• A consumer study of the effect of castration and slaughter age of lambs on the sensory quality of meat

      Gravador, Rufielyn S.; Pace, Elaine; Mooney, Bernard R.; Jaeger, Sara R.; Gkarane, Vasiliki; Fahey, Alan G.; Brunton, Nigel P.; Claffey, Noel A.; Allen, Paul; Diskin, Michael G.; et al. (Elsevier, 2018-09-20)
      Meat from ram lambs is often considered inferior to meat from castrated lambs, especially in older or heavier animals. This study aimed to determine if differences exist in the sensory quality and acceptability of meat from rams and castrates, slaughtered at mean ages of 196 or 385 days. Rams had higher average daily gain, feed conversion efficiency, total weight gain and lower carcass fatness than castrates. A triangle test (n = 81 consumers) showed a difference (P < 0.05) in the sensory quality of meat from rams vs castrates. A 9-point hedonic test involving 100 consumers showed that, although meat from both rams and castrates was ‘liked’, meat from castrates scored higher (P < 0.05) in Overall Liking, Flavour Liking and Tenderness Liking. Meat from castrates was also rated lower (P < 0.05) in Unpleasant Taste/Off-Flavour Intensity. Flavour Intensity and Unpleasant Taste/Off-Flavour Intensity increased (P < 0.05) with age at slaughter. This consumer study revealed that while meat from castrates was higher in Overall Liking, Flavour Liking and Tenderness Liking and lower in Unpleasant Taste/Off-Flavour Intensity than meat from rams, both meats were ‘liked’ by consumers.
    • Effect of castration and age at slaughter on sensory perception of lamb meat

      Gkarane, Vasiliki; Allen, Paul; Gravador, Rufielyn S.; Diskin, Michael G.; Claffey, Noel A.; Fahey, Alan G.; Brunton, Nigel P; Farmer, Linda J.; Moloney, Aidan P; Monahan, Frank J; et al. (Elsevier, 2017-11-02)
      This study assessed the effect of castration and slaughter age (196–385 days old) on sensory quality of lamb meat from two sheep breeds (Scottish Blackface, SB; Texel x Scottish Blackface, TxSB). Results obtained using a trained sensory panel showed small but statistically significant differences due to castration, with rams having higher scores for Intensity of Lamb Aroma, Animal Smell/Farm Smell, Woolly Aroma, Rancid Aroma, Manure/Faecal Aroma, Sweaty Aroma and Off-flavours. SB lamb had higher scores for Intensity of Lamb Aroma, Lamb Flavour, Lamb Aftertaste, Tenderness and Juiciness. Age effects on sensory attributes were not linear and significant age × gender interactions were observed. The number of samples considered “extreme” in undesirable flavour attributes was higher among rams and T × SB animals. The impact of the sensory differences on consumer acceptability of lamb remains to be established.
    • Effect of finishing diet and duration on the sensory quality and volatile profile of lamb meat

      Gkarane, Vasiliki; Brunton, Nigel; Allen, Paul; Gravador, Rufielyn S.; Claffey, Noel A.; Diskin, Michael G.; Fahey, Alan G.; Farmer, Linda J.; Moloney, Aidan P; Alcalde, Maria J.; et al. (Elsevier, 2018-08-02)
      Animal production factors can affect the sensory quality of lamb meat. The study investigated the effect of diet composition and duration of consumption on the proximate analysis, volatile profile and sensory quality of lamb meat. Ninety-nine male Texel × Scottish Blackface lambs were raised at pasture for 10 months before being assigned in groups of 11 to one of the following treatments: 100% Silage (S) for 36 (S36), 54 (S54) or 72 (S72) days; 50% Silage - 50% Concentrate (SC) for 36 (SC36), 54 (SC54) or 72 (SC72) days; 100% Concentrate (C) for 36 (C36) or 54 (C54) or 72 (C72) days. A trained sensory panel found Intensity of Lamb Aroma, Dry Aftertaste and Astringent Aftertaste to be higher in meat from lambs on the concentrate diet. Discriminant analysis showed that the volatile profile enabled discrimination of lamb based on dietary treatment but the volatile differences were insufficient to impact highly on sensory quality. Muscle from animals in the S54 group had higher Manure/Faecal Aroma and Woolly Aroma than the SC54 and C54 groups, possibly related to higher levels of indole and skatole. Further research is required to establish if these small differences would influence consumer acceptability.
    • Effects of castration and slaughter age on the fatty acid composition of ovine muscle and adipose tissue from two breeds

      Gravador, Rufielyn S.; Moloney, Aidan P; Brunton, Nigel; Gkarane, Vasiliki; Allen, Paul; Fahey, Alan G; Claffey, Noel A.; Diskin, Michael G.; Farmer, Linda J.; Monahan, Frank J; et al. (Elsevier, 2018-10-04)
      Fatty acids (g/100 g total fatty acids) in M. longissimus thoracis et lumborum (LTL) and total branched chain fatty acids (μg/g fat) in subcutaneous adipose tissue (SAT) of rams and castrates from Scottish Blackface (SB) or Texel × Scottish Blackface (T × SB) lambs, slaughtered at mean ages of 196, 242, 293, 344 or 385 days were determined. Lambs were fed pasture prior to a 36-day finishing period on a barley/maize-based concentrate ration. The intramuscular fat content (IMF; %) was higher (P < 0.001) in castrates than in rams and in SB compared to T × SB lambs (P < 0.001). The proportions of c9-C18:1 and total monounsaturated fatty acids (MUFA) were higher (P < 0.001) in LTL of castrates than rams. The proportions of C18:2n-6 and total n-6 polyunsaturated fatty acids (PUFA) were lower (P = 0.001) in LTL of castrates compared to rams related to differences in IMF content. The proportions of C14:0, C16:0, c9-C18:1 and total MUFA were higher (P < 0.05), while the proportions of C18:2n-6, C20:4n-6, C20:5n-3, total PUFA, n-6 and n-3 PUFA were lower (P < 0.05), in SB than in T × SB lambs, which was related to differences in IMF content. There was a higher (P < 0.001) proportion of conjugated linoleic acid (CLA) c9,t11-C18:2 in LTL from SB compared to T × SB. The effects of slaughter age on the proportions of fatty acids in LTL did not show a clear trend. The concentration of 4-methylnonanoic acid was higher (P = 0.002) in SAT of rams than castrates, particularly in older lambs. Despite the differences in the muscle fatty acid composition due to gender, slaughter age or breed of lambs, the ratio of n-6/n-3 PUFA (≤3.11) was within the dietary recommendation of <4.0 for human health.
    • A note on muscle composition and colour of Holstein-Friesian, Piedmontese × Holstein-Friesian and Romagnola × Holstein-Friesian steers.

      Keane, Michael G.; Allen, Paul (Teagasc, Oak Park, Carlow, Ireland, 2009)
      Holstein-Friesian (HF), Piedmontese × Holstein-Friesian (PM) and Romagnola × Holstein-Friesian (RO) steers were compared for muscle composition and colour. A total of 120 steers in a 3 breed types (HF, PM and RO) × 2 feeding levels (low and high) × 2 finishing periods (short, S and extended, E) factorial experiment were used. Three samples of m. longissimus were taken for chemical analysis, measurement of drip loss and Hunterlab colour measurements. Muscle moisture and protein concentrations were lower, and lipid concentration was higher for HF than for PM and RO, which were similar. There were no effects of feeding level on chemical composition, but after blooming all colour values except hue were lower for the higher feeding level. The E finishing period reduced moisture, protein, drip-loss, L (lightness), a (redness) and chroma values. It is concluded that PM and RO had similar muscle composition but HF had a higher lipid concentration. Feeding level had few effects on muscle composition, but extended finishing increased all measures of fatness and reduced colour values.