Abstract #636

# 636
Effects of dairy slurry application and bale moisture concentration on voluntary intake and digestibility of alfalfa silage by sheep.
Jessica K. Clark*1,2, Bruce C. Shanks1, James D. Caldwell6, Ken P. Coffey2, Wayne K. Coblentz3, R. E. Muck4, Dirk Phillip2, M. A. Borchardt3, Robert T. Rhein2, Ashley N. Young2, Marshal D. Basham2, W. E. Jokela3, Elizabeth A. Backes2, Keith A. Center2, M. G. Bertram5, 1Lincoln University, Jefferson City, MO, 2University of Arkansas, Fayetteville, AR, 3USDA-ARS, Marshfield, WI, 4USDA-ARS, Madison, WI, 5University of Wisconsin, Arlington, WI, 6Land O’ Lakes,.

Dairy slurry is used commonly as a fertilizer in agriculture. However, residual effects of slurry application on intake and digestibility of alfalfa silage from subsequent harvests are not well known. The objective of this study was to determine if moisture concentration of alfalfa silage and timing of dairy slurry application relative to subsequent harvest affect intake and digestibility by sheep. Pregnant crossbred ewes (n = 18; 3–5 yr old; 47.6 ± 5.34 kg) were stratified by BW and allocated randomly each period to 1 of 6 treatments arranged in a 2 × 3 factorial consisting of high (HM; 46.8%) or low (LM; 39.7%) moisture at baling after no slurry application (NS), slurry applied to stubble immediately after removal of the previous cutting (S0), or slurry applied 14 d after the previous cutting (S14). Period 1 consisted of a 14-d adaptation and a 7-d fecal collection. Period 2 immediately followed period 1 and consisted of an 11-d adaptation with a 7-d fecal collection. Ewes were housed individually in 1.4 × 4.3-m pens equipped with rubber mats and feces were swept from the floor twice daily, weighed, and dried at 50°C. Ewes had ad libitum access to water, were offered chopped silage based on 10% refusal, and were offered commercial sheep mineral (14 g) daily. Intake (g/d) of DM and OM and NDF digestibility (%) did not differ (P ≥ 0.13) across moisture or slurry application treatments. However, DM and OM digestibility (%) tended (P < 0.10) to be greater from LM vs. HM. Total white blood cell concentrations, hematocrits, and red blood cell concentrations were greater (P < 0.05) from S0 and S14 vs. NS. Lymphocytes were greater (P < 0.05) from LM vs. HM and from NS vs. S0 and S14. Serum urea N concentrations did not differ (P > 0.13) across treatments. Therefore, moisture level of alfalfa silage and time of dairy slurry application may not affect voluntary intake or NDF digestibility, but moisture concentration may have a slight effect on DM and OM digestibility. Also, moisture concentration of alfalfa silage and time of dairy slurry application may affect specific blood hemograms.

Key Words: digestibility, silage, dairy slurry