Increasing levels of grain supplementation for intensive-early stocked steers: three-year summary

During the initial 3 years of a 4-year experiment, average daily gain tended to increase in direct proportion to increasing levels of grain sorghum supplementation (2.3, 2.5 and 2.7 lb gain per day for the control and 2 and 4 lb supplement per day, respectively). The amount of grass remaining in the pastures at the end of the growing season (October 1) was greater in each of the 3 years when cattle were supplemented at 4 lb/day. During the 2 years (1989 and 1990) that feedlot performance was monitored, level of supplementation for grazing steers did not influence subsequent feedlot gain or efficiency

Effect of fats and ionophores on in vitro fermentation of a high concentrate diet

Batch culture fermentations were used to determine the effects of fat type [none, animal tallow (AT), soybean oil soapstock (SOY), or yellow grease (YG)] and ionophore type [none, lasalocid (L), monensin + tylosin in a ratio of 2.5:1 (MT), or a 50:50 combination of Land MT (LMT)] on in vitro concentrations of lactate (LA) and volatile fatty acids (VFA). Fat-containing substrates had 4% fat on a dry basis. No significant interactions between fat and ionophore treatments were observed. Ionophore treatment resulted in a reduced pH, with the greatest reduction in the L treatment. lbtal VFA and LA increased with ionophore treatment and were highest with L treatment. All ionophore treatments decreased molar proportions of acetate and butyrate and increased propionate. Lasalocid produced a lower molar proportion of acetate and a higher molar proportion of propionate than did MT. Adding fat resulted in a reduction in total VFA and an increase in pH. The reduction in total VFA was less for SOY than AT or YG treatments. No significant differences in LA or VFA molar proportions were observed among fat treatments. Our results indicate that the rate of starch digestion may be slowed by fat, which may translate into a decreased incidence of ruminal acidosis

Influence of fat and ionophores on performance of finishing steers

One hundred ninety-two crossbred steers were used in a 2 x 4 factorially arranged experiment to study the effects of including fat and ionophores in finishing rations. Main effects were level of supplemental fat (0 or 4% tallow) and ionophore type [none, Bovatece (B), Rumensine + 'JYlane (RT), or daily rotation of Band RT (BRT)]. Daily feed intake (P<.10) and daily gain (P<.OO5) were reduced for steers fed R'T, but only when fat was included in the diet. In diets containing no supplemental fat, RT increased daily gain 10%. RT improved feed efficiency 8% (P<.05) in nonfat diets, but there was no difference between ionophores in diets containing fat. Adding fat improved feed efficiency of steers fed no ionophore or B. This study suggests that response of finishing steers to ionophores can be modified by the inclusion of fat in the diet

Increasing levels of grain supplementation for intensive-early stocked steers: two-year summary

During the first 2 yr of a 4-yr experiment, increasing the level of grain sorghum supplementation (from 2 to 4 Ibid) for steers managed within an intensive-early stocking program tended to increase average daily gain in direct proportion to supplement level (2.3 (no supplement) to 2.5 and 2.7 lb/d, respectively). During both years, the amount of grass remaining in the pastures after the cattle were removed (July 15) and at the end of the growing season (October 1) was greater when cattle were supplemented with 4 lb of grain sorghum. Level of supplementation for grazing steers did not influence subsequent feedlot performance