Influence of slaughter age and carcass suspension on meat quality in Angus heifers

Abstract

This study investigated the effects of pelvic suspension and slaughter age on longissimus thoracis et lumborum (LTL) from 40 heifers with at least 75% Angus breeding. A total of 20 heifers were slaughtered directly from pasture at 18 months of age, and carcass sides were hung either by the Achilles tendon or the pelvic bone. The other 20 heifers were assigned to an additional winter housing period and slaughtered at 22 months of age; carcass sides were hung only by Achilles suspension. All carcasses were electrically stimulated and assessed according to the EUROP carcass classification system. In addition, the LTL muscles were aged for 7 or 14 days before meat quality was evaluated for intramuscular fat (IMF), drip loss, colour, shear force, compression and sensory analysis. The 22-month-old heifers were heavier, fatter and had more IMF than 18-month-old heifers. Conformation scores (muscling) did not differ between the two slaughter groups. Pelvic suspension reduced both between-and within-animal variation for peak force, total energy and compression peak force. For the 18-month-old heifers, pelvic suspension also decreased peak force, total energy and compression variables for the LTL muscles from both ageing periods, whereas Achilles-suspended samples had lower shear force values only at day 14. Sensory analysis showed that pelvic-suspended sides had greater tenderness, lower bite resistance, less threadiness, higher juiciness and meat flavour and less visible marbling than meat from Achilles-suspended sides. Pelvic-suspended sides at 18 months of age were similar in peak force and total energy values to the 22-month-old heifers. The importance of ageing the Achilles-suspended sides was more obvious for samples from 18-month-old heifers than from the 22-month-old animals. The correlations between the different instrumental measurements and sensory tenderness were considerably higher for carcasses suspended by the Achilles tendon (r 5 20.55 to 0.20) than for those hung by the pelvic bone (r 5 20.25 to 0.19). More correlations between sensory-evaluated tenderness and shear variables were significant after 7 days (n 5 6) of ageing than after 14 days (n 5 4) of ageing. This study clearly shows the benefits of pelvic suspension, which reduces the need for additional feeding after pasture.

Preliminary Study to Determinate the Effect of the Rearing Managements Applied during Heifers’ Whole Life on Carcass and Flank Steak Quality

“…In the literature, the fattening period was the most frequently studied period and many rearing factors were known to influence carcass traits. Our results disagree with the results of many studies, which displayed that the heifers slaughtered at an older age were heavier [ 2 , 5 ]. The heavier carcass from WLP-E could be explained by the fattening period duration.…”

“…In the literature, the fattening period was mainly studied using experimental devices by controlling one or two rearing factors. The factors that have been most frequently studied during this period are the slaughter age [ 2 , 4 , 5 , 6 ], the slaughter weight [ 7 , 8 ], the fattening duration [ 9 , 10 , 11 ], the fattening diet [ 12 , 13 , 14 ], and the fattening management, i.e., a pasture period during the fattening period or the whole fattening in housing [ 15 , 16 , 17 , 18 ]. The rearing managements applied during the animal’s whole life period (i.e., from birth to slaughter, WLP) are a complex combination of many rearing factors to achieve carcass traits expected by the target market and to maximize their value.…”

Influence of age and method of carcass suspension on meat quality attributes of pure bred Ankole bulls

“…Pelvic suspension decreased percentage cooking loss across all age groups. These results are in agreement with other studies on meat from pelvic-suspended carcasses (Sørheim et al, 2001;Wahlgren et al, 2002;Ahnström et al, 2012). According to Sørheim and Hildrum (2002), reduction of cooking loss by pelvic suspension is highly attributed to less contracted muscles in pelvicsuspended sides compared to Achilles suspended sides.…”

“…According to Sørheim and Hildrum (2002), reduction of cooking loss by pelvic suspension is highly attributed to less contracted muscles in pelvicsuspended sides compared to Achilles suspended sides. Less contracted muscles have stretched sarcomeres with less overlap between thick and thin filaments and hence larger interfilament space which enables more room for water (Wahlgren et al, 2002;Ahnström et al, 2012). Furthermore, Weaver et al (2008) noted that pelvic suspension decreased overlaps of thick and thin filaments in long sarcomeres which increased the availability of proteolytically susceptible sites for enzyme degradation.…”

“…A study where variation in animal age was included, investigations were only carried out on heifers and this study only covered a short age range (18 to 22 months). Furthermore, connective tissue characteristics were not included (Ahnström et al, 2012). It is therefore not understood whether there would be interactive effects between animal age and pelvic suspension on the connective tissue component and hence tenderness of muscles.…”