TY - JOUR
AU1 - Clark, J K
AU2 - Coffey, K P
AU3 - Coblentz, W K
AU4 - Shanks, B C
AU5 - Caldwell, J D
AU6 - Muck, R E
AU7 - Philipp, D
AU8 - Borchardt, M A
AU9 - Rhein, R T
AU1 - Jokela, W E
AU1 - Backes, E A
AU1 - Bertram, M G
AU1 - Smith, W B
AB - Abstract Dairy slurry is used commonly as an animal-sourced fertilizer in agronomic production. However, residual effects of slurry application on intake and digestibility of alfalfa (Medicago sativa L.) 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 affected intake and digestibility by sheep. Katahdin crossbred ewes (n = 18; 48 ± 5.3 kg) in mid-gestation were stratified by BW and allocated randomly in each of two periods to one of six treatments arranged in a two × three factorial arrangement. Treatments consisted of recommended (RM; 46.8%) or low (LM; 39.7%) moisture at baling after either no slurry application (NS), slurry application to stubble immediately after removal of the previous cutting (S0), or slurry application 14 d after removal of the previous cutting (S14). Silages were chopped through a commercial straw chopper, packed into plastic trash cans, and then offered to ewes within 4 d of chopping. Period 1 of the intake and digestion study consisted of a 14-d adaptation followed by a 7-d fecal collection period. Period 2 followed period 1 after a 4-d rest and consisted of an 11-d adaptation followed by 7 d of fecal collection. Ewes were housed individually in 1.4 × 4.3-m pens equipped with rubber mat flooring. Feces were swept from the floor twice daily, weighed, and dried at 50 °C. Ewes had ad libitum access to water and were offered chopped silage for a minimum of 10% refusal (DM). Blood samples were collected immediately prior to feeding, and 4 and 8 h after feeding on the day prior to the end of each period. Organic matter intake (g/kg BW) and OM digestibility tended (P < 0.10) to be, and digestible OM intake (g/kg BW) was reduced by slurry application. Lymphocytes (% of total white blood cells) were greater (P < 0.05) from LM vs. RM and from NS vs. S0 and S14. Red blood cell concentrations were greater (P < 0.05) from S14 vs. S0 and from S0 and S14 vs. NS. Serum urea N concentrations did not differ (P > 0.17) across treatments. Therefore, moisture concentration of alfalfa silage within the range used in this study may not affect voluntary intake or digestibility, but slurry application may have an effect on digestible OM intake. Also, moisture concentration of alfalfa silage and time of dairy slurry application may affect specific blood hemograms. INTRODUCTION Moisture concentration at which alfalfa (Medicago sativa L.) is stored for silage can affect fermentation efficiency and subsequent acceptability by animals. More desirable fermentation, as demonstrated by greater lactic acid concentrations and lower pH, was reported from alfalfa silage baled at greater moisture concentrations (Hawkins et al., 1970; Etheridge et al., 1993; Shinners et al., 2009). Animal responses were less conclusive however, as DMI increased as alfalfa silage moisture concentration decreased in one study (Hawkins et al., 1970), but not in others (Etheridge et al., 1993; Han et al., 2004). The range of moisture concentrations for ensiling alfalfa in large bales that maximizes intake of digestible OM is inconclusive presently. Proper manure management and application also are important as animal operations continue to move to greater reliance on confinement production systems (Crotty et al., 2014). Intakes of hay and silage may be reduced following foliar application of animal manures prior to harvest (Heikkilä et al., 2004). However, dairy slurry application increased intake and digestibility of subsequent forage crops in other scenarios (Heikkilä et al., 2004; Miron et al., 2011). Application of cattle slurry prior to a subsequent silage harvest increased concentrations of clostridia spores in the silage (Heikkilä et al., 2004; Coblentz et al., 2014). Therefore, both slurry application and silage moisture concentration may impact changes in silage composition that affect voluntary intake and digestibility as well as animal health. The objective of this study was to determine the effects of moisture concentration of alfalfa silage and timing of dairy slurry application relative to subsequent harvest on intake and digestibility by sheep. Our hypothesis is that timing of application of dairy slurry in proximity to a subsequent harvest will interact with ensiling moisture concentration to differentially affect intake and digestibility by sheep. MATERIALS AND METHODS Silage Production Alfalfa silage used in this study was produced at the University of Wisconsin Marshfield Agricultural Research Station near Stratford, Wisconsin, as described by Coblentz et al. (2014). Briefly, replicated plots in a randomized complete-block design received either no dairy slurry or dairy slurry was applied to stubble immediately after removal of a first cutting on June 4, 2012 or was applied on June 18, 2012 corresponding to 2 wk after removal of a first cutting. Slurry was applied by broadcast at 42,400 ± 5,271 L/ha. Dairy slurry was 5% DM, 3.9% N, 1.7% NH4-N, 0.78% P, 4.5% K, 0.30% S, 30.3% ash, and had a C:N ratio of 10.3. Alfalfa was harvested again from those plots on July 10, 2012 and wrapped in 0.9 × 1.8-m rectangular bales at two moisture concentrations (46.8 and 39.7%; Coblentz et al., 2014). Subsequently, silage bales were wrapped in additional plastic as a precaution to maintain plastic integrity during shipping and then transported by flatbed truck to the University of Arkansas North Farm, where they were stored outside on a concrete pad until offered to sheep. Prior to the start of the feeding study, the field replications were assigned randomly to individual periods in the feeding study. Immediately prior to the start of each period, bales from each treatment within a particular field replication that was chosen at random for the particular feeding period were opened on one end. Forage was removed and chopped through a commercial bedding chopper (model 3915; US Bedding Chopper, US Farm Systems, Inc., Janesville, WI) and packed into plastic trash containers, which were covered with plastic lids to reduce air circulation. Forage was chopped approximately every 4 d, and the experiment was conducted during March and April when ambient temperatures were cooler (average of 9 and 14 °C in March and April, respectively) in order to maintain silage freshness. Immediately following chopping, open bale ends were covered with the existing plastic wrap and weighted with concrete blocks to reduce exposure to oxygen and to environmental conditions. Animals and Design All management and procedures were approved by the Institutional Animal Care and Use Committee at the University of Arkansas (Protocol # 13007). This study took place at the University of Arkansas North Farm in Washington County, Fayetteville, AR. Pregnant Katahdin ewes (n = 18; 3 to 5 yr old; 48 ± 5.3 kg) were stratified by BW and allocated randomly each period to one of six treatments arranged in a 2 × 3 factorial structure consisting of recommended (RM; 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 (36 d prior to subsequent harvest; S0), or slurry applied 14-d after removal of the previous cutting (22 d prior to subsequent harvest; S14). Period 1 began March 5, 2014 and consisted of a 14-d adaptation followed by 7 d of total fecal collection. After a 4-d rest and co-mingling period, period 2 followed and consisted of an 11-d adaptation followed by 7 d of total fecal collection. As mentioned previously, silages offered in each period were comprised only of bales from specific field blocks that were allocated randomly to be offered during a specific period prior to the start of the study. Field block was thereby confounded purposefully with period so that the field replication structure could be maintained. Ewes were maintained on alfalfa silage during the 4-d rest and co-mingling period from a mix of bales that were opened during period 1. Ewes were housed individually in 1.4 × 4.3-m pens with sloped floors and equipped with solid rubber mat flooring, and solid partitions between each pen to prevent transfer of feces between pens. Solid partitions also prevented animals from accessing forage from adjacent pens. Pens were located in an enclosed metal barn. Large doors at either end of the barn were kept open during the day for airflow, but the barn was not climate controlled. Pens were swept clean twice daily. Artificial lighting was provided between 0700 and 1900 h daily. Ewes had ad libitum access to water and were offered a commercially available mineral for sheep that did not contain antibiotics (14 g ewe−1 d−1). (Preferred Mineral for Sheep and Goats [Ragland Mills Inc., Neosho, MO]. The mineral contained 350 to 400 g/kg salt, 90 to 100 g/kg Ca, and not less than 80 g/kg P, 10 g/kg Mg, 10 g/kg K, 125 ppm Co, 150 ppm I, 5,000 ppm Fe, 10 ppm Se, 140 ppm Zn, 352,000 IU/kg of Vitamin A, 88,000 IU/kg of Vitamin D3, and 330 IU/kg of Vitamin E.) Chopped silage was offered daily based on a minimum of 10% refusal (DM basis). At 0700 h daily, orts were removed from feeders and loose mineral was offered. Fresh silage was offered initially at 0900 h and replenished from a pre-weighed container as necessary throughout the day. Water containers were emptied after initial feeding and refilled daily. Chemical Analyses and Analytical Procedures Fresh silage samples were taken daily starting 2 d prior to the collection period and ending 2 d prior to the end of each period. One sample from each treatment was dried to a constant weight in paper bags at 50 °C. Another treatment sample was frozen in plastic sealable bags. Starting 1 d prior to collections and ending 1 d prior to the end of each period, orts were collected, placed in paper bags and dried at 50 °C. Total feces were removed from each pen twice daily during each collection period, placed in paper bags, and dried to a constant weight at 50 °C. Urine contamination with feces was minimal because the sloped floor allowed urine to move off of the floor and out of the pens. Two blood samples were collected via jugular venipuncture 1 d prior to the end of each period and immediately before feeding at 0900 h. Samples for complete blood counts were collected in vacuum-sealed collection tubes containing 10.8 mg of K2 EDTA (BD Vacutainer Plus K2 EDTA; Becton, Dickinson, and Co., Franklin Lakes, NJ) and samples for serum urea N (SUN) determination were collected in vacuum-sealed collection tubes with a gel plug (Becton, Dickinson, and Co.). Blood was collected again at 4 and 8 h after initial feeding to determine SUN. Blood samples for subsequent SUN determination were immediately placed on ice, then centrifuged (Beckman Coulter T J6 refrigerated centrifuge, Fullerton, CA) at 1,425 × g for 20 min. Serum was collected and stored at −20 °C until further analysis. Dried forage samples were composited by treatment across days within period, whereas ort and fecal samples were composited by animal across days within period. All samples were ground to pass through a 1-mm screen using a Wiley mill (Arthur H. Thomas, Philadelphia, PA). Organic matter was determined via combustion in a muffle furnace at 500 °C (Method 942.05; AOAC, 2000). Neutral detergent fiber was determined using an ANKOM200 Fiber Analyzer (ANKOM Technology Corporation, Fairport, NY; Vogel et al., 1999). Heat-stable α-amylase was included in the NDF solution and residual ash was not removed. Nitrogen was measured using the Dumas total combustion method on dried feed samples only (Elementar Americas, Mt. Laural, NJ; Method 990.03; AOAC, 2000). Frozen silage samples were sent to a commercial laboratory (Cumberland Valley Analytical Services, Maugansville, MD) to be analyzed for ammonia–crude protein equivalent (NH3–CPE), pH, total fermentation acids, lactic acid, acetic acid, and titratable acidity. All analyses were corrected for DM (Method 934.01; AOAC, 2000). Complete blood counts were enumerated using a Cell-Dyn 3700 SL (Abbott GmbH & Co., Wiesbaden, Germany). Serum urea N was measured using a clinical diagnostic kit (Teco Diagnostics, Anaheim, CA) adapted for use in microtiter plates. The inter- and intra-assay CVs were 3.5 and 3.0%, respectively. Statistical Analyses All data were analyzed using PROC MIXED of SAS (SAS Inst., Inc., Cary, NC). Forage chemical composition and silage fermentation measurements were analyzed using the field plot within block as the experimental unit (n = 2 per interactive treatment) from the original randomized complete-block design used for the field plot study. The experimental unit for the animal measurements was the individual ewe. Period was considered a random effect since field blocks were allocated randomly to, and purposely confounded with feeding periods, and animals were allocated randomly to treatments in both periods with the stipulation that no animal received the same diet in both periods. The model for intake, digestibility, and complete blood count data included fixed effects of silage moisture concentration, dairy slurry application treatment, and their interaction. Orthogonal contrasts were used to assess slurry application treatments across moisture concentrations when the moisture concentration × dairy slurry application interaction was not detected (P > 0.10). These contrasts compared 1) NS with the mean of S0 and S14 and 2) S0 with S14. Serum urea N data were analyzed as repeated measures with fixed effects of silage moisture concentration, dairy slurry application treatment, sampling time, and their two- and three-way interactions. Time was a repeated measurement with ewe within moisture by slurry application treatment as the subject. The heterogeneous autoregressive covariance structure was used. Treatment means are reported as least squares means. Considerable variability was encountered with the acetic acid data, and outliers were removed from the acetic acid data using the box-and-whisker plot function in Microsoft Excel. RESULTS No moisture × slurry interactions (P ≥ 0.22) were detected for chemical components or silage fermentation measurements. Therefore, these measures were reported as main effects of moisture concentration and dairy slurry application treatment (Table 1). There was a tendency (P = 0.08) for NDF content to be greater from LM than RM, but no other measurements differed because of moisture treatments (P ≥ 0.14) or dairy slurry application treatments (P ≥ 0.27). Table 1. Chemical and ensiling properties of alfalfa silage baled at different moisture concentrations and fertilized with dairy slurry at different times and offered to gestating ewes to measure voluntary intake and digestibility1,2 Item  Moisture concentration3  SEM6  P-value  Dairy slurry application4  SEM6  Contrast P-values5  LM  RM  NS  S0  S14  S  D  Moisture, %  33.0  39.4  4.81  0.39  29.4  36.8  42.4  5.89  0.21  0.53  OM, %  90.9  91.1  0.46  0.77  91.7  90.8  90.5  0.56  0.17  0.71  CP, %  18.5  19.0  0.76  0.39  18.7  19.0  18.5  0.47  0.99  0.55  NDF, %  44.1  41.1  0.96  0.08  42.9  42.5  42.5  1.18  0.76  0.97  NH3–CPE, %7  1.7  2.1  0.56  0.60  1.2  1.9  2.6  0.69  0.31  0.57  pH  5.4  6.0  0.41  0.14  5.5  5.7  5.8  0.44  0.44  0.72  Total silage acids, %  2.1  0.7  1.01  0.23  0.7  1.6  2.0  1.14  0.38  0.77  Lactic acid, %  1.0  0.3  0.79  0.37  0.0  0.8  1.1  0.87  0.29  0.82  Lactic acid, % total silage acids  34.1  30.8  11.48  0.74  26.2  37.6  33.7  12.39  0.39  0.73  Acetic acid, %  0.9  0.5  0.38  0.38  0.5  0.7  0.8  0.33  0.43  0.77  Titratable acidity  1.6  1.1  0.53  0.23  1.2  1.3  1.5  0.57  0.69  0.78  Item  Moisture concentration3  SEM6  P-value  Dairy slurry application4  SEM6  Contrast P-values5  LM  RM  NS  S0  S14  S  D  Moisture, %  33.0  39.4  4.81  0.39  29.4  36.8  42.4  5.89  0.21  0.53  OM, %  90.9  91.1  0.46  0.77  91.7  90.8  90.5  0.56  0.17  0.71  CP, %  18.5  19.0  0.76  0.39  18.7  19.0  18.5  0.47  0.99  0.55  NDF, %  44.1  41.1  0.96  0.08  42.9  42.5  42.5  1.18  0.76  0.97  NH3–CPE, %7  1.7  2.1  0.56  0.60  1.2  1.9  2.6  0.69  0.31  0.57  pH  5.4  6.0  0.41  0.14  5.5  5.7  5.8  0.44  0.44  0.72  Total silage acids, %  2.1  0.7  1.01  0.23  0.7  1.6  2.0  1.14  0.38  0.77  Lactic acid, %  1.0  0.3  0.79  0.37  0.0  0.8  1.1  0.87  0.29  0.82  Lactic acid, % total silage acids  34.1  30.8  11.48  0.74  26.2  37.6  33.7  12.39  0.39  0.73  Acetic acid, %  0.9  0.5  0.38  0.38  0.5  0.7  0.8  0.33  0.43  0.77  Titratable acidity  1.6  1.1  0.53  0.23  1.2  1.3  1.5  0.57  0.69  0.78  1Concentrations of propionic, butyric, and isobutyric acids were below 0.1% and were not affected by moisture concentration, dairy slurry application treatment, or their interaction (P ≥ 0.24). 2There were no moisture × slurry interactions (P ≥ 0.22) for any of the variables measured. 3LM = low moisture at baling (39.7%); RM = recommended moisture at baling (46.8%). 4NS = no slurry application; S0 = slurry application immediately after previous cutting; S14 = slurry application 14 d after previous cutting. 5Probability of the orthogonal contrasts S and D where S = no slurry application vs. the mean of S0 and S14 and D = S0 vs. S14. 6SEM = pooled standard error of the mean. 7NH3–CPE = ammonia–crude protein equivalent (percent of N in ammonia compared to percent of total N). View Large Table 1. Chemical and ensiling properties of alfalfa silage baled at different moisture concentrations and fertilized with dairy slurry at different times and offered to gestating ewes to measure voluntary intake and digestibility1,2 Item  Moisture concentration3  SEM6  P-value  Dairy slurry application4  SEM6  Contrast P-values5  LM  RM  NS  S0  S14  S  D  Moisture, %  33.0  39.4  4.81  0.39  29.4  36.8  42.4  5.89  0.21  0.53  OM, %  90.9  91.1  0.46  0.77  91.7  90.8  90.5  0.56  0.17  0.71  CP, %  18.5  19.0  0.76  0.39  18.7  19.0  18.5  0.47  0.99  0.55  NDF, %  44.1  41.1  0.96  0.08  42.9  42.5  42.5  1.18  0.76  0.97  NH3–CPE, %7  1.7  2.1  0.56  0.60  1.2  1.9  2.6  0.69  0.31  0.57  pH  5.4  6.0  0.41  0.14  5.5  5.7  5.8  0.44  0.44  0.72  Total silage acids, %  2.1  0.7  1.01  0.23  0.7  1.6  2.0  1.14  0.38  0.77  Lactic acid, %  1.0  0.3  0.79  0.37  0.0  0.8  1.1  0.87  0.29  0.82  Lactic acid, % total silage acids  34.1  30.8  11.48  0.74  26.2  37.6  33.7  12.39  0.39  0.73  Acetic acid, %  0.9  0.5  0.38  0.38  0.5  0.7  0.8  0.33  0.43  0.77  Titratable acidity  1.6  1.1  0.53  0.23  1.2  1.3  1.5  0.57  0.69  0.78  Item  Moisture concentration3  SEM6  P-value  Dairy slurry application4  SEM6  Contrast P-values5  LM  RM  NS  S0  S14  S  D  Moisture, %  33.0  39.4  4.81  0.39  29.4  36.8  42.4  5.89  0.21  0.53  OM, %  90.9  91.1  0.46  0.77  91.7  90.8  90.5  0.56  0.17  0.71  CP, %  18.5  19.0  0.76  0.39  18.7  19.0  18.5  0.47  0.99  0.55  NDF, %  44.1  41.1  0.96  0.08  42.9  42.5  42.5  1.18  0.76  0.97  NH3–CPE, %7  1.7  2.1  0.56  0.60  1.2  1.9  2.6  0.69  0.31  0.57  pH  5.4  6.0  0.41  0.14  5.5  5.7  5.8  0.44  0.44  0.72  Total silage acids, %  2.1  0.7  1.01  0.23  0.7  1.6  2.0  1.14  0.38  0.77  Lactic acid, %  1.0  0.3  0.79  0.37  0.0  0.8  1.1  0.87  0.29  0.82  Lactic acid, % total silage acids  34.1  30.8  11.48  0.74  26.2  37.6  33.7  12.39  0.39  0.73  Acetic acid, %  0.9  0.5  0.38  0.38  0.5  0.7  0.8  0.33  0.43  0.77  Titratable acidity  1.6  1.1  0.53  0.23  1.2  1.3  1.5  0.57  0.69  0.78  1Concentrations of propionic, butyric, and isobutyric acids were below 0.1% and were not affected by moisture concentration, dairy slurry application treatment, or their interaction (P ≥ 0.24). 2There were no moisture × slurry interactions (P ≥ 0.22) for any of the variables measured. 3LM = low moisture at baling (39.7%); RM = recommended moisture at baling (46.8%). 4NS = no slurry application; S0 = slurry application immediately after previous cutting; S14 = slurry application 14 d after previous cutting. 5Probability of the orthogonal contrasts S and D where S = no slurry application vs. the mean of S0 and S14 and D = S0 vs. S14. 6SEM = pooled standard error of the mean. 7NH3–CPE = ammonia–crude protein equivalent (percent of N in ammonia compared to percent of total N). View Large Intake and digestibility of NDF was affected by tendencies (P = 0.08 and 0.06, respectively) for moisture concentration at baling × dairy slurry application treatment interactions. Digestible NDF intake was affected by the moisture concentration at baling × dairy slurry application treatment interaction (P = 0.04). In all instances pertaining to NDF intake or digestibility, the greatest values were from LM silages without slurry applied (Fig. 1). However, no other intake, digestion or blood measurements were affected (P ≥ 0.31) by moisture × slurry interactions. Therefore, these data are presented as main effects of moisture concentration and dairy slurry application treatments. Figure 1. View largeDownload slide Neutral detergent fiber intake (g/kg BW; A), digestibility (%; B), and digestible NDF intake (g/kg BW; C) by ewes offered alfalfa silage baled at low (LM) or recommended (RM) moisture following no dairy slurry application (NS) or dairy slurry applied immediately after baling the first cutting (S0) or 14 d after baling the first cutting (S14). A tendency for the moisture concentration × slurry application treatment interaction was detected for both NDF intake (P = 0.08) and NDF digestibility (P = 0.06), whereas the moisture concentration × slurry application treatment interaction affected (P = 0.04) digestible NDF intake (g/kg BW). a,bMeans without a common superscript letter differ (P ≤ 0.08). Standard error of the mean = 0.98 and 2.63 for intake and digestibility, respectively. x,yMeans without a common superscript letter differ (P = 0.04). Standard error of the mean = 0.80 for digestible NDF intake. Figure 1. View largeDownload slide Neutral detergent fiber intake (g/kg BW; A), digestibility (%; B), and digestible NDF intake (g/kg BW; C) by ewes offered alfalfa silage baled at low (LM) or recommended (RM) moisture following no dairy slurry application (NS) or dairy slurry applied immediately after baling the first cutting (S0) or 14 d after baling the first cutting (S14). A tendency for the moisture concentration × slurry application treatment interaction was detected for both NDF intake (P = 0.08) and NDF digestibility (P = 0.06), whereas the moisture concentration × slurry application treatment interaction affected (P = 0.04) digestible NDF intake (g/kg BW). a,bMeans without a common superscript letter differ (P ≤ 0.08). Standard error of the mean = 0.98 and 2.63 for intake and digestibility, respectively. x,yMeans without a common superscript letter differ (P = 0.04). Standard error of the mean = 0.80 for digestible NDF intake. Silage Moisture Effects Moisture concentration at baling had no effect on any of the intake or digestibility measurements evaluated in this study (P ≥ 0.29; Table 2). Likewise, moisture concentration did not affect (P ≥ 0.41) intake of digestible DM or OM (g/d or g/kg BW). As mentioned above, NDF intake and digestibility tended (P = 0.08 and 0.06, respectively) to and intake of digestible NDF was affected (P < 0.05) by the moisture × slurry interaction. In all instances, ewes offered LM–NS tended to or had the greatest intake or digestibility of NDF, without further differences (P ≥ 0.46) among the remaining treatments (Fig. 1). Table 2. Intake and digestibility by gestating ewes offered alfalfa silage baled at different moisture concentrations and averaged across different dairy slurry application treatments1 Item3  Moisture2  SEM4  P-value  LM  RM  DMI, g/d  1,675  1,639  58.2  0.57  OMI, g/d  1,522  1,491  53.1  0.60  DMI, g/kg BW  34.1  33.8  1.02  0.81  OMI, g/kg BW  30.9  30.6  1.19  0.83  DMD, %  65.2  64.4  0.75  0.32  OMD, %  64.4  63.4  0.78  0.29  DDMI, g/d  1086  1051  35.4  0.41  DOMI, g/d  977  946  33.8  0.45  DDMI, g/kg BW  22.1  21.7  0.84  0.66  DOMI, g/kg BW  19.8  19.5  0.78  0.72  Item3  Moisture2  SEM4  P-value  LM  RM  DMI, g/d  1,675  1,639  58.2  0.57  OMI, g/d  1,522  1,491  53.1  0.60  DMI, g/kg BW  34.1  33.8  1.02  0.81  OMI, g/kg BW  30.9  30.6  1.19  0.83  DMD, %  65.2  64.4  0.75  0.32  OMD, %  64.4  63.4  0.78  0.29  DDMI, g/d  1086  1051  35.4  0.41  DOMI, g/d  977  946  33.8  0.45  DDMI, g/kg BW  22.1  21.7  0.84  0.66  DOMI, g/kg BW  19.8  19.5  0.78  0.72  1There were no moisture × slurry interactions (P ≥ 0.11). 2LM = low moisture at baling (39.7%); RM = recommended moisture at baling (46.8%). 3DMI = dry matter intake; OMI = organic matter intake; DMD = dry matter digestibility; OMD = organic matter digestibility; NDFD = neutral detergent fiber digestibility; DDMI = digestible dry matter intake; DOMI = digestible organic matter intake. 4SEM = pooled standard error of the mean. View Large Table 2. Intake and digestibility by gestating ewes offered alfalfa silage baled at different moisture concentrations and averaged across different dairy slurry application treatments1 Item3  Moisture2  SEM4  P-value  LM  RM  DMI, g/d  1,675  1,639  58.2  0.57  OMI, g/d  1,522  1,491  53.1  0.60  DMI, g/kg BW  34.1  33.8  1.02  0.81  OMI, g/kg BW  30.9  30.6  1.19  0.83  DMD, %  65.2  64.4  0.75  0.32  OMD, %  64.4  63.4  0.78  0.29  DDMI, g/d  1086  1051  35.4  0.41  DOMI, g/d  977  946  33.8  0.45  DDMI, g/kg BW  22.1  21.7  0.84  0.66  DOMI, g/kg BW  19.8  19.5  0.78  0.72  Item3  Moisture2  SEM4  P-value  LM  RM  DMI, g/d  1,675  1,639  58.2  0.57  OMI, g/d  1,522  1,491  53.1  0.60  DMI, g/kg BW  34.1  33.8  1.02  0.81  OMI, g/kg BW  30.9  30.6  1.19  0.83  DMD, %  65.2  64.4  0.75  0.32  OMD, %  64.4  63.4  0.78  0.29  DDMI, g/d  1086  1051  35.4  0.41  DOMI, g/d  977  946  33.8  0.45  DDMI, g/kg BW  22.1  21.7  0.84  0.66  DOMI, g/kg BW  19.8  19.5  0.78  0.72  1There were no moisture × slurry interactions (P ≥ 0.11). 2LM = low moisture at baling (39.7%); RM = recommended moisture at baling (46.8%). 3DMI = dry matter intake; OMI = organic matter intake; DMD = dry matter digestibility; OMD = organic matter digestibility; NDFD = neutral detergent fiber digestibility; DDMI = digestible dry matter intake; DOMI = digestible organic matter intake. 4SEM = pooled standard error of the mean. View Large Total white blood cell (WBC) counts and percentage of neutrophils, eosinophils, and basophils were not affected (P ≥ 0.19) by moisture concentration at baling (Table 3). Likewise, blood concentrations (K/µL) of neutrophils, lymphocytes, eosinophils, and basophils were not affected (P ≥ 0.16) by silage moisture concentration. When expressed as a percentage of total WBC, lymphocyte concentrations were greater (P = 0.01) from ewes offered LM compared with those offered RM, and monocyte concentrations tended (P = 0.07) to be greater from ewes offered RM compared with LM. Blood monocyte concentrations (K/µL) were greater (P = 0.03) from RM compared with LM. Other hemogram concentrations did not differ (P ≥ 0.26) across silage moisture concentrations at baling. Table 3. Complete blood count and serum urea N concentrations in gestating ewes offered alfalfa silages baled at different moisture concentrations and averaged across different dairy slurry application treatments1   Moisture2      Item3  LM  RM  SEM4  P-value  WBC, K/µL  6.2  6.8  0.29  0.19  NEU, %  34.2  38.0  2.31  0.32  NEU:LYM  1.0  1.4  0.24  0.25  LYM, %  39.7  32.2  1.54  0.01  MONO, %  12.6  16.4  1.20  0.07  EOS, %  11.2  10.4  1.51  0.74  BASO, %  2.3  3.1  0.44  0.28  NEU, K/µL  2.1  2.8  0.32  0.24  LYM, K/µL  2.5  2.1  0.18  0.24  MONO, K/µL  0.8  1.1  0.07  0.03  EOS, K/µL  0.7  0.7  0.11  0.90  BASO, K/µL  0.1  0.2  0.03  0.16  RBC, M/µL  10.8  10.7  0.13  0.71  HGB, g/dL  11.7  11.3  0.23  0.31  HCT, %  35.8  35.4  0.40  0.58  MCV, fL  33.2  33.1  0.12  0.88  MCH, pg  10.8  10.5  0.14  0.26  MCHC, g/dL  32.6  31.9  0.45  0.35  PLT, K/µL  455  536  150.6  0.74  SUN5, mg/dL  25.7  24.1  1.56  0.17    Moisture2      Item3  LM  RM  SEM4  P-value  WBC, K/µL  6.2  6.8  0.29  0.19  NEU, %  34.2  38.0  2.31  0.32  NEU:LYM  1.0  1.4  0.24  0.25  LYM, %  39.7  32.2  1.54  0.01  MONO, %  12.6  16.4  1.20  0.07  EOS, %  11.2  10.4  1.51  0.74  BASO, %  2.3  3.1  0.44  0.28  NEU, K/µL  2.1  2.8  0.32  0.24  LYM, K/µL  2.5  2.1  0.18  0.24  MONO, K/µL  0.8  1.1  0.07  0.03  EOS, K/µL  0.7  0.7  0.11  0.90  BASO, K/µL  0.1  0.2  0.03  0.16  RBC, M/µL  10.8  10.7  0.13  0.71  HGB, g/dL  11.7  11.3  0.23  0.31  HCT, %  35.8  35.4  0.40  0.58  MCV, fL  33.2  33.1  0.12  0.88  MCH, pg  10.8  10.5  0.14  0.26  MCHC, g/dL  32.6  31.9  0.45  0.35  PLT, K/µL  455  536  150.6  0.74  SUN5, mg/dL  25.7  24.1  1.56  0.17  1There were no moisture × slurry interactions (P ≥ 0.13). 2LM = low moisture at baling (39.7%); RM = recommended moisture at baling (46.8%). 3WBC = white blood cells; NEU = neutrophils; NEU:LYM = neutrophil to lymphocyte ratio; LYM = lymphocytes; MONO = monocytes; EOS = eosinophils; BASO = basophils; RBC = red blood cells; HGB = hemoglobin; HCT = hematocrit; MCV = mean corpuscular volume; MCH = mean corpuscular hemoglobin; MCHC = mean corpuscular hemoglobin concentration; PLT = platelets; SUN = serum urea N. 4SEM = pooled standard error of the mean. 5SUNs are averaged across collection times as there were no two- and three-way interactions of treatments with time (P ≥ 0.17). View Large Table 3. Complete blood count and serum urea N concentrations in gestating ewes offered alfalfa silages baled at different moisture concentrations and averaged across different dairy slurry application treatments1   Moisture2      Item3  LM  RM  SEM4  P-value  WBC, K/µL  6.2  6.8  0.29  0.19  NEU, %  34.2  38.0  2.31  0.32  NEU:LYM  1.0  1.4  0.24  0.25  LYM, %  39.7  32.2  1.54  0.01  MONO, %  12.6  16.4  1.20  0.07  EOS, %  11.2  10.4  1.51  0.74  BASO, %  2.3  3.1  0.44  0.28  NEU, K/µL  2.1  2.8  0.32  0.24  LYM, K/µL  2.5  2.1  0.18  0.24  MONO, K/µL  0.8  1.1  0.07  0.03  EOS, K/µL  0.7  0.7  0.11  0.90  BASO, K/µL  0.1  0.2  0.03  0.16  RBC, M/µL  10.8  10.7  0.13  0.71  HGB, g/dL  11.7  11.3  0.23  0.31  HCT, %  35.8  35.4  0.40  0.58  MCV, fL  33.2  33.1  0.12  0.88  MCH, pg  10.8  10.5  0.14  0.26  MCHC, g/dL  32.6  31.9  0.45  0.35  PLT, K/µL  455  536  150.6  0.74  SUN5, mg/dL  25.7  24.1  1.56  0.17    Moisture2      Item3  LM  RM  SEM4  P-value  WBC, K/µL  6.2  6.8  0.29  0.19  NEU, %  34.2  38.0  2.31  0.32  NEU:LYM  1.0  1.4  0.24  0.25  LYM, %  39.7  32.2  1.54  0.01  MONO, %  12.6  16.4  1.20  0.07  EOS, %  11.2  10.4  1.51  0.74  BASO, %  2.3  3.1  0.44  0.28  NEU, K/µL  2.1  2.8  0.32  0.24  LYM, K/µL  2.5  2.1  0.18  0.24  MONO, K/µL  0.8  1.1  0.07  0.03  EOS, K/µL  0.7  0.7  0.11  0.90  BASO, K/µL  0.1  0.2  0.03  0.16  RBC, M/µL  10.8  10.7  0.13  0.71  HGB, g/dL  11.7  11.3  0.23  0.31  HCT, %  35.8  35.4  0.40  0.58  MCV, fL  33.2  33.1  0.12  0.88  MCH, pg  10.8  10.5  0.14  0.26  MCHC, g/dL  32.6  31.9  0.45  0.35  PLT, K/µL  455  536  150.6  0.74  SUN5, mg/dL  25.7  24.1  1.56  0.17  1There were no moisture × slurry interactions (P ≥ 0.13). 2LM = low moisture at baling (39.7%); RM = recommended moisture at baling (46.8%). 3WBC = white blood cells; NEU = neutrophils; NEU:LYM = neutrophil to lymphocyte ratio; LYM = lymphocytes; MONO = monocytes; EOS = eosinophils; BASO = basophils; RBC = red blood cells; HGB = hemoglobin; HCT = hematocrit; MCV = mean corpuscular volume; MCH = mean corpuscular hemoglobin; MCHC = mean corpuscular hemoglobin concentration; PLT = platelets; SUN = serum urea N. 4SEM = pooled standard error of the mean. 5SUNs are averaged across collection times as there were no two- and three-way interactions of treatments with time (P ≥ 0.17). View Large Serum urea N was affected (P < 0.05) by time, but not two-way (time × moisture: P = 0.37; time × slurry: P = 0.17) or three-way (P = 0.25) interactions of time with main effects (Table 3). Concentrations of SUN were greatest (P < 0.05) at 4 h after feeding followed by those at 8 h after feeding and were least (P < 0.05) immediately prior to feeding. Dairy Slurry Effects Dairy slurry treatments had no effect (P ≥ 0.26) on DMI or OM intake (OMI; g/d) or DMI (g/kg BW), but OMI (g/kg BW) tended (P = 0.09) to be greater from NS than from the mean of S0 and S14 (Table 4). Likewise, DMD was not affected (P = 0.36) by dairy slurry treatments, but OMD tended (P = 0.06) to be greater from NS compared with the mean of S0 and S14. Digestible DMI (g/kg BW) tended (P = 0.09) to be greater and digestible OMI (g/d and g/kg BW) was greater (P ≤ 0.05) by ewes offered NS silages compared with the mean of those fertilized with dairy slurry (S0 and S14). WBC were greater (P = 0.048) from ewes offered the silages treated with slurry (S0 and S14) compared with those offered NS (Table 5). Blood neutrophil concentrations (K/µL) tended (P = 0.08) to be greater from the slurry treatments compared to NS, but there were no differences (P = 0.46) across dairy slurry treatments for neutrophils when expressed as a percentage of total WBC. Concentrations of lymphocytes (% of total WBC) were greater (P = 0.014) from ewes offered NS compared with the mean of S0 and S14, but actual blood concentrations (K/µL) were not different (P = 0.38) among treatments. The neutrophil to lymphocyte ratio tended (P = 0.06) to be greater from the ewes offered S0 and S14 compared with NS. Monocyte concentrations expressed as a percentage of total WBC were not different (P = 0.44) among slurry application treatments, and actual blood concentrations were not different (P = 0.33) between NS and the mean of S0 and S14. However, monocyte concentrations (K/µL) in the blood were greater (P = 0.03) from ewes offered S0 vs. those offered S14. Concentrations of eosinophils and basophils (K/µL or % of total WBC) were not affected by slurry application (P ≥ 0.29). Red blood cell concentrations were greater from ewes offered S0 and S14 vs. those offered NS (P = 0.02) and from those offered S14 vs. S0 (P = 0.02). Hemoglobin concentrations tended to be greater (P = 0.09) and hematocrit concentration was greater (P = 0.03) from ewes offered S14 vs. S0. Mean corpuscular volume was greater (P < 0.01) from ewes offered NS vs. those offered the silages that were fertilized with dairy slurry. Dairy slurry application had no effect (P ≥ 0.19) on mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, platelets, or SUN. As mentioned previously, only sampling time affected (P < 0.05) SUN concentrations, but main effects or interactions of main effects and sampling time did not (P ≥ 0.17). Table 4. Intake and digestibility by gestating ewes offered alfalfa silage with different slurry application treatments and averaged across different moisture concentrations at baling   Dairy slurry application1    Contrast P-values2  Item3  NS  S0  S14  SEM4  S  D  DMI, g/d  1,722  1,656  1,594  65.6  0.19  0.49  OMI, g/d  1,579  1,500  1,440  62.6  0.12  0.46  DMI, g/kg BW  35.6  33.6  32.5  1.55  0.14  0.59  OMI, g/kg BW  32.6  30.4  29.3  1.42  0.09  0.56  DMD, %  65.7  64.3  64.4  0.90  0.16  0.97  OMD, %  65.2  63.4  63.0  0.93  0.06  0.77  DDMI, g/d  1123  1066  1,017  42.8  0.11  0.40  DOMI, g/d  1024  954  906  40.9  0.06  0.40  DDMI, g/kg BW  23.3  21.6  20.8  1.01  0.09  0.54  DOMI, g/kg BW  21.2  19.3  18.5  0.94  0.05  0.55    Dairy slurry application1    Contrast P-values2  Item3  NS  S0  S14  SEM4  S  D  DMI, g/d  1,722  1,656  1,594  65.6  0.19  0.49  OMI, g/d  1,579  1,500  1,440  62.6  0.12  0.46  DMI, g/kg BW  35.6  33.6  32.5  1.55  0.14  0.59  OMI, g/kg BW  32.6  30.4  29.3  1.42  0.09  0.56  DMD, %  65.7  64.3  64.4  0.90  0.16  0.97  OMD, %  65.2  63.4  63.0  0.93  0.06  0.77  DDMI, g/d  1123  1066  1,017  42.8  0.11  0.40  DOMI, g/d  1024  954  906  40.9  0.06  0.40  DDMI, g/kg BW  23.3  21.6  20.8  1.01  0.09  0.54  DOMI, g/kg BW  21.2  19.3  18.5  0.94  0.05  0.55  1NS = no slurry application; S0 = slurry application immediately after baling the first cutting; S14 = slurry application 14 d after baling the first cutting. 2Probability of the contrasts S and D where S = no slurry application vs. the mean of S0 and S14 and D = S0 vs. S14. 3DMI = dry matter intake; OMI = organic matter intake; DMD = dry matter digestibility; OMD = organic matter digestibility; DDMI = digestible dry matter intake; DOMI = digestible organic matter intake. 4SEM = pooled standard error of the mean. 5There were no moisture × slurry interactions (P ≥ 0.35) for variables other than NDFD. View Large Table 4. Intake and digestibility by gestating ewes offered alfalfa silage with different slurry application treatments and averaged across different moisture concentrations at baling   Dairy slurry application1    Contrast P-values2  Item3  NS  S0  S14  SEM4  S  D  DMI, g/d  1,722  1,656  1,594  65.6  0.19  0.49  OMI, g/d  1,579  1,500  1,440  62.6  0.12  0.46  DMI, g/kg BW  35.6  33.6  32.5  1.55  0.14  0.59  OMI, g/kg BW  32.6  30.4  29.3  1.42  0.09  0.56  DMD, %  65.7  64.3  64.4  0.90  0.16  0.97  OMD, %  65.2  63.4  63.0  0.93  0.06  0.77  DDMI, g/d  1123  1066  1,017  42.8  0.11  0.40  DOMI, g/d  1024  954  906  40.9  0.06  0.40  DDMI, g/kg BW  23.3  21.6  20.8  1.01  0.09  0.54  DOMI, g/kg BW  21.2  19.3  18.5  0.94  0.05  0.55    Dairy slurry application1    Contrast P-values2  Item3  NS  S0  S14  SEM4  S  D  DMI, g/d  1,722  1,656  1,594  65.6  0.19  0.49  OMI, g/d  1,579  1,500  1,440  62.6  0.12  0.46  DMI, g/kg BW  35.6  33.6  32.5  1.55  0.14  0.59  OMI, g/kg BW  32.6  30.4  29.3  1.42  0.09  0.56  DMD, %  65.7  64.3  64.4  0.90  0.16  0.97  OMD, %  65.2  63.4  63.0  0.93  0.06  0.77  DDMI, g/d  1123  1066  1,017  42.8  0.11  0.40  DOMI, g/d  1024  954  906  40.9  0.06  0.40  DDMI, g/kg BW  23.3  21.6  20.8  1.01  0.09  0.54  DOMI, g/kg BW  21.2  19.3  18.5  0.94  0.05  0.55  1NS = no slurry application; S0 = slurry application immediately after baling the first cutting; S14 = slurry application 14 d after baling the first cutting. 2Probability of the contrasts S and D where S = no slurry application vs. the mean of S0 and S14 and D = S0 vs. S14. 3DMI = dry matter intake; OMI = organic matter intake; DMD = dry matter digestibility; OMD = organic matter digestibility; DDMI = digestible dry matter intake; DOMI = digestible organic matter intake. 4SEM = pooled standard error of the mean. 5There were no moisture × slurry interactions (P ≥ 0.35) for variables other than NDFD. View Large Table 5. Complete blood count and serum urea N concentrations by gestating ewes offered alfalfa silage with different dairy slurry application treatments across different moisture concentrations at baling1   Dairy slurry application2    Contrast P-values3  Item4  NS  S0  S14  SEM5  S  D  WBC, K/µL  5.7  7.3  6.5  0.43  0.05  0.34  NEU, %  32.4  36.8  39.1  3.43  0.23  0.70  LYM, %  41.5  33.5  32.9  2.29  0.01  0.88  NEU:LYM  0.6  1.3  1.7  0.36  0.06  0.53  MONO, %  14.2  16.5  12.7  1.78  0.86  0.23  EOS, %  9.5  10.1  12.9  2.24  0.49  0.47  BASO, %  2.4  3.2  2.4  0.66  0.64  0.54  NEU, K/µL  1.7  2.7  2.9  0.47  0.08  0.79  LYM, K/µL  2.5  2.4  1.9  0.27  0.32  0.26  MONO, K/µL  0.8  1.2  0.7  0.11  0.32  0.03  EOS, K/µL  0.5  0.7  0.8  0.16  0.34  0.60  BASO, K/µL  0.1  0.2  0.1  0.04  0.50  0.20  RBC, M/µL  10.3  10.5  11.4  0.19  0.02  0.02  HGB, g/dL  11.0  11.2  12.3  0.34  0.11  0.09  HCT, %  34.8  34.8  37.2  0.59  0.13  0.03  MCV, fL  33.6  33.0  32.8  0.17  <0.01  0.56  MCH, pg  10.7  10.6  10.8  0.21  0.87  0.60  MCHC, g/dL  31.7  32.2  32.9  0.66  0.32  0.54  PLT, K/µL  239  445  802  223.8  0.20  0.37  SUN, mg/dL5  26.1  23.0  25.7  1.31  0.24  0.13    Dairy slurry application2    Contrast P-values3  Item4  NS  S0  S14  SEM5  S  D  WBC, K/µL  5.7  7.3  6.5  0.43  0.05  0.34  NEU, %  32.4  36.8  39.1  3.43  0.23  0.70  LYM, %  41.5  33.5  32.9  2.29  0.01  0.88  NEU:LYM  0.6  1.3  1.7  0.36  0.06  0.53  MONO, %  14.2  16.5  12.7  1.78  0.86  0.23  EOS, %  9.5  10.1  12.9  2.24  0.49  0.47  BASO, %  2.4  3.2  2.4  0.66  0.64  0.54  NEU, K/µL  1.7  2.7  2.9  0.47  0.08  0.79  LYM, K/µL  2.5  2.4  1.9  0.27  0.32  0.26  MONO, K/µL  0.8  1.2  0.7  0.11  0.32  0.03  EOS, K/µL  0.5  0.7  0.8  0.16  0.34  0.60  BASO, K/µL  0.1  0.2  0.1  0.04  0.50  0.20  RBC, M/µL  10.3  10.5  11.4  0.19  0.02  0.02  HGB, g/dL  11.0  11.2  12.3  0.34  0.11  0.09  HCT, %  34.8  34.8  37.2  0.59  0.13  0.03  MCV, fL  33.6  33.0  32.8  0.17  <0.01  0.56  MCH, pg  10.7  10.6  10.8  0.21  0.87  0.60  MCHC, g/dL  31.7  32.2  32.9  0.66  0.32  0.54  PLT, K/µL  239  445  802  223.8  0.20  0.37  SUN, mg/dL5  26.1  23.0  25.7  1.31  0.24  0.13  1SUNs are averaged across collection times as there were no two- and three-way interactions of treatments with time (P ≥ 0.17); ns = not significant (P > 0.10); there were also no moisture × slurry interactions (P ≥ 0.21). 2NS = no slurry application; S0 = slurry application immediately after baling the first cutting; S14 = slurry application 14 d after baling the first cutting. 3Probability of the contrasts S and D where S = no slurry application vs. the mean of S0 and S14 and D = S0 vs. S14. 4WBC = white blood cells; NEU = neutrophils; NEU:LYM = neutrophil to lymphocyte ratio; LYM = lymphocytes; MONO = monocytes; EOS = eosinophils; BASO = basophils; RBC = red blood cells; HGB = hemoglobin; HCT = hematocrits; MCV = mean corpuscular volume; MCH = mean corpuscular hemoglobin; MCHC = mean corpuscular hemoglobin concentration; PLT = platelets; SUN = serum urea N. 5SEM = pooled standard error of the mean. View Large Table 5. Complete blood count and serum urea N concentrations by gestating ewes offered alfalfa silage with different dairy slurry application treatments across different moisture concentrations at baling1   Dairy slurry application2    Contrast P-values3  Item4  NS  S0  S14  SEM5  S  D  WBC, K/µL  5.7  7.3  6.5  0.43  0.05  0.34  NEU, %  32.4  36.8  39.1  3.43  0.23  0.70  LYM, %  41.5  33.5  32.9  2.29  0.01  0.88  NEU:LYM  0.6  1.3  1.7  0.36  0.06  0.53  MONO, %  14.2  16.5  12.7  1.78  0.86  0.23  EOS, %  9.5  10.1  12.9  2.24  0.49  0.47  BASO, %  2.4  3.2  2.4  0.66  0.64  0.54  NEU, K/µL  1.7  2.7  2.9  0.47  0.08  0.79  LYM, K/µL  2.5  2.4  1.9  0.27  0.32  0.26  MONO, K/µL  0.8  1.2  0.7  0.11  0.32  0.03  EOS, K/µL  0.5  0.7  0.8  0.16  0.34  0.60  BASO, K/µL  0.1  0.2  0.1  0.04  0.50  0.20  RBC, M/µL  10.3  10.5  11.4  0.19  0.02  0.02  HGB, g/dL  11.0  11.2  12.3  0.34  0.11  0.09  HCT, %  34.8  34.8  37.2  0.59  0.13  0.03  MCV, fL  33.6  33.0  32.8  0.17  <0.01  0.56  MCH, pg  10.7  10.6  10.8  0.21  0.87  0.60  MCHC, g/dL  31.7  32.2  32.9  0.66  0.32  0.54  PLT, K/µL  239  445  802  223.8  0.20  0.37  SUN, mg/dL5  26.1  23.0  25.7  1.31  0.24  0.13    Dairy slurry application2    Contrast P-values3  Item4  NS  S0  S14  SEM5  S  D  WBC, K/µL  5.7  7.3  6.5  0.43  0.05  0.34  NEU, %  32.4  36.8  39.1  3.43  0.23  0.70  LYM, %  41.5  33.5  32.9  2.29  0.01  0.88  NEU:LYM  0.6  1.3  1.7  0.36  0.06  0.53  MONO, %  14.2  16.5  12.7  1.78  0.86  0.23  EOS, %  9.5  10.1  12.9  2.24  0.49  0.47  BASO, %  2.4  3.2  2.4  0.66  0.64  0.54  NEU, K/µL  1.7  2.7  2.9  0.47  0.08  0.79  LYM, K/µL  2.5  2.4  1.9  0.27  0.32  0.26  MONO, K/µL  0.8  1.2  0.7  0.11  0.32  0.03  EOS, K/µL  0.5  0.7  0.8  0.16  0.34  0.60  BASO, K/µL  0.1  0.2  0.1  0.04  0.50  0.20  RBC, M/µL  10.3  10.5  11.4  0.19  0.02  0.02  HGB, g/dL  11.0  11.2  12.3  0.34  0.11  0.09  HCT, %  34.8  34.8  37.2  0.59  0.13  0.03  MCV, fL  33.6  33.0  32.8  0.17  <0.01  0.56  MCH, pg  10.7  10.6  10.8  0.21  0.87  0.60  MCHC, g/dL  31.7  32.2  32.9  0.66  0.32  0.54  PLT, K/µL  239  445  802  223.8  0.20  0.37  SUN, mg/dL5  26.1  23.0  25.7  1.31  0.24  0.13  1SUNs are averaged across collection times as there were no two- and three-way interactions of treatments with time (P ≥ 0.17); ns = not significant (P > 0.10); there were also no moisture × slurry interactions (P ≥ 0.21). 2NS = no slurry application; S0 = slurry application immediately after baling the first cutting; S14 = slurry application 14 d after baling the first cutting. 3Probability of the contrasts S and D where S = no slurry application vs. the mean of S0 and S14 and D = S0 vs. S14. 4WBC = white blood cells; NEU = neutrophils; NEU:LYM = neutrophil to lymphocyte ratio; LYM = lymphocytes; MONO = monocytes; EOS = eosinophils; BASO = basophils; RBC = red blood cells; HGB = hemoglobin; HCT = hematocrits; MCV = mean corpuscular volume; MCH = mean corpuscular hemoglobin; MCHC = mean corpuscular hemoglobin concentration; PLT = platelets; SUN = serum urea N. 5SEM = pooled standard error of the mean. View Large DISCUSSION Forage Chemical Composition and Fermentation The lack of a difference in moisture concentration between LM and RM may have been due to a number of factors, but most likely due to exposure and a low number of replications. Since field replication was purposely confounded with period in the animal feeding study and only two periods were conducted, this resulted in only two replications per treatment for silage quality and fermentation parameters. The initial intent was to conduct three periods in the animal feeding study, but warm weather resulted in greater heating and instability of the silage once the bales were opened and period 3 was therefore discontinued. Furthermore, both moisture treatments decreased in moisture at approximately the same magnitude, indicating an effect of exposure on moisture concentration at feeding. Moisture concentration at the time of feeding was 33.0 and 39.4% for LM and RM, respectively, whereas original moisture concentrations of bales used in this study were 39.9 and 44.8% at the time of baling for LM and RM, respectively. As mentioned previously, silage bales were not re-wrapped after being opened for chopping. The ends of the bales were covered with the existing plastic and secured with concrete blocks, which possibly allowed a small amount of air to circulate around the face of the silage bale thereby resulting in moisture loss. Moisture concentration at baling would not be expected to have an effect on OM, NDF, or CP concentrations (Hancock and Collins, 2006; Shinners et al., 2009), particularly considering the narrow range in actual moisture concentrations from the bales used in this study. Effects of bale moisture at ensiling on concentrations of fermentation products for baled silages has been illustrated clearly by Nicholson et al. (1991); in that experiment, alfalfa-grass baled silages were made at 51 and 62% moisture. After fermentation, greater concentrations of acetic acid, lactic acid, and total fermentation acids were observed in the wetter silage, resulting in a more acidic final pH (5.3 vs. 4.8). Other studies, such as Shinners et al. (2009), have demonstrated similar restrictions in fermentation within baled silages when bale moisture is reduced by wilting from normal recommended ranges (45 to 55%; Shinners, 2003) to levels below that target (<45%). However, in studies where the moisture concentrations approached those in the present study, pH values were generally at or greater than 5 and lactic acid concentrations were low (<2% of DM; Hancock and Collins, 2006; Shinners et al., 2009). Application of cattle slurry had little impact on the nutrient composition or fermentation profiles of grass silages (Heikkilä et al., 2004). However, the nutritive value of orchardgrass has varied throughout the growing season in response to chemical fertilization compared to manure application (Hedtcke et al., 2011). Silage Moisture Effects on Animal Responses The DMI results from the current study are consistent with those documented by Han et al. (2004) and Etheridge et al. (1993) who also reported no differences in intake between different moisture concentrations of silage. However, other studies have reported that animals consumed less DM when offered forages greater in moisture concentration (Hawkins et al., 1970; Lahr et al., 1983). Also, similar to our findings, Hawkins et al. (1970) and Han et al. (2004) reported that DMD did not differ on the basis of silage moisture concentrations. However, Pasha et al. (1994) reported greater DMD for hay compared with high-moisture forages. Ultimately, intake of digestible OM is a better measure of overall energy intake. In the present study, moisture concentration at baling did not affect digestible OMI and, therefore, is likely to have minimal impact on energy status of the animal within the moisture concentrations evaluated in this study. The interpretation of WBC differential count values differed in some instances depending on whether the data were expressed as actual blood concentrations (K/µL) or as a percentage of total WBC. Therefore, data are presented using both conventions. Of the blood hemogram measurements evaluated in this study, only lymphocyte and monocyte concentrations were affected by moisture concentrations at baling. When expressed as a percentage of total WBC, lymphocyte concentrations were at the low end of the normal range for sheep from LM and were below the normal range from RM (Jones and Allison, 2007). However, blood concentrations of lymphocytes (K/µL) were at the low end of the normal range for sheep from both treatments and blood concentrations did not differ between moisture treatments. Reduced lymphocyte concentrations, or lymphocytopenia, can result from a number of infectious conditions or even Zn deficiencies and stress (Henry, 1984; Jones and Allison, 2007; Naeim et al., 2013). Considering that the actual blood concentrations were at the lower end of the normal range, it is likely that the effects of treatment contributing to the lower lymphocyte concentrations (% of total WBC) were minimal and not sufficient to cause severe lymphocyte reductions. Furthermore, differences in lymphocyte concentrations between LM and RM did not affect forage intake in the present study and cannot be explained by Clostridial cluster enumeration which was not different between LM and RM when quantified after ensiling, but prior to the bales being shipped to Arkansas (Coblentz et al., 2014). Monocyte concentrations whether expressed as a percentage of total WBC or as K/µL of blood were greater than normal (Jones and Allison, 2007) from both LM and RM and were greater from RM vs. LM. Increases in monocyte concentrations may accompany a number of abnormalities including chronic inflammation, stress (Jones and Allison, 2007), or increased parasitism (Esmaeilnejad et al., 2012). Fecal parasite egg counts were not determined in the present study, but BWs at the end of period 2 were greater (data not shown) than at the beginning of period 1, indicating that potential abnormalities were minimal. Other blood hemogram measurements were not different between LM and RM and were within normal ranges for sheep (Jones and Allison, 2007). Blood urea N concentrations can be used to monitor N utilization and N metabolism (Tshuma et al., 2014). Although SUN concentrations were outside the normal range for sheep, none of the animals exhibited any outward symptoms of related illness. Serum urea N concentrations were least immediately before feeding and greatest 4 h after feeding, which was expected due to the high CP levels of the silages. Dairy Slurry Effects on Animal Responses Slurry application treatments had no impact on DMI in the present study. This is consistent with findings of Hedtcke et al. (2011) who reported no differences in DMI when pregnant Holstein heifers were offered orchardgrass (Dactylis glomerata L.) hay that had been fertilized with ammonium sulfate or dairy slurry. Intake of DM and NDF was greater from wheat (Triticum aestivum L.) hay fertilized with manure vs. commercial fertilizer when weeds were not controlled in the hay fields, but intake was not different among fertilizer treatments when weeds were controlled (Miron et al., 2011). This indicated that plant species as well as other factors may impact the intake response to forages fertilized with manure vs. commercial fertilizer. This is further substantiated by Heikkilä et al. (2004), who reported that surface slurry application decreased DMI of frozen grass compared with commercial fertilizer or injected slurry, but did not affect intake of silages containing different silage additives. In the present study, NDF intake tended to be greater from low-moisture silage that had no dairy slurry application, but the reason that this particular treatment combination was different from the other forages is not apparent. In the present study, DMD was not affected by slurry application, but OM digestibility tended to be reduced by slurry application. Miron et al. (2011) reported no difference in digestibility of wheat forage between that fertilized with manure or fertilized with commercial fertilizer when weeds were not controlled, but digestibility was improved in wheat forage fertilized with manure vs. commercial fertilizer when weeds were controlled. This is again indicative of differential responses among forages. Digestible DMI was not affected by slurry application in the present study, but digestible OMI (g/kg BW) was reduced by slurry application. Although not calculated and analyzed as such in a previous study, digestible DMI was actually increased by slurry application when weeds were controlled and also when slurry was applied that did not have weed seed contamination (Miron et al. (2011). Therefore, direct effects of slurry application on intake of digestible DM and OM is likely affected by a number of other contributing factors, such as the amount of rainfall between application and subsequent harvest, the time delay between application and harvest, or the interaction of manure application with bale moisture, where relatively wet baled silages may further encourage clostridial activity and the formation of butyric acid and ammonia. A major concern with fertilizing a forage crop with dairy slurry prior to a subsequent harvest would be the potential for pathogen inoculation, particularly if the subsequent crop were harvested as silage. The increase in total WBC concentrations from ewes fed silages that had slurry applied prior to harvest seems somewhat incriminating but all concentration were well within normal ranges for sheep (Jones and Allison, 2007). Lymphocytes (% of total WBC) were low for slurry treatments compared with the NS treatment. However, both lymphocyte concentrations (K/µL and % of total WBC) were within normal ranges in sheep, indicating that cytotoxins may not have been present in the sheep (Jones and Allison, 2007). Monocytes (K/µL) were above the normal range for NS and S0, whereas monocytes expressed as a percentage of total WBC was above the normal range for all slurry treatments, indicating that infectious organisms may have been present. Eosinophils were slightly above the normal range as a percentage of total WBC for both slurry treatments, but not for NS. However, total blood concentrations (K/µL) for eosinophils were well within normal ranges for all treatments (Jones and Allison, 2007). Basophil concentrations (% of total WBC) were only above the normal range for S0 treatments indicating that there may have been slight inflammation in those sheep. However, the actual blood concentrations (K/µL) were well within normal concentrations, thereby likely dispelling any inflammation. Although differences were observed among treatments for red blood cells, hemoglobin concentrations, hematocrit, and mean corpuscular volume, all values were well within normal ranges for these measurements (Jones and Allison, 2007). Therefore, these differences are likely not meaningful physiologically to the sheep ingesting the different silages. Platelets were above the normal range in sheep for S14 treatments, but not for NS or S0 treatments (Jones and Allison, 2007). Platelet count for S14 treatments could be an indicator of some type of injury that caused bleeding. When considered in totality, some of the WBC concentrations were outside of normal ranges depending on whether the data were expressed as concentrations in the blood or as a proportion of total WBC, but no outward symptoms of illness were observed. CONCLUSION Ensiling alfalfa silage at what is considered to be lower moisture concentrations may have little impact on digestibility, intake, or intake of digestible dry matter or organic matter. Likewise, dairy slurry application as late as 2 wk following a previous harvest may not affect intake or digestibility of the following harvest of alfalfa silage. Although some differences were observed in blood measurements, no visible health abnormalities were observed in sheep offered silages baled at different moisture concentrations following varied dairy manure application strategies. Therefore, when alfalfa is baled within the moisture ranges reported within this study, producers may feed fermented alfalfa silages fertilized with dairy slurry without observing any adverse effects on intake, digestibility, or animal health. Footnotes 1 The project was supported by Specific Cooperative Agreement 427046 between the University of Arkansas and USDA, ARS, Dairy Forage Research Center, and in part by the USDA National Institute for Food and Agriculture, Hatch Project 1005233. LITERATURE CITED AOAC. 2000. Official methods of analysis. 17th ed. Gaithersburg, MD: Association of Official Analytical Chemists International . Coblentz, W. K., R. E. Muck, M. A. Borchardt, S. K. Spencer, W. E. Jokela, M. G. Bertram, and K. P. Coffey. 2014. 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TI - Voluntary intake and digestibility by sheep of alfalfa ensiled at different moisture concentrations following fertilization with dairy slurry
JF - Journal of Animal Science
DO - 10.1093/jas/skx061
DA - 2018-03-01
UR - https://www.deepdyve.com/lp/oxford-university-press/voluntary-intake-and-digestibility-by-sheep-of-alfalfa-ensiled-at-0dpkegNq1H
SP - 964
EP - 974
VL - 96
IS - 3
DP - DeepDyve
ER -