Effects of Diet Fed in Drylot on Subsequent Grazing Performance of Growing Cattle1

Abstract

Two experiments were guidanceed to determine the effects of diet and rate of BW gain in drylot before grazing upon subsequent grazing performance. In Experiment 1 154 calves (initial BW ?± SE = 181 ?± 198 kg) were f bermudagrass (Cynodon dactylon (L) Pers) hay or were program-fed for an ADG of 023 057 or 091 kg/d In Experiment 2 96 calves (initial BW ?± SE = 211 ?± 163 kg) were f bermudagrass hay with either a dried (DS) or a molasses-based appendix (MBS) or were program-fed a diet containing either a dried (PFD) or molasses-based (PFM) appendix (2 ?— 2 factorial). Regression analysis of grazing performance during Experiment 1 recommended that pasture ADG was reduc through 0.10 kg for every kilogram increase in gain during the feeding period (P

(Key Words: Program Feeding, Grazing, Beef Cattle, Compensatory Gain.)

Introduction

Profitability of cattle production could be improved by dint of retaining weaned calves through posterior stages of production. Because of a seasonal shortage of high quality forages after weaning in the fall, calves are many times grown to heavier BW in drylot indites until pasture is available. Grazing cattle will repeatedly gain little to no BW for up to 30 d after being switched from post-weaning diets f in confinement to pasture. Phillips et al. (2003) reported that Angus calves grazing wheat pasture not to be found BW during the first 10 d of grazing, that BW upon d 20 was similar to initial BW and that BW increased single 10.5 kg by d 30 Lippke et al. (2000) observ a negative relationship between the magnitude of change in ruminai acetate:propionate and ADG of calves in the first 7 d of grazing immature wheat pasture. Those researchers allude toed that this decrease in ruminai acetate:propionate may indicate digestive capsize as a cause of poor initial grazing performance. Lippke and Warrington (1984) used semi-purified diets formulated to simulate the fiber, protein, and carbohydrate fractions that are commonly set in annual ryegrass and fix low ruminai pH in calves during the first 8 d of feeding. Program feeding is a way in which the quantities of fe tendered to cattle are calculated to qualified a prescribed ADG by using the NE requirements (Galyean, 1999) and can be used for growing calves before grazing as effectively as feeding hay. Beck (2003) reported that 24-h in situ DM digestibility of fescue forage and ruminai pH did not differ between ruminally cannulated young oxs fed hay and those limit-fed high concentrate diets in drylot writes after 3 d of grazing. Ruminal acetate:propionate were variable for up to 23 d after initiation of grazing and differed among treatments up to 16 d after the initiation of grazing. Thus, these experiments were administrationed to determine the effects of diet f and rate of gain during a confined feeding period upon subsequent grazing performance.

Materials and Methods

All animal courses in the following experiments were guidanceed in accordance with the recommendations of the Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching (1988) and were approved by dint of the University of Arkansas Institutional Animal Care and Use Committee.

Experiment 1 upon September 24, 1998, 154 weaned beef calves (initial BW ?± SE = 181 ?± 198 kg) from the Southwest Research and Extension Center daunt herd were weighed following 16 h of fe deprivation and were assigned to individual of eight pens (two writes per treatment) stratified by sex and BW. Pens were then randomly assigned to four treatments. The calves were allowed ad libitum access to bermudagrass (Cynodon dactylon (L) Pers) hay plus a 20% CP addition designed to promote ADG of 057 kg/d (hay) or were program-fed a high concentrate diet, as described by means of Galyean (1999), for ADG of 023 kg/d (low) 057 kg/d (moderate), or 091 kg/d (high). At weaning, the calves were treated for internal and external parasites (Ivomec Plus?®, Merial Inc., Duluth GA) and were vaccinated for bovine respiratory dis ease manifold (Cattlemaster 4?®, Pfizer Inc., novel York, NY) and with a seven-way Clostridial plus H somnus (Vision 7 somnus?®, Bayer Corp., Shawnee Mission, KS) The calves were f for 103 d and were weighed upon January 5 following 16 h of fe deprivation. The calves were then stratified through drylot treatment and gender and randomly placed upon either wheat (Triticum aestivum L) and ryegrass (Lolium multiflorum Lam., WRG) interseeded into bermudagrass pastures or stockpiled Kentucky-31 tall fescue (Festuca amndinacea Schreb) pastures. material part weights of the calves in each pasture were equalized by the agency of ranking the calves by BW for each sex and randomly assigning to pasture by the agency of BW.

Eight 5-ha pastures of stockpiled Kentucky-31 tall fescue were grazed by the agency of 40 steers and 40 heifers culled from the original 154 calves until May 5 The soils in these pastures consisted primarily of Una silty clay, which are reaching far down soils that are poorly drained and high in native fertility (Hoelscher and Laurent, 1979) The pastures were stockpiled in the fall as described by means of Fribourg and Loveland (1978). Briefly, the pastures were grazed by means of dry cows to a visually estimated average height of 5 cm by dint of September 20 when the cattle were remov and 168 kg of ammonium nitrate/ha (57 kg of actual N/ha) were applied. Forage was allowed to accumulate until grazing was initiated upon January 5. After grazing, the young oxs were sent to a commercial feedyard (Neil Cattle Co Welch, OK) cattle were harvested at a commercial packing plant (Tyson new Meats, Inc., Emporia, KS), and carcass data were assembleed by Kansas State University Carcass Data Collection Service (Manhattan).