Effect of forage species on fatty acid content and performance of pasture-finished steers

Carcass characteristics, meat quality, sensory palatability and chemical composition of Thai native cattle grazing in lowland and Phu Phan mountain forest

OBJECTIVE

The aim of this study was to assess the effect of Thai native cattle grazing in the lowland or mountain forest on carcass characteristics, meat quality, sensory palatability, and chemical composition.

METHODS

Twelve male Thai native cattle with an average weight of 110±10 kg are allowed to be grazing in the lowland or Phu Phan mountain forest during the rainy season in northeastern Thailand.

RESULTS

The carcass characteristics, meat pH, and meat color were unaffected by treatment (p>0.05). The boiling loss was lower in the cattle grazing on the mountain forest (p = 0.027). The cattle grazing in the mountain forest had increased shear force (p = 0.039), tenderness (p = 0.011), and flavor intensity (p = 0.003). The protein and fat were higher (p<0.001 and p = 0.035, respectively) in cattle grazing in the mountain forest. The different grazing systems of the cattle had no effect (p>0.05) fatty acids in meat, except for capric acid (C10:0) and lauric acid (C12:0), which were higher (p = 0.046 and p = 0.049, respectively) when the cattle were grazing in the mountain forest. The different grazing systems did not influence (p>0.05) the unsaturated fatty acids in meat.

CONCLUSION

Thai native cattle grazing in the Phu Phan mountain forest in the rainy season improves meat quality, sensory evaluation, and chemical composition.

Can botanically-diverse pastures positively impact the nutritional and antioxidant composition of ruminant meat? - Invited review

A desire for more sustainable pasture-based ruminant feeding systems has led to growing interest in utilising botanically-diverse pastures (BDP) over monoculture pastures. Research suggests that, from a human consumption viewpoint, grass-based ruminant feeding leads to more nutritionally desirable fatty acid (FA) and antioxidant concentrations in meat compared with concentrate feeding, which can affect meat quality. The FA, antioxidant and secondary metabolite content of plants differ, depending on species, maturity and seasonality, offering the potential through targeted feeding of BDP to produce meat with superior nutritional and antioxidant profiles. This review explores the effect, if any, that grazing ruminants on BDP has on the FA profile, fat-soluble vitamin, and antioxidant content of meat. The input-output relationship between forage and red meat constituents is complex and is likely affected by species diversity, forage consumption patterns and modulation of rumen fermentation processes. Further investigation is required to fully understand the effect that BDP may have on the composition and quality of ruminant meat.

Lipid Metabolism, Carcass Characteristics and Longissimus dorsi Muscle Fatty Acid Composition of Tropical Crossbred Beef Cattle in Response to Desmanthus spp. Forage Backgrounding

Lipid metabolism, carcass characteristics and fatty acid (FA) composition of the Longissimus dorsi (loin eye) muscle were evaluated in tropical crossbred steers backgrounded on Desmanthus spp. (desmanthus) with or without feedlot finishing. It was hypothesized that steers backgrounded on isonitrogenous diets augmented with incremental proportions of desmanthus will produce carcasses with similar characteristics and FA composition. Forty-eight Brahman, Charbray and Droughtmaster crossbred beef steers were backgrounded for 140 days on Rhodes grass (Chloris gayana) hay augmented with 0, 15, 30 or 45 percent desmanthus on dry matter basis. Lucerne (Medicago sativa) hay was added to the 0, 15 and 30 percent desmanthus diets to ensure that they were isonitrogenous with the 45 percent desmanthus diet. After backgrounding, the two heaviest steers in each pen were slaughtered and the rest were finished in the feedlot for 95 days before slaughter. Muscle biopsy samples were taken at the beginning and end of the backgrounding phase. Carcasses were sampled at slaughter for intramuscular fat (IMF) content, fat melting point (FMP) and FA composition analyses. Increasing the proportion of desmanthus in the diet led to a linear increase in docosanoic acid (p = 0.04) and omega-6/omega-3 polyunsaturated FA ratio (n-6/n-3 PUFA; p = 0.01), while docosahexaenoic acid decreased linearly (p = 0.01). Feedlot finishing increased hot carcass weight, subcutaneous fat depth at the P8 site and dressing percentage (p ≤ 0.04). The n-6/n-3 PUFA ratio was within the recommended < 5 for human diets. IMF was within the consumer-preferred ≥3% level for palatability. The hypothesis that steers backgrounded on isonitrogenous diets augmented with incremental proportions of desmanthus will produce similar carcass characteristics and FA composition was accepted. These findings indicate that a combination of tropical beef cattle backgrounding on desmanthus augmented forage and short-term feedlot finishing produces healthy and highly palatable meat.

Effects of forage finishing methods with alfalfa on cattle growth performance and beef carcass characteristics, eating quality, and nutrient composition

Over 2 yr, yearling steers (n = 200) were used to evaluate growth performance, carcass, meat quality, and nutrient composition traits as affected by management regimen comparing three methods of forage finishing (alfalfa pasture, hay, and silage) versus a high corn diet. Management regimen × year interactions (P < 0.01) for average daily gain, dry matter intake, gain-to-feed, carcass weight, and grade fat were due to lower performance for hay-fed cattle in years 1 vs. 2. Carcass, meat quality, and taste panel traits were generally similar (P > 0.10) across method of forage finishing. Trained taste panels found longissimus muscle from grain-fed beef to be more (P < 0.01) tender, juicy, and flavourful than forage finished beef, with lower (P ≤ 0.05) ratings for tenderness and juiciness for hay- vs. silage-finished beef. Corn finished beef contained greater amounts of oleic and monounsaturated fatty acids and lower amounts of omega-3 and polyunsaturated fatty acids than forage finished beef (P ≤ 0.04). Although the method of forage finishing may not affect most performance, carcass, and meat quality (pH, colour, intramuscular fat content, and shear force) traits, there may be concerns with tenderness and juiciness for beef from cattle finished on alfalfa hay.

Effect of Dietary Olive Cake Supplementation on Performance, Carcass Characteristics, and Meat Quality of Beef Cattle

Simple Summary

The consumer’s liking of meat is measured in relation to color, intramuscular fat content, healthy composition of fatty acids, tenderness, juiciness, flavor, and aroma; these qualitative characteristics, influencing the consumer’s choice, guide the market whose objective is to provide safe beef with high food characteristics. The use of agro-industrial co-products, containing appreciable amounts of vegetable oils, could be a feasible strategy to influence the quality of meat. In this study, the effect of the partially destoned olive cake supplementation on the performance, carcass characteristics, and meat quality of beef cattle was evaluated. The experiment was carried out on 45 Limousin bulls divided into three homogenous groups, fed with a diet containing 0%, 7.5%, and 15.0% of the olive cake. Results show that the olive cake supplementation influenced the animal performance, increased the tenderness of meat, the intramuscular fat content and unsaturated fatty acids (oleic acid and essential fatty acids), affecting the meat quality indices and suggesting olive cake as a strategy for the sustainability of the animal food chain, rural economies, and environment, providing healthy animal products.

Abstract

Dietary partially destoned olive cake supplementation on performance, carcass traits and meat quality of intensively finished bulls was evaluated. Forty-five Limousin bulls, divided into three homogenous groups, received a diet with no supplementation (Control-CTR), 7.5% (Low Olive Cake-LOC), and 15.0% of olive cake supplementation (High Olive Cake-HOC). The trial was realized for 150 days; all bulls were individually weighed at the beginning, middle, and end of the trial, to calculate the individual average daily gain (ADG). At slaughtering, on each carcass, hot weight was recorded and, after 7 days, the pH and temperature were measured. On Longissimus lumborum muscle, color, cooking loss, and shear force of the cooked sample were determined. The chemical composition and the fatty acid content of muscle were determined. Olive cake inclusions (7.5% and 15.0%) increased (p < 0.05) the body weight, ADG, slaughter traits and intramuscular fat content and influenced (p < 0.05) the quality indices. The 15.0% of the inclusion reduced (p < 0.05) the cooking loss and shear force, and increased the unsaturated fatty acid content. The olive cake can be considered as a functional component in beef production and, in substitution to a quote of cereals into the diet of bulls, could be an opportunity to improve agriculture sustainability.

Diet and Genetics Influence Beef Cattle Performance and Meat Quality Characteristics

A comprehensive review of the impact of tropical pasture grazing, nutritional supplementation during feedlot finishing and fat metabolism-related genes on beef cattle performance and meat-eating traits is presented. Grazing beef cattle on low quality tropical forages with less than 5.6% crude protein, 10% soluble starches and 55% digestibility experience liveweight loss. However, backgrounding beef cattle on high quality leguminous forages and feedlot finishing on high-energy diets increase meat flavour, tenderness and juiciness due to improved intramuscular fat deposition and enhanced mono- and polyunsaturated fatty acids. This paper also reviews the roles of stearoyl-CoA desaturase, fatty acid binding protein 4 and fatty acid synthase genes and correlations with meat traits. The review argues that backgrounding of beef cattle on Desmanthus, an environmentally well-adapted and vigorous tropical legume that can persistently survive under harsh tropical and subtropical conditions, has the potential to improve animal performance. It also identifies existing knowledge gaps and research opportunities in nutrition-genetics interactions aimed at a greater understanding of grazing nutrition, feedlot finishing performance, and carcass traits of northern Australian tropical beef cattle to enable red meat industry players to work on marbling, juiciness, tenderness and overall meat-eating characteristics.

Meat quality, fatty acids, volatile compounds, and antioxidant properties of lambs fed pasture versus mixed diet

The aim of the present work was to investigate the effects of feeding regimens (pasture vs. mixed diet) on meat quality, fatty acids, volatile compounds, and antioxidant properties in lamb meat. In total, 24 lambs were allotted into two feeding regimens at 10.23 kg live weight. Lambs were fed on pasture grass (PG group, n = 12) or mixed diet (M group, n = 12). Longissimus thoracis (LT) muscle samples from the M group had a higher intramuscular fat (IMF) (p < 0.05), pH45minvalue (p < 0.01), and ash (p < 0.05) than the PG group. In contrast, the shear force (p < 0.05), L*(p < 0.05), and b* (p < 0.001) in M group were lower than in PG group. Analyses indicated that PG group contained higher linolenic acid (C18:3n3) and docosatrienoic acid (C22:3n6) (p < 0.05) than the M group. Major volatile compounds in the muscles included hexanal, heptanal, nonanal, octanal, 1-pentanol, 1-hexanol, 1-octen-3-ol, and 2,3-octanedione. The levels of hexanal, nonanal, and 2,3-octanedione were significantly lower in PG lamb muscle (p < 0.01). In contrast, 1-pentanol and 1-hexanol levels were higher in M lamb muscle (p < 0.01). Muscle from PG lamb exhibited higher catalase (CAT) and glutathione peroxidase (GPx) activity (p < 0.05). PG muscle also contained a higher radical-scavenging ability (RSA; p < 0.001) and cupric-reducing antioxidant capacity (CUPRAC; p < 0.05). Overall, the improved antioxidant status in PG muscle inhibited lipid peroxidation (aldehydes and ketones), thereby improving the meat quality.

Growth performance and carcass traits of steers finished on three different systems including legume-grass pasture and grain diets

Inclusion of legume in grass pastures optimizes protein values of the forage and promotes improved digestibility. Therefore, we hypothesized that finishing steers on a novel combination of legumes and grass pasture would produce carcasses with acceptable traits when compared to carcasses from steers finished in feedlot systems. In this study, we evaluated the effects of finishing steers on three systems including: grazing legume-grass pasture containing oats, ryegrass, white and red clover (PAST), grazing PAST plus supplementation with whole corn grain (14 g/kg BW (SUPP)), and on a feedlot-confined system with concentrate only (28 g/kg BW, consisting of 850 g/kg of whole corn grain and 150 g/kg of protein-mineral-vitamin supplement (GRAIN)) on growth performance of steers, carcass traits and digestive disorders. Eighteen steers were randomly assigned to one of three dietary treatments and finished for 91 days. Data regarding pasture and growth performance were collected during three different periods (0 to 28, 29 to 56 and 57 to 91 days). Subsequently, steers were harvested to evaluate carcass traits, presence of rumenitis, abomasitis and liver abscesses. The legume-grass pasture provided more than 19% dry matter of protein. In addition, pasture of paddocks where steers were assigned to SUPP and PAST treatments showed similar nutritional quality. When compared to PAST, finishing on SUPP increased total weight gain per hectare, stocking rate, daily and total weight gains. The increase of weight gain was high to GRAIN than SUPP and PAST. Steers finished on GRAIN had high hot carcass weight, fat thickness and marbling score when compared to PAST. However, these attributes did not differ between GRAIN and SUPP. Abomasum lesions were more prevalent in steers finished on GRAIN when compared to PAST. Results of this research showed that it is possible to produce carcasses with desirable market weight and fat thickness by finishing steers on legume-grass pasture containing oats, ryegrass, white and red clover. Moreover, supplementing steers with corn when grazing on legume-grass pasture produced similar carcass traits when compared to beef fed corn only.

Performance and ingestive behavior of steers on integrated system using legume and/or energy supplementation

This study aimed to evaluate the effect of a mixture of temperate and legume grasses with or without energy supplementation on the performance and feeding behavior of finishing beef steers. Eighteen Nellore-Zebu steers, average 23 months old and body weight (BW) of 380 kg, were used in a continuous grazing system, in a randomized block experimental design. Treatments were ORS: oat (Avena strigosa Schreb) + annual ryegrass (Lolium multiflorum Lam) + supplementation with corn bran; ORVS: oat + ryegrass + vetch (Vicia sativa L.) + supplementation with corn bran; and ORV: oat + ryegrass + vetch. Evaluations were conducted on pasture (forage mass, sward height, herbage accumulation, botanical composition, and chemical composition) and animal (performance and ingestive behavior). Stocking rate and forage mass were greater in treatments with energy supplementation (ORVS and ORS), thus presenting greater sward heights compared to the treatment without supplementation. There was greater participation of oats and ryegrass when vetch was absent (ORS). The presence of supplement (ORS and ORVS) increased the presence of oat stem. The presence of the supplement caused the contribution of the vetch to be lower, likely because of the higher animal load of these treatments. The higher presence of vetch increased crude protein content in the ORV treatment. The ORS exhibited greater gain per area compared to the ORV. Supplemented animals had lower grazing and greater idle time. The ORS treatment animals spent more time in other activities and consumed supplementation and less time grazing than the other treatments. The absence of supplement (ORV) caused the animals to spend more time grazing. Animals not supplemented showed a higher duration of daily chewing, number of chews per minute, number of daily chews, daily number of bites, and station numbers.

Effects of feeding legume-grass pasture and different concentrate levels on fatty acid profile, volatile compounds, and off-flavor of the M. longissimus thoracis

Pasture-finished beef is becoming more popular among consumers due to concerns related to fatty acid content and sustainable practices. The effects of finishing crossbred steers on legume-grass pasture comprised of oats, ryegrass, and clover (PAST), legume-grass pasture plus whole corn grain (WCG) supplementation (SUPP), and only with WCG (GRAIN) on fatty acids profile, volatile compounds, sensory, and texture attributes were studied. Pasture diets (PAST and SUPP) led to lower n-6/n-3 ratio (P < 0.001), and highest deposition of C18:2 cis-9 trans-11 (P < 0.001) in the lean. Beef from steers fed GRAIN had the highest values of volatile compounds associated with lipid oxidation. Off-flavor intensity was significantly greater on beef from steers fed GRAIN when compared to PAST. Overall, muscles from steers finished on PAST and SUPP showed similar attributes but differ when compared to GRAIN. The presence of forage is essential to improve fatty acid profile, decrease volatile compounds associated with lipid oxidation, and minimize off-flavor.

Fatty acid profile in vertical strata of elephant grass subjected to intermittent stocking

The milk and meat from animals with a pasture-based diet have higher proportions of CLA and C18:3 and lower omega-6:omega-3 ratios than products from animals with diets based on corn silage and concentrate. However, most of the published studies have evaluated fatty acid profiles in temperate climate grasses and the literature with tropical grasses is scarce. Thus, the aim of this study was to evaluate the morphological and fatty acid compositions in the vertical strata of elephant grass (Pennisetum purpureum Schum.) swards subjected to grazing heights (90 or 120 cm pre-grazing heights) and levels of defoliation (50% or 70% removal of the initial pre-grazing height). There were no interactions among pre-grazing height, the level of defoliation and grazing stratum. However, higher proportion of C18:3 (58% and 63%) was found in the 90-cm swards and in the half upper stratum. A higher proportion of C18:3 was associated with a higher leaf proportion and crude protein content. Thus, the upper stratum of sward or a grazing management scheme (e.g. first-last stocking) resulting in a higher proportion of leaves and crude protein both provide higher proportions of C18:3 to animals grazing in elephant grass swards.

BILL E. KUNKLE INTERDISCIPLINARY BEEF SYMPOSIUM: Coping with tall fescue toxicosis: Solutions and realities

Beef cattle consume more tall fescue [ (Schreb.) Darbysh.] than any other perennial cool-season grass in North America. Tall fescue forms a mutualistic relationship with the fungus (Morgan-Jones and W. Cams) C.W. Bacon & Schardl, comb. nov.; these plants are often referred to as endophyte-infected tall fescue. Agronomically, endophyte infection is good; endophyte-infected plants resist biotic and abiotic stresses better than do endophyte-free plants. However, tall fescue plants infected with a common toxic endophyte produce the ergot alkaloids that cause tall fescue toxicosis. Several agronomic practices can eliminate or reduce the effects of tall fescue toxicosis. Renovating tall fescue fields infected with a common toxic endophyte to new cultivars infected with a novel (or nontoxic) endophyte eliminates the problem for that field. Although the cost to renovate currently exceeds US$600/ha, most economic analyses show it to be a good long-term investment, especially on fields with high forage production potential. Less effective, but popular, methods of dealing with tall fescue toxicosis include adding clovers ( spp.) or other forage species to the pastures to dilute the effects of the toxins, avoiding the use of high rates of nitrogen fertilizers, feeding supplements, and rotating cattle to warm-season forages in summer. Also, the alkaloid concentration in forage can be reduced by making it (drying) into hay. Recent research shows that animal tolerance to tall fescue toxicosis is possible, although there is still much to learn about this topic. Tall fescue toxicosis is likely a reality in the beef industry for some time to come. We contend that renovation of the most productive fields to cultivars infected with a novel endophyte coupled with the prospect of using tolerant livestock in scenarios where renovation is not possible will give innovative producers a competitive edge.

Terminação de novilhos em pastagem de aveia branca consorciada com leguminosa ou associada à suplementação energética

O objetivo do experimento foi avaliar a associação da ervilhaca (Vica sativa) ou da suplementação energética em pastagem de aveia branca (Avena sativa) sobre o desempenho de novilhos de corte na fase de terminação. Foram utilizados 18 novilhos castrados, 1/4 Marchegiana 1/4Aberdeen Angus2/4 Nelore, com peso vivo e idade média de 360kg e 19 meses, respectivamente, divididos em três tratamentos: pastagem de aveia branca, pastagem de aveia branca consorciada com ervilhaca e pastagem de aveia branca com suplementação energética (milho grão triturado, 1% do peso vivo por dia, na matéria seca). O delineamento experimental utilizado foi o de blocos ao acaso com três tratamentos e três repetições. Houve interação significativa entre o período de avaliação e os tratamentos para participação do componente folha da aveia na pastagem. A participação da ervilhaca aumentou no decorrer do experimento de 3,51% para 12,21% consequentemente a participação da aveia diminuiu no decorrer do experimento. Não houve diferença significativa (P>0,05) para massa de forragem, carga animal, oferta de forragem e taxa de acúmulo diário entre os tratamentos. Os animais que receberam suplementação apresentaram maior (P<0,05) ganho de peso médio diário (1,08kg/dia), ganho de peso vivo por hectare (4,47kg/ha/dia) e ganho de peso vivo total (242,82kg) em comparação com aqueles que receberam somente a pastagem de aveia (0,68kg; 2,50kg/ha/dia; 123,49kg, respectivamente). Já os animais que permaneceram em pastagem consorciada de aveia e ervilhaca apresentaram resultados intermediários (0,89kg/dia; 2,99kg/ha/dia e 154,26kg, respectivamente). O melhor peso final foi para o tratamento com suplementação (424,44kg). A suplementação energética em pastagem de aveia branca apresentou melhores resultados de desempenho animal. No entanto, a consorciação de aveia branca e ervilhaca é uma alternativa quando o suplemento (grão de milho) está com um custo elevado, uma vez que o desempenho, apesar de menor, não foi diferente dos animais suplementados.

Carcass parameters and meat quality in meat-goat kids finished on chicory, birdsfoot trefoil, or red clover pastures

This study was conducted during the 2009 and 2010 grazing seasons to assess carcass parameters and chevon (goat meat) quality when meat-goat kids (n=72) were finished on pastures of red clover (Trifolium pratense L.; RCL), birdsfoot trefoil (Lotus corniculatus L.; BFT), or chicory (Cichorium intybus L.; CHIC). Final live weight (P<0.05) and carcass weight (P=0.10) were greater when goats were finished on RCL compared to CHIC with BFT being intermediate. Ribeye area, backfat thickness, body wall thickness, internal fat score, and leg score were not different (P>0.10) among treatments when adjusted for the covariate of carcass weight. Finishing meat-goat kids on RCL, BFT, or CHIC impacted concentrations of fatty acids (FAs) 18:1 trans-10, 18:1 cis-11, 18:2, 18:3 polyunsaturated fatty acids (PUFAs), omega-6, omega-3, and PUFA:saturated fatty acid ratio in longissimus lumborum samples. Finishing meat-goat kids on CHIC, RCL, or BFT pastures produced carcass weights acceptable for most ethnic markets in the USA.

Effects of forage silage species on yearling growth performance, carcass and meat quality, and nutrient composition in a forage based beef production system

Berthiaume, R., Lafrenière, C., Girard, C., Campbell, C. P., Pivotto, L. M. and Mandell, I. B. 2015. Effects of forage silage species on yearling growth performance, carcass and meat quality, and nutrient composition in a forage based beef production system. Can. J. Anim. Sci. 95: 173–187. Forty weaned, crossbred beef calves (predominantly Angus and Simmental) were forage-finished using all-silage diets (red clover–timothy versus tall fescue) to examine forage species’ effects on growth performance, carcass traits, meat quality, and nutrient composition. Weaned calves (257 d of age) were forage-finished using red clover–timothy or tall fescue silage and harvested at approximately 1 yr of age. During carcass processing, one side from each carcass was covered with a polyliner to examine if reducing rates of chilling could compensate for limited fat cover expected from low dietary energy contents fed, and limited time on feed. Longissimus thoracis, semimembranosus, and semitendinosus steaks were aged 10, 14, and 21 d to examine effects on Warner–Bratzler shear force values while fatty acid and vitamin B12 composition were determined on 10-d-aged steaks. Average daily gain, feed efficiency, hot carcass weights, and longissimus muscle area were greater (P<0.03) when cattle were fed red clover–timothy versus tall fescue silage, most likely due to the higher protein content of red clover–timothy silage. Shear force was greater (P<0.002) in steaks from all muscles evaluated from cattle fed tall fescue versus red clover–timothy silage. In comparison to 10-d-aged steaks, 14 d of ageing were needed to reduce (P<0.001) shear force for longissimus steaks, while 21 d of ageing were needed to reduce (P<0.001) shear force for semitendinosus steaks. Use of a polyliner decreased (P=0.0001) the rate of temperature decline at selected carcass sites, but did not reduce shear force values. The percent of n-3 fatty acids and polyunsaturated fatty acid/saturated fatty acid ratio were greater (P<0.04) in longissimus from cattle fed red clover–timothy versus feeding tall fescue silage. Feeding red clover–timothy silage improved growth performance, carcass, shear force, and fatty acid composition traits versus feeding tall fescue silage.

Effect of slaughter season and muscle type on the fatty acid composition, including conjugated linoleic acid isomers, and nutritional value of intramuscular fat in organic beef

BACKGROUND

Consumer awareness regarding the intake of beef of organic origin is strongly associated with the beneficial outcomes to human health, the environment and animal welfare. In this paper the effects of slaughter season and muscle type on the fatty acid composition, conjugated linoleic acid (CLA) isomeric profile, total cholesterol, α-tocopherol and β-carotene contents and nutritional quality of intramuscular fat in organic beef (n = 30) are reported for the first time.

RESULTS

Organic beef showed a very low total lipid content, with seasonal changes in the levels of some fatty acids, CLA isomers, n-6/n-3 polyunsaturated fatty acid (PUFA) ratio, total cholesterol and β-carotene. In addition, differences between longissimus lumborum (relatively red) and semitendinosus (relatively white) muscles were found for many fatty acids, specific CLA contents, many CLA isomers and both PUFA/saturated fatty acid (SFA) and n-6/n-3 ratios. However, in spite of the seasonal and carcass variations, all organic meats analysed had values of beef similar to pasture-fed cattle.

CONCLUSION

From a nutritional perspective, organic meat from both slaughter seasons seems to have high CLA contents, PUFA/SFA and n-6/n-3 indices within the recommended values for the human diet. The data indicate that intramuscular fat in organic meat has a high nutritional value throughout the year.

Inclusion of flaxseed in hay- and barley silage diets increases alpha-linolenic acid in cow plasma independent of forage type

Feeding flaxseed to cattle may be a means of increasing omega-3 fatty acid levels in ruminant products, but possible interactions with conserved forages have not been investigated. Twelve Holstein cows were used in a replicated 4 × 4 Latin Square experiment. Cows were fed one of four 50:50 forage:concentrate diets (DM basis): hay (hay control, HC), hay plus 15% ground flaxseed (hay-flaxseed, HF), barley silage (silage control, SC), and barley silage plus 15% ground flaxseed (silage-flaxseed, SF). Plasma concentrations of alpha-linolenic acid (ALA) did not differ between SC and HC diets. Flaxseed increased ALA (P < 0.05), but levels were not influenced by forage type. Flaxseed slightly increased 18:2n-6 (P < 0.05) and some n-6 and n-3 elongation and desaturation products, particularly arachidonic acid (ARA) and eicosapentaenoic acid (EPA). Flaxseed also increased C18:0 (P < 0.05) with this increase being greater (P < 0.01) for cows fed SF than HF. Feeding flaxseed also increased plasma C18:1-trans isomers (P < 0.01), predominantly vaccenic acid (VAA, 18:1-t11), with this increase being greater (P < 0.05) in cows fed HF than SF. Although conjugated linoleic acid (CLA) was increased (P < 0.001) with flaxseed it was not influenced by forage type (P = 0.06). Overall, feeding flaxseed increased plasma ALA, EPA, ARA and CLA independently of forage type. Feeding flaxseed with silage, however, resulted in more 18:0, while feeding flaxseed with hay resulted in greater accumulations of plasma 18:1-trans isomers mainly in the form of VAA.

Comparison of conventional and organic management conditions on growth performance, carcass characteristics and haematological parameters in Karacabey Merino and Kivircik breeds

Growth performance, carcass characteristics, post-slaughtering and haematological parameters of Kivircik and Karacabey Merino male lambs in conventional and organic management systems were compared. The animals which were weaned at 7 weeks of age were divided into Kivircik conventional, Kivircik organic (KO), Karacabey Merino conventional and Karacabey Merino organic (MO) groups containing 12 lambs each. Fattening was ended when lambs attained 35 kg of live weight. The time to attain the determined fattening weight was significantly different among the groups, and Merino lambs having higher live weight gain were earlier than Kivircik lambs (p < 0.05). Overall conventional (CG) and organic group lambs were also compared. Live weight gain, intra-abdominal fat amount, external fat thickness and visceral organ weight were significantly higher in CG lambs (p < 0.05). Higher haematocrit and erythrocyte counts were obtained with the CG group (p < 0.05), whilst triglyceride, total plasma cholesterol and lipoprotein (HDL, LDL, VLDL) levels between groups were not significant. Pneumonia was the unique infection, with an incidence of 50% (six lambs) and 16.6% (two lambs) for MO and KO animals, respectively. The mortality rate was 16.6% (two lambs) for MO group, whilst no mortality was recorded for KO group animals. The present study has shown that although Karacabey merino lambs had higher growth performance compared to Kivircik lambs, organically fattened lambs in whole exhibited inferior growth performance. Lower infection and mortality observed with Kivircik lambs suggested that they could be more resistant to infections and outdoor environmental conditions.