Table 7.
Effects of pre-grazing sward height and energy supplementation level on total tract digestibility of DM, CP, and NDF of the forage and total DM (forage + supplement) of Nellore steers grazing Marandu Palisadegrass (B. brizantha [Hochst. Ex A. Rich.] Stapf. cv. Marandu) during the rainy season
| Pre-grazing sward height, cm | Supplememntation1, %BW | P-value | ||||||
|---|---|---|---|---|---|---|---|---|
| Item2 | 25 | 35 | 0 | 0.3 | SEM | Sward height | Supplementation | Interaction |
| Forage digestibility, % | ||||||||
| DM | 68.1 | 65.4 | 67.3 | 66.2 | 0.78 | <0.001 | 0.16 | 0.65 |
| CP | 74.6 | 63.8 | 70.1 | 68.3 | 0.94 | <0.001 | 0.18 | 0.85 |
| NDF | 63.4 | 62.5 | 62.4 | 63.5 | 1.19 | 0.51 | 0.39 | 0.55 |
| Diet digestibility, % | ||||||||
| DM | 70.1 | 68.4 | 67.3 | 71.2 | 0.97 | 0.05 | <0.001 | 0.12 |
| CP | 75.8 | 66.5 | 70.1 | 72.2 | 1.36 | <0.001 | 0.13 | 0.17 |
| NDF | 63.1 | 62.1 | 62.4 | 62.8 | 1.16 | 0.44 | 0.77 | 0.63 |
1Supplementation levels were 0% or 0.3% BW of ground corn on an as-fed basis.
2The experiment lasted 64 d and consisted of four experimental periods of 16 d each. On day 1 and for 13 consecutive days of each period, 10 g of chromium oxide, previously weighed in two paper capsules (5 g each), was manually dosed into the rumen to all steers, one dose in the morning (1000 hours) and a second dose in the evening (1700 hours). Fecal grab samples (approximately 200 g per steer) were manually obtained from the rectum of each steer between days 9 and 13, twice a day (1000 and 1700 hours). The digestibility of feeds (pasture and supplement) was estimated using the iNDF content as an internal marker as described by Casali et al. (2008).