1. Effects of feeding system and slaughter age on the growth and carcass characteristics of tropical-breed steers
- Author
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Agastin, Aurélie, Navès, Michel, Farant, Alain, Godard, Xavier, Bocage, Bruno, Alexandre, Gisèle, Boval, Maryline, Unité de Recherches Zootechniques (URZ), Institut National de la Recherche Agronomique (INRA), Plateforme Tropicale d'Expérimentation sur l'Animal (PTEA), and We gratefully acknowledge the financial support awarded by the Guadeloupe Region and EU Social Funds for the grant given to Aurélie Agastin and the support on experiments given under the Agroecotrop program.
- Subjects
pasture ,slaughter age ,cattle ,[SDV]Life Sciences [q-bio] ,average daily gain ,carcass trait ,indoor - Abstract
Chantier qualité GA; International audience; This study aimed to compare the growth performances and carcass characteristics of tropical-breed steers reared in 2 contrasted feeding systems (indoor vs. pasture) and slaughtered at different ages (early vs. late). A total of 309 Creole steers (growing at an initial BW of 173 +/- 3 kg and an initial age of 252 +/- 4 d) were used over a continuous 12-yr study. Indoor steers were housed in a cattle shed, fed fresh-cut grass plus concentrate, and slaughtered at 14.5 or 17.1 +/- 0.1 mo of age. Pasture steers were pasture grazed without supplemental feed, and slaughtered at 17.6 and 21.2 +/- 0.1 mo of age. Indoor-fed steers had a greater ADG (786 vs. 517 +/- 29 g.d(-1); P < 0.0001) and more carcass fat (164 vs. 145 +/- 4.5 g.kg(-1); P = 0.001) than pasture-fed steers. Late-slaughtered steers had decreased ADG (630 vs. 673 +/- 27 g.d(-1); P = 0.001) but greater dressing percentages (hot dressing percentage = 55.7 vs. 54.7 +/- 0.34%; chilled dressing percentage = 54.5 vs. 53.4 +/- 0.34%; P < 0.0001) than early-slaughtered steers. The interaction between feeding system and slaughter age was significant for carcass tissue composition. Whole-carcass muscle content was greater in late-slaughtered steers than early-slaughtered steers, especially in pasture-fed steers (720 vs. 698 +/- 6.0 g.kg(-1); P < 0.0001), but less so in indoor-fed steers (707 vs. 700 +/- 5.9 g.kg(-1); P = 0.046). Furthermore, increasing slaughter age had no effect on carcass fat in indoor-fed steers (162 vs. 166 +/- 4.8 g.kg(-1); P = 0.342), but decreased carcass fat in pasture-fed steers (150 vs. 140 +/- 5.0 g.kg(-1); P = 0.014). The results showed that slaughter age and feeding system are 2 major factors that independently affect most of the growth and carcass traits of tropical-breed steers but jointly influence tissue deposition. Our study found that in tropical-breed steers that are grazing, late slaughtering grazing steers increased carcass muscle content without extra fat, thus yielding a carcass quality better suited to consumer choices.
- Published
- 2013
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