Performance of light vs heavy steers grazing Plains Old World bluestem at three stocking rates.

Abstract

Live weight gains of light and heavy calves grazing Plains Old World bluestem at three stocking rates were evaluated during the summers of 1997 and 1998. Initial weights of mixed-breed light-weight steers (LHT) were 141 SD = 17 kg (n = 214) in 1997 and 160 SD = 23 kg (n = 193) in 1998. Initial weights of mixed-breed heavy steers (HWT) were 265 SD = 17 kg (n = 115) in 1997 and 248 SD = 13 kg (n = 126) in 1998. Initial stocking rates for both sizes of steers were as follows: light, 392 kg of live weight/ha; moderate, 504 kg of live weight/ha (increased to 616 kg live weight/ha in 1998); and heavy, 840 kg of live weight/ ha. Averaged gain and gain/hectare are reported as stocking rate by steer type within year. Heavy steers had greater ADG than LHT steers during both years. Forage intake, expressed as a percentage of BW, was greater (P = 0.05) for LHT (3.1%) than for HWT (2.8%) calves. Grazing time (min/d; 1998 only) was greater (P = 0.05) for LHT (665) than for HWT (624) steers. Forage CP and in vivo digestible organic matter (DOM) were slightly greater (P < 0.05) in pastures grazed by HWT vs LHT cattle. Gain/hectare was greater (P < 0.05) for LHT than for HWT calves at all three stocking rates during both years. A linear decline in ADG was observed (P < 0.07) as stocking rates increased for HWT steers in 1997 and LHT steers in 1998. However, ADG did not decline with increasing stocking rate for LHT calves during 1997 or HWT calves during 1998. Forage intake was not different among stocking rates in either 1997 or 1998. Grazing time was greatest (P < 0.05) for steers in the moderate and heavy stocking rates. Forage in vivo DOM decreased (P < 0.05) as stocking rate increased. Both LHT and HWT steers had lower (P < 0.05) ADG at all three stocking rates during 1998 compared with 1997. Despite lower ADG, LHT steers had greater gain/hectare than HWT steers during both 1997 and 1998.

Comportamento ingestivo de novilhos sob suplementação em pastagens de capim-tanzânia sob diferentes intensidades de desfolhação

“…Entretanto, Ackerman et al (1998) observaram que o aumento na taxa de lotação e, conseqüen-temente, na intensidade de desfolhação resultou em acrés-cimo de 522 para 609 minutos/dia no tempo de pastejo de novilhos.…”

088 Evaluation of initial body weight and supplementation levels on health and performance of newly received stocker calves

“…On the other hand, young lightweight cattle offer promise through a lower initial investment, a higher stocking rate, and more weight gain potential (Ackerman et al, 2001). …”

“…Ackerman et al (2001) conducted 2 trials spanning over two years that examined the ADG of crossbred light weight steers at an average weight of 150 kg to heavier weight steers weighing an average of 257 kg on native forage. The ADG was higher for the heavier weight steers throughout the study.…”

“…days, and reported heifers having initial body weights of 182 to 226 kg had an increased gained compared to cattle weighing less than 181 kg on arrival. Ackerman et al (2001) conducted two trials that compared the gain of lightweight steers weighing 141 ± 17 kg (n = 214) in trial 1 and 160 ± 23 kg (n = 193) in trial 2 to heavyweight steers that weighed 265 ± 17 kg (n = 115) in trail 1 and 248 ± 13 kg (n = 126) in trial 2. Both studies showed that heavier weight steers out gained the lighter weight steers while grazing native grass.…”

“…Perhaps a longer period of time is needed to detect differences in gain. Also, stocking rates were based on a per head basis in the current study and Ackerman et al (2001) calculated stocking rate on a pound/acre basis.…”