Environmental Effects on Limit-Fed Feedlot Finishing Diets

Ninety-six crossbred yearling steers were allotted to either ad libitum or 93% of ad libitum intake treatments in a 117-day winter finishing trial. Intake restriction began once the 93% treatment group was started on its finishing diet. Finishing diets were formulated to result in similar absolute intakes of nutrients and feed additives. Restricted treatment dry matter intake was lower than ad libitum as intended (P\u3c.05), but average daily gain was also less, 3.71 and 3.50 Ib per day (P\u3c.05) and resulted in similar feed/gain, 6.01 and 6.07 (P\u3e.82). These results are in contrast to two previous trials conducted during summer and mild winter/spring conditions and suggest that cold stress may affect the response to limit-feeding of feedlot finishing diets

Ammoniated Oat Hulls for Growing Calves

Eighty-one steer calves were fed growing diets that contained 50% of either 1) ground brome hay (BROME), 2) unground oat hulls (OH), or 3) unground oat hulls treated with 3% ammonia and enough water to raise the moisture content to 20% (NH3-OH). Treated oat hulls were allowed to react for 63 days prior to feeding. Daily gains of NH3-OH fed steers were 18 and 13% greater than those of OH and BROME fed steers, respectively, during the 88-day study (P\u3c.01). Dry matter intakes were not affected by diet (P\u3e.10). However, feed efficiency was 13% better for NH3-OH fed steers than steers fed OH and 9% better than those fed the BROME diet (Pc.05). Calculated NEm and NEg estimates for the brome hay, untreated and 9 treated oat hulls used in this study were 53.9 and 31.9, 51.0 and 29.2, and 64.7 and 40.8 Mcal/cwt DM, respectively. Oat hulls respond well to ammonia treatment and may contain as much as 23% more net energy than brome hay in calf growing diets

Conventional Versus High Energy Receiving and Step-Up Diets for Feedlot Cattle

Two hundred sixty-four yearling steers with an initial average weight of 730 Ib were randomly allotted to 24 pens and fed ad libitum either conventional (CONV) receiving or step-up diets (hay content decreased from 50% to 40, 30, 20, and 10% of diet dry matter) or high energy (HE) diets (hay content was maintained throughout at 10% but wet corn distillers grain (WDG) decreased from 43% to 30, 20, 10, and 0%). The feeding of WDG in place of hay was designed to maximize energy intake while not overloading the rumen with starch during the grain adaptation period. Long grass hay was fed on day 1. Diets 1 through 4 were fed 7, 5, 6, and 4 days, respectively. Diet 5 (finishing diet) composition was the same for both treatments and was fed for 5 days. Average daily gain (CONV = 4.39 and HE = 4.41 Ib per day) during the 28-day receiving/step-up trial was not affected by diet composition (P \u3e. 10). However, dry matter intake was 22% less (P\u3c.001) for cattle fed the HE diets (16.0 vs 20.5 1b per day), resulting in a 23% improvement (P\u3c.001) in feed efficiency (feed:gain 3.68 vs 4.76). Although HE diets also contained more protein than CONV diets, equal gains suggest protein was not limiting. The inclusion of low starch, high energy feeds such as WDG in receiving and step-up diets may improve efficiency but not rate of gain

Limiting Intake of Finishing Diets by Restricting Access Time to Feed and the Interaction with Monensin

One hundred seventy-six yearling steers were randomly allotted to 16 pens and fed ad libitum or restricted amounts of finishing diets with or without monensin. lntake of the restricted cattle was limited by allowing only 6 to 7 hours access time to feed per day. All cattle were fed once daily. Monensin and restricting access time reduced feed intake by 5.6% and 7.9% (P\u3c.01), respectively. lntake tended to be lowest for restricted cattle fed monensin (P=.13). lntake of restricted cattle as a percent of ad libitum intake varied greatly during the study. This may have contributed to the 7% reduction in daily gain of the restricted-monensin fed cattle and the fact that only nonsignificant trends toward improved feed efficiency due to intake restriction were found (P=.13). Factors affecting rate of feed intake must be considered if limited access time is to be used successfully to improve feed efficiency

Effect of Straw and Newspaper Bedding on Cold Season Feedlot Performance in Two Housing Systems

Two hundred seventy-three crossbred steer calves were fed until slaughter (November through May, 189 days) in either semi-confinement (partial overhead shelter, 88 sq. ft. per steer, concrete pen surface) or conventional open lots (windbreak, 448 sq. ft. per steer, dirt surface with mound). Within each housing system, cattle were provided with no bedding or bedding in the form of oat straw or shredded newspaper. Bedding was provided in amounts necessary to maintain a relatively dry, manure-free area large enough for all cattle to lay down at the same time. There were no interactions between housing systems or bedding treatments (P\u3e.10). Feed intake did not dilfer (P\u3e.10) between treatments at any time during the study. On the other hand, overall (day 1 through 189) daily gain was 8.6% greater for steers fed in semi-confinement pens compared to open lots (P\u3c.001). Bedding also improved overall gain by 8.3% (P\u3c.001) compared to no bedding, with newspaper generally being as effective as straw. Similar benefits of housing and bedding were evident in feed efficiency as well. Housing and bedding improved overall feed efficiency 8.2% and 6.8%, respectively (P\u3c.001). Less newspaper than straw was used in this study (232 vs 266 Ib per 100 head per day) and break-even values were $141.88 and$1 14.21 per ton, respectively. Both housing and bedding improved feedlot performance, with bedding being as effective in open lots containing mounds as on concrete. Newspaper can be an effective replacement for more conventional bedding materials

Effect of Synovex, Synovex + FinaPlix, and Revalor on Daily Gain and Carcass Characteristics of Yearling Steers

The objective of this study was to determine if there were differences in daily gain and carcass traits of yearling steers implanted with Synovex-S (S), Synovex-S + Finaplix-S (S + F), or Revalor-S (R). Upon arrival at the feedlot, 264 steers (average weight 731 Ib) were allotted to 24 pens and adapted to a 90% concentrate diet over a period of 23 days. They were implanted on day 20 with either S, S+F, or R. No differences were found between S + F and R (P\u3e.10) at any time during the study. However, combination implants (S+F and R) both resulted in 10% greater weight gains (P\u3c .01) between days 57 and 84 of the study (37 and 64 days postimplanting) than S implanted steers. Some of this advantage was lost after day 11 3 (93 days postimplanting), as combination implant cattle gained almost 8% less per day than those implanted with S (P\u3c .01). During the portion of the study when all implants could be expected to be fully functional (days 9 through 93 postimplanting), combination implant treatments increased daily gain by 3.7% (P\u3c.05) over S. Steers were slaughtered at an average of 11 5 days postimplanting. No differences in carcass characteristics were found (P \u3e .20)