanded model to two assemblies where the existing literature gives reason to expect nonrandom abstentions, and we demonstrate how our extensions yield nuanced analyses of legislative politics. We also acknowledge limits to our ability to decide on the adequacy of alternative assumptions about abstentions, since these assumptions are not readily verifiable.
Laws and Roll Calls in the U.S. Congress, 1891–1994
Authors: CLINTON JOSHUA D. , LAPINSKI JOHN
Published: March 2010

Recent empirical studies of lawmaking activity by legislatures rely heavily on roll call based measures and assume that roll call activity reflects lawmaking activity. We question this assumption for the case of the U.S. Congress. We examine several plausible sources of dissonance between the set of enacted public statutes and the universe of recorded votes in the U.S. Congress, using a comprehensive dataset of public enactments and roll call activity between 1891 and 1994. Because only 11.9% of the bills signed into law receive a recorded vote in the House, only 7.9% receive a recorded vote in the Senate, and only 5.5% receive a recorded vote in both the House and Senate, we provide guidance as to when studying voting behavior is likely a reasonable proxy for lawmaking behavior. There are sometimes important differences between the laws that do and do not receive a roll call that researchers should account for when using roll calls to study lawmaking in the U.S. Congress.
Legislative Productivity in the 93d–105th Congresses
Authors: COX GARY W. , TERRY WILLIAM C.
Published: March 2010

We exploit a large new dataset in order to revisit the determinants of “legislative success” in Congress. Previous studies have focused on one or (rarely) two Congresses. Ours is the first study based on panel data, allowing us to better measure such causal effects as how a member's productivity increases when they become a committee chair or their party attains a majority. While corroborating several previous findings, we also differ on several important points—e.g., whereas the most sophisticated previous study finds greater seniority and committee leadership posts boosting productivity in neither party, we find them boosting productivity in both.
Comparing Cosponsorship and Roll‐Call Ideal Points
Authors: ALEMÁN EDUARDO , CALVO ERNESTO , JONES MARK P. , KAPLAN NOAH
Published: March 2010

We use bill cosponsorship and roll‐call vote data to compare legislators' revealed preferences in the U.S. House of Representatives and the Argentine Chamber of Deputies. We estimate ideal points from bill cosponsorship data using principal‐component analysis on an agreement matrix that included information on all bills introduced in the U.S. House (1973–2000) and Argentine Chamber (1983–2002). The ideal‐point estimates of legislators' revealed preferences based on cosponsorship data strongly correlate with similar estimates derived from roll‐call vote data. Also, cosponsorship activity in the U.S. House has lower dimensionality than cosponsorship has in the Argentine Chamber. We explain this lower discrimination as a function of individual‐ and district‐level factors in both countries.
Partisan Stacking on Legislative Committees
Authors: HEDLUND RONALD D. , COOMBS KEVIN , MARTORANO NANCY , HAMM KEITH E.
Published: March 2010

One aspect of the partisan model for legislative committee development that is rarely studied is the degree to which the majority party seeks to control legislative committees—and, thereby, chamber decisions—via numerically “overproportional” majority party representation on standing committees. This form of “party stacking” is often mentioned in the literature but has received little systematic examination and hypothesis testing. Using data from state legislative committees for all 49 partisan legislatures in the 2003–04 and 2005–06 sessions, we found support for the partisan model: majority party stacking is associated with a slim majority party advantage in a state legislative chamber.
Legislative Oversight and the Substantive Representation of Black and Latino Interests in Congress
Authors: MINTA MICHAEL D.
Published: March 2010

When determining whether or not legislators are representing their constituents' interests, scholars using voting studies may overstate the role of strategic factors, such as reelection goals and constituent influence, while understating the effect of descriptive characteristics. I argue that race and ethnicity matter in congressional oversight of bureaucratic policymaking. My examination of hearing transcripts from the 107th Congress indicates that minority legislators are more likely than white legislators to participate in racial‐oversight hearings but not more likely than whites to participate in social welfare hearings. The results show that descriptive representation contributes to substantive representation, even if the costs of participating outweigh the electoral benefits.
Latino Representation on Congressional Websites
Authors: WILSON WALTER
Published: March 2010

Do Latino representatives enhance or “enlarge” Latino representation (Walsh 2002)? I examined the content of websites posted by members of the 110th Congress and found that the websites of Latino representatives are not more accessible to Spanish‐speaking users than the websites of non‐Latino representatives, nor are the sites more likely to exhibit pro‐immigrant positions or offer immigration assistance. The websites of Latino representatives are, however, more likely to present Latino perspectives. Latino representatives enhance Latino representation in this forum by enlarging or broadening the presence of a Latino voice in policy discussion.
Different Houses: The Distribution of Earmarks in the U.S. House and Senate
Authors: LAZARUS JEFFREY , STEIGERWALT AMY
Published: March 2010

Nearly all studies of pork‐barrel politics in the U.S. Congress focus on the House, biasing our conception of how politics influences federal spending and skewing our attention toward factors that are active in the House. This article highlights differences between the Senate and House in how pork is allocated. We identify four important differences between the House and Senate, generate hypotheses regarding how each difference should influence the distribution of pork projects, and test these hypotheses using data from earmarks in the Appropriations bills passed by the two chambers for fiscal year 2008. The results support three of our four hypotheses, suggesting that senators are driven by different motivations than House members. These results imply that theoretical accounts of pork‐barrel spending need to account for these interchamber differences. Our findings also highlight how studies of legislative behavior, more generally, need to account for important differences in legislative structure and organization.
The Institutional and Demographic Determinants of Latino Representation
Authors: CASELLAS JASON P.
Published: March 2010

Under what conditions are Latino candidates elected to Congress and state legislatures? How much does the ethnic composition of a district affect the chances that a Latino candidate will be elected in that district? Latinos constitute the single largest minority group in the country, one that is growing at an exponential rate. Post‐2000 redistricting created more majority‐Latino districts, but the absolute number of Latino legislators did not increase correspondingly. My analysis demonstrates that states with citizen legislatures and with higher legislative turnover rates are more conducive to the election of Latino candidates than are other states. Institutional and demographic differences among states affect the states' Latino descriptive representation. Namely, the institutional design of the legislature matters in terms of electoral responsiveness, with Arizona and California being the most responsive bodies and New York and the U.S. House the least responsive.
Making a Good Impression: Resource Allocation, Home Styles, and Washington Work
Authors: PARKER DAVID C.W. , GOODMAN CRAIG
Published: March 2010

Members of Congress engage in a variety of representational activities, but existing research suggests that the effect of these activities on reelection margins is mixed. Reframing the question, we examined whether or not constituents notice the home styles of members and members' efforts to communicate their activities through the allocation of official resources. Combining new data on members' office expenditures with data from the American National Election Studies, we found evidence that constituents perceive the representational activities of their members in a meaningful fashion. Franking, office expenditures, and travel back home to the district provide positive benefits to incumbents, shaping how constituents view these members and their activities.
Agenda Control, Majority Party Power, and the House Committee on Rules, 1937–52
Authors: SCHICKLER ERIC , PEARSON KATHRYN
Published: March 2010

The role of the U.S. House Rules Committee is consequential for theories of congressional parties, yet its role during the “conservative coalition” era is not well understood. We systematically analyzed the politics surrounding all special rules considered in Democratic Congresses from 1937 to 1952. We found that Rules repeatedly used its agenda power to push to the floor conservative initiatives that were opposed by the Democratic administration, the Rules Committee chair, and most northern Democrats, especially in Congresses that followed Republican election gains. The 44 conservative initiatives we identified include many of the most important policy issues considered during the period. Our findings challenge the idea that the majority party has consistently enjoyed a veto over which initiatives reach the floor, and they underscore the limits of roll‐call‐vote analysis in assessments of agenda control.
Isolated Facial Nerve Palsy in Childhood Acute Myeloid Leukemia
Authors: Hafiz MG , Islam A , Mannan MA , Rahman F
Published: March 2010

Case report-1: Sabarna, a female baby of fifteen months old was admitted in Pediatric Hematology and Oncology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh with the complaints of deviation of the angle of mouth to right side and inability to close the left eye for five days. Systemic examination revealed an incision scar mark on the left mastoid region. Facial asymmetry as evidenced by smooth forehead, absence of nasolabial fold, drooping of the angle of mouth and nonclosure of eyelid on left side. She was mildly pale, mild hepatomegaly, no lymphadenopathy, bone pain or bleeding manifestation. Physical, hematological and histopathological investigations the features were suggestive of facial nerve palsy due to granulocytic sarcoma (GS) with acute myeloid leukemia (AML). Following second day of chemotherapy her vital signs suddenly deteriorated and succumbed probably due to the leukostasis or intracranial hemorrhage. Case report-2: Chayon, another nine month old female baby was admitted in the same unit with the history of fever, proptosis of both eye balls, deviation of the angle of mouth to the right side and unable to close the left eye for one month. Physical examination revealed facial asymmetry with the features of left sided facial nerve palsy along with proptosis of eyeballs. She was moderately pale, moderate hepatosplenomegaly, no bleeding manifestation or bone pain. Physical, hematological and cerebrospinal fluid (CSF) examination the features were suggestive of facial nerve palsy due to leukemic cell infiltration with AML. Following induction and consolidation the baby is on continuation phase with regular follow up for last 9 month having significant improvement of her facial nerve palsy along with hematological remission. DOI: 10.3329/jbcps.v28i1.4646 J Bangladesh Coll Phys Surg 2010; 28: 53-58
Parturition induction two days prior to term decreases birth weight and lactational growth, but not piglet maturity, health or post-weaning growth
Authors: Olson G L , Robine L. , Rosengren L B , Baker C D , Duggan M. , Chirino M. , Weber L P , Harding J C.S.
Published: March 2010

Premature parturition induction may adversely affect postnatal health and performance. The objective of this study was to evaluate the impact of cloprostenol induction 2 d prior to term on piglet maturity (liver glycogen), postnatal productivity (birth weight, growth rate), and health (morbidity, mortality, passive antibody, fecal Clostridium perfringens). Two hundred and sixteen pregnant sows and their progeny (2827 piglets) were assigned to the study. Induction decreased gestation length 2.1 d (P < 0.0001), birth weight 107.2 g pig-1 (P = 0.0004), lactational growth 10.1 g d-1 (P = 0.05), and day 16 weight 0.30 kg pig-1 (P < 0.05). Liver glycogen concentration was 71.2 µg g-1 higher in the stillborns of induced sows (P = 0.03), suggesting the pre-term sows were catabolic. No group differences in post-weaning growth rate, pre-weaning mortality or morbidity, passive antibody transfer or fecal Clostridium perfringens level were found. Reduced lactational growth appeared attributable to the reductions in gestation length and birth weight, rather than in piglet maturity. In spite of reducing lactational growth and body weight at 16 d of age, the administration of cloprostenol 2 d prior to term, under the conditions of this study, resulted in no measureable long-term health or performance consequences. Key words: Porcine, parturition-induction, cloprostenol, prostaglandin F2α, glycogen, Clostridium perfringens
Genetic effects on reproductive traits in Warmblood horses
Authors: Wolc A. , Torzynski G. , Szwaczkowski T.
Published: March 2010

Reproductive efficiency is an important issue in horse breeding. However, almost no estimates of genetic parameters of reproductive traits in horses can be found in the literature. The objective of the study was to estimate heritability and genetic trends of foaling rate and number of reproductive seasons in Warmblood horses. The records of 3965 mares from six studs were analyzed. Mares were on average kept for 7.3 reproductive seasons with a foaling rate of 66%. Models included fixed effects of stud, period of birth, breed and random additive genetic effect. Heritability estimates were 0.12 for foaling rate and 0.17 for number of reproductive seasons. Key words: Heritability, reproduction, horse
Potential use of Acacia mearnsii condensed tannins to reduce methane emissions and nitrogen excretion from grazing dairy cows
Authors: Grainger C. , Clarke T. , Auldist M J , Beauchemin K A , McGinn S M , Waghorn G C , Eckard R J
Published: March 2010

We measured the effect of condensed tannins (CT) extracted from the bark of the Black Wattle tree (Acacia mearnsii) on the milk production, methane emissions, nitrogen (N) balance and energy partitioning of lactating dairy cattle. Sixty lactating cows, approximately 32 d in milk grazing ryegrass pasture supplemented with 5 kg d-1 cracked triticale grain, were allocated to three treatments: Control, Tannin 1 (163 g CT d-1) or Tannin 2 (326 g CT d-1 initially, reduced to 244 g d-1 CT by day 17). Cows were dosed twice daily after milking for 5 wk with the powdered CT extract (mixed 1:1 with water). Low and high CT supplementation reduced (P < 0.05) methane emissions by 14 and 29%, respectively (about 10 and 22% on an estimated dry matter intake basis). However, milk production was also reduced by the CT (P < 0.05), especially at the high dose rate. Milk yields were 33.0, 31.8 and 29.8 kg cow-1 d-1. Tannin 2 also caused a 19% decline in fat yield and a 7% decline in protein yield, but protein and lactose contents of milk were not affected by CT supplementation. After the initial 5-wk period, five cows representative of each treatment group were moved to metabolism facilities to determine effects of CT on energy digestion and N balance over 6 d. The energy digestibility was reduced (P < 0.05) from 76.9 (Control) to 70.9 (Tannin 1) and 66.0% (Tannin 2) and the percentage of feed N lost to urine was reduced (P < 0.05) from 39 to 26% and 22% for the respective treatments. The CT also caused a reduction (P < 0.05) in intake during the metabolism study, effectively increasing CT as a percentage of intake. Although CT can be used to reduce methane and urinary N losses from cows fed pastures with a high crude protein (CP) concentration, reduced milk yield in this study suggested the dietary concentration was too high. If CT are to be considered as a means for lowering methane emissions further research is needed to define impacts of lower doses of A. mearnsii CT on methane production and cow productivity. Dairy producers will be reluctant to adopt feeding practices that compromise profitability.Key words: Dairy cow, condensed tannins, methane, milk production, energy, nitrogen balance
Effects of feed delivery time on milk production and sorting of dairy cows
Authors: Furedi C J , Kennedy A D , Plaizier J C
Published: March 2010

The effects of delivery time (0900 or 2100) of a diet consisting of 45% of dry matter as chopped hay and 55% of dry matter as concentrates on milk production of dairy cows were determined in a 6-wk experiment consisting of 3 wk of adaptation and 3 wk of sampling. Feed delivery time did not affect feed intake and milk production. Average milk fat percentage decreased from 2.14% during week 4 to 1.73% during week 6. The low milk fat could was assumed to be caused by the short dietary particle lengths, and could have prohibited effects of feeding time on milk production. The decrease in milk fat over time might have been due to increased sorting against long and medium length feed particles. This increase in sorting was greater in 0900-fed cows than in 2100-fed cows. Key words: Time of feeding, dairy cows, milk production, sorting
Lactation induces upregulation of the ubiquitin-mediated proteolytic pathway in skeletal muscle of dairy cows but does not alter hepatic expression
Authors: Greenwood S L , Wright T C , Purdie N G , Doelman J , Cant J P , McBride B W
Published: March 2010

The current study investigates regulation of mRNA expression of components of ubiquitin-mediated proteolysis in transition dairy cows. Longissimus dorsi muscle (exp. 1) and liver (exp. 2) biopsies were collected from Holstein dairy cows at 27 and 16 d pre-partum, respectively, and 3 and 10 d post-partum, respectively. Regulation of C8, E2, and ubiquitin mRNA expression was determined. Upregulation of skeletal muscle C8 (P = 0.09) and ubiquitin (P = 0.004) mRNA expression occurred post-partum compared with pre-partum. No regulation of hepatic mRNA expression was observed. In conclusion, ubiquitin-mediated proteolysis may contribute to skeletal muscle protein degradation during the periparturient period, and could provide a potential mechanism for attenuation of body protein loss at the onset of lactation.Key words: Lactation, ubiquitin-mediated proteolytic pathway, muscle (skeletal), liver
Survey of the fatty acid composition of Canadian beef: Backfat and longissimus lumborum muscle
Authors: Aldai N. , Dugan M E.R. , Rolland D C , Kramer J K.G.
Published: March 2010

A survey of Canadian retail beef was undertaken with emphasis on the trans fatty acid (TFA) and conjugated linoleic acid (CLA) isomers, and compared with current health recommendations. Thirty striploin steaks were collected in the winter and summer from major grocery stores in Calgary (Alberta, Canada). Steak fatty acid compositions (backfat and longissimus lumborum muscle analysed separately) showed minor seasonal differences with lower total saturates (P < 0.05) and higher total monounsaturates (P < 0.01) in winter, but no differences in total polyunsaturated fatty acids. The ratio of n-6 and n-3 polyunsaturated fatty acid in longissimus lumborum averaged 5.8. The average TFA content in longissimus lumborum was 0.128 g 100 g-1 serving size, and 10t-18:1 was found to be the predominant isomer (32% of total trans), while vaccenic acid was second most abundant (15% of total trans). The CLA content in longissimus lumborum was similar to that of backfat, ranging from 0.43 to 0.60% and rumenic acid represented 60% of total isomers. Overall, there is still room for improvement in the saturated, mono- and polyunsaturated fatty acid composition of Canadian beef to meet general dietary guidelines for human consumption and additional targets should include reducing 10t-18:1 while increasing both rumenic and vaccenic acids.Key words: Survey, beef, conjugated linoleic acid, survey, trans fatty acids, vaccenic acid
Protective effect of soluble fiber from Undaria pinnatifida on vascular endothelium in hypercholesterolemic rabbits
Authors: Xiao Hongbo , Fang Jun , Lu Xiangyang , Liu Zhikui , Chen Xiaojun , Liu Jinhui , Su Jianming , Yi Jine , Sun Zhiliang
Published: March 2010

Dietary fiber could improve endothelial function and abnormal production of nitric oxide (NO) and elevated endothelin-1 (ET-1) concentration induce endothelial dysfunction. In the present study, we tested the effect of soluble fiber extracted from Undaria pinnatifida (UP) on endothelial function and NO and ET-1 production in hypercholesterolemic rabbits. After treatment with UP soluble fiber (5 or 10%) for 8 wk, endothelium-dependent vasorelaxation in isolated aortic rings, the concentrations of NO and ET-1 and malondialdehyde (MDA), and the expression of endothelial NO synthase (eNOS) gene were measured. The UP soluble fiber (5 or 10%) treatment significantly attenuated the impairment of endothelium-dependent vasorelaxation concomitantly with increase of plasma NO concentration and expression of aortic endothelial nitric oxide synthase (eNOS), reduction of plasma MDA level and ET-1 concentration and aortic ET-1 concentration. The present study indicates that the protective effects of UP soluble fiber on endothelium-mediated vasorelaxation may be related to an improved NO production and a reduced ET-1 concentration in hypercholesterolemic rabbits.Key words: Undaria pinnatifida, soluble fiber, endothelium, nitric oxide, endothelin-1, rabbit
Comparison of canola and mustard presscake from biodiesel production as protein sources for growing cattle
Authors: McKinnon J J , Walker A M
Published: March 2010

Two studies were conducted to examine in situ rumen degradation kinetics of biodiesel presscake from canola (CPC) (Brassica napa) and mustard (MPC) (Brassica hirta) relative to regular canola meal (CM) and performance of cattle fed these meals as protein supplements in backgrounding diets. In the in situ trial CPC and MPC had similar (P > 0.05) rates of DM, CP, fibre and crude fat disappearance. However, CPC and MPC exhibited greater (P < 0.05) soluble DM, CP, ADF and NDF fractions and, as a result, the effective degradability of each of these fractions was greater (P < 0.05) than that of canola meal. No differences (P > 0.05) in effective degradability of crude fat were observed. The feedlot trial involved 391 steers (323 ± 24 kg) that were fed one of three experimental diets: a control diet consisting of barley silage (213 g kg-1) oat hulls (306 g kg-1), chopped straw (63 g kg-1), rolled barley (255 g kg-1) and CM (101 g kg-1), or a diet containing either CPC or MPC in place of CM as the protein supplement. Backgrounding performance was unaffected by treatment as no differences in DMI (P = 0.127), ADG (P = 0.679) or feed:gain (P = 0.792) were observed. Composition of gain estimated by ultrasound measurement of longissimus dorsi area and subcutaneous fat depth was unaffected by dietary treatment. It is concluded that biodiesel presscake from both canola and mustard seed provides a superior source of rumen degradable nutrients relative to CM and can be used as protein supplements for growing cattle without any adverse affects on performance at levels up to 10% of the diet DM.Key words: Beef cattle, backgrounding, biodiesel presscake, canola, mustard
Effect of ractopamine on whole body and splanchnic energy metabolism in Holstein steers
Authors: Koontz A F , El-Kadi S W , Harmon D L , Vanzant E S , Matthews J C , Boling J A , McLeod K R
Published: March 2010

This study was designed to examine the influence of ractopamine (RAC) on whole-body and splanchnic energy balance. Six growing Holstein steers [body weight (BW) = 402 ± 39.5 kg] surgically fitted with an arterial and portal, hepatic, and mesenteric venous indwelling catheters were used in a repeated measures study. Treatments were a basal diet of alfalfa cubes fed at approximately 1.5× maintenance energy requirements (days 1-21) and basal plus RAC (430 mg head d-1; days 22-42). On day 14 of each period, splanchnic and portal-drained viscera (PDV) energy balances were determined as the product of arterio-venous O2 difference and blood flow. Blood flow was determined using down-stream dilution of p-aminohippuric acid. Whole-body energy balance was determined on days 15-21 of each period, which included 7 d total excreta collection and 3 d of respiratory gas exchange measurements. Body weight and DM intake were greater (P < 0.05) for steers receiving RAC compared with those receiving the control diet; however, no difference was observed in either BW or DMI when expressed on a BW0.75 basis. Similarly, as a function of BW0.75, whole-body heat production (691 kJ kg BW0.75 d-1; P = 0.96) and retained N (0.85 g kg BW0.75 d-1; P = 0.34) and energy (298 kJ kg BW0.75 d-1; P = 0.71) were unaffected by RAC. In contrast, RAC tended to decrease (P = 0.09) energy use by splanchnic tissues (191 vs. 156 kJ kg BW0.75 d-1), largely due to a reduction (P = 0.12) in energy use by the PDV (100 vs. 86 kJ kg BW0.75 d-1). These data indicate that although whole-body energy use is not affected by RAC, energy use by splanchnic tissues is decreased, thereby increasing energy use by peripheral tissues.Key words: Bovine, ractopamine, beta-agonist, energy balance, metabolism
Sugar transport in arbuscular mycorrhizal symbiosis
Authors: Sun S. , Xu G.
Published: March 2010

In arbuscular mycorrhizal (AM) symbioses, there is a reciprocal nutrient exchange, mainly sugar and phosphate, between partners. Transport of phosphate from fungus to plant has been well characterized, and this aspect of AM symbiosis has been reviewed. This mini-review is specifically devoted to sugar transport from plant to fungus in AM symbiosis and discusses the possible links between sugar transporters and AM-inducible inorganic phosphate (Pi) transporters and plasma membrane proton-ATPases in the arbuscule-cortical cell interface. Exploring the sugar transport mechanisms could further contribute to our understanding of nutrient exchange between the two symbiotic partners. Key words: Arbuscular mycorrhizal symbiosis, sugar flux, sugar transporter, phosphate transporter, plasma membrane, H+-ATPase
Thermal time models for estimating wheat phenological development and weather-based relationships to wheat quality
Authors: Saiyed I. M. , Bullock P. R. , Sapirstein H. D. , Finlay G. J. , Jarvis C. K.
Published: March 2010

Accurate prediction of crop phenology is a key requirement for crop development models. The prediction of spring wheat yield and quality from meteorological data can be improved by quantifying heat and moisture conditions during specified phenological phases; therefore, accurate prediction of phenological development is important for estimating weather impacts on wheat quality. The objective of this study was to test the accuracy of biometeorological time (BMT), growing degree days (GDD), and physiological days (Pdays) for prediction of wheat phenological stages and impacts of growing season weather during those stages on wheat bread-making quality. Observed crop phenological stages and detailed weather data across 17 site-years in western Canada for six hard spring wheat varieties were collected to assess BMT, GDD and Pdays. Biometeorological time was most consistent for predicting the length of the seeding to jointing and seeding to anthesis growth stages and second most consistent behind GDD for predicting seeding to soft dough and seeding to maturity. The ability of the BMT and GDD models to predict calendar days to anthesis and maturity were further tested using field data from 166 farms across western Canada. Both GDD and BMT models were effective for predicting time from seeding to anthesis (R2 = 0.84 and 0.90, respectively) and seeding to maturity (R2 = 0.62 and 0.66, respectively). BMT- and GDD-predicted wheat growth phases were used to calculate modeled crop water use by growth period for producer fields. Crop water use is significantly correlated to key bread-making quality parameters of flour protein, farinograph dough development time and farinograph stability. Biometeorological time predicted water use was more highly correlated to these quality parameters than GDD predictions. Accordingly, the BMT scale is recommended for estimation of wheat phenological development especially for modeling weather impacts on wheat end-use quality.Key words: Spring wheat, phenological development, biometeorological time, growing degree day, physiological day, wheat quality
Long-term conservation tillage in potato rotations in Atlantic Canada: Potato productivity, tuber quality and nutrient content
Authors: Carter M. R. , Sanderson J. B. , Peters R. D.
Published: March 2010

Conservation tillage in combination with mulches in potato (Solanum tuberosum L.) farming systems can maintain crop productivity and improve soil properties, in comparison with conventional tillage systems. However, information is needed on the long-term influence of such practices on potato crop parameters. A study was initiated in 1994 on a Charlottetown fine sandy loam (Orthic Podzol) in Prince Edward Island to assess the feasibility of using conservation tillage practices in combination with crop residue mulches (after the potato harvest) on potato production in two different potato rotations: a 2-yr barley-potato rotation and a clover-based 3-yr (barley-red clover -potato) rotation. In the conservation tillage system, the primary tillage event was moved from the autumn to spring and the degree and depth of tillage were reduced by replacing the conventional mouldboard plough (20 cm depth) with a shallow (15 cm depth) one-pass chisel plough just prior to potato planting. Potato yield and tuber quality, surface residue levels after potato planting, and tuber mineral content were evaluated from 2000 to 2007. Adoption of conservation tillage over the long-term did not adversely influence total or marketable potato yield, or tuber quality. The clover-based 3-yr rotation, compared with the 2-yr rotation, had little effect on total potato yield (42 vs. 44 Mg ha-1), but produced significantly higher marketable tuber yields (38 vs. 32 Mg ha-1), for four of the eight yrs of the study. The conservation tillage system, for both rotations, provided relatively high surface residue levels (>30%) after potato planting, compared with the bare soil surface in the conventional tillage system. Nutrient and trace element contents in tuber dry matter were similar between conservation and conventional tillage. Tuber uptake of nitrogen and other nutrients were slightly greater under the 3-yr, compared with the 2-yr rotation, and associated with tuber dry-matter yield differences. The results of the 14-yr study confirm the conclusions of previous short-term studies that a reduction in depth and intensity of tillage for potato culture is yield neutral, and a viable alternative to conventional tillage systems for potato production on sandy loams in eastern Canada. Key words: Conservation tillage, potato, crop rotation, fine sandy loam, crop yield, surface residue, eastern Canada
Impact of tillage on field pea following spring wheat
Authors: Carr P. M. , Martin G. B. , Horsley R. D.
Published: March 2010

Tillage is being reduced in semiarid regions. The impact of changing tillage practices on field pea (Pisum sativum L.) performance has not been considered in a major pea-producing area within the US northern Great Plains. A study was conducted from 2000 through 2005 to determine how field pea performance compared following spring wheat (Triticum aestivum L.) in clean-till (CT), reduced-till (RT), and no-till (NT) systems arranged in a randomized complete block at Dickinson in southwestern North Dakota. Seed yield increased over 1600 kg ha-1 in 2000 and almost 400 kg ha-1 in 2003 under NT compared with CT, and by 960 kg ha-1 in 2000 under NT compared with RT (P < 0.05). Differences in seed yield were not detected between tillage systems in other years. Plant establishment was improved as tillage was reduced, averaging 66 plants m-2 under NT and RT compared with 60 plants m-2 under CT management. The soil water conservation that can occur after adopting NT may explain the increased seed yields that occurred in some years. These results suggest that field pea seed yield can be increased by eliminating tillage in semiarid areas of the US northern Great Plains, particularly when dry conditions develop and persist. Key words: Zero tillage, field pea, cropping system, N-fixation, legume
In vitro evaluation of antimicrobial peptides against Fusarium species
Authors: Badea A , Eudes F , Graf R , Laroche A , Berg A E , Misra S
Published: March 2010

The in vitro activity of five antimicrobial peptides was evaluated against several Fusarium species that affect wheat in Canada. Among the peptides tested (10R, 11R, BMAP-18, MsrA2 and MsrA3) 10R was most effective against conidial germination, whereas MsrA2 showed activity against mycelial growth. Antimicrobial peptides 10R and MsrA2 were identified as potential candidates for engineering resistance against common species causing fusarium head blight in wheat. Key words: Antimicrobial peptides, fusarium head blight, conidia, mycelia
The Biology of Canadian Weeds. 143. Apocynum cannabinum L.
Authors: DiTommaso A , Clements D R , Darbyshire S J , Dauer J T
Published: March 2010

Hemp dogbane, Apocynum cannabinum (Apocynaceae), is a perennial herb with white to greenish flowers in terminal clusters that produces pencil-like pods 12-20 cm long. A highly variable plant, A. cannabinum may be distinguished from spreading dogbane (Apocynum androsaemifolium) by its shorter corolla (2-6 mm compared with 5-10 mm), erect greenish-white petals (compared with recurved or spreading pinkish petals), seeds more than 3 mm long (compared with seeds less than 3 mm), and more erect leaves (compared with spreading or drooping leaves), although frequent hybridization between the two species obscures the identity of some individuals. Hemp dogbane is native to the United States and southern Canada, but most abundant in the upper Mississippi River Valley and east to the Atlantic coast. It has been increasing in other areas, and becoming more of a problem where conservation tillage is adopted. It infests crops such as corn (Zea mays), soybeans (Glycine max), wheat (Triticum aestivum), sorghum (Sorghum bicolor) and forages, and may cause livestock poisoning due to cardiac glycosides within its milky sap (but livestock generally avoid it). Potential medicinal uses of these compounds have been investigated, and the roots are a source of fibre. Control of A. cannabinum with various herbicides is difficult due to a thick cuticle, and one solution may be to target susceptible stages, such as seedlings or early spring growth. Cultivation may also control A. cannabinum, but care must be taken not to promote the proliferation of the plant through regrowth from fragmented roots and rhizomes. Rotation with alfalfa also reduces populations of A. cannabinum.Key words: Hemp dogbane, APCCA, Apocynum cannabinum, Apocynaceae, weed biology