An experiment was conducted to determine if growth rate, as affected by level of feeding, during a 10-or 20-week period prior to slaughter could influence the tenderness and palatability of beef from young (approx. 14 months old at the start of experiment) steers. Steers, comprising 18 Aberdeen Angus (AA), 18 Charolais (CH) and 18 Holstein (HO) purebreds, were allocated, within genotype, to one of three levels of feeding: (a) moderate ((M/M) 750 kJ metabolizable energy (ME) per day per kg M0·75), (b) high ((H/H) 1050 kJ ME per day per kg M0·75) both for 20 weeks; or (c) moderate for the first 10 weeks followed by high for the remaining 10 weeks (M/H). The steers were slaughtered at a fixed age (approx. 19 months old) and samples of m. longissimus lumborum (from all three genotypes) m. vastus lateralis and m. biceps femoris (from AA and CH only) separated, vacuum packed and stored at 2ºC for both 7 and 14 days before freezing. These cuts were subsequently assessed by a 12 member taste panel and texture analysis performed using Volodkevitch-type jaws.

Growth rates during the final 10 weeks of the experimental period differed between dietary regimen (M/M = 0·87; M/H = 1·25; and H/H = 1·02 kg/day; s.e.d. = 0·08; P < 0·001). Steers offered the M/M level of feeding grew more slowly (0·97 kg/day) than those offered the M/H and H/H level of feeding (1·20 kg/day; s.e.d. = 0·06; P < 0·001) over the entire 20 week experimental period. In spite of these differences in growth rate, there were no consistent effects on beef tenderness and general palatability. Mean growth rates for CH, HO and AA steers were 1·21, 1·13 and 1·03 kg/day (s.e.d. = 0·06; P < 0·05). Beef samples from AA steers consistently scored better for various sensory attributes than those from CH and HO steers; this may have been due, in part, to level of carcass fatness and rate of carcass cooling post mortem. Accounting for factors such as genotype within the experimental design and slaughtering animals at a relatively constant age reduced the variance associated with each sensory attribute to 0·6 of that observed in commercial practice. The data suggest that there is little opportunity to improve beef eating quality by increasing growth rate by dietary means in steers provided that moderate levels of gain (equivalent to the UK average) are maintained.

Three hundred and eight cattle, comprising steers and heifers from continental and British crosses were finished on an 18-month beef production system at Warren Farm, Lambourn, Berkshire and slaughtered across a range of fatness levels. The eating quality of roasting joints (semimembranosus.) and sirloin steaks (longissimus thoracis et lumborumj was evaluated and the chemical composition of the lean tissue was taken on a subset of the samples. Results suggested that the greatest differences between the breeds was in the joints. There were significant (P < 0·01) differences in the lipid, moisture and collagen contents of the lean tissue of the joints from the different sire breeds. The Belgian Blue sire progeny had significantly lower lipid content than the Charolais or Aberdeen Angus crosses, and significantly lower collagen content than the Aberdeen Angus cross. In addition joints from Belgian Blue crosses were more tender than joints from other breed crosses. Although the lipid and moisture contents of the steaks from different sire crosses were significantly different there was no evidence of differences in eating quality. Perhaps surprisingly there were no significant relationships between the eating quality and chemical composition between or within breed. Irrespective of breed, carcass fatness influenced the juiciness of both the joints and the steaks although the response was different for continental crosses and British crosses and depended on carcass sex. Over and above this response, steer meat was generally more juicy than heifer meat.

Carcass and eating quality characteristics of crossbred wether and female lambs sired by Charollais (C), Suffolk (S) and Texel (T) rams out of Mule ewes (Bluefaced Leicester ♂ × Scottish Blackface ♀ or Swaledale ♀J)were evaluated in a study carried out over a 3-year period in an upland flock. A total of 10 unrelated rams of each breed were used as sires. Lambs (no. = 280) were selected for slaughter at the same estimated subcutaneous fat level on four occasions within each year (i.e. at weaning in July and at approx. monthly intervals thereafter). Following slaughter, the left side of each carcass was physically dissected. A loin joint from lambs slaughtered in the 2nd and 3rd years of the study (no. = 184) was used to evaluate eating quality.

Suffolk-sired lambs were heavier at slaughter (S: 42·2; C: 41·0; T: 40·7 (s.e. 0·35) kg) but had similar killing-out proportions compared with the other two breeds (S: 444; C: 450; T: 452 (s.e. 26) g/kg). Texel-sired lambs had higher lean proportion (S: 543; C: 550; T: 567 (s.e. 4·4) g/kg) and lower total carcass fat proportion (S: 240; C: 242; T: 233 (s.e. 5·3) g/kg) compared with S and C sired lambs. Bone proportion was similar for C and T lambs but was higher for S (S: 199; C: 191; T: 191 (s.e. 2·1) g/kg). Lean: bone (S: 2·75; C: 2·90; T: 2·99 (s.e. 0·037)) and lean:fat (S: 2·38; C: 2·40; T: 2·54 (s.e. 0·034)) ratios were higher for T-sired lambs. Female lambs were lighter (40·4 v. 42·2 (s.e. 0·24) kg), and had proportionately more intermuscular fat than wethers (122 v.118 (s.e. 1·3) g/kg) but the sex differences for other tissue proportions were small. Carcass weights and total carcass fat proportions increased and lean proportions decreased across the four slaughter dates. There were no effects of breed or sex on eating quality. However, samples from lambs slaughtered at weaning were judged to be more tender than those slaughtered later in the season.