Relationships Between Estimated Breeding Values (EBV) for Growth, and Meat Quality of Lot-fed Cattle PDF Download

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ISBN:
Category : Beef
Languages : en
Pages : 18

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Author: Erika Elaine Blair
Publisher:
ISBN:
Category :
Languages : en
Pages :

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It is important for animals to be feed efficient and reproductively sound to optimize profits for cow- calf producers. The objective of this study was to determine the relationship between feed efficiency and reproductive performance. Feed efficiency measures included residual feed intake (RFI), feed to gain ratio (F:G) and daily dry matter intake (DMI). Reproductive measurements were pregnancy rate, first service conception rate, pregnancy type (AI, natural. open), calving percentage, calving day (CD) and age at first calving. Two data sets which included 136 crossbred Angus females sired by bulls with high or low RFI estimated breeding values (EBV) with multiple parity information and 56 purebred Hereford heifers with their first parity calving information were analyzed. Initially, the crossbred Angus females were analyzed based on their phenotypic RFI values. There was no difference in pregnancy rate between the feed efficiency measures. Second parity pregnant females had lower (F:G) with first service conception (P=0.053), and pregnancy types (P=0.014) than the open (less efficient) females. In parity 5, phenotypically efficient RFI Angus females were pregnant to first service conception versus inefficient RFI Angus females (P=0.052) and those with lower DMI were diagnosed pregnant (P=0.0002). When evaluated as a repeated trait, RFI was not a significant indicator of CD (P=0.514). Crossbred Angus females were analyzed based on their sire's RFI EBV and grouped accordingly into high (inefficient) or low (efficient) RFI sires. Females sired by high or low RFI (EBV) bulls showed no difference for the reproductive traits, except for a tendency for inefficient sired heifers to have a lower calving percentage in parity 2 (P=0.048). When CD was analyzed as a repeated measure, no difference between sire groups was found (efficient CD of 35.64 d, inefficient CD of 34.23, p = 0.789). In the Hereford heifers, RFI was not an indicator of CD (P = 0.774). There was also no difference in RFI between pregnant and open Hereford females with pregnant females having an LSMean of 0.11 kg/d and the open females having an LSMean of 0.14 kg/d (P = 0.860). Further research needs to be done to confirm any relationships between feed efficiency and reproduction.

Author: Kari L. White
Publisher:
ISBN:
Category :
Languages : en
Pages :

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The objective of this research is to add needed information on economically relevant traits (ERT) to the existing American Gelbvieh Association National Cattle Evaluation. Substantive pieces were added to that vision by identifying selection tools that have not previously been established for that evaluation, or by re-assessing current selection tools to include the most efficient analysis. The topics of research included are traits that are often difficult or expensive to measure, which will benefit the greatest from further research into developing efficient and effective selection tools. The objectives of the feed energy utilization study were to estimate genetic parameters for dry matter intake (DMI), percent daily dry matter required (PDMR), residual feed intake (RFI), adjusted weaning weight (AWWT), and post weaning gain (PWG) in a multi-breed population of growing beef cattle, in addition to implementing an economic selection index identify genetically favorable animals in the complex of traits associated with feed energy utilization. Feed intake and performance data for this analysis included records on animals collected by twelve individual breeders using Growsafe® systems and were later submitted to the AGA. Feed efficiency parameters were estimated to be moderately heritable in this data set of Gelbvieh influenced cattle, indicating producers can make genetic improvement through selection for the traits. In addition, correlations among certain feed efficiency traits indicate selection for one trait should result in a correlated response in others. Index selection is preferable for genetic improvement in feed efficiency traits because of a large unfavorable genetic correlation between feed intake and growth. Continued collection of feed efficiency phenotypes is essential to identifying animals that are profitable in feed energy utilization. The objectives of the sustained productivity study were to calculate an estimated breeding value (EBV) for each sire for relative risk of failing to calve consecutively within 425 days from 1 to 9 parities. The EBV for relative risk could then be used as genetic selection tool for sires whose daughters are more likely to reproduce in the herd within 425 days from 1 to 9 parities. Data for this analysis were birth dates and disposal codes reported by breeders to the AGA. Every animal in the AGA database has an associated code. For the purposes of this analysis, a female was considered to have a complete record (uncensored, code "0") if she failed to calve within 425 days of the previous calving, with no reported disposal code. A female was also considered uncensored, or considered to have a complete record, if she was greater than 11 years and 60 days old at the time of data extraction without a calving interval greater than 425 days in her lifetime. A female was considered to have an incomplete record (censored, code 1) if she had a defined non-reproductive disposal code, indicating she was culled from the herd for a reason other than reproduction. Females still active and producing in the herd at the time of data extract were also considered censored, since the upper bound of their productive life was still unknown. Analysis indicated that animals in our data set that failed to calve within 425 days of previous calving, or those who were still producing in the herd at 11 years 60 days of age (uncensored) exited the herd at an average of 2.19 years old. Animals with a defined non-reproductive disposal code, or those still active in the herd at less than 11 years 60 days of age (censored) exited the herd at an average of 2.39 years old. Younger parities had a greater culling rate that decreased at later parities. This indicates failure occurs at a higher rate at younger ages. It should be noted that while it appears younger parities have a greater risk of failure, animals most likely to be culled for reproductive failure have already left the herd by later parities. As a result, culling rate is lower in advanced parities. Sustained reproductive success and length of productive life as indicators of cow fertility are of great economic importance to the beef industry. The current study is a prototype genetic evaluation that will allow the AGA to select for sires that have daughters with improved length of productive life. The objectives of the tenderness study were to quantify the genetic and phenotypic relationships between various methods of tenderness evaluation for fresh and frozen samples, quantitatively estimate breed effects of tenderness, and to assess the interaction of breed with calpastatin (CAST) and [mu]-calpain (CAPN1) markers. Data used in this analysis included SSF predicted by visible spectroscopy (LED), visible/near-infrared hyperspectral imaging (VISNIR) predicted SSF, fresh and frozen SSF aged to approximately 14 days (SSF14), frozen SSF aged to approximately 3 and 4 days combined (SSF3), and frozen WBSF aged to approximately 14 days and 3 and 4 days combined (WBS14 and WBS3). Predicted measures of meat tenderness (LED and VISNIR) were estimated to be highly heritable at 0.78 and 0.59, respectively. High heritability in predicted measures of tenderness indicate they may be useful as correlated traits for selection. Slice shear force 3 and WBS3 had the greatest genetic correlation of 0.93 (0.03). Genetic correlations between estimated tenderness values (LED and VIS) and measured tenderness values (SSF and WBSF) ranged from low (0.02) to moderate (0.36) for LED and from low (-0.01) to moderate (0.48) for VIS. Warner-Bratzler shear force values at different days of post-mortem aging were found to be highly genetically correlated at 0.81 (0.05). Genetic correlations between SSF and WBSF values ranged from moderate (0.39) to high (0.93) depending on age. Breed was found to be a significant effect at p

Author: David S. Beggs
Publisher:
ISBN: 9780980796797
Category : Bulls
Languages : en
Pages : 108

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This manual is intended as an update of the 2003 publication "Evaluating and Reporting Bull Fertility", edited by Keith Entwistle and Geoffry Fordyce. Published by the Australian Association of Cattle Veterinarians - now the Australian Cattle Veterinarians (ACV) - this has been the yardstick used by Australian cattle veterinarians evaluating the fertility of bulls. But both science and society have evolved over the last ten years. The body of knowledge surrounding the evaluation of bull breeding soundness has increased, with new diseases, new diagnostic tests, and new understandings.

Author: Dixon D. Hubbard
Publisher:
ISBN:
Category : Beef
Languages : en
Pages : 84

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ISBN:
Category : Agriculture
Languages : en
Pages : 930

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Author: Flavio Forabosco
Publisher:
ISBN: 9781849030748
Category : Science
Languages : en
Pages : 208

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Author: Graham C. Burdge
Publisher: Elsevier
ISBN: 012811231X
Category : Science
Languages : en
Pages : 256

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Polyunsaturated Fatty Acid Metabolism explores a number of major roles of PUFA in the body, including its role as a component of cell membranes and how it provides substrates for the synthesis of lipid second messengers. Recent studies are unraveling the effect of interactions between diet and endocrine factors and genetic and epigenetic variation on the regulation of PUFA biosynthesis in animals. Together, these recent findings provide novel insights into the impact of differences in PUFA supply on health. This book captures these findings in a manner that marks the state-of-the-art, placing them in the wider context of PUFA metabolism and nutritional science. Users will find a comprehensive discussion on the topic that presents the contributions of leading researchers who combine their knowledge to create a cohesive academic resource for researchers, those involved in production, and health policymakers. - Provides a comprehensive view of polyunsaturated fatty acid metabolism - Describes underlying metabolism on lipids that include polyunsaturated fatty acids - Includes discussions on recent findings on the genetic and epigenetic regulation of polyunsaturated fatty acid metabolism

Author: Rodney A. Hill
Publisher: John Wiley & Sons
ISBN: 0470959525
Category : Science
Languages : en
Pages : 328

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Feed Efficiency in the Beef Industry provides a thorough and concise overview of feed efficiency in beef cattle. It frames the great importance of feed efficiency to the industry and details the latest findings of the many scientific disciplines that intersect and aim to improve efficient and sustainable production of nutritious beef. The vast majority of production costs are directly tied to feed. With increased demand for grains to feed a rapidly increasing world population and to supply a new demand for alternative fuels, feed costs continue to increase. In recent years, the negative environmental impacts of inefficient feeding have also been realized; as such feed efficiency is an important factor in both economic viability and environmental sustainability of cattle production. Feed Efficiency in the Beef Industry covers a broad range of topics ranging from economic evaluation of feed efficiency to the physiological and genetic bases of efficient conversion of feed to high quality beef. Chapters also look at how a fuller understanding of feed efficiency is leading to new selective breeding efforts to develop more efficient cattle. With wide-ranging coverage from leading international researchers, Feed Efficiency will be a valuable resource for producers who wish to understand the complexities, challenges, and opportunities to reduce their cost of production, for students studying the topic and for researchers and professionals working in the beef industry.

Author: Lewis Kahn
Publisher: CSIRO PUBLISHING
ISBN: 0643109900
Category : Technology & Engineering
Languages : en
Pages : 894

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Beef Cattle Production and Trade covers all aspects of the beef industry from paddock to plate. It is an international text with an emphasis on Australian beef production, written by experts in the field. The book begins with an overview of the historical evolution of world beef consumption and introductory chapters on carcass and meat quality, market preparation and world beef production. North America, Brazil, China, South-East Asia and Japan are discussed in separate chapters, followed by Australian beef production, including feed lotting and live export. The remaining chapters summarise R&D, emphasising the Australian experience, and look at different production systems and aspects of animal husbandry such as health, reproduction, grazing, feeding and finishing, genetics and breeding, production efficiency, environmental management and business management. The final chapter examines various case studies in northern and southern Australia, covering feed demand and supply, supplements, pasture management, heifer and weaner management, and management of internal and external parasites.