Effect of Prolonged Backgrounding on Growth Performance and Carcass Composition of Crossbred Beef Steers (Nutrition Update, Volume 10)

 
The objective of this study was to determine the effect of feeding strategy (prolonged backgrounding prior to high-energy finishing versus immediate high-energy finishing) on growth performance and carcass composition and quality of cross-bred beef steers. One hundred and twenty crossbred beef steers derived from Charolais, Simmental, Angus and Hereford breeding were divided into light (346 kg) and heavy (394 kg) groups based on body weight. Steers were fed to slaughter on a high-energy finishing ration (GRAIN) or given barley silage during the winter, grazed 90 days, and then finished on the high–energy ration (FORAGE). Steers were slaughtered when the pen USFAT depth averaged 8 mm.

Compared with steers on the GRAIN program, FORAGE steers had lower ADGs, took 119 days longer to finish and finished at heavier live and carcass weights. Heavy animals grew faster and were slaughtered 15 days earlier at heavier weights than light animals. Light animals had smaller l. thoracis area than heavy animals. The proportion of carcasses with slight or small marbling was greater for light steers, particularly those with a higher proportion of "British" breeding.

The results of this study indicate that when fed to a fat constant end point, backgrounding increased the carcass weight of both light and heavy cattle relative to those finished directly on a high-energy finishing diet. Subjecting the cattle to a prolonged growing period increased the age of the animals at slaughter, but did not improve carcass marbling scores. Backgrounding was an effective method of increasing the carcass weight of light steers without adversely affecting carcass composition. The greater degree of marbling was exhibited by cattle with a high proportion of typical British breeding. Feeding programs aimed at producing carcasses with acceptable weight and relatively high degrees of marbling may benefit from the use of medium-framed cattle.

Reference: Vaage et al.. 1998. Can. J. An. Sci. 78: 359-367.
Nutrition Update
Volume 10 No.2, November 1999