The purpose of this study was to determine if estimated breeding value (EBV) of an animal’s sire and or the animal’s nutrition affected the structure of its M. longissimus thoracis et lumborum (LL) and, hence, the eating quality of meat derived from its carcass. Lambs were chosen based on the EBV of their sires in terms of post-weaning live weight (PWWT), post weaning fat at the C-site (PFAT), and post-weaning eye muscle depth (PEMD). Morphometric techniques were used to characterise muscle structure in terms of the distribution of intramuscular connective tissue; the variables together are called fascicular structure. Perimysial seam thickness and fascicular width were both influenced by sire estimated breeding values for PWWT, PFAT, and PEMD. Variation in fascicular structure was associated with an interaction between PEMD-EBV and PFAT-EBV of the sire. Fascicular width decreased with increased PEMD-EBV and increased with PFAT-EBV, but was not affected by PWWT-EBV. When the total seam thickness was adjusted to a common fascicular width, the lambs on a low plane of nutrition had relatively more intramuscular connective tissue than those on a high plane. The total seam thickness was negatively associated with PFAT-EBV and positively associated with PEMD-EBV. Warner Bratzler shear (WBS) peak force (PF) and initial yield were not associated with differences in sire EBV. The residual WBS shear force, peak force minus initial yield (PFIY), and compression values were negatively associated with nutrition but were positively associated with PWWT-EBV and PEMD-EBV of the sires. These latter 2 effects were moderated by nutrition. The data support the hypothesis that morphological characteristics of perimysium are genetically determined and nutritionally responsive. Variance in morphology accounted for some variance in the biophysical attributes of meat and may help explain why sheep with high muscling potential have tougher meat.
The objective of this study was to compare feeding behavior between red and black Angus heifers during a 161-d finishing period as a potential explanation for performance differences. Sixty-eight single-sourced purebred red (n = 35) and black (n = 33) Angus heifers, leptin genotype TT, and average starting weight 360 kg (±19 kg) were used. Heifers were randomly and equally allocated into one of two feedlot pens, equipped with five feed bunks that recorded feeding behavior. Individual time spent at the feed bunk, interval between feeding events, feed intake, and meal frequency were recorded daily, and eating rate was calculated. Heifers were fed a barley-based diet (>75% concentrate). After 161 d, at the end of the feeding period, feedlot performance was calculated as average daily gain (ADG) and gain to feed conversion rate. Additionally, carcass data were obtained from the abattoir. Overall, black Angus heifers ate more, spent more time at the feed bunk, and had more meals compared with red Angus (P < 0.001). Red Angus heifers had better gain to feed ratios (P < 0.02) and significantly more red heifers were assigned to Canadian yield category 1 (≥59% lean meat) compared with black heifers (P = 0.02), whereas black heifers had higher back fat thickness throughout the study (P ≤ 0.04). All other performance parameters (ADG and carcass weight) were not different.Key words: cattle, Angus, feedlot, color, feeding behavior.Résumé : L'objectif de cette étude était de comparer les comportements à l'alimentation entre les génisses Angus rouges et noires pendant la période de finition de 161 jours comme explication potentielle des différences de performances. Soixante-huit génisses Angus pure race d'une seule source, rouges (n = 35) et noires (n = 33), au génotype leptine TT, de poids initial moyen de 360 kg (±19 kg), ont été utilisées. Les génisses ont été assignées de façon aléatoire et égale à l'une de deux enclos de parcs d'engraissement équipés de cinq mangeoires capables d'enregistrer le comportement à l'alimentation. Le temps individuel à la mangeoire, l'intervalle entre les événements d'alimentation, la prise alimentaire et la fréquence des repas ont été enregistrés quotidiennement et le taux d'alimentation a été calculé. Les génisses ont reçu une diète à base d'orge (>75 % de concentrés). Après 161 jours, à la fin de la période d'alimentation, la performance au parc d'engraissement a été calculée par le gain moyen quotidien et l'indice de consommation. De plus, les données de la carcasse ont été obtenues de l'abattoir. De façon générale, les génisses Angus noires ont plus mangé, ont passé plus de temps aux mangeoires et ont pris plus de repas que les génisses Angus rouges (P < 0,001). Les génisses Angus rouges avaient un meilleur indice de consommation (P < 0.02) et significativement plus de génisses rouges ont été assignées à la catégorie canadienne 1 de rendement (≥59 % de viande maigre) par rapport aux génisses noires (P = 0,02), tandis que les génisses noires avaient des épaisseurs de gras dorsal p...
Two experiments are described involving 33 crossbred (mainly Simmental and Jersey X Zebu) and 33 Zebu (Horro and Boran) bulls and steers. In experiment I, growth rates of crossbred and Zebu cattle rotationally grazed on either native pasture or Rhodes grass (Chloris gayana) were compared during a 140 day grazing period at a stocking rate of 2.4 animals/ha. In experiment II, growth rate of cattle rotationally grazed for 140 days on native pasture was compared with that of a similar group grazed on Rhodes grass either rotationally or continuously at a stocking rate of seven animals/ha. On native pasture the average daily gain by Zebu animals was similar to that of the crossbreds whilst on Rhodes grass liveweight gain of Zebu animals was lower than that of the crossbreds. Daily gains of cattle were significantly (P less than 0.01) greater on continuous compared with rotationally grazed Rhodes grass.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.