Effect of temporary weaning and creep feeding on calf growth and the reproductive efficiency of their Hereford dams.

OBJECTIVE: The objective was to test if creep feeding (CF) improves the average daily gain (ADG) and weaning weight of calves submitted to temporary weaning (TW) and if the combination of CF and TW improves conception and pregnancy rates of cows. METHODS: Primiparous (n = 74) and primiparous and multiparous (n = 104) cows grazing native grasslands were used in experiment 1 and 2; respectively. The experimental design was in plots divided into complete random blocks with two replications. The CF was the big plot and TW the small plot, thus four experimental groups were formed: i) -CF-TW (n = 21 and 27); ii) -CF+TW (n = 16 and 24); iii) +CF-TW (n = 20 and 26); iv) +CF+TW (n = 17 and 27) with cow-calf pairs for experiments 1 and 2; respectively. Nose plate application for TW had a duration of 14 and 15 days for experiment 1 and 2: respectively. In experiment 1, calves were fed at 1% of live weight for 112 days using a commercial supplement with 18.4% crude protein. In experiment 2, the supplementation lasted 98 days, and was carried out with corn dried distillers grains with soluble (DDGS) at 40% of the potential intake on a daily basis. RESULTS: The TW reduced ADG during the TW period and the following 14 days, but the negative effect of TW was maintained until the final weaning only in experiment 2. The CF increased ADG during TW period in both experiments. The TW promoted an earlier conception of the dams (12 days in -CF treatment and 19 days in +CF treatment, p<0.01) and CF increased pregnancy rate in experiment 1, being the effects not consistent between experiments. CONCLUSION: The CF consistently promoted an increase in ADG during the period of TW and increased final weaning weight of calves, therefore it is economically viable.

Long-term effect of early nutrition on endocrine parameters and liver and endometrial gene expression of the members of the somatotrophic axis in Hereford heifers.

This study compared the effect of different management systems on endocrine parameters, and gene expression of members of the somatotrophic axis in the liver and endometrium of beef heifers. Twenty-two 709-days-old heifers submitted to Early Weaning (EW, n = 8), Traditional Weaning (TW, n = 7) and TW plus creep feeding (TW+CF, n = 7) were used. Animals were synchronized with two prostaglandin (PG) injections at 11-day interval (Oestrus = Day 0). Blood samples were collected daily for progesterone (P4) determination, and endometrial and liver biopsies on Days 7 and 16 for transcript determination of members of the somatotrophic axis. Progesterone concentrations were greater on Days 15 and 16 (p < .02) of the cycle in TW+CF than TW and EW heifers. On Day 7, TW+CF heifers expressed greater liver total growth hormone receptor transcripts than TW heifers (p = .05) and greater insulin-like growth factor (IGF)-binding protein 3 mRNA than both EW and TW groups (p < .05). On Days 7 and 16, TW+CF expressed more endometrial IGF1 mRNA than the other groups (p < .01). We conclude that increasing the plane of nutrition of nursing calves may have a long-term effect on the functioning of the somatotrophic axis both in the liver and in the endometrium.

Growth, carcass traits and palatability: can the influence of the feeding regimes explain the variability found on those attributes in different Uruguayan genotypes?

It is well known what genetic and nutritional factors affect growth and meat quality, but there is less information related to interactive importance of them during the productive process. These systems are mainly based on rangelands affecting animal growth in early stages of life thus producing smaller cattle and reduced retail yield comparing with well grown calves. During the last ten years, Uruguayan livestock production systems have been intensified using improved pastures, concentrates and better genetic. The main breeds in Uruguay are Hereford, Angus and their crosses. These British breeds are under genetic evaluation programs which consider carcass trait parameters. It is important for beef industry to know if interactions between genotype and nutrition during growth and fattening phases are influencing production, efficiency, carcass weight and meat quality attributes. The aim of this article is to present information obtained under different feeding strategies during the post weaning and fattening and their influence on those attributes.

Animal welfare and meat quality: the perspective of Uruguay, a "small" exporter country.

Public sensitivity towards animal welfare has risen in recent years. Uruguay is a primary meat exporter. Therefore, it is compulsory not only to provide good quality and safe meat, but also to project a welfare friendly image. Uruguayan meat production systems are mainly based on rangeland pastures but, due to international meat prices and the opening of new markets, intensive fattening systems increased. These systems include a wide range of feeding alternatives between pasture and concentrate utilization, involving differences in terms of animal welfare, carcass and meat quality, that require to be studied. Accordingly, some husbandry practices associated mainly with extensive systems must be evaluated, as well as their applicability to international recommendations related to pre-slaughter handling which may not be suitable for local conditions. In the present paper we share scientific results related to the impact of different production systems, husbandry practices and pre-slaughter procedures associated to animal welfare and meat quality in Uruguayan conditions.

Sustainable sheep production and consumer preference trends: compatibilities, contradictions, and unresolved dilemmas.

There are increasing concerns of society towards the consumption of animal products which have been produced and transformed in a sustainable manner. This trend influences consumer purchasing decision making, particularly in developed countries. On the other hand, in the next years, the pressure to increase the volume and efficiency of meat production will be much higher to cope with the expected unsatisfied demand. At least in part, current and future technologies could contribute to solve this challenge. However, the use of some of these innovations could have a negative effect on consumer preferences. There is no consensus in our society about this dilemma. The objective of this paper is to review the scientific evidence related to these topics and to analyze and discuss the effect of some of the extrinsic and intrinsic factors linked with the sheep industry which could affect the acceptability of lamb meat by consumers.

Spanish, French and British consumers' acceptability of Uruguayan beef, and consumers' beef choice associated with country of origin, finishing diet and meat price.

The effect of country of origin (local, Switzerland, Argentina, Uruguay), finishing diet (grass, grass plus concentrate, concentrate), and price (low, medium, high) on consumer's beef choice and segmentation was evaluated in Spain, France and United Kingdom. Sensory acceptability of Uruguayan beef from different production systems was also evaluated and contrasted with consumers' beef choices. Origin was the most important characteristic for the choice of beef with preference for meat produced locally. The second most important factor was animal feed followed by price with preference for beef from grass-fed animals and lowest price. The least preferred product was beef from Uruguay, concentrate-fed animals and highest price. Sensory data showed higher acceptability scores for Uruguayan beef from grass-fed animals with or without concentrate supplementation than animals fed concentrate only. Consumer segments with distinct preferences were identified. Foreign country promotion seems to be fundamental for marketing beef in Europe, as well as the development of different marketing strategies to satisfy each consumer segment.

Sensory quality of beef from different finishing diets.

Beef production under different local husbandry systems might have meat sensory quality implications for the marketing of these products abroad. In order to assess the effect of finishing diet systems on beef quality, a trained sensory taste panel assessed meat aged for 20 days from 80 Uruguayan Hereford steers that were finished on one of the following diets: T1=Pasture [4% of animal live weight (LW)], T2=Pasture [3% LW plus concentrate (0.6% LW)], T3=Pasture [3% LW plus concentrate (1.2% LW)], or T4=Concentrate plus hay ad libitum. Beef odour and flavour intensities decreased with an increase in the energy content of the diet. The meat from T2 had the lowest acid flavour and strange odours intensities. In general, steers fed only concentrate plus hay (T4) produced meat that had an inferior sensory quality because they had more pronounced off-flavours and was tougher.

Finishing diet, temperament and lairage time effects on carcass and meat quality traits in steers.

Sixty Hereford (H) and Braford (B: 3/8 Zebu and 5/8 H) steers were finished on: D1) rangeland plus corn grain (1% of live weight) (H n=15, B n=15); and D2) high quality pasture (H n=15, B n=15) to study the effect of diet, temperament and lairage time on carcass and meat quality. Steers were slaughtered the same day in two groups, spending 15 and 3h in pens, respectively (50% from D1, 50% from D2 in each group). Animals from D1 had better carcass performance without effect of the diet on meat quality. Regardless of breed, calmer steers showed higher average daily gain and lower shear force values. Carcasses from animals in the long lairage group had a better rate of pH decline and more tender meat, suggesting that more than 3h preslaughter time should be necessary to rest and recover, mainly depending on lairage conditions.

Video image analysis as a potential grading system for Uruguayan beef carcasses.

A study was conducted in 2 phases to evaluate the effectiveness of 1) the VIAscan Beef Carcass System (BCSys; hot carcass system) and the CVS BeefCam (chilled carcass system), used independently or in combination, to predict Uruguayan beef carcass fabrication yields; and 2) the CVS BeefCam to segregate Uruguayan beef carcasses into groups that differ in the Warner-Bratzler shear force (WBSF) values of their LM steaks. The results from the meat yield phase of the present study indicated that the prediction of saleable meat yield percentages from Uruguayan beef carcasses by use of the BCSys or CVS BeefCam is similar to, or slightly better than, the use of USDA yield grade calculated to the nearest 0.1 and was much more effective than prediction based on Uruguay National Institute of Meat (INAC) grades. A further improvement in fabrication yield prediction could be obtained by use of a dual-component video image analysis (VIA) system. Whichever method of VIA prediction of fabrication yield is used, a single predicted value of fabrication yield for every carcass removes an impediment to the implementation of a value-based pricing system. Additionally, a VIA method of predicting carcass yield has the advantage over the current INAC classification system in that estimates would be produced by an instrument rather than by packing plant personnel, which would appeal to cattle producers. Results from the tenderness phase of the study indicated that the CVS BeefCam output variable for marbling was not (P > 0.05) able to segregate steer and heifer carcasses into groups that differed in WBSF values. In addition, the results of segregating steer and heifer carcasses according to muscle color output variables indicate that muscle maturity and skeletal maturity were useful for segregating carcasses according to differences in WBSF values of their steaks (P > 0.05). Use of VIA to predict beef carcass fabrication yields could improve accuracy and reduce subjectivity in comparison with use of current INAC grades. Use of VIA to sort carcasses according to muscle color would allow for the marketing of more consistent beef products with respect to tenderness. This would help facilitate the initiation of a value-based marketing system for the Uruguayan beef industry.

Effect of finishing diet on consumer acceptability of Uruguayan beef in the European market.

Eighty Hereford steers were used to evaluate the effect of finishing diet [A: pasture, B: pasture plus concentrate (0.6% live weight), C: pasture plus concentrate (1.2% live weight), D: concentrate] on consumer acceptability of Uruguayan beef in France (FR), United Kingdom (UK), Spain (ES) and Germany (DE). Consumers (200 per country) evaluated overall, tenderness and flavour acceptability of beef (8 point scale: 1 'dislike extremely', 8 'like extremely'). FR and UK rated lower acceptability scores for beef from D compared with A, B, and C. ES showed similar results for tenderness, but flavour scores did not differ between A and D. German consumers preferred beef from B and C. Overall, low levels of supplementation on pasture produced beef with the highest consumer acceptability followed by beef from pasture-fed animals. Feeding cattle with concentrate only may not be necessary to satisfy the EU market resulting in more profitable production systems for Uruguayan producers.

Fatty acid and vitamin E composition of intramuscular fat in cattle reared in different production systems.

The aim of this study was to evaluate the fatty acid composition of intramuscular fat and the vitamin E content of beef from different production systems. Four cattle production systems were used: cattle reared under intensive conditions and fed concentrate (INT1) from Spain, cattle raised at pasture and supplemented with concentrate (SUP1) from the United Kingdom, cattle raised at pasture and on corn silage (SUP2) from Germany and cattle reared under extensive conditions slaughtered at two and three years old (EXT2 and EXT3) from Uruguay. The highest proportion and content (mg per 100g of muscle) of linoleic acid (C18:2n-6) and arachidonic acid (C20:4n-6) and the lowest saturated fatty acids (SFA) was found in INT1 beef. In contrast, beef reared under extensive conditions showed the highest proportion and content of linolenic acid (C18:3n-3), docosapentaenoic acid (DPA, C22:5n-3) and eicosapentaenoic acid (EPA, C20:5n-3), and SUP1 and SUP2 beef showed the highest level of palmitic acid (C16:0) and SFA. Beef from intensive system (INT1) had the lowest P/S (PUFA/SFA) ratio, whereas beef from extensive system (EXT2 and EXT3) had the lowest n-6/n-3 ratio. The results of the PCA (principal components analysis) of fatty acid composition showed that beef from intensive system (INT1) was clearly differentiated from the other meats and was located with the C18:2n-6 and C20:4n-6 and the n-6/n-3 ratio. EXT2 and EXT3 beef were located with C18:3n-3 and long chain fatty acids. Beef from extensive systems had the highest concentration of vitamin E (3.91mg α-tocopherol/kg muscle).

Sensory evaluation of castrated lambs finished on different proportions of pasture and concentrate feeding systems.

Castrated male Corriedale lambs from Uruguay were finished under one of four feeding systems, which differed in the level of pasture and the amount of concentrates. Treatment 1 (T(1)) was all pasture (P), T(2) was P plus concentrate (C; 0.6% of live weight [LW]), T(3) was P+C (1.2% of LW), and T(4) was C plus alfalfa hay as a source of fibre (both ad libitum). A trained taste panel analysed samples from 96 lambs, using a quantitative descriptive method in a complete and balanced design. Eight of the 11 sensory attributes were affected by Treatment (p<0.05). The inclusion of concentrate in the lamb diet improved the sensory quality of the meat, being related to its effect on lowering the intensity of undesirable odours and flavours (strange, rancid and acid), generating higher intensity of typical lamb aromas as well as producing higher tenderness. The frequencies of odour/flavour unsolicited observations also showed disadvantages to pasture feeding. Lambs fed only concentrates (T(4)) produced meat that had the highest fat flavour intensity and the best overall acceptability given by the panellists.

Acceptability of lamb fed on pasture, concentrate or combinations of both systems by European consumers.

It is well known that the eating quality of lamb is highly affected by feeding systems. The aim of this study was to ascertain acceptability of Uruguayan lamb meat from animals fed on different diets (only pasture-D1, only concentrate-D4 and two combinations of both systems-D3 and D4) by consumers from different European countries (Spain, Germany, United Kingdom and France). One hundred and twenty castrated Corriedale lambs were reared to 28.2±0.8 kg live weight and then thirty lambs were allocated to each diet and reared to 40kg live weight. Sections of loin were cooked using contact grills until the internal temperature of the muscle reached 72°C (65°C in France), cut and then served to consumers. A minimum of 180 consumers per country evaluated overall liking, flavour and tenderness acceptability of lamb from the 4 diets in sessions of 10 consumers using 8-point category scales. Globally consumers preferred lamb fed on concentrate or the combination of concentrate and pasture to lamb fed only on pasture. However, different segments of consumers were identified in each country based on their lamb acceptability. This information contributes to the identification of developing different commercial strategies in relation to the consumer segments found.

Effects of feeding strategies including different proportion of pasture and concentrate, on carcass and meat quality traits in Uruguayan steers.

Eighty four steers were randomly assigned to three pasture treatments with increasing levels of grain (T1: 0%; T2: 0.6%; T3: 1.2% of live weight) and to an ad libitum concentrate treatment, T4, to study the effects on carcass and meat quality. Animals were slaughtered with 500 kg of average live weight per treatment. Average daily gain increased with increasing levels of energy, determining different slaughter dates. Intermediate treatments showed higher carcass weight than T1. T4 and T3 had a higher weight of valuable cuts than T1 and T4. Pistolas from T4 had a higher fat proportion and lower bone percentage. Increasing levels of energy in diet decreased fat yellowness. After 20 days of aging, T4 had the lowest muscle a(∗) values and shear force was higher for T4 than for T1. With pastures finishing strategy, no adverse effects on meat quality were detected and tenderness was enhanced.

Acceptability of lamb meat from different producing systems and ageing time to German, Spanish and British consumers.

In the present study German (DE), Spanish (ES) and British (UK) consumers' acceptance of lamb from their own country compared to lamb from Uruguay (UY) was evaluated. Two-hundred consumers in each country evaluated tenderness, flavour and overall acceptability of four types of lamb, two from UY (light and heavy lambs aged 20 d) and 2 local (with two ageing times, 7 and 20 d). In each country 1.5cm-thick slices of lamb were evaluated by previously selected consumers in controlled conditions. DE and UK consumers showed significantly (P<0.05) different acceptability scores between samples, the lamb from heavier animals and aged 20 d being the most appreciated. On the other hand the majority of the ES consumers significantly (P<0.05) preferred the meat from lighter lambs. Production systems, cultural aspects and consumption habits seem to affect the acceptability of the lamb to the consumers.

Eating quality of beef, from different production systems, assessed by German, Spanish and British consumers.

The acceptability of beef from Uruguay (UY), based on eating quality, was compared with beef produced in different European countries (Germany, DE, Spain, ES and United Kingdom, UK). Consumer tests were conducted in DE, ES and UK (each comprising 200 consumers) using 'Hall Tests'. In each country four samples were evaluated, two from Hereford steers from UY (finished at 2 and 3 years) and two from local meat (the same meat sample aged 7 or 20d). Consumers evaluated tenderness, flavour and overall acceptability using 8-point category scales. Hierarchical cluster analysis, highlighted the existence of different clusters of consumers. Two main clusters were identified in DE and UK. The main cluster identified in DE, was labelled as Prefer foreign-imported beef (n=128). These consumers preferred (P<0.05) the samples from UY_2y in terms of tenderness and overall acceptability. The other cluster was labelled as Prefer local beef in terms of flavour and overall acceptability (P<0.05) and comprised the majority of consumers from ES (n=176) and UK (n=153) and the cluster 2 from DE (n=69). UK, cluster 2 (n=33) that did not discriminate between origin and ageing time of beef. These results indicate that consumers did not prefer the same type of meat within the same country and it is possible that there are individual preferences that could lead to the concept of market segmentation being based on taste preferences. It would appear that Uruguayan beef would be very acceptable in Germany and to a lesser extent in Britain and Spain, although further studies are required that include labelling information.

Fatty acid composition of meat from typical lamb production systems of Spain, United Kingdom, Germany and Uruguay.

The fatty acid composition of commercial lambs from different production systems of Spain, Germany, United Kingdom and of two types of Uruguayan lambs (heavy and light) was studied. Concentrate fed lambs, as Spanish lambs, displayed the highest proportions of linoleic acid (C18:2), while Uruguayan lambs, reared under extensive grazing conditions, showed the highest proportions of linolenic acid (C18:3), due to the great concentration of this fatty acid in grass. German and British lambs, which were fed grass and concentrate, displayed intermediate proportions of linolenic acid (C18:3). Heavy Uruguayan lambs had higher intramuscular fat content (5.92%) than German (4.25%) and British (4.32%) lambs, and this content was twofold higher than light lambs (Spanish (2.41%) and light Uruguayan (3.05%)). Heavy Uruguayan, German and British lambs had a low polyunsaturated/saturated (P/S) ratio due to their high saturated fatty acid (SFA) content and proportion. Principal component analysis was performed to study the relationship between fatty acids. Spanish lambs were clearly separated from the other types and were situated close to the proportions of short chain and n-6 fatty acids and n-6/n-3 ratio in the data plot for fatty acid proportions. Light Uruguayan lambs were located close to long chain fatty acids, and heavy Uruguayan and British lambs were placed near the antithrombotic potential (ATT), stearic acid (C18:0), SFA and conjugated linoleic acid (CLA) proportions. German lambs were located between Spanish lambs and the other types.