Effects of calf weaning age and subsequent management systems on growth performance and carcass characteristics of beef steers

Abstract

Brahman × British crossbred steers (n = 40 and 38 in yr 1 and 2, respectively) were used to evaluate the effects of calf management systems following early weaning (EW) on growth performance, muscle gene expression, and carcass characteristics. On the day of EW (d 0), steers were stratified by BW and age (95 ± 14 kg; 74 ± 14 d) and randomly assigned to a control treatment that was normally weaned (NW) on d 180 (n = 10 steers/yr) or to 1 of 3 EW treatments: 1) EW and limit fed a high-concentrate diet at 3.5% of BW (as-fed basis) in drylot until d 180 (EW180; n = 10 steers/yr), 2) EW and limit fed a high-concentrate diet at 3.5% of BW (as-fed basis) in drylot until d 90 and then grazed on bahiagrass pastures until d 180 (EW90; n = 10 steers/yr), or 3) EW and grazed on annual ryegrass pastures until d 60 (yr 1; n = 10 steers) or 90 (yr 2; n = 8 steers) and then on bahiagrass pastures until d 180 (EWRG). Early-weaned steers on ryegrass and bahiagrass pastures were supplemented with high-concentrate diet at 1.0% of BW (as-fed basis) until d 180. From d 180 to 270 (yr 1), all EW steers remained in their respective treatments, whereas NW steers were provided high-concentrate diet at 1.0% of BW (as-fed basis) on bahiagrass pastures. In yr 1, feedlot finishing period began on d 270. In yr 2, the study was terminated on d 180. In both years, EW180 steers were heaviest (P < 0.0001) on d 180. On d 180 of yr 1, EWRG steers were lightest (P < 0.0001) and EW90 steers were heavier (P = 0.05) than NW steers, whereas EW90, EWRG, and NW steers had similar BW on d 180 of yr 2 (P ≥ 0.14). On d 90, muscle PPARγ mRNA expression tended (P = 0.07) to be greater for EW180 steers and was greater (P = 0.008) for EW90 vs. EWRG steers but similar (P = 0.25) between EW180 and NW steers. On d 180, PPARγ mRNA was greater (P ≤ 0.06) for EW180 vs. NW, EW90, and EWRG steers. From d 274 to 302, EW180 steers had the least ADG (P ≤ 0.09), whereas EW90 steers had similar (P = 0.19) ADG compared with EWRG steers but greater (P = 0.03) ADG than NW steers. At slaughter, carcass characteristics did not differ (P ≥ 0.22) among treatments. In summary, EW steers provided a high-concentrate diet in drylot for at least 90 d were heavier at the time of normal weaning than NW steers and EW steers grazed on ryegrass pastures for 60 to 90 d and supplemented with concentrate at 1.0% of BW. Feeding a high-concentrate diet immediately after EW enhanced the muscle PPARγ expression but did not enhance marbling at slaughter.

Creep-feeding to stimulate metabolic imprinting in nursing beef heifers: impacts on heifer growth, reproductive and physiological variables

“…Hence, nutritional interventions that improve nutrient utilization, body fat accretion, and increase circulating concentrations of hormones that facilitate the puberty process, such as IGF-I and leptin, are known to hasten puberty attainment in heifers (Williams et al, 2002; Cooke et al, 2008). Metabolic imprinting, defined as biological responses to a nutritional intervention during early life that permanently alters physiological outcomes later in life (Du et al, 2010), has been shown to enhance nutrient metabolism and fat accretion in cattle (Graugnard et al, 2010;Moriel et al, 2014a). Scheffler et al (2014) reported that feeding a highconcentrate diet to early-weaned beef steers from 100 to 205 days of age enhanced carcass marbling compared with forage-fed steers weaned at 205 days of age.…”

“…Nevertheless, mRNA expression can be increased without equivalent translation into the final product (Clancy and Brown, 2008). Moriel et al (2014a and2014b) reported that high-concentrate diets increased hepatic mRNA expression of hepatic IGF-I or muscle PPARγ without concurrent changes in plasma IGF-I concentration, carcass marbling, or backfat thickness in early-weaned cattle. Graugnard et al (2010) also reported altered PPARγ and FASN mRNA expression in the longissimus lumborum, but similar carcass marbling score, in beef steers receiving highor low-starch diets for 112 days after weaning at 5 months of age.…”

“…(1) puberty in cattle is highly influenced by nutritional status and body development (Schillo et al, 1992), including growth rate, body fat accretion, and circulating concentrations of hormones associated with nutrient metabolism and lipogenesis such as IGF-I and leptin (Williams et al, 2002;Cooke et al, 2008), and (2) management systems that stimulate metabolic imprinting enhance nutrient metabolism and body fat accretion in cattle (Graugnard et al, 2010;Scheffler et al, 2014;Moriel et al, 2014a). Supporting our rationale, Moriel et al (2014b) reported reduced age and BW at puberty in heifers weaned at 72 days of age and fed a high-concentrate diet for 90 days compared with forage-fed cohorts weaned at 252 days of age.…”

Effect of different early weaning regimens for calves on adipogenic gene expression in Hanwoo loin at the fattening stage

“…Due to the high cost, the period of feeding high-concentrate diets is reduced by beef producers for adaptation to EW management (Moriel et al, 2014a). Usually this EW strategy involves maintaining a high concentrate diet for a short period before allowing the cows to forage freely in the fields.…”

“…Supplying appropriate nutrition can enhance the calf's performance during early life and consequently, improve the production limit providing distinctive opportunities to optimize feeding strategies and increase the profitability of beef cattle production. Some studies have already suggested that exposure to high grain diets for early weaned (EW) calves leads to greater fat deposition and increased marbling scores and carcass quality at slaughter (Myers et al, 1999a, Myers et al, 1999bSithyphone et al, 2011;Moriel et al, 2014aMoriel et al, , 2014b.…”