Effects of forage vs grain feeding on carcass characteristics, fatty acid composition, and beef quality in Limousin-cross steers when time on feed is controlled.

Abstract

Limousin-cross steers ( n = 135; 258 ± 26 kg) were used to compare forage vs grain feeding on carcass composition and palatability attributes of beef when time on feed was controlled. Diets included a 95% alfalfa silage ration (AS) or a 68% highmoisture corn, 25% alfalfa silage ration (HMC). These were incorporated into six treatments to allow comparisons of end points based on similar days on feed or backfat finish. Dietary treatments included 1 ) HMC ( 4 mm), or cattle allowed ad libitum intake of HMC until slaughter at 4 mm ultrasound backfat; 2 ) AS (HMC-4), or cattle allowed ad libitum intake of AS until slaughter, regardless of finish, when HMC ( 4 mm) cattle were slaughtered; 3 ) AS ( 4 mm), or cattle allowed ad libitum intake of AS until slaughter at 4 mm backfat; 4 ) HMC (AS-4), or cattle allowed ad libitum intake of HMC until slaughter, regardless of finish, when AS ( 4 mm) cattle achieved 4 mm backfat; 5 ) HMC (RES), or cattle fed HMC at restricted intakes until slaughter at 4 mm backfat with feed offered at 75% of intake achieved by HMC ( 4 mm) and HMC (AS-4) cattle; and 6 ) AS ( 8 mm) or cattle allowed ad libitum intake of AS ration until slaughter at 8 mm backfat. Grain feeding generally increased ( P < .01) ADG, carcass weight, grade fat, and intramuscular fat content when compared with forage feeding at similar times on feed. Palatability attributes of ribeye roasts and ground beef were generally unaffected ( P > .10) by diet with the exception of slightly less beef flavor and more offflavor in forage-fed vs grain-fed beef. Higher ( P < .01) concentrations of linolenic acid and lower ( P < .10) concentrations of oleic acid in forage-fed beef may be partially responsible for diet differences in flavor.

Effect of nutritional factors on biochemical, structural and metabolic characteristics of muscles in ruminants, consequences on dietetic value and sensorial qualities of meat

“…Indeed, no significant difference in juiciness has been observed between grass-fed and grain-fed young bulls despite differences in carcass fatness and meat tenderness [114]. Similarly, no significant difference has been observed in juiciness of meats of young bulls fed either an alfalfa silage-diet or a concentrate-diet indoors [66]. However, meat from the Longissimus thoracis and Semitendinosus muscles of young bulls fattened with hay is more juicy than meat from muscles of young bulls fed grass silage [61].…”

“…The differences in tenderness can be explained by differences in growth rate, fatness or age. To avoid the last two effects, meat from steers fed the 2 previous types of diets have been compared to animals being slaughtered at various ages and with various fatnesses [66]. The meat tenderness of the two types of animals, after correction by taking into account these 2 factors, were not significantly different.…”

Genetic parameters for fatty acid composition and feed efficiency traits in Japanese Black cattle

“…Beef content includes lipids and various biomolecules, such as fatty acids. Fatty acid composition is related to the taste and flavor of beef (Westerling and Hedrick, 1979;Melton et al, 1982;Mandell et al, 1998). Therefore, the quality of fat as measured by fatty acid composition and fat melting point (MP), which has a high correlation with fatty acid composition, is one of the most important factors affecting beef quality.…”

“…Fatty acid composition is influenced by sex (Yoshimura and Namikawa, 1985;Zembayashi et al, 1995), diet (Melton et al, 1982;Mandell et al, 1998) and age (Huerta-Leidenz et al, 1996). Genetic influences, such as breed (Yoshimura and Namikawa, 1985;May et al, 1993) and sire (Xie et al, 1996), have also been reported, including sire-based differentiation in Japanese Black cattle (Oka et al, 2002).…”

Environmental effects on the fatty acid composition of subcutaneous beef fat

“…Duckett et al 1993;Camfield et al 1997) and finishing regime (e.g. Mandell et al 1998) on fatty acid composition; although these studies have been restricted to animals raised in 1 environment. We are not aware of studies that have examined the effect of changing nutrition levels during the grow-out period (from weaning to finishing).…”