ORCID

https://orcid.org/ 0000-0002-0294-3796

Department

Biological Sciences

Year of Study

2

Full-time or Part-time Study

Full-time

Level

Postgraduate

Presentation Type

Oral Presentation

Supervisor

Dr Deirdre Purfield

Supervisor

Dr Nicky Byrne

Supervisor

Dr Craig Murphy

Abstract

Background

Reducing slaughter age, while maintaining carcass output, will improve the sustainability of beef production systems. This will result in lower lifetime emissions from cattle, while also reducing the carbon equivalent per kilogram of beef carcass. The objective of this study was to investigate the strategic use of concentrate feed within pasture-based dairy-beef steer production systems, to establish its effectiveness in reducing slaughter age in differing animal genotypes.

Methods

Three contrasting supplementation strategies were implemented: 1) grass only (GO), pasture only diet in the first and second grazing season, 2) intermediate (INTER), concentrate supplementation throughout the first grazing season, pasture only thereafter, and 3) high concentrate supplementation (HIGH), concentrate supplementation throughout the first grazing season, and from July until slaughter/housing of the second grazing season. Two genotypes were assigned to each supplementation treatment, Holstein Friesian (HF; n = 80 animals) and Angus X Holstein Friesian (AAX; n = 160 animals).

Results

The slaughter age of AAX steers was 80 days earlier than HF across concentrate treatments. HIGH treatment AAX steers were slaughtered 43 days earlier and with a carcass weight proportionately 0.96 that of GO and INTER AAX steers. Irrespective of concentrate treatment, slaughter age did not differ for HF steers. HIGH HF steers produced a heavier carcass than GO and INTER HF steers, however, they consumed significantly more concentrate.

Conclusion

Slaughter age of AAX steers can be reduced by strategic concentrate use during the second grazing season, producing a carcass meeting market specifications. However, the slaughter age of HF steers remained unchanged, emphasising the importance of substituting low carcass merit HF male calves for high carcass merit beef x dairy animals.

Keywords:

Dairy-beef, age at slaughter, grass-based, sustainability

Start Date

2-11-2023 10:45 AM

End Date

2-11-2023 11:00 AM

Included in

Beef Science Commons

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Nov 2nd, 10:45 AM Nov 2nd, 11:00 AM

Grass-based supplementation to reduce slaughter age in dairy-beef steers

Background

Reducing slaughter age, while maintaining carcass output, will improve the sustainability of beef production systems. This will result in lower lifetime emissions from cattle, while also reducing the carbon equivalent per kilogram of beef carcass. The objective of this study was to investigate the strategic use of concentrate feed within pasture-based dairy-beef steer production systems, to establish its effectiveness in reducing slaughter age in differing animal genotypes.

Methods

Three contrasting supplementation strategies were implemented: 1) grass only (GO), pasture only diet in the first and second grazing season, 2) intermediate (INTER), concentrate supplementation throughout the first grazing season, pasture only thereafter, and 3) high concentrate supplementation (HIGH), concentrate supplementation throughout the first grazing season, and from July until slaughter/housing of the second grazing season. Two genotypes were assigned to each supplementation treatment, Holstein Friesian (HF; n = 80 animals) and Angus X Holstein Friesian (AAX; n = 160 animals).

Results

The slaughter age of AAX steers was 80 days earlier than HF across concentrate treatments. HIGH treatment AAX steers were slaughtered 43 days earlier and with a carcass weight proportionately 0.96 that of GO and INTER AAX steers. Irrespective of concentrate treatment, slaughter age did not differ for HF steers. HIGH HF steers produced a heavier carcass than GO and INTER HF steers, however, they consumed significantly more concentrate.

Conclusion

Slaughter age of AAX steers can be reduced by strategic concentrate use during the second grazing season, producing a carcass meeting market specifications. However, the slaughter age of HF steers remained unchanged, emphasising the importance of substituting low carcass merit HF male calves for high carcass merit beef x dairy animals.