Evaluation of Two Equations for Prediction of Digestible Energy in Mixed Feeds and Diets for Horses.

Several authors have developed equations for estimating digestible energy in horse feeds as an alternative to the inconveniences of in vivo digestibility assays. We aimed to evaluate two of such equations. A dataset was constructed from the literature with 32 mixed feeds and diets of known proximate composition, whose digestibility was measured in in vivo assays. Then, the digestible energy of the mixed feeds and diets was predicted with both equations from their proximate components. Precision, accuracy, reproducibility, bias, and decomposition of total error of predictions were determined. Both equations performed almost equally well (R2 = 0.89 vs. 0.87, root mean square error of prediction = 183 vs. 217 kcal/kg dry matter, concordance correlation coefficient = 0.91 vs. 0.86, and linear error = 24.6 vs. 33.6% of total error). Linear bias (p < 0.01 in both equations) resulted in overvaluation of low digestible energy feeds and, to a lesser extent, undervaluation of high digestible energy feeds and was significantly (p < 0.05) related to crude fiber. The obtained results indicate that the accuracy of both equations could be improved by reassessing the effects of crude fiber on the digestibility of the other proximate components.

Effects of Extending Milk Replacer Feeding during the Fattening Period on the Behaviour and Welfare of Lambs: A Preliminary Study.

There is a lack of information on the behavioural and welfare effects of sustaining artificial milk feeding in fattening lambs. Therefore, the present work aimed to study the effects of prolonged artificial milk feeding during fattening with a high concentrate diet on the behaviour of lambs. The behaviour of 16 non castrated male lambs of the Manchega sheep breed (eight lambs were in the group that were fed daily a bottle of milk, and the other eight were in the weaned group) was recorded with four fixed cameras just before bottle feeding (~8:30 a.m.) of the unweaned group till four hours later, every day for 7 weeks. The solid diet (pelleted concentrate plus cereal straw) and housing conditions were the same in both groups. Solid feeds were offered ad libitum. There were no differences between groups in time spent eating nor in drinking, playing, scratching and oral activity behaviours (p > 0.05), but resting episodes were longer in weaned lambs (p < 0.05). Weaned lambs presented a higher frequency of self-grooming behaviour (p < 0.05), while the unweaned group performed a higher frequency of interaction behaviour (p < 0.05). In conclusion, the behaviours of lambs that were fed daily a bottle of milk during the fattening period did not substantially differ from the weaned individuals.

Influence of Dietary Algae Meal on Lipid Oxidation and Volatile Profile of Meat from Lambs with Competent Reticular Groove Reflex.

Dietary lipid sources influence intramuscular fatty acid composition, which in turn may affect the volatile profile of meat. The aim of this work was to investigate the effects of marine algae supplementation (Aurantiochytrium limacinum) on volatile compounds of cooked lamb meat. Forty-eight lambs with 42 days of age were divided into three groups: lambs fed a conventional diet without algae meal supplementation (NOALG), lambs with competent reticular groove reflex (RGR) fed the same diet supplemented with 2.5% marine algae meal mixed in the concentrate (ALGCON), and lambs with competent RGR, receiving the same diet and fed with 2.5% marine algae meal in a milk replacer to bypass the rumen (ALGMILK). Lipid and protein oxidation in raw meat was assessed and volatile compounds in grilled meat were determined. The highest and lowest lipid oxidations were observed in the ALGMILK and NOALG groups, respectively. Protein oxidation was unaffected. Out of 56 identified compounds, 12 volatiles significantly increased in both algae groups and 6 of them exclusively in the ALGCON treatment. Algae meal supplementation and its form of administration, either protected or not from rumen degradation, are important factors to consider in lipid oxidation and the aromatic profile of lamb meat.

Beef from Calves Finished with a Diet Based on Concentrate Rich in Agro-Industrial By-Products: Acceptability and Quality Label Preferences in Spanish Meat Consumers.

Conjoint analysis was used to estimate the relative importance of some of the main extrinsic attributes and quality labels of beef in three Spanish cities (Córdoba, Marbella, and Santa Pola) in a study performed with 300 individuals. Consumers were segmented according to their frequency of consumption. Willingness to pay for different meats was also calculated from the conjoint analysis results. Consumer liking of beef that had been finished with an alternative concentrate rich in agro-industrial by-products and aged for three different durations as compared to conventionally finished beef was also evaluated using the same consumers. The most important attribute for Spanish consumers was the price (28%), followed by origin (25%), animal welfare certification (19%), protected geographical indication (14%), and organic agriculture certification (14%). Most consumers preferred beef from Spain at the lowest possible price and with the highest number of quality labels. Consumers were willing to pay a premium of 1.49, 3.61, and 5.53 EUR over 14 EUR/kg for organic certification, protected geographical indication, and animal welfare certification, respectively. Sensory analysis revealed that, for regular consumers, beef finished with an alternative concentrate rich in agro-industrial by-products offered several hedonic advantages (color, flavor, and tenderness) when compared to beef finished using a conventional diet, while occasional consumers did not find any difference between the two kinds of meat.

Intramuscular Fatty Acids in Meat Could Predict Enteric Methane Production by Fattening Lambs.

Methane (CH4) emissions pose a serious problem for the environmental sustainability of ruminant production. The aim of the present study was to explore the usefulness of the intramuscular fatty acid (FA) profile to estimate CH4 production of lambs fattened under intensive feeding systems. A statistical regression analysis of intramuscular FA derived from ruminal metabolism was carried out to assess the best predictive model of CH4 production (g/d) in lambs fed with different diets. CH4 was calculated with three distinct equations based on organic matter digestibility (OMD) at maintenance feeding levels. The OMD of the experimental diets was determined in an in vivo digestibility trial by means of the indicator method. Regression models were obtained by stepwise regression analysis. The three optimized models showed high adjusted coefficients of determination (R2adj = 0.74-0.93) and concordance correlation coefficients (CCC = 0.89-0.98), as well as small root mean square prediction errors (RMSPE = 0.29-0.40 g/d). The best single predictor was vaccenic acid (trans-11 C18:1), a bioactive FA that is formed in the rumen to a different extent depending on dietary composition. Based on our data and further published lamb research, we propose a novel regression model for CH4 production with excellent outcomes: CH4 (g/d) = -1.98 (±1.284)-0.87 (±0.231) × trans-11 C18:1 + 0.79 (±0.045) × BW (R2adj = 0.97; RMSPE = 0.76 g/d; CCC = 0.98). In conclusion, these results indicate that specific intramuscular FA and average BW during fattening could be useful to predict CH4 production of lambs fed high concentrate diets.

Assessment of Age Effects on Ovarian Hemodynamics Using Doppler Ultrasound and Progesterone Concentrations in Cycling Spanish Purebred Mares.

In equine reproduction, accurate and timely detection of the moment of ovulation is of great importance. Power Doppler ultrasound technology is a non-invasive method that enables to assess the morpho-echogenic features and blood flow changes during the estral cycle in mares. The objective of the present study was to evaluate the influence of age on ultrasonographic parameters (follicular diameter, follicular blood flow-FBF, corpus luteum (CL) area and corpus luteum blood flow-CLBF) and blood plasma progesterone concentrations in cycling Spanish Purebred mares (15 less than 8 years old and 15 equal o higher than 8 years old). The ultrasound images obtained were analyzed with the Image Colour Summarizer software, which allows the quantification of the pixels of each image. Young mares had significantly higher FBF, CLBF and plasma progesterone levels. Moreover, linear regression analysis showed that blood progesterone levels could be predicted in both groups from CLBF with moderate precision and accuracy. In conclusion, Power Doppler was useful to assess ovarian hemodynamics. Our results support that age is a factor that significantly influences FBF and CLBF as well as blood progesterone concentration in mares. More studies would be needed to develop high precision and accuracy predictive models of blood progesterone concentration from CLBF measured by Power Doppler.

Effects of Algae Meal Supplementation in Feedlot Lambs with Competent Reticular Groove Reflex on Growth Performance, Carcass Traits and Meat Characteristics.

There is growing interest in increasing omega-3 fatty acid (FA) contents in ruminant meat by means of dietary manipulation, but the effects of such manipulation on productive results and meat quality need to be ascertained. The aim of the present study was to assess the effects of supplementing lambs with competent reticular groove reflex (RGR) with marine algae as a source of omega-3 fatty acids on growth performance, carcass traits, and meat quality characteristics. Forty-eight feedlot lambs were distributed into three equal groups: the control group neither consumed marine algae nor had competent RGR, the second group received daily 2.5% of algae meal mixed in the concentrate, and the last group consumed the same amount of algae meal, but emulsified in a milk replacer and bottle-fed. Lambs in the second and third groups had competent RGR. There were not any negative effects on performance, carcass or meat quality parameters with algae supplementation. However, the results of the oxidative stability parameters were not conclusive. Ageing for 6 days improved meat tenderness and color, and increased lipid oxidation. In conclusion, algae meal inclusion in the diet of fattening lambs with competent RGR has no detrimental effects on animal performance, carcass traits or meat quality characteristics.

Effects of A Concentrate Rich in Agro-Industrial By-Products on Productivity Results, Carcass Characteristics and Meat Quality Traits of Finishing Heifers.

Finishing diets in intensive beef production systems are mainly based on cereals, which does not take advantage of the capacity of the ruminant digestive system to digest fibrous feeds, cannot be considered sustainable and does not contribute to the circular bioeconomy. Our aim was to investigate the effects of an alternative concentrate rich in agro-industrial by-products for finishing crossbred Limousine heifers. Four pens with 12 heifers and four pens with 13 heifers were randomly allocated to one of two treatments: control (CON), a commercial concentrate with a 43.3% cereal composition, and alternative (ALT), a concentrate with a composition of 26% cereals and up to 73.5% agro-industrial by-products. Growth performance data were collected along the 91 days of the experimental period. Carcass characteristics were collected after slaughter and 24 h later. Vacuum-packaged samples from longissimus muscle were aged for 7, 21 or 28 days to study meat quality traits. Feed intake was higher and feed conversion rate was lower in the ALT treatment, but no differences were found in average daily gain and feeding costs. Treatment had no effects on any of the measured carcass traits (grading, hot and cold carcass weight, dressing out, chilling losses, subcutaneous fat depth, pH, temperature and lean and fat colour) nor on the meat quality traits (drip loss, cooking loss, shear force, oxidative stability, chromatic indices and pigment contents). Ageing time decreased drip loss and shear force, increased lightness and did not affect redness or surface colour stability. In conclusion, feeding crossbred Limousine heifers a finishing diet rich in agro-industrial by-products did not have any negative effects on performance, carcass and meat quality traits, which might be considered positive from the point of view of sustainability of beef production. Under the conditions assayed, ageing for 21 and 28 days improved tenderness of meat, without detrimental effects on oxidative stability or traits related to visual acceptability.

Ensilability, in vitro and in vivo values of the agro-industrial by-products of artichoke and broccoli.

By-products of raw artichoke (RA) (Cynara scolymus L.) and boiled broccoli (BB) (Brassica oleracea, var. italica) were ensiled in plastic bags for 24 days. Then, chemical composition, nutritive characteristics, in vitro rumen degradability, in vivo digestibility and phytosanitary residue contents of the silages were evaluated. The fermentative parameters studied indicated that plastic bags were a suitable method to silage RA and BB by-products. Both silages had a high in vitro rumen DM disappearance at 72 h, although it was higher in the BB silage (96.8 vs. 82.1%). In vivo digestibility of DM was similar and high in both silages (78.5 and 80.0% in RA and BB), but crude protein and NDF digestibilities were higher in the BB silage (83.0 and 88.3% vs. 55.1 and 78.8%). No residues of analysed phytosanitary were found. In conclusion, silages of wastes from the processing of artichoke and broccoli were free from the analysed several phytosanitary residues, their nutritive value made them adequate for feeding ruminant animals and are an environmentally friendly way of disposal of such residues.