|Coffey, Kenneth - University Of Arkansas|
|Chow, Edgard - Kuraray America, Inc|
Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: 4/22/2016
Publication Date: 7/19/2016
Citation: Coblentz, W.K., Coffey, K.P., Chow, E.A. 2016. Effects of wrapping time delays on the nutritive value of baled alfalfa silages. Journal of Dairy Science. ADSA/ASAS Joint Meeting, July 19-23, 2016. Salt Lake City, UT.
Technical Abstract: Baled silages are an attractive forage conservation option, especially for small and mid-sized beef and dairy producers. Our objectives were to test the effects of delayed wrapping on the nutritive value of baled alfalfa silages on a pre- and post-storage basis. A secondary objective was to evaluate a prototype bale wrap containing an O2-limiting barrier against an identical polyethylene wrap without the O2 barrier. Sixty-four 1.19 × 1.25-m large-round bales were wrapped in plastic film within 4 h of baling (d 0), or after delays of 1, 2, or 3 d. All bales were wrapped with 7 polyethylene layers. The internal bale temperature for all bales declined to < 30oC by 23 d post-baling, regardless of wrapping time delay. Internal bale temperatures ranged from 34.9 to 63.9oC, 38.1 to 66.7oC, and 29.7 to 39.6oC when determined at the time of wrapping, as the maximum temperature during storage, and as mean for the initial 23 d of storage, respectively. In each case, these responses were explained by linear (P < 0.01) effects of time delay; a quadratic (P = 0.01) effect of time also was observed for the 23-d mean temperature. After completing a 97-d storage period, NDF concentrations could be related linearly to internal bale temperature at wrapping (Y = 0.14 x + 40.5%; r2 = 0.67). Concentrations of neutral-detergent insoluble CP (Y = - 0.0009 x2 + 0.16 x - 1.3% of DM; R2 = 0.84) and acid-detergent insoluble CP (Y = - 0.0003 x2 - 0.014 x + 2.1% of DM; R2 = 0.70) both increased quadratically with internal bale temperature at wrapping. Energy density calculated as TDN with the summative approach declined in a quadratic relationship with internal bale temperature at wrapping (Y = - 0.0039 x2 + 0.31 x + 51.2% of DM; R2 = 0.61), which represented a loss of approximately 3 TDN units when wrapping was delayed by 3 d. Generally, responses were less clear when samples of unfermented forage were obtained immediately before bales were wrapped in polyethylene. The type of bale wrap had no effect (P = 0.32) on any aspect of forage nutritive value, likely because of the conservative (7-layer) wrapping protocol. The nutritive value of fermented round-bale silages deteriorated with time delays before wrapping, but responses were exacerbated with delays longer than 1 d.