Effects of hay quality on intake, growth path, body composition and muscle characteristics of Salers heifers

Abstract

-A comparison between continuously (CG group, n = 9) and discontinuously (DG, n = 14) growing Salers heifers during a two year growth period after weaning was performed. Feed was available to all animals ad libitum throughout the experiment. Growth differences in the winter resulted from a different quality of the offered hay. In the summer, the animals were conducted indoors and offered the same good quality hay. Serial slaughter was carried out in order to estimate the evolution of body composition and muscle characteristics (fibre type and area, collagen) which may influence meat quality. This experimental scheme made it possible to simulate two types of nutritional environment (poor and rich) and to study their impact on intake, growth, body composition and muscle characteristics of the animals. DG heifers always underwent a summer compensatory growth, even though not complete, when compared with CG animals. The final slaughter was carried out at the same live weight, approximately 700 kg. On average, DG heifers were therefore slaughtered 56 days later than CG animals. The differences in mean daily weight gains always neared 300 g.d -1 , respectively in favour of CG in the winter and DG in the summer. Growth compensation was attributable to an increased intake (between +6 and +7%) in the summer and a tendency for a higher growth efficiency of DG animals. No significant major difference was detected between CG and DG body composition at the final slaughter at which final carcass was approximately 400 kg and total adipose tissue weight reached approximately 130 kg (21.5% of the empty body weight). Final muscle characteristics were not modified by growth type either. It was concluded that growth path can vary according to food availability, without affecting the characteristics of the finished carcasses at constant weight. Résumé -Effets de la qualité du foin sur l'ingestion, l'itinéraire de croissance, la composition corporelle et les caractéristiques musculaires de génisses Salers. Deux lots de génisses Salers conduites en croissance continue (lot CG, n = 9 ) ou discontinue (DG, n = 14) ont été comparés pendant deux années de croissance post-sevrage. Pendant toute l'expérience, les animaux étaient alimentés à volonté. Les écarts hivernaux de croissance étaient dus à la distribution de foins de qualité distincte. En été, les génisses restaient à l'étable et recevaient un foin identique de bonne qualité. Les évolutions de la composition corporelle et des caractéristiques musculaires (type et surface des fibres, collagène) susceptibles d'influer sur la qualité de la viande, ont été estimées après des abattages en série. Ce schéma expérimental a permis de simuler deux types de milieu nutritionnel (pauvre et riche) et d'en étudier l'impact sur l'ingestion, la croissance, la composition corporelle et les caractéristiques musculaires des animaux. Le lot DG a systématiquement réalisé une croissance compensatrice estivale, bien qu'incomplète, par rapport au lot CG. Du fait d'un abattage final à même poids vif...

A Data Warehouse of Muscle Characteristics and Beef Quality in France and A Demonstration of Potential Applications

“…Effect of the type of diet on muscle characteristics and meat quality Bauchart et al, 2001;Dozias and Picard, 1997;Faulconnier et al, 2007;Hoch et al, 2005;Jurie et al, 1995aJurie et al, , 2006Listrat et al, 1999Listrat et al, , 2001. Effect of livestock practices (castration, age, housing methods Brandstetter et al, 1998aBrandstetter et al, , 1998bCassar-Malek et al, 2004;, and compensatory growth) on muscle characteristics and meat quality Jurie et al, 1995aJurie et al, , 19982007b;Picard et al, 1995aPicard et al, , 1995b.…”

Effect of growth intensity of bulls on the microstructure of musculus longissimus lumborum and meat quality

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