Growth, development and nutritional manipulation of marbling in cattle: a review

Abstract

This review describes the pattern of intramuscular fat accretion in cattle and the potential for its manipulation during both the pasture (or backgrounding) and intensive grain-finishing phases of development. A growth curve for the development of marbling in British and Japanese Black type breeds is discussed with the conclusion that 3 phases of development exist: (i) a period of growth up to ~200 kg hot carcass weight where intramuscular fat does not increase; (ii) a period of linear development as carcass weight increases from 200 to 450�kg; and (iii) the attainment of mature body size (~500 kg carcass weight depending on genotype) at which intramuscular fat content appears to reachea maximum. Data are also presented to show that the intramuscular and other fat depots develop at similar rates indicating that intramuscular fat is not a late maturing depot. Pre-finishing growth checks reduce the initial intramuscular fat at the start of finishing and this is translated into lower levels at the end of finishing. It is argued that the greatest potential for the manipulation of intramuscular fat accretion during fattening is via an increase in the net energy of the ration. Increasing net energy can be achieved by increasing the cereal grain content of the diet (grain v. grass); by feeding processed cereal grain, which allows both maximal rumen fermentation and small intestinal digestion of starch, and by increasing the lipid content of the diet. In addition it is proposed that the substrate supply or hormonal milieu can also be optimised, along with the availability of net energy to maximise fat accretion. The role of lipolysis (fat turnover) as a regulator of fat accretion is also discussed.

Inclusion of sunflower seed and wheat dried distillers’ grains with solubles in a red clover silage-based diet enhances steers performance, meat quality and fatty acid profiles

“…Overall, odd-chain FA and BCFA in animal fat are primarily derived from rumen microbes compared with de novo synthesis (Vlaeminck et al, 2006). The decrease in odd-chain FA and BCFA in the current study may, therefore, largely related to a direct inhibition of 18:2n-6 on rumen microbes (Vlaeminck et al, 2006) and the reduction of propionate production from readily fermentable starch in the rumen (Pethick et al, 2004). Propionate and its carboxylation product methylmalonate are primers for the biosynthesis of odd-chain FA and BCFA, respectively (Vlaeminck et al, 2006).…”

Longitudinal muscle gene expression patterns associated with differential intramuscular fat in cattle

“…The profile of postnatal IMF content over development is schematically characterised in Figure 1a. Hudson, Reverter, Greenwood, Guo, Cafe and Dalrymple This was based on the study by Pethick et al (2004), which documented the relationship between carcass weight and IMF% in crossbred Angus × Hereford, Angus and Japanese Black × Holstein cross cattle. We previously identified two closely related sets of fat metabolism genes whose expression was highly correlated (co-expressed) across development (Hudson et al, 2009b).…”

Effects of growth path, sire type, calving time and sex on growth and carcass characteristics of beef cattle in the agricultural area of Western Australia

“…For each prefinishing growth pathway and market destination, after adjusting for differences in carcass weight between finishing diet, P8 fat, rib fat and IMF% were higher for the feedlot-finished animals. Pethick et al (2004) in reviewing results of the Beef Cooperative Research Centre studies concluded that at the same carcass weight IMF content in pasture-finished animals was reduced by 40% for every 10-kg increase in carcass weight compared with feedlot-finished animals.…”