South African Journal of Animal Science
versión On-line ISSN 2221-4062
ESTERHUIZEN, J.; GROENEWALD, I.B.; STRYDOM, P.E. y HUGO, A.. The performance and meat quality of Bonsmara steers raised in a feedlot, on conventional pastures or on organic pastures. S. Afr. j. anim. sci. [online]. 2008, vol.38, n.4, pp. 303-314. ISSN 2221-4062.
The effects of production system (feeding regime and time on feed) on growth performance, yield and economics and the effects of feeding regime, pre-slaughter treatment and electrical stimulation on meat quality were evaluated. Sixty Bonsmara steers were divided into three treatment groups, viz. feedlot, organic pasture and conventional pasture feeding. The feedlot and conventional pasture groups received a diet consisting of the same components, while the organic group received a diet with approved organic components. Initial weight, final live weight, warm carcass weight, cold carcass weight, warm and cold dressing percentage, average daily gain (ADG), pH at one and 24 hours post mortem, intramuscular fat content of the loin and subcutaneous back fat thickness were measured. The effects of electrical stimulation, feeding regime and pre-slaughter rest (recovery days at the abattoir) on meat tenderness were also investigated. Feedlot cattle had significantly higher final weights, warm and cold carcass weights, warm and cold dressing percentage, ADG, intramuscular fat content and back fat thickness measurements than organic and conventional pasture cattle. Pre-slaughter resting of animals for a week at the abattoir had no effect on meat tenderness, but electrical stimulation showed a significant positive response. Growth and carcass results were used to calculate price and feed margin for the different production systems. Feedlot cattle showed a higher profit than conventional and organic pasture groups, mainly due to faster and more efficient growth. The organic pasture cattle showed higher profit than the conventional pasture cattle as a result of the premium paid for the organically produced meat.
Palabras clave : Production system; organic; meat quality; profit margins; feedlot; beef cattle.