Relative Feeding Value of Rhizoma Perennial Peanut Hay as a Supplement to Bahiagrass Hay for Wintering Cows and Heifers

Rhizoma perennial peanut (Arachis glabrata Benth.) hay was evaluated as a replacement for purchased concentrate supplement given to cows and heifers being wintered on residual bahiagrass (Paspalumnotatum Fiugge) pasture and bahiagrass hay in central Florida. Data were collected over 2 yr from 237 Hereford and 177 Senepol cows and first-calf heifers. Treatments were .9 kg · head- 1 · d- 1 of a commercially available 20% CP supplement (CUBE) or 2.3 kg · head- 1 · d- 1 of perennial peanut hay (PNUT). Supplements were fed for 16 wk from January through April each year. Response variables evaluated were cow and heifer body weight (BW) change, body condition score (CS) change, pregnancy rate, plasma urea nitrogen concentration (PUN), calf birth weight (CBW), and adjusted 205-d calf weaning weight (AWW). Both years, AWW was higher (P < .01) for calves with Senepol dams than for calves with Hereford dams (year 1: 209 vs. 184 kg; year 2: 226 vs. 172 kg), but AWW was not affected by treatment. Treatment did not affect pregnancy rate in either year; however, more (P < .05) Hereford (74%) compared to Senepol cows and heifers (62%) were palpated pregnant in year 2. Also in year 2, CBW was heavier (P < .01) for Senepol dams compared with Hereford dams (35.1 vs. 30.3 kg), and BW and CS changes were greater (P < .01) in Senepol cows and heifers compared with Hereford (-90 vs. -67 kg; -2.6 vs. -1.9). There were a few differences in PUN between treatments and breeds, but the greatest changes in PUN were observed over time through the wintering period. No other treatment or breed effects were observed either year. These data indicate that 2.3 kg of the perennial peanut hay used in this study had a replacement value about equal to .9 kg of a 20% CP concentrate cube supplement.