Reproductive Systems for North American Beef Cattle Herds

2016 ◽  
Vol 32 (2) ◽  
pp. 249-266 ◽  
Author(s):  
Robert L. Larson ◽  
Brad J. White
2011 ◽  
Vol 129 (1) ◽  
pp. 20-29 ◽  
Author(s):  
N.T. Pegolo ◽  
D. Laloë ◽  
H.N. de Oliveira ◽  
R.B. Lôbo ◽  
M.-N. Fouilloux
Keyword(s):  

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 244-245
Author(s):  
Shannon Beard ◽  
Doug C Hodgins ◽  
Julie Schmied ◽  
Jeff Caswell ◽  
Michael M Lohuis ◽  
...  

Abstract Including immune response traits in breeding programs has been suggested as a solution to improve overall animal health and enhance disease resistance but is not yet available for Angus cattle in North America. One way to measure immune response is to use the High Immune Response (HIR™) technology, which identifies animals with superior heritable immunity by evaluating antibody-mediated (AMIR) and cell-mediated (CMIR) immune response, allowing for the calculation of an estimated breeding value for total adaptive immune response for each animal. Before HIR™ can be included in beef cattle breeding programs, genetic parameters, including heritability, must be estimated for the traits involved. The objective of this study was to estimate a preliminary heritability for AMIR and CMIR in North American Angus beef cattle. On day 0 of the phenotyping protocol, cattle were immunized intramuscularly with a preparation of type 1 (CMIR) and type 2 (AMIR) antigens with adjuvant. On day 14, cattle received an intradermal injection of 0.1 mL of the CMIR test antigen in the right tail fold, and 0.1 mL PBS in the left tail fold. Change in cutaneous double skinfold thickness after 24 hours was used to assess CMIR. Blood was collected on days 0 and 14 to evaluate serum antibody to the type 2 antigen by ELISA to quantify AMIR. Heritability estimates were calculated for Canada and the USA separately, and then for both countries combined using single-trait animal models in ASReml and are presented in Table 1. The results of this study indicate that the heritabilities of AMIR and CMIR are moderate and emphasize the potential for its inclusion into Angus breeding schemes.


2015 ◽  
Vol 120 (2) ◽  
pp. 236-240 ◽  
Author(s):  
E. Elnekave ◽  
L. Zamir ◽  
F. Hamd ◽  
B. Even Tov ◽  
E. Klement

2009 ◽  
Vol 9 (18) ◽  
pp. 7183-7212 ◽  
Author(s):  
P. A. Makar ◽  
M. D. Moran ◽  
Q. Zheng ◽  
S. Cousineau ◽  
M. Sassi ◽  
...  

Abstract. A unified regional air-quality modelling system (AURAMS) was used to investigate the effects of reductions in ammonia emissions on regional air quality, with a focus on particulate-matter formation. Three simulations of one-year duration were performed for a North American domain: (1) a base-case simulation using 2002 Canadian and US national emissions inventories augmented by a more detailed Canadian emissions inventory for agricultural ammonia; (2) a 30% North-American-wide reduction in agricultural ammonia emissions; and (3) a 50% reduction in Canadian beef-cattle ammonia emissions. The simulations show that a 30% continent-wide reduction in agricultural ammonia emissions lead to reductions in median hourly PM2.5 mass of <1 μg m−3 on an annual basis. The atmospheric response to these emission reductions displays marked seasonal variations, and on even shorter time scales, the impacts of the emissions reductions are highly episodic: 95th-percentile hourly PM2.5 mass decreases can be up to a factor of six larger than the median values. A key finding of the modelling work is the linkage between gas and aqueous chemistry and transport; reductions in ammonia emissions affect gaseous ammonia concentrations close to the emissions site, but substantial impacts on particulate matter and atmospheric deposition often occur at considerable distances downwind, with particle nitrate being the main vector of ammonia/um transport. Ammonia emissions reductions therefore have trans-boundary consequences downwind. Calculations of critical-load exceedances for sensitive ecosystems in Canada suggest that ammonia emission reductions will have a minimal impact on current ecosystem acidification within Canada, but may have a substantial impact on future ecosystem acidification. The 50% Canadian beef-cattle ammonia emissions reduction scenario was used to examine model sensitivity to uncertainties in the new Canadian agricultural ammonia emissions inventory, and the simulation results suggest that further work is needed to improve the emissions inventory for this particular sector. It should be noted that the model in its current form neglects coarse mode base cation chemistry, so the predicted effects of ammonia emissions reductions shown here should be considered upper limits.


1999 ◽  
Vol 61 (5) ◽  
pp. 549-551 ◽  
Author(s):  
Kyoung-Oh Cho ◽  
Sothy Meas ◽  
Nam-Yong Park ◽  
Yong-Hwan Kim ◽  
Yoon-Kyu Lim ◽  
...  

2010 ◽  
Vol 103 (4) ◽  
pp. 210-220 ◽  
Author(s):  
D. Villalba ◽  
G. Ripoll ◽  
R. Ruiz ◽  
A. Bernués

EDIS ◽  
2019 ◽  
Vol 2006 (5) ◽  
Author(s):  
Gary R. Hansen

The purpose of this paper is to discuss how producers can evaluate and manage bull fertility within beef cattle herds. This document is AN153, one of a series of the Animal Science Department, UF/IFAS Extension. Original publication date February 2006.


EDIS ◽  
2006 ◽  
Vol 2006 (17) ◽  
Author(s):  
Gary R. Hansen

AN165, a 5-page fact sheet by Gary R. Hansen, explains to beef cattle producers this breeding strategy that leads to increased performance and productivity in beef cattle herds. Published by the UF Department of Animal Science, September 2006.


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