| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
ANIMAL PRODUCTION |
* Department of Animal Science, University of California, Davis 95616 and
and
Dirección de Servicios Técnicosa la Cadena Agroindustrial, Instituto Nacional de Carnes, Montevideo, Uruguay
1 Correspondence: 1 Shields Ave. (phone: 530-752 0526; fax: 530-752 0175; e-mail: rdsainz{at}ucdavis.edu).
Abstract
Over three consecutive years, 180 (60/yr) fall-born steer calves were weaned in May (average initial BW = 238 kg, SD = 36.2 kg) and allocated to one of three groups: 1) calf-fed steers that entered the feedlot at weaning; 2) short yearlings that grazed irrigated pasture for another 4 mo and entered the feedlot in September; and 3) long yearlings that grazed with short yearlings during the summer, remained on annual California foothills range through the fall, winter, and spring, and entered the feedlot the following May. All steers were fed until the average group backfat (BF), determined by ultrasound, reached 11 to 12 mm. On pasture, short- and long-yearling steers gained weight in the summer; long yearlings then slightly lost weight in the fall and winter, and then gained weight again the following spring. Average days in the feedlot were 188, 158, and 94 (P < 0.10) for calves, short yearlings, and long yearlings, respectively. Feedlot DMI increased with age (and weight) at feedlot entry, with no difference among groups in gain:feed ratio. The gain of BF was nil on pasture, even when animals were gaining weight, and then increased rapidly when animals were placed on a high-energy diet. Final body weights were heaviest (P < 0.10) in long yearlings, followed by short yearlings and then calves, indicating that a prolonged growing period increases the apparent mature size of the animal. Moreover, total carcass fat contents and percentage of Choice or above were all lower (P < 0.10) in cattle that were older at feedlot entry (i.e., long yearlings) compared with the other groups. In conclusion, increasing the backgrounding period decreased time and total concentrate requirements in the feedlot of Angus-Hereford steers. Older cattle reached 10 mm of BF at heavier weights. Grazing animals gained weight without increasing BF; however, BF increased rapidly in the feedlot. Prolonged grazing may decrease quality grade, either by impairing the ability of the animal to deposit intramuscular fat or by decreasing the time during which dietary energy supply is adequate for intramuscular fat deposition to occur.
Key Words: Beef • Carcass • Feedlot • Performance • Stocker
This article has been cited by other articles:
|
|
 |
|
  S. J. Winterholler, D. L. Lalman, M. D. Hudson, C. E. Ward, C. R. Krehbiel, and G. W. Horn Performance, Carcass Characteristics, and Economic Analysis of Calf-Fed and Wheat Pasture Yearling Systems in the Southern Great Plains Professional Animal Scientist, June 1, 2008; 24(3): 232 - 238. [Abstract] [PDF]
|
|
|
|
 |
|
 T. E. Lawrence, R. L. Farrow, B. L. Zollinger, and K. S. Spivey Technical note: The United States Department of Agriculture beef yield grade equation requires modification to reflect the current longissimus muscle area to hot carcass weight relationship J Anim Sci, June 1, 2008; 86(6): 1434 - 1438. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. B. Smith, M. R. Dally, R. D. Sainz, K. L. Rodrigue, and A. M. Oberbauer Enhanced skeletal growth of sheep heterozygous for an inactivated fibroblast growth factor receptor 3 J Anim Sci, November 1, 2006; 84(11): 2942 - 2949. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. J. McPhee, J. W. Oltjen, T. R. Famula, and R. D. Sainz Meta-analysis of factors affecting carcass characteristics of feedlot steers J Anim Sci, November 1, 2006; 84(11): 3143 - 3154. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
