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Submitted to: Crop Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/5/2010 Publication Date: 5/27/2011 Citation: Burns, J.C. 2011. Maturity and Regrowth Influences on Quality of Caucasian Bluestem Hay. Crop Science. 51:1840-1849. Interpretive Summary: Initial growth, as well as regrowth of Caucasian bluestem (CBS) was cut at early boot, anthesis and at post anthesis and evaluated as a potential hay source by both lambs and steers. When cut at the early-boot stage CBS was readily consumed by both sheep and steers. Regardless of whether initial growth or regrowth of CBS was cut for hay, increasing maturity beyond the early-boot stage resulted in reduced hay quality. In general, sheep and steers responded relatively similarly to changes in the composition of CBS hays with increasing maturity. This occurred whether animals were fed initial or regrowth hay and was consistent with changes in composition between initial and regrowth hays. These data indicate that hays, whether as initial growth or regrowth, cut at the boot stage would be expected to result in steer gains of up to 0.7 kg d-1 and sheep gains of about 200 g d-1. When both sheep and steers were fed the same four hays their dry matter intake (DMI) were positively correlated (r = 0.95) as was their dry matter digestion (DMD) (r = 0.94) and digestible DMI (r = 0.87). Caucasian bluestem, cut as either initial growth or regrowth forage, can be readily preserved as hay with acceptable quality. The cut forage cured rapidly and is an alternative to the grazing of stands. The preserved hay provided a good source of nutrients if cut prior to, or by the boot stage. Hays cut at the early-boot stage resulted in sheep daily DMI of 1.88 kg 100-1 BW with DMD of 647 g kg-1. Steer daily DMI of 2.73 kg 100-1 kg body weight and DMD of 670 g kg-1. Delaying harvest beyond the boot stage until post anthesis, in this study, resulted in both reduced DMI and DMD. Caucasian bluestem preserved as hay provided a good source of nutrients if cut prior to or by the boot stage and can contribute to ruminant production systems. Technical Abstract: Caucasian bluestem [Bothriochloa caucasia (Trin.) C.E. Hubbard ‘Caucasian’], appears adapted to the mid-Atlantic region. Three experiments (Exp.), one with sheep and two with steers were conducted to assess hay quality. In Exp. 1, initial growth was cut at early boot, anthesis, and post-anthesis and regrowth cut at early boot and anthesis (five treatments) and evaluated by wether lambs. Four of the five original treatments were also evaluated in a preliminary Exp. with steers. In Exp. 2, regrowth was cut at the same grow stages and evaluated by steers. Lambs readily ate Caucasian bluestem (CBS) hay consuming 1.88 kg 100-1kg body weight (BW) when cut at early boot with apparent dry matter digestion (DMD) of 647 g kg-1. Intake decreased linearly by post anthesis to 1.45 kg 100-1 kg BW with DMD of 548 g kg-1. Steers also readily ate early-boot CBS hay averaging 2.49 kg 100-1 kg BW with DMD of 661 g kg-1 . Intake decreased linearly by post anthesis to 1.48 kg 100-1 kg BW with a DMD of 589 g kg-1. Sheep and steer intake was well correlated (r = 0.951; P = 0.05) as was DMD (r = 0.939; P = 0.06). In Exp. 2, steers readily consumed regrowth hay averaging 2.73 kg 100-1 kg BW for the early-boot cut with a DMD of 670 g kg-1. Intake declined linearly by post anthesis to 1.57 kg 100-1 kg BW with DMD of 517 g kg-1. Initial and regrowth CBS can provide hay of desirable quality if cut by the early-boot stage and can contribute to animal production systems in the mid-Atlantic region. |
