Supplementation of poultry diets with medicinal plants containing bioactive molecules have shown promising results in promoting growth performance, enhancing feed efficiency, and improving carcass traits and meat quality. There are many studies using herbal plants and their derivatives involving liquorice (Glycyrrhiza glabra), while studies using only liquorice are very limited. Liquorice contains bioactive components such as glycyrrhizin and flavonoids, and has been linked to many pharmacological effects like immunomodulatory, anti-oxidant, antiviral and anti-inflammatory activity. Supplementation of liquorice in poultry diets had beneficial impacts on growth and performance by improving organ development. In addition, there are appetite and digestion stimulating factors in liquorice. Dietary liquorice supplementation at level of 2.5 g/kg showed the best results in broiler chicken, and demonstrated it can be safely used in poultry diets. Addition of liquorice in diets up to 0.5% inclusion before sexual maturity enhanced performance of laying hens. Furthermore, broilers receiving drinking water containing 450 mg/l liquorice under heat stress significantly improved feed conversion and economic efficiency. Abdominal fat in broiler chickens was decreased when liquorice was included at 2 g/kg in feed or 0.3 g/l in drinking water. Broiler chickens with access to drinking water containing 450 mg/l of liquorice increased the dressing percentage, with or without giblets. Carcass organoleptics were improved in birds receiving drinking water with liquorice at levels of either 1, 2 and 4 mg/ kg body weight. This review describes the chemical composition, health benefits and beneficial applications of the liquorice herb and its effect on growth and productive performance, carcasses and meat quality, which will be useful for researchers, physiologists, nutritionists, veterinarians, scientists, pharmacists, pharmaceutical industries, and poultry breeders.

Two selection indexes, one intended for lamb producers and finishers and one for store lamb producers, were derived using genetic parameters for carcass and maternal characteristics from Conington et al. (2001) and economic values from Conington et al. (2004). This paper summarizes responses to selection for lamb traits only, after 5 years of selection (1998 to 2003) on two farms using these selection indexes. The index for lamb producers and finishers, evaluated on farm 1, with a flock size of 680 ewes, includes economic weightings for maternal traits as well as carcass weight, fat and conformation grades, whereas the index for store lamb producers, evaluated on farm 2, with a flock size of 580 ewes, only includes economic values for maternal traits and lamb growth to weaning. Three selection lines of Scottish Blackface sheep per farm were created with the first lambs born to each line in 1999. These lines were selection (S), control (C) and industry (I); they were of equal size on each farm. Five top- and five average-performing ram lambs were selected each year for the S and C lines respectively using a multi-trait best linear unbiased prediction (BLUP) implementation of the indexes. The I-line used four mature rams bought from industry, selected on appearance only, i.e. adherence to breed ‘type’. Results showed that 5 years after the implementation of the index, the S line had significantly higher index scores than the C or I lines on both farms. The means (s.d.) for the average index scores in 2003 are 114 (328), 119 (371) and 451 (328) (farm 1), and −8 (146), −11 (130), and 250 (129) (farm 2) for the C, I and S lines, respectively, giving predicted net differences (S-C) of £3·38 (farm 1) and £2·58 (farm 2) per ewe. Phenotypic responses showed significant S v. C differences in weaning weight on both farms. As predicted from previous analyses, no changes in carcass quality traits were seen at farm 1 although S-line carcass weights tended to be heavier than those from the C or I lines. The results show that genetic improvement using multi-trait selection indices has been successful and it is a viable, long-term strategy to improve levels of production for hill sheep in extensive environments.

Classification of pig carcasses in the European Community (EC) is based on the lean meat percentage of the carcasses. The lean meat percentage is predicted from instrumental carcass measurements, such as fat and muscle depth measurements, obtained in the slaughterline. The prediction formula for an instrument is derived from the data of a dissection experiment. When the relationship between percentage lean and instrumental carcass measurements differs between subpopulations, such as sexes or breeds, accuracy of prediction may differ between these subpopulations. In particular for some subpopulations predicted lean meat percentages may be systematically too low and for other subpopulations systematically too high. Producers or buyers that largely specialize in subpopulations where the percentage lean is underestimated, are put at a financial disadvantage.

The aim of this paper is to gain insight, on the basis of real data, into the effects of differences between subpopulations on the accuracy of the predicted percentage lean meat of pig carcasses. A simulation study was performed based on data from dissection trials in The Netherlands, comprising gilts and castrated males, and trials in Spain, comprising different genetic types. The possible gain in accuracy, i.e. reduction of prediction bias and mean squared prediction error, by the use of separate prediction formulae for (some of) the subpopulations was determined.

We concluded that marked bias in the predicted percentage lean meat may occur between subpopulations when a single overall prediction formula is employed. Systematic differences in predicted percentage lean between subpopulations that are overestimated and underestimated may exceed 4% and for selected values of instrumental measurements may run up to 6%. Bias between subpopulations may be eliminated, and prediction accuracy may be markedly improved, when separate prediction formulae are used. With the use of separate formulae the root mean squared prediction error may be reduced by 13 to 26% of the expected value when a single prediction formula is used for all pig carcasses.

These are substantial reductions on a national scale. This suggests that there will be a commercial interest in the use of separate prediction formulae for different subpopulations. In the near future, when the use of implants becomes more reliable, subpopulations will be recognized automatically in the slaughterline and use of different prediction formulae will become practically feasible. Some possible consequences for the EC regulations and national safeguards for quality of prediction formulae are discussed.

Forty-eight sucking lambs (26 males and 22 females) of the Manchega breed were used in this work. Lambs were slaughtered at 10, 12 and 14 kg live weight. Carcass degree of fatness was assessed by three assessors from colour photographs of the carcasses, using the European Union scale for light lambs (EU), the Colomer-Rocher method (CF) and another new scale developed by our group (sucking lambs scale, SL). Carcass conformation was assessed according to the Colomer-Rocher method (CC). Fatness and conformation scales were divided to give 0·25 points in each interval. Left half-carcasses were jointed and dissected into lean, fat and bone. Muscle proportion, bone proportion and whole fat proportion (obtained by addition of every fat depot: subcutaneous fat, intermuscular fat, inguinal fat and kidney knob and channel fat) were determined. Male and female carcasses showed a very different tissue composition: both groups had statistically significant differences (P < 0·05) in 20 out of 25 tissue composition variates. Males showed a higher number of variates that were well correlated with assessors’ scoring than females. Correlation coefficients between most of the tissue composition variates and assessors’ scores were higher in males. Furthermore, the number of variates that were significantly correlated with assessors’ scores was lower in females. Therefore, subjective methods for the estimation of carcass degree of fatness and of carcass conformation are poor predictors of tissue composition in female sucking lamb carcasses.