Journal of Animal Science, Vol 73, Issue 8 2390-2405, Copyright © 1995 by American Society of Animal Science

JOURNAL ARTICLE

Effects of growth rate on carcass composition and lipid partitioning at puberty and growth hormone, insulin-like growth factor I, insulin, and metabolites before puberty in beef heifers

J. V. Yelich, R. P. Wettemann, H. G. Dolezal, K. S. Lusby, D. K. Bishop and L. J. Spicer
Animal Science Department, Oklahoma Agricultural Experiment Station, Stillwater 74078-0425, USA.

The effect of three rates of gain on carcass composition, lipid partitioning, age and BW at puberty, and concentrations of growth hormone (GH), IGF-I, insulin, glucose, and NEFA in plasma were evaluated in 38 Angus x Hereford heifers. Heifers were allotted by BW and age to three treatments with a replication in each of 2 yr: full-fed (n = 13; FF) to gain 1.36 kg/d; limit-fed (n = 12; LF) to gain .68 kg/d; maintenance-full-fed (n = 13; MFF) to gain .23 kg/d for 16 wk, then full-fed to gain 1.36 kg/d. Heifers were slaughtered within 10 d after the onset of puberty. At slaughter, kidney, pelvic, and heart fat (KPH) and udder (UDDER) were separated from carcass, as was fat surrounding viscera (OM). After 48 h at 4 degrees C a carcass side was dissected into subcutaneous fat (SC), intermuscular fat (SEAM), soft tissue (SFT = inseparable lean and fat), LEAN, and BONE. In yr 1, LF heifers (431 d) were older (P < .05) than MFF heifers (371 d) at puberty, but age of FF heifers (389 d) did not differ (P > .10) from that of LF and MFF heifers. In yr 2, FF heifers (351 d) were younger (P < .05) than LF and MFF heifers (398 and 434 d, respectively). The FF heifers had greater (P < .05) BW and a greater (P < .01) percentage of lipid in the carcass at puberty than LF and MFF heifers. During the first 16 wk of treatment, concentrations of NEFA were greater in heifers with slower daily gains (MFF > LF > FF; P < .01). Concentrations of NEFA were lesser and concentrations of IGF-I and insulin were greater in plasma of FF than in that of MFF heifers during the 10 wk before puberty. Treatment significantly altered age, BW, carcass composition, and lipid partitioning at puberty in beef heifers. We conclude that the percentage of body fat is not the sole regulator of puberty, and age may be an important modulator in determining the onset of puberty in beef heifers.

This article has been cited by other articles:

				C. L. Gasser, D. E. Grum, M. L. Mussard, F. L. Fluharty, J. E. Kinder, and M. L. Day Induction of precocious puberty in heifers I: Enhanced secretion of luteinizing hormone J Anim Sci, August 1, 2006; 84(8): 2035 - 2041. [Abstract] [Full Text] [PDF]

				N. H. Ciccioli, S. L. Charles-Edwards, C. Floyd, R. P. Wettemann, H. T. Purvis, K. S. Lusby, G. W. Horn, and D. L. Lalman Incidence of puberty in beef heifers fed high- or low-starch diets for different periods before breeding J Anim Sci, November 1, 2005; 83(11): 2653 - 2662. [Abstract] [Full Text] [PDF]

				C. A. Lents, R. P. Wettemann, F. J. White, I. Rubio, N. H. Ciccioli, L. J. Spicer, D. H. Keisler, and M. E. Payton Influence of nutrient intake and body fat on concentrations of insulin-like growth factor-I, insulin, thyroxine, and leptin in plasma of gestating beef cows J Anim Sci, March 1, 2005; 83(3): 586 - 596. [Abstract] [Full Text] [PDF]

				M. J. Hersom, R. P. Wettemann, C. R. Krehbiel, G. W. Horn, and D. H. Keisler Effect of live weight gain of steers during winter grazing: III. Blood metabolites and hormones during feedlot finishing J Anim Sci, July 1, 2004; 82(7): 2059 - 2068. [Abstract] [Full Text] [PDF]

				N. H. Ciccioli, R. P. Wettemann, L. J. Spicer, C. A. Lents, F. J. White, and D. H. Keisler Influence of body condition at calving and postpartum nutrition on endocrine function and reproductive performance of primiparous beef cows J Anim Sci, December 1, 2003; 81(12): 3107 - 3120. [Abstract] [Full Text] [PDF]

				T. N. Bodine and H. T. Purvis II Effects of supplemental energy and/or degradable intake protein on performance, grazing behavior, intake, digestibility, and fecal and blood indices by beef steers grazed on dormant native tallgrass prairie J Anim Sci, January 1, 2003; 81(1): 304 - 317. [Abstract] [Full Text] [PDF]

				M. R. Garcia, M. Amstalden, S. W. Williams, R. L. Stanko, C. D. Morrison, D. H. Keisler, S. E. Nizielski, and G. L. Williams Serum leptin and its adipose gene expression during pubertal development, the estrous cycle, and different seasons in cattle J Anim Sci, August 1, 2002; 80(8): 2158 - 2167. [Abstract] [Full Text] [PDF]

				I. Bossis, R.P. Wettemann, S.D. Welty, J. Vizcarra, and L.J. Spicer Nutritionally Induced Anovulation in Beef Heifers: Ovarian and Endocrine Function During Realimentation and Resumption of Ovulation Biol Reprod, May 1, 2000; 62(5): 1436 - 1444. [Abstract] [Full Text]

				K. Stagg,, L.J. Spicer,, J.M. Sreenan,, J.F. Roche,, and M.G. Diskin Effect of Calf Isolation on Follicular Wave Dynamics, Gonadotropin and Metabolic Hormone Changes, and Interval to First Ovulation in Beef Cows Fed Either of Two Energy Levels Postpartum Biol Reprod, October 1, 1998; 59(4): 777 - 783. [Abstract] [Full Text]