Three experiments evaluated whether effects of altered frequency of supplementation on forage use and cow performance depended on supplement CP concentration and (or) grain type when fed to cattle eating low-quality forages. All experiments included supplementation frequency (daily = 7x; three times weekly = 3x) as one factor in a factorialized arrangement of treatments. In Exp. 1 and 2, the second factor was supplement CP concentration (10, 20, 30, and 40% CP), altered by changing the ratio of soybean meal to sorghum grain in supplements. Supplements were fed at 13.9 and 14.1 kg of DM/wk for Exp. 1 and 2, respectively. In Exp. 3, the second factor was supplement grain type (sorghum grain or corn) and supplements containing 21% CP were fed at 14.8 kg of DM/wk. In Exp. 1, eight ruminally fistulated steers (456 kg) consumed wheat straw ad libitum. Pregnant beef cows grazing dormant tallgrass prairie were used in Exp. 2 (475 kg; n = 128) and 3 (504 kg; n = 120). In Exp. 1, reducing supplementation frequency decreased (P < .01) straw intake but increased (P < or = .03) DM and NDF digestion. As CP concentration in supplements increased, straw DMI (P = .06) increased quadratically, whereas DM and NDF digestion increased linearly (P < .01). In Exp. 2, increasing CP concentration in supplements enhanced cows' ability to maintain BW and condition up to calving, with decreasing magnitude of difference between treatments at higher CP concentrations (P < .01). Increasing CP in supplements fed to the dams linearly (P = .05) increased calf weaning weight in Exp. 2. In Exp. 2 and 3, reducing supplementation frequency increased (P < or = .02) winter weight loss through calving. Grain type did not significantly affect most performance variables. In summary, response to supplementation frequency was not dependent on supplement CP concentration or grain type. Daily supplementation maximized forage intake and cow performance, although the magnitude of performance differences was not large.

Four ruminally and duodenally fistulated, 2-yr-old Angus x Hereford steers (average initial BW = 370 kg) were used to evaluate the effect of method of processing supplemental alfalfa on intake and digestion of dormant bluestem-range forage (2.8% CP, 78% NDF). Treatments (4 x 4 Latin square) were 1) control, no supplement; 2) ground and pelleted alfalfa hay (PELLET; 21% CP, 37% NDF); 3) ground and pelleted dehydrated alfalfa (DEHY; 21% CP, 44% NDF); and 4) longstem alfalfa hay (HAY; 20% CP, 37% NDF). All supplements were from a single cutting of alfalfa and fed at .5% BW (as-fed basis). Supplementing steers with alfalfa increased (P < or = .07) bluestem forage OM intake (FOMI); total OM intake (TOMI); true ruminal OM digestibility; total tract OM digestibility (TTOMD); total N, microbial N, and nonammonia-nonmicrobial N (NANM) flows to the duodenum; ruminal OM and fluid fill; fluid dilution rates; dietary DE concentration; and ruminal total VFA and NH3 N concentrations. Because of the enhanced FOMI and TOMI associated with alfalfa supplementation and the concomitant improvement in TTOMD, digestible OM intake (DOMI) also increased (P < .01) when supplemental alfalfa was fed. Method of processing alfalfa had little impact on forage utilization, except FOMI (P = .11), TOMI (P = .10), and ruminal OM fill (P = .09) tended to be greater when supplemental alfalfa pellets were dehydrated. Similarly, processing method tended to alter the molar proportions of some minor VFA. In conclusion, alfalfa supplementation exerted a dramatic impact on utilization of low-quality forage.(ABSTRACT TRUNCATED AT 250 WORDS)

A digestion trial was conducted to determine the effect of method of processing supplemental alfalfa on the intake and utilization of dormant, bluestem-range forage. Supplement treatments were 1) control: no supplement; 2) ground and pelleted, suncured alfalfa; 3) ground and pelleted dehydrated alfalfa; and 4) longstem alfalfa hay. Bluestem forage intake (% BW), diet digestibility, and ruminal dry matter fill 4 hours after feeding were increased (P<.10) when supplemental alfalfa was fed, compared with no supplementation. Little difference was evident among different forms of supplemental alfalfa for most of the forage utilization characteristics measured. However, a weak trend (P=.18) was observed for increased intake of bluestem forage by the steers supplemented with dehydrated alfalfa pellets compared with suncured alfalfa pellets. SummaryA digestion trial was conducted to determine the effect of method of processing supplemental alfalfa on the intake and utilization of dormant, bluestem-range forage. Supplement treatments were 1) control: no supplement; 2) ground and pelleted, suncured alfalfa; 3) ground and pelleted dehydrated alfalfa; and 4) longstem alfalfa hay. Bluestem forage intake (% BW), diet digestibility, and ruminal dry matter fill 4 hours after feeding were increased (P<.10) when supplemental alfalfa was fed, compared with no supplementation. Little difference was evident among different forms of supplemental alfalfa for most of the forage utilization characteristics measured. However, a weak trend (P=.18) was observed for increased intake of bluestem forage by the steers supplemented with dehydrated alfalfa pellets compared with suncured alfalfa pellets.

Fifteen ruminally cannulated beef steers were used in a pasture supplementation experiment to determine the effects of frequency of energy supplementation on intake and digestion of tallgrass prairie forage during early to mid-summer. Steers grazed a common pasture and were assigned to the following treatments: no supplement (control); 4 lb rolled sorghum grain/head/day; 9.3 lb grain/head/3 times weekly. Steers in the two supplemented groups consumed the same amount of sorghum grain/head/week. In general, supplementation was not harmful (P =.17) to forage intake. However, providing supplement 3 times weekly tended (P =.11) to depress forage intake compared with daily supplementation. Although supplementation tended (P =.07) to cause selection of less fiber in the diet, total forage digestion tended (P<.07) to be depressed by supplementation. However, total diet organic matter digestibility was not significantly altered by treatment, probably because of the impact of the highly digestible supplement. Based on trends in intake and grazed forage selection, achieving optimal benefit from supplementation of cattle grazing relatively highquality forage appears more likely when its provided daily rather than 3 times weekly. SummaryFifteen ruminally cannulated beef steers were used in a pasture supplementation experiment to determine the effects of frequency of energy supplementation on intake and digestion of tallgrass prairie forage during early to mid-summer. Steers grazed a common pasture and were assigned to the following treatments: no supplement (control); 4 lb rolled sorghum grain/head/day; 9.3 lb grain/head/3 times weekly. Steers in the two supplemented groups consumed the same amount of sorghum grain/head/week. In general, supplementation was not harmful (P =.17) to forage intake. However, providing supplement 3 times weekly tended (P =.11) to depress forage intake compared with daily supplementation. Although supplementation tended (P =.07) to cause selection of less fiber in the diet, total forage digestion tended (P<.07) to be depressed by supplementation. However, total diet organic matter digestibility was not significantly altered by treatment, probably because of the impact of the highly digestible supplement. Based on trends in intake and grazed forage selection, achieving optimal benefit from supplementation of cattle grazing relatively high-quality forage appears more likely when its provided daily rather than 3 times weekly.

One hundred twenty, pregnant, Angus x Hereford cows (1111 lb) grazing dormant bluestem range were used to evaluate whether the effect of altered frequency of supplementation on cow performance depended on the grain type in the supplement. Two supplementation frequencies (daily and three times weekly) and two grain types in the supplements (sorghum grain or corn) were evaluated. Both supplements contained 21% CP and were fed to provide 32.6 lb DM/week. Interactions were not significant. Winter weight loss through calving was greater (P#.02) for the cows supplemented three times weekly, although the magnitude of the effect was not large. Use of different grain types in the supplements did not significantly affect most performance variables. SummaryOne hundred twenty, pregnant, Angus × Hereford cows (1111 lb) grazing dormant bluestem range were used to evaluate whether the effect of altered frequency of supplementation on cow performance depended on the grain type in the supplement. Two supplementation frequencies (daily and three times weekly) and two grain types in the supplements (sorghum grain or corn) were evaluated. Both supplements contained 21% CP and were fed to provide 32.6 lb DM/week. Interactions were not significant. Winter weight loss through calving was greater (P#.02) for the cows supplemented three times weekly, although the magnitude of the effect was not large. Use of different grain types in the supplements did not significantly affect most performance variables.