The project objective was to determine the CLA content of three muscles (Longissimus lumborum, LD; Semimembranosus, SM; Triceps brachii, TB), in both raw and cooked states, in cattle finished on pasture or with grain supplements. Cattle were randomly assigned to one of four finishing regimens; pasture (n = 11), pasture with grain supplement (n = 11), pasture with grain supplement containing soyoil (n = 12), and feedlot (n = 12). In the raw state, TB had higher (P < 0.05) CLA than LD or SM on a mg/g sample basis. Total CLA was higher (P < 0.05) in the soyoil diet when compared to the other three feeding regimes on a mg/g sample basis and when expressed as mg/g fat in both raw and cooked analyses. Pasture inclusion produced higher levels (P < 0.05) of total CLA than the feedlot diet on a mg/g fat basis for cooked samples while maintaining acceptable eating quality. ?? 2006 Elsevier Ltd. All rights reserved.

Meat Science, volume 75, issue 1, pages 159-167

beef, conjugated linoleic acid, muscle

Twenty Angus crossbred steers were assigned to one of four treatments and followed from weaning to slaughter to study the effect of diet on the conjugated linoleic acid (C 18:2 cis-9, trans-11 and C 18:2 trans-10, cis-12 CLA isomers) content and quality of beef. During the adaptation period, treatments 1 (CTL), 2 (CLA), and 3 (GPS) received a diet consisting of 520 g corn silage, 213 g alfalfa hay, 250 g rolled barley, and 17 g mineral-vitamin premix/kg of dry matter (DM). Treatment 4 (PS) received alfalfa hay only. During the finishing period, CTL and CLA steers received a diet consisting of 123 g corn silage, 67 g alfalfa hay, 764 g rolled barley, and 46 g mineral-vitamin premix/kg of diet dry matter. In addition to the basal diet, CLA steers received 84 g/head/day of a synthetic mixture of partially rumen protected CLA isomers. The GPS and PS treatments were finished solely on pasture. Subcutaneous adipose tissue samples were collected from the M. longissimus dorsi at the end of the adaptation period, and both adipose and muscle tissues were collected from the longissimus and M. semitendinosus of each carcass at slaughter for fatty acid analysis. Beef tissues from PS and GPS steers had 466% and 218% more CLA (C 18:2 cis-9, trans-11 isomer) at slaughter compared with beef tissues from CTL steers, respectively. Supplementing synthetic CLA did not increase C 18:2 cis-9, trans-11 CLA content of beef, but increased trans-10, cis-12 CLA by 380% compare to beef from CTL animals. A trained taste panel detected no differences in tenderness or juiciness among treatments. However, beef from PS received higher off-flavor scores than other treatments. Raising cattle on forage and pasture with no grain supplementation enhances beef CLA content. Additionally, finishing cattle on pasture increased the vitamin E content of beef by 300% compared to beef from animals finished on a traditional high-grain diet. ?? 2004 Elsevier B.V. All rights reserved.

Livestock Production Science, volume 91, issue 1, pages 117-128

beef, conjugated linoleic acid, fat, meat, pasture

The objective of this study was to examine the effects of feeding system and breed on the content of the beneficial n-3 polyunsaturated fatty acids and conjugated linoleic acids (CLA) in beef muscle. German Simmental (GS) (n=31) and German Holstein (GH) (n=33) bulls were produced on either an indoor concentrate system or a grass-based system consisting of a period of summer pasture feeding followed by a winter indoor period on grass silage and a concentrate containing linseed. All animals were slaughtered at 620 kg. The grass-based system increased (P<0.05) the percentage of n-3 fatty acids in the longissimus muscle lipids of bulls (GS 2.22 vs. 0.46%, GH 1.61 vs. 0.34%). The n-6 fatty acid proportions were not affected by the feeding system in GS and GH loin muscle. Therefore, the n-6/n-3 ratio of grass-based GS bulls was 2.0 and of GH was 1.9 in contrast to 8.3 and 6.5 for bulls fed concentrates indoors. The grass-based system increased the percentage of C18:1trans fatty acid isomers in both breeds. The percentage of CLAcis-9,trans-11 (0.87% vs. 0.72% in GS, 0.84% vs. 0.75% in GH) in muscle was significantly higher in animals on the grass-based system. ?? 2004 Elsevier B.V. All rights reserved.

Livestock Production Science, volume 94, issue 1, pages 137-147

beef, cla, sensory traits, shelf life, n-3 fatty acids

Inspired by the health conscious consumer, several studies in meat producing domesticated animals have been completed that have aimed at increasing the polyunsaturated fatty acid content, and in particular the n-3 or ??-3 long chain fatty acids, as well as the conjugated linoleic acid (CLA) content in intramuscular fat of beef, lamb and pork meat. Increasing the n-3 content in animal meats can be achieved by including fish oil/fish meal in the diet (i.e. rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)), linseed (oil) and/or forages (i.e. rich in linolenic acid (LNA)). Diets rich in LNA result in an increased level of LNA, EPA and docosapentaenoic acid (DPA) in the meat, while in most cases no effect on intramuscular DHA level was observed. Increasing DHA contents in meat was mainly achieved when fish oil/fish meal was included in the animals diet. In most studies, an increased n-3 content in the intramuscular fat was accompanied with a decreased n-6 deposition, mainly due to a lower n-6 dietary supply between the treatments. This resulted in a more favourable n-6/n-3 ratio in the meat while the polyunsaturated fatty acid/saturated fatty acid (P/S) ratio was less affected. Attempts to increase the intramuscular c9t11CLA content was accomplished by feeding ruminants n-3 rich diets (linseed either or not in combination with grass (silage)), fish oil or high concentrate diets rich in linoleic acid (LA). The c9t11CLA content in beef and lamb meat varied between 0.2 and 1.0g/100g of total fatty acids and was not increased to a high extent by nutritional factors. In contrast, including CLA-oils consisting of several CLA isomers in the diet of monogastrics markedly increased the intramuscular CLA content. ?? 2003 Elsevier B.V. All rights reserved.

Animal Feed Science and Technology, volume 113, issue 1, pages 199-221

conjugated linoleic acid, intramuscular fat, meat, polyunsaturated fatty acids, n-6/n-3 ratio

(Abstract not available.)

Journal of Animal Science, volume 70, pages 3055-3065

1992, 3055-3065, 70, anim, beef, cattle, j, meat color, optical properties, sci, vitamin e

Thirty Hereford steers were finished either on pasture (n = 10) or concentrate (n = 20) to determine dietary and antioxidant treatment effects on carcass characteristics, fatty acid composition, and quality of Uruguayan beef. Half of the steers finished on concentrate were supplemented with 1000 I.U. vitamin E head-1 day-1 for 100 days. Postmortem vitamin C was added to ground beef (0.05% v/w) displayed for 8 days at 2 ??C. Carcasses from steers finished on concentrate had greater (P < 0.05) carcass weight, conformation, degree of finishing, fat depth, and ribeye area than pasture finished animals. Carcasses from pasture-fed steers showed darker (P < 0.05) longissimus color and yellower (P <0.05) fat at 24 h postmortem than concentrate-fed. Initial longissimus Warner-Bratzler shear force (WBSF) values were similar (P >0.05) between pasture- and concentrate-fed animals. However, beef from pasture-fed cattle had lower (P < 0.05) WBSF values at 7 and 14 days postmortem. Longissimus ??-tocopherol concentrations were greater (P < 0.01) for pasture- and concentrate-fed animals that were supplemented with vitamin E compared to concentrate-fed. Steaks from pasture-fed and vitamin E supplemented cattle had similar (P > 0.05) TBARS values, which were lower (P < 0.05) than steaks from concentrate-fed steers during 21 days of display. Ground beef from vitamin E supplemented steers had the lowest TBARS values; whereas samples from pasture-fed animals had the lowest lipid stability with higher TBARS levels than other treatments. Vitamin C addition to ground beef did not (P > 0.05) reduce lipid oxidation. Vitamin E supplementation of concentrate-fed cattle had no effect (P > 0.05) on color stability of ground beef or steaks. The a* (redness) and b* (yellowness) values were higher (P < 0.05) when vitamin C was added to ground beef. Longissimus fatty acid content of concentrate-fed animals was twofold greater (P < 0.01) than pasture-fed. The percentages of C14:0, C16:0, and C18:1 fatty acids were higher (P < 0.01) in the intramuscular fat of concentrate-fed steers, whereas pasture-fed cattle showed greater (P < 0.01) proportions of C18:0, C18:2, C18:3, C20:4, C20:5, and C22:5. Total conjugated linoleic acid (CLA) and CLA isomer c9t11 were higher (P < 0.01) for pasture- than concentrate-fed cattle. Vitamin E supplementation of concentrate-fed steers increased lipid stability of ground beef and steaks, but was unable to improve color stability; whereas vitamin C addition to ground beef increased color stability without altering lipid oxidation. Finishing cattle on pasture enhanced the unsaturated fatty acid profile of intramuscular fat in beef including CLA and omega-3 fatty acids. ?? 2003 Elsevier Ltd. All rights reserved.

Meat Science, volume 66, issue 3, pages 567-577

antioxidants, beef, concentrate, pasture

(Abstract not available.)

Proc. 22nd Conf. on Rumen Function. Chicago, IL (Abst.)., issue 1995

2000, 725, 727, 80, anim, apparition du météorisme chez, b, bloat, brooke, can, cattle, croissance de la luzerne, d, de l, de la première récolte, des groupes de bouvil-, différents stades de croissance, effet du stade de, en manipulant les dates, et majak, g, garland, hall, herbage de luzerne de, j, la fréquence d, legumes, les bovins, m, medicago sativa l, nous avons obtenu simultanément, sci, sur, thompson, w

The effects of dietary vitamin E supplementation of grain-fed cattle on lipid oxidation and meat colour have been extensively investigated, but little attention has been given to pasture-fed cattle where meat is likely to contain naturally high amounts of [alpha]-tocopherol and carotenoids. In the work described, we evaluated the effects of pasture-feeding alone and with vitamin E supplementation on tissue levels of anti-oxidants and compared the findings with those obtained for grain-fed cattle with and without supplementation. Sorghum was the major component of the grained-based ration. [alpha]-Tocopherol concentrations in plasma, muscle and fat tissues of pasture-fed cattle were not affected by vitamin E supplementation (2500 IU/head/day for 132 days prior to slaughter) while those of grain-fed cattle increased significantly. The [alpha]-tocopherol concentrations in the supplemented grain-fed cattle were similar in muscle and liver to pasture-fed animals but were lower in their fat (PP<0.05) by supplementation with vitamin E. Carotenoids were essentially absent in grain-fed cattle except for small amounts in liver. The implication of this study for the meat industry is that cattle grazed on good pasture can achieve concentrations of [alpha]-tocopherol in muscles and other tissues at least as high as those obtained by supra-nutritional supplementation of grain-fed cattle with vitamin E. However, [alpha]-tocopherol supplementation of pasture-fed cattle reduced tissue concentrations of [beta]-carotene, which would reduce carcase fat yellowness and make pasture-fed cattle more acceptable to some Asian markets.

Meat Science, volume 60, issue 1, pages 35-40

fat colour, pasture- and grain-fed beef, vitamin e supplementation, [alpha]-tocopherol, [beta]-carotene

An increase in the intake of the n-3 series polyunsaturated fatty acids (PUFA) is recommended by nutritionists for the human diet and beef is a significant source of these fatty acids. Enhancing the n-3 PUFA content of beef is important in view of the generally saturated nature of fatty acids in ruminant meats and the potentially negative effect this can have on human health. This study examined the effects of breed and diet on the fatty acid composition of beef M. longissimus. Ninety-six steers were used, 48 Aberdeen Angus cross (AA) and 48 Holstein-Friesian (HF). At 6 months of age, 3 groups were identified, to be slaughtered at 14, 19 and 24 months, respectively. Each group consisted of eight steers of each breed fed on a concentrate or a grass silage diet, rich in n-6 and n-3 PUFA, respectively. The intake of the concentrate diet was restricted so that steers of each breed grew at a similar rate on each diet. The early maturing AA produced heavier, fatter carcasses with better conformation. Animals fed grass silage had higher carcass fatness and conformation scores and higher levels of neutral lipid and total lipid in muscle than those fed concentrate. When all animals were pooled, a decline in PUFA% as total muscle lipid increased was evident. Feeding a grass silage diet rich in α-linolenic acid (18:3n-3) increased levels of this fatty acid in muscle neutral lipid by a factor of about 3.0 compared with the concentrate diet, as well as enhancing the synthesis of the n-3 series long-chain C20-22 PUFA in the phospholipid fraction, including docosahexaenoic acid (DHA, 22:6n-3). In contrast, both levels and proportions of linoleic acid (18:2n-6) and the n-6 series C20-22 PUFA were higher in animals fed the concentrate diet. The proportions of 18:1trans and conjugated linoleic acid (CLA) in muscle neutral lipid were higher in animals fed concentrate compared with silage in all 3 groups. This was partly due to increased consumption of 18:2n-6. The ratio of PUFA to saturated fatty acids (P:S) in muscle was reduced by feeding grass silage, partly as the result of increased fat deposition. However, the increase in levels of n-3 series fatty acids with silage-feeding resulted in beneficially low n-6:n-3 ratios in muscle in all age groups (approximately 1.2 compared with 12.0 in the concentrate diet). Subtle breed differences in PUFA amounts and proportions were noted. Holstein-Friesians had higher proportions of PUFA and higher P:S ratios compared with AA, partly due to a higher proportion of phospholipid in total lipid. In phospholipid itself, HF in the 19 and 24 months groups had higher proportions of most n-3 PUFA. In all age groups the ratio of DHA to its precursor, 18:3n-3 was higher in HF. © 2007 Elsevier Ltd. All rights reserved.

Meat Science, volume 78, issue 3, pages 256-269

age, beef, breed, fatty acids, forage, grass, health

— Grass feeding has been reported to affect several meat quality characteristics, in particular colour and flavour. In this paper we have reviewed some differences in meat colour and flavour between ruminants fed concentrates and animals allowed to graze pasture. The possible factors influ-encing the differences have been also examined. We have examined a total of 35 experiments which report the effect of pasture vs concentrate finishing systems on beef meat colour. Meat from cattle raised on pasture is reported to be darker than meat from animals raised on concentrates if measured by objec-tive (P < 0.001) as well as subjective (P < 0.05) methods. Several factors, not a specific one are responsible for this difference, variations in ultimate-pH and in intramuscular fat content between ani-mals finished at pasture and those finished on concentrates, seem to play a major role. Diet also affects meat flavour in both sheep and cattle but the components involved seem to be different. In sheep pastoral flavour is mostly determined by the branched-chain fatty acids and 3-methylindole (ska-tole). An important role seems to be played also by some products of oxidation of linolenic acid and its derivates. In cattle the role of skatole seems to be less important than sheep because of the lack of the branched-chain fatty acids. The pastoral flavour seems to be mostly determined by products of oxidation of linolenic acid and its derivates which derives substantially from grass. grass feeding / meat colour / meat flavour / ruminants Résumé — Effets d'une alimentation à base d'herbe sur la couleur et la flaveur de la viande de ruminants. L'alimentation à base d'herbe est souvent proposée comme un facteur pouvant influer sur la qualité de la viande et notamment ses caractéristiques de couleur et de flaveur. Dans cette revue bibliographique sont regroupées des différences de couleur et de flaveur observées entre viandes de boeufs ou d'agneaux provenant d'animaux alimentés au pâturage ou avec des régimes concentrés (souvent à base de maïs) et les rares éléments d'explication. L'analyse de la couleur de la viande bovine repose sur 35 essais différents. La viande provenant des animaux qui pâturent est plus sombre, quelle que soit la méthode de mesure, objective (luminosité L* mesurée au photomètre P < 0,001) ou sub-jective (critère visuel P < 0,05). Parmi les principaux facteurs pouvant expliquer cette différence, se trouvent les variations du pH ultime et celles du gras intramusculaire. Le régime alimentaire affecte aussi la flaveur des viandes de boeuf et d'agneau, mais les facteurs impliqués semblent différer entre A. Priolo et al.

Anim. Res, volume 50, pages 185-200

Enhancing the polyunsaturated fatty acid (PUFA) and decreasing the saturated fatty acid content of beef is an important target in terms of improving the nutritional value of this food for the consumer. The present study examined the effects of feeding a ruminally protected lipid supplement (PLS) rich in PUFA on the fatty acid composition of longissimus thoracis muscle and associated subcutaneous adipose tissue. Animals were fed ad libitum on grass silage plus one of three concentrate treatments in which the lipid source was either Megalac (rich in palmitic acid; 16 : 0) or PLS (soybean, linseed and sunflower-seed oils resulting in an 18 : 2n-6:18 : 3n-3 value of 2.4:1). Treatment 1 contained 100 g Megalac/kg (Mega, control); treatment 2 (PLS1) contained 54 g Megalac/kg with 500 g PLS/d fed separately; treatment 3 (PLS2) contained no Megalac and 1000 g PLS/d fed separately. The PLS was considered as part of the overall concentrate allocation per d in maintaining an overall forage:concentrate value of 60:40 on a DM basis. Total dietary fat was formulated to be 0.07 of DM of which 0.04 was the test oil. Total intramuscular fatty acids (mg/100 g muscle) were decreased by 0.31 when feeding PLS2 compared with Mega (P<0.05). In neutral lipid, the PLS increased the proportion of 18 : 2n-6 and 18 : 3n-3 by 2.7 and 4.1 on diets PLS1 and PLS2 v. Mega, respectively. Similar responses were noted for these fatty acids in phospholipid. The amounts or proportions of 20 : 4n-6, 20 : 5n-3 or 22 : 6n-3 were not influenced by diet whereas the amounts and proportions of 22 : 4n-6 and 22 : 5n-3 in phospholipid were decreased with inclusion of the PLS. The amounts of the saturated fatty acids, 14 : 0, 16 : 0 and 18 : 0, in neutral lipid were on average 0.37 lower on treatment PLS2 compared with Mega. Feeding the PLS also decreased the proportion of 16 : 0 in neutral lipid. The amount of 18 : 1n-9 (P=0.1) and the amount and proportion of 18 : 1 trans (P<0.01) were lower on treatments PLS1 and PLS2 in neutral lipid and phospholipid. Conjugated linoleic acid (cis-9, trans-11) was not influenced by diet in the major storage fraction for this fatty acid, neutral lipid. The PUFA:saturated fatty acids value was increased markedly (x2.5) with inclusion of the PLS (P<0.001) while the Sigman-6 : n-3 value increased slightly (x1.2; P=0.015). The results suggest that the protected lipid used, which was rich in PUFA, had a high degree of protection from the hydrogenating action of rumen micro-organisms. The PLS resulted in meat with a lower content of total fat, decreased saturated fatty acids and much higher 18 : 2n-6 and 18 : 3n-3. The net result was a large shift in polyunsaturated: saturated fatty acids, 0.28 v. 0.08, on feeding PLS2 compared with Mega, respectively.

The British Journal of Nutrition, volume 90, issue 3, pages 709-716

beef, fatty acids, healthy eating, rumen

Much research has been conducted and published about metabolic modifiers that increase growth rate, improve feed efficiency, increase carcass leanness, and decrease carcass fatness. Most of these metabolic modifiers have been developed to improve efficiency and profitability of livestock production and to improve carcass composition, with fewer of them developed and researched specifically to improve meat quality. Some of the metabolic modifiers can have negative effects on visual and sensory meat quality, especially when not used as recommended. This review evaluates the various kinds of metabolic modifiers that have been researched for their effects on production efficiency, carcass composition, and meat quality. Nutritional composition of meat generally is improved from use of most of the metabolic modifiers, visual quality is improved by others, but some can have a negative effect on marbling and tenderness. Anabolic steroid implants are very cost effective and practical for beef cattle production but aggressive implants used within 70 days of slaughter or too frequent use of them will reduce tenderness and marbling. Somatatropin and approved ??-agonists are very effective in improving growth performance and carcass leanness in pigs, and ??-agonists are effective in cattle, but improper use of them can have negative effects on marbling and tenderness. Feeding supplemental levels of vitamin E is quite beneficial for improving meat color and shelf-life of beef, lamb, and pork, whereas not supplementing diets with vitamin A has potential for improving marbling in cattle. Immunocastration shows promise for capitalizing on the efficiency of muscle growth of young boars up to a few weeks before slaughter, at which time boar taint is prevented and marbling is improved by immunocastration. Potential exists for improving the fatty acid profile of lipids and increasing conjugated linoleic acid content in beef through dietary manipulation. Supplementing swine diets with conjugated linoleic acid can improve carcass composition of swine, but is not yet cost effective to use. Dietary inclusion of magnesium, manganese, or chromium in diets of pigs and sheep has potential to improve meat color and water-holding capacity. Although, not all of these metabolic modifiers are approved in all countries, proper use of the ones that are approved offers opportunities for economically improving production efficiency and carcass leanness while maintaining acceptable marbling and tenderness, while some provide opportunities to enhance meat color and quality. ?? 2007 Elsevier Ltd. All rights reserved.

Meat Science, volume 77, issue 1, pages 121-135

carcass traits, dietary manipulation, growth performance, meat quality, metabolic modifiers

The objective of this thesis was to determine the effects of bedding dry matter on lying behaviour of Holstein cows. Over time bedding becomes wet with urine, feces and milk, but no research is available to guide recommendations for farmers regarding how often bedding should be replaced. I carried out two replicates of an experiment testing the effects of varying dry matter content of sawdust bedding systematically over five treatment levels. One replicate was conducted during the summer and one in the winter to test if the effects of damp bedding varied with season. The five bedding treatments averaged (± SD) 89.8 ± 3.7, 74.2 ± 6.4, 62.2 ± 6.3, and 43.9 ± 4.0, and 34.7 ± 3.8 % dry matter. Over the course of the trial, minimum and maximum temperatures in the barn were 2.6 ± 2.0 and 6.8 ± 2.2º C in the winter and 13.3 ± 2.5 and 22.6 ± 4.1º C in the summer. In both seasons, five groups of three non-lactating cows were housed in free stalls bedded with sawdust. Following a five day acclimation period on dry bedding, groups were exposed to the five bedding treatments in a five by five Latin square. Each treatment lasted four days, followed by one day when the cows were provided with dry bedding. Stall usage was assessed by 24 hour video scanned at five minute intervals averaged over two days. Responses were analyzed in a mixed model with group as the observational unit. Bedding dry matter affected lying time, averaging 10.4 ± 0.4 hours per day on the wettest treatment and increasing to 11.5 ± 0.4 hours per day on the driest bedding. Lying time varied with season, averaging 12.1 ± 0.4 hours per day across treatments during the winter and 9.9 ± 0.6 hours per day during the summer, but season and bedding dry matter did not interact. These results show that wet bedding reduces lying time in a dose dependent manner during both winter and summer seasons.

Design

Thesis