Effects of lactic acid / Lactobacillus product and bale moisture of Bermudagrass hay on storage, voluntary intake by lambs, and in situ digestibility by cannulated cows

Bermudagrass [Cynodon dactylon (L.) Pers.] is commonly used for grazing and haying in Northwest Arkansas. However, production of high-quality hay can be challenging in this area due to adverse weather conditions during spring and summer. A field of common bermudagrass was divided into 12 plots using a randomized complete block design with a 2 x 2 factorial treatment arrangement. Half of the plots were sprayed with a lactic acid- Lactobacillus fermentation product (T) at the time of mowing and half were not treated (U). Within T and U treatments, half of the plots were baled at either 18% moisture (L) or 25% moisture (H). The first objective of this research was to determine the influence of bale moisture and use of a lactic acid-Lactobacillus fermentation spray product applied at the time of mowing on hay nutritive value. Six square bales from each plot were randomly selected for analysis. The six bales from each of the plots were stored in a covered barn, with insulation surrounding each of the 12 stacks to keep treatments separated; 3 bales were sampled prior to storage. The storage period was 42 d with bale temperatures recorded twice daily. After the storage period, 3 bales from each stack not previously sampled were selected for lab analysis. Analyses included dry matter (DM), ash, nitrogen (N), acid detergent insoluble nitrogen (ADIN), neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL). Results indicated that NDF, ADF, and ADL differed between moisture treatment, after storage ( P < 0.05), but no differences were detected for ash, N, or ADIN (P > 0.05). The second objective was to study the influence of the same hay on intake and digestibility by lambs. Sixteen wether lambs were allocated randomly to these treatment combinations and fed hay ad libitum. Daily DM intake was not different across spray or moisture treatments at baling. However, DM digestibility (g kg-1) and digestible DM intake (g d-1) were greater (P < 0.05) for untreated versus spray treated hay. Baling bermudagrass hay at 25% moisture did not appear to negatively affect intake and digestibility by lambs. The third objective of this study was to evaluate the effects of hay from Objective 1 on in situ ruminal disappearance in cows. Samples of the resulting hay were ground, placed in dacron bags, and placed in the rumen of 6 ruminally cannulated heifers. Bags were removed at varied times over a 5-d period to determine ruminal digestion kinetics. The water soluble fraction was greater (P < 0.05) and the potentially digestible fraction was lower (P < 0.05) for hay baled at low moisture compared with high moisture. The digestion rate, lag time, undegradable fraction, and effective ruminal digestion did not differ (P > 0.05) between moisture concentrations at baling. None of the ruminal digestion measurements was affected by spray treatment. Therefore, baling bermudagrass hay at 25% moisture versus 18% moisture may result in loss of water-soluble components, but may not affect overall effective ruminal digestion. Treating bermudagrass with the lactic acid- Lactobacillus preservative at the time of mowing had minimal impacts on ruminal DM digestibility.