Performance, carcass, cartilage calcium, sensory and collagen traits of longissimus muscles of open versus 30-month-old heifers that produced one calf.
One hundred eleven Simmental x Hereford (3/8 to 5/8 Simmental) heifers were used to determine the effects of age, parturition and implantation on performance, carcass and meat-sensory traits, muscle-collagen characteristics and thoracic-button calcification. Eighty-five heifers that calved at about 2 yr of age, designated as single-calf heifers (SCH), were either implanted (I-SCH) with Synovex-H or not implanted (NI-SCH). The remaining 26, 2-yr-old non-pregnant heifers (2-OH) served as controls. Additionally, 24, 1-yr-old open heifers (1-OH) from the same genetic source were utilized as the standard heifer-production system. The 1-OH and 2-OH were slaughtered after being fed a high-grain diet for 137 and 112 d, respectively. The SCH were fed the same high-grain diet beginning about 1 mo after calving and were fed 137 d before slaughter. The 33 I-SCH were implanted when started on the high-grain diet. Calves were weaned about 5 wk before the SCH were slaughtered. The 2-OH had the highest (P less than .05) feedlot ADG, whereas no differences (P greater than .05) occurred among other treatments. Dressing percentages were higher (P less than .01) for I-SCH than for NI-SCH. Carcass weights were lowest (P less than .05) and percentage kidney, pelvic and heart fat was highest (P less than .01) for 1-OH. Fat thickness, yield grades, marbling scores and quality grades were similar (P greater than .05) and desirable for all treatments.(ABSTRACT TRUNCATED AT 250 WORDS)
Kansas State University, Manhattan 66506.
A W
AW
Waggoner
M E
ME
Dikeman
J R
JR
Brethour
K E
KE
Kemp
D000818:Animals; D002118:Calcium / Q000032:analysis; D002356:Cartilage / Q000032:analysis; D002417:Cattle / Q000033:anatomy & histology* / Q000254:growth & development; D003094:Collagen / Q000032:analysis; D005260:Female; D008460:Meat / Q000592:standards*; D009132:Muscles / Q000032:analysis / Q000033:anatomy & histology*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*; D015430:Weight Gain
D003094:Collagen; D002118:Calcium