Supplementation of ammoniated wheat straw: performance and forage utilization characteristics in beef cattle receiving energy and protein supplements2

Abstract

Two experiments were conducted to evaluate performance and forage utilization characteristics of beef cattle fed ammoniated wheat straw (AWS) unsupplemented except for minerals or supplemented with energy and protein. In Exp. 1, 194 crossbred beef cows (BW = 472 kg) in late gestation were allotted by weight, breed type, and age during two consecutive winters to 12 drylot pens (three pens/treatment) for a 60-d feeding trial. The AWS (3% NH3 wt/wt) was tubground through a 7.6-cm screen, and cows were allowed ad libitum access to the AWS. In Exp. 2, 16 ruminally fistulated Angus x Hereford steers (BW = 300 kg) were blocked by weight and randomized to treatments in a 35-d intake-digestion trial. Daily supplementation treatments in both experiments were Control, no supplemental energy or protein; LSG, 1.36 kg of sorghum grain (SG); HSG, 2.72 kg of SG; and SG + SBM, 1.02 kg of SG + .34 kg of soybean meal (SBM). All animals received .23 kg of mineral mixture formulated to meet a pregnant cow's mineral requirements. Supplements LSG and SG + SBM were fed to provide the same daily ME, and HSG and SG + SBM were fed to provide the same daily CP. Cows were managed as one group during and after calving. In Exp. 1, all supplements increased gain (P less than .01) vs Control, and cows fed SG + SBM had higher (P = .05) gains than those fed LSG. The SG + SBM supplement increased (P less than .01) change in cow body condition score compared with LSG.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of supplementation and stocking rate on body condition and production parameters of multiparous beef cows

“…In agreement with a number of studies ( Miner et al, 1990;Beck et al, 1992;Fike et al, 1995;Farmer et al, 2001), supplementation was also without effect on birth weight. Birth weight also appears to be resistant to the effects of under nutrition as neither a 0·20 nor a 0·43 proportional restriction in the dietary energy, below the NRC requirements, resulted in a decrease in birth weight (Freetly and Cundiff, 1998;Hough et al, 1990, respectively, ).…”

“…Selk et al (1988) showed no effect of pre-partum nutrition on PPI, interval to ovarian luteal activity or the percent of cows showing luteal activity at 85 days post partum. Beck et al (1992) also showed no effect of supplementation on the percentage of cows cycling by the onset of the breeding season.…”

“…Previous evidence at this location suggests that supplementation does not affect reproductive performance ( Morris, 1985;Raguse et al, 1989). Both Beck et al (1992) and Fike et al (1995) showed that supplementation did not affect the pregnancy rate of cows following a 60-day breeding season. Furthermore, pre-partum supplementation for either 90 or 84 days did not affect pregnancy rates in the studies by DeRouen et al (1994) or Weder et al (1999), respectively.…”

“…The heavier calves that result from supplementation may be due to an increase in milk production by the dam (Rusche et al, 1993;Beaty et al, 1994). Studies demonstrating no effect of pre-partum supplementation on weaning weight support the hypothesis that increased milk production facilitates the effect of postpartum supplementation on weaning weight (Beck et al, 1992;Fike et al, 1995;Weder et al, 1999).…”

Effects of winter feeding strategies with alternative feeds on the performance of mature suckler cows and their progeny

“…Indoor feeding of beef cows is usually based on inexpensive, low-energy feeds such as straw, treated straw (Mann et al 1988, Fike et al 1995, Manninen et al 2000 or straw with protein or energy supplements (Alawa et al 1986, Alawa et al 1987, Alawa et al 1988, Beck et al 1992). Good quality grass silage is not used for beef cows ad libitum due to its high energy content, especially for cows in good body condition score pre-calving.…”