Performance and carcass characteristics of lambs ½ Dorper + ½ Santa Inês, slaughtered with different thicknesses of subcutaneous fat

Abstract

SUMMARY The aim of this study was to evaluate the effect of subcutaneous fat thickness (SFT) on slaughter in lambs ½ Dorper + ½ Santa Inês (DSI) on performance, carcass characteristics and commercial cuts. It was used twenty-four lambs, slaughtered with 2mm, 3mm and 4mm SFT. There was an effect of SFT on performance: for days of confinement (2mm = 51.38, 3mm = 66.50, 4mm = 91.63 days), age at slaughter (2mm = 139.38, 3mm = 159.88, 4mm = 171.00 days), final body weight (2mm = 33.50, 3mm = 42.81, 4mm = 46.19 kg), total weight gain (2mm = 18.75, 3mm = 25.08, 4mm = (2mm = 0.44, 3mm = 0.39, 4mm = 0.28kg), slaughter weight (2mm = 32.76, 3mm = 39.79, 4mm = 44.88 kg), body condition score (2mm = 2.97, 3mm = 3.13, 4mm = 3.56); for carcass characteristics: warm carcass weight (2mm = 15.33, 3mm = 19.16, 4mm = 21.90 kg) and cold (2mm = 15.03, 3mm = 18.75, 4mm = 21.47), cooling losses (2mm = 0.00234; 3mm = 0.00333; 4mm = 0.00201 kg), carcass yields: in the refrigerator (2mm=46,79; 3mm=48,30; 4mm=48,79%); commercial (2mm = 45.88, 3mm = 47.25, 4mm = 47.82%) and true (2mm = 52.93, 3mm = 54.51, 4mm = 55.67%); carcass compactness index (2mm= 0,250; 3mm=0,30; 4mm=0,33 kg/cm) for cut weights; neck (2mm=0,44; 3mm=0,55; 4mm=0,56 kg); palette (2mm=1,38; 3mm=1,61; 4mm=2,14 kg), flank steak (2mm=2,16; 3mm=2,73; 4mm=3,19 kg), loin (2mm=0,93; 3mm=1,14; 4mm=1,25 kg), and leg (2mm=2,68; 3mm=3,20, 4mm=3,76 kg). For the tissue composition of only the muscular cuts of the neck (2mm = 50.24, 3mm = 51.44, 4mm = 55.34%), bone of the neck (2mm = 30.24, 3mm = 29.63, 4mm = 25.91%), of the loin (2mm=15,05; 3mm=24,63; 4mm=24,71%) and the leg (2mm=11,38; 3mm=13,33; 4mm=13,13%), they presented differences between the SFT (p> 0.05). It is recommended to slaughter lambs ½ Dorper + ½ Santa Inês with 3mm of SFT.

Inclusion of Yerba Mate (Ilex paraguariensis) Extract in the Diet of Growing Lambs: Effects on Blood Parameters, Animal Performance, and Carcass Traits

“…Animal performance data presented in this study showed positive results and is similar to results reported in the literature using Dorper breed and its cross-breeds [ 57 , 58 , 59 ]. The effect of high levels of yerba mate extract (4%) resulted in a reduction in dry matter intake and, consequently, a reduction in the general performance of the lambs; on the other hand, inclusions of up to 2% caused an increase in dry matter intake, total weight gain, and daily weight gain.…”

Allometric growth of ½ Dorper + ½ Santa Inês lambs slaughtered with different subcutaneous fat thicknesses

“…The precocity of most cuts in relation to the half carcass indicates that the Dorper breed contributed to the formation of a carcass with an accelerated growth and better cut yields (Cartaxo et al, 2017), providing desirable characteristics of compactness that are transmitted to its progeny (Nascimento et al, 2018). It should be noted that, despite their greater SFT and weights, these lambs did not reach physiological maturity in the present study, since their bone and muscle tissues continued to show accelerated growth.…”

“…The maintained growth rate of these tissues presupposes that the lambs had not yet reached their mature weight. Therefore, the SFT at slaughter did not affect the muscle yield of the carcass; however, a greater thickness of the subcutaneous fat may protect carcasses from losses during their freezing process (Nascimento et al, 2018).…”

“…An important parameter to obtain quality meat is body weight; however, it should not be the only criteria used for slaughtering (Osório et al, 2012), since lambs of different breeds with similar weights still present varying amounts of tissue deposition, which influences carcass characteristics (Camacho et al, 2015). The measurement of subcutaneous fat thickness (SFT) with the real-time ultrasound technique can be used as an indicator of the best time for the slaughter of lambs (Nascimento et al, 2018), as SFT allows predicting the composition and relative growth of other carcass cuts and tissues (Wood et al, 1980;Teixeira et al, 2006;Mora et al, 2014).…”

“…In addition, it is also important to determine the best SFT for slaughter. There are reports that lambs in a confinement system should be slaughtered with 3.0 mm SFT, since lower thicknesses may result in deficient fat coverage in the carcass and higher ones, in a greater amount of fat and reduced feed conversion (Andrade et al, 2017;Nascimento et al, 2018).…”