Concentrate Supplementation Effects on Forage Characteristics and Performance of Early Weaned Calves Grazing Rye–Ryegrass Pastures
- J. M. B. Vendraminia,
- L. E. Sollenberger *b,
- J. C. B. Dubeuxc,
- S. M. Interranteb,
- R. L. Stewartd and
- J. D. Arthingtone
- a Soil and Crop Science Dep., Texas A&M Univ., Agricultural Research and Extension Center, Overton, TX 75684
b Agronomy Dep., Univ. of Florida, Gainesville, FL 32611-0300
c Dep. De Zootecnia/UFRPE, Av. Dom Manoel de Medeiros, S/N, Dois Irmaos, 52171-900, Recife-PE, Brazil
d Dep. of Animal and Poultry Sciences, Virginia Polytechnic and State Univ., Blacksburg, VA 24061-0306
e Dep. of Animal Sciences, Univ. of Florida Range Cattle Research and Education Center, Ona, FL 33865
Early weaning of calves (Bos spp.) increases pregnancy rates of beef cows; however, there is little information on nutritional management of the weaned calf on pasture. This research evaluated the effect of concentrate supplementation level on performance of early weaned (90 d of age) beef calves grazing annual ryegrass (Lolium multiflorum Lam.)–rye (Secale cereale L.) mixtures on Adamsville (uncoated, hyperthermic, Aquic Quartzipsamment) and Pomona (sandy, siliceous, hyperthermic Ultic Alaquod) sands. Three levels of supplement (10, 15, and 20 g kg−1 of calf body weight [BW]) were evaluated in a completely randomized design with three replicates. The concentrate contained 146 and 700 g kg−1 of crude protein (CP) and total digestible nutrients (TDN). Pastures were rotationally stocked with a 7-d grazing and 21-d rest period. Two calves were assigned as testers to each pasture, and additional animals were used to maintain a similar herbage allowance across treatments. There was no effect of concentrate supplementation level on herbage mass, accumulation, allowance, or nutritive value. Calf average daily gain (ADG; 0.74–0.89 kg), liveweight gain (LWG) per hectare (950–1320 kg), and stocking rate (SR; 5.5–6.5 animal units [AU] ha−1) increased linearly, and forage intake decreased linearly (18–11 g kg−1 BW) as concentrate rate increased. Grazing time was 284, 230, and 234 min d−1 (linear and quadratic effects) for the 10, 15, and 20 g kg−1 BW supplement treatments, respectively. Feeding systems with modest levels of supplementation (10 g kg−1 BW) of calves grazing cool-season grasses are practical options for early weaned calves during winter in the southeastern USA.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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