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Coblentz W.K.,U.S. Department of Agriculture | Bertam M.G.,University of Wisconsin Marshfield Agricultural Research Station | Martin N.P.,U.S. Department of Agriculture | Berzaghi P.,University of Padua
Agronomy Journal | Year: 2012

Fall-grown oat (Avena sativa L.) shows potential to fill an important niche as a fall forage option throughout central Wisconsin. Our objectives were to assess the effects of planting date on the nutritive value of fall-grown oat from four cultivars exhibiting diverse maturation characteristics. During a 3-yr trial, three grain- and one forage-type cultivar were established on 15 July, 1 August, or 15 August, and subsequently harvested at 15-d intervals beginning 15 September. Cultivar × harvest date interactions (P ≤ 0.041) were observed consistently within individual planting dates. Estimates of 48-h in vitro neutral detergent fiber digestibility (NDFD) declined throughout the fall for all cultivars, and ranged from 416 to 548, 529 to 704, and 665 to 798 g kg -1 neutral detergent fiber (NDF) following the 15 July, 1 August, and 15 August planting dates, respectively. Within planting date, these changes generally were explained by linear, quadratic, and cubic (P < 0.001) trends over time. Overall, means for ForagePlus were greater by 127, 102, and 32 g kg -1 NDF than grain-type cultivars following the 15 July, 1 August, and 15 August planting dates, respectively. Generally, similar trends were observed for estimates of total digestible nutrients with respective ranges of 503 to 592, 581 to 687, 685 to 747 g kg -1 across the three establishment dates. Selection of a forage-type cultivar likely will result in superior yield and nutritive value for planting dates as late as the first week of August. Thereafter, these advantages become less distinct, and grain-type cultivars often may be better management choices. © 2012 by the American Society of Agronomy, 5585 Guilford Road, Madison, WI 53711. All rights reserved.


Coblentz W.K.,U.S. Department of Agriculture | Esser N.M.,University of Wisconsin Marshfield Agricultural Research Station | Hoffman P.C.,University of Wisconsin - Madison | Akins M.S.,University of Wisconsin - Madison
Journal of Dairy Science | Year: 2015

Gravid heifers consuming high-quality forage diets are susceptible to excessive weight gains and overconditioning. One approach for controlling this problem is to dilute diets with low-energy forages, such as straw, that reduce the caloric density and dry matter intake (DMI) of that diet by heifers. These diluting agents are often sortable by dairy heifers, but previous visual evidence has suggested that eastern gamagrass haylage may be a nonsortable alternative. Our objectives were (1) to compare the growth performance of dairy heifers offered a high-quality forage diet (control) with diets containing 1 of 3 diluting agents [eastern gamagrass haylage (EGH), chopped wheat straw (WS), or chopped corn fodder (CF)]; and (2) evaluate sorting behaviors of heifers offered these forage diets. Holstein heifers (n. =. 128) were stratified (32 heifers/block) on the basis of initial body weight (heavy, 560 ± 27.7. kg; medium-heavy, 481 ± 17.7. kg; medium-light, 441 ± 22.0. kg; and light, 399 ± 14.4. kg), and then assigned to 1 of 16 identical research pens (4 pens/block; 8 heifers/pen), where each of the 4 research diets were assigned to 1 pen within each block. Diets were offered in a 118-d feeding trial with heifers crowded to 133% of capacity at the feed bunk. Inclusion of low-energy forages was effective in reducing both diet energy density and DMI. Concentrations of physically effective fiber (. pef) particles did not change during the 24-h period following feeding for either the control or EGH diets; however, this response for pef particles masked the competing (and cancelling) responses for individual large and medium particles, which heifers sorted with discrimination and preference, respectively. Sorting against pef particles was detected for WS, and much more severely for the CF diet. Sorting of forage particles by heifers could not be related to heifer performance. Compared with control (1.16. kg/d), average daily gains (ADG) were reduced by dilution in all cases, but were virtually identical between EGH (0.98. kg/d) and CF (0.97. kg/d), which exhibited no sorting and extensive sorting of pef, respectively. Furthermore, ADG for WS was approximately 0.2. kg/d less than EGH or CF, despite exhibiting sorting characteristics intermediate between EGH and CF. Diets diluted with low-energy forages were formulated to be isonitrogenous and isocaloric; within that context, WS was most effective in reducing DMI and maintaining ADG within typical recommendations for Holstein heifers. © 2015 American Dairy Science Association.


Coblentz W.K.,U.S. Department of Agriculture | Brink G.E.,U.S. Department of Agriculture | Hoffman P.C.,University of Wisconsin - Madison | Esser N.M.,University of Wisconsin Marshfield Agricultural Research Station | Bertram M.G.,University of Wisconsin Arlington Agricultural Research Station
Journal of Dairy Science | Year: 2014

Our objective was to assess the pasture productivity and forage characteristics of 2 fall-grown oat (Avena sativa L.) cultivars, specifically for extending the grazing season and reducing reliance on harvested forages by replacement dairy heifers. A total of 160 gravid Holstein heifers (80 heifers/yr) were stratified by weight, and assigned to 1 of 10 identical research pens (8 heifers/pen). Initial body weights were 480. ±. 43.5. kg in 2011 and 509. ±. 39.4. kg in 2012. During both years of the trial, four 1.0-ha pasture replicates were seeded in August with Ogle oat (Schumitsch Seed Inc., Antigo, WI), and 4 separate, but similarly configured, pasture replicates were seeded with Forage Plus oat (Kratz Farms, Slinger, WI). Heifer groups were maintained as units, assigned to specific pastures, and then allowed to graze fall-oat pastures for 6. h daily before returning to the barn, where they were offered a forage-based basal total mixed ration. Two heifer groups were retained in confinement (without grazing) as controls and offered the identical total mixed ration as pasture groups. During 2011, available forage mass increased with strong linear and quadratic effects for both cultivars, peaking at almost 9. Mg/ha on October 31. In contrast, forage mass was not affected by evaluation date in 2012, remaining ≤2,639. kg/ha across all dates because of droughty climatic conditions. During 2012, Ogle exhibited greater forage mass than Forage Plus across all sampling dates (2,678 vs. 1,856. kg/ha), largely because of its more rapid maturation rate and greater canopy height. Estimates of energy density for oat forage ranged from 59.6 to 69.1% during 2011, and ranged narrowly from 68.4 to 70.4% during 2012. For 2011, responses for both cultivars had strong quadratic character, in which the most energy-dense forages occurred in mid November, largely due to accumulation of water-soluble carbohydrates that reached maximum concentrations of 18.2 and 15.1% for Forage Plus and Ogle, respectively. Across the 2-yr trial, average daily gain for grazing heifer groups tended to be greater than heifers remaining in confinement (0.85 vs. 0.74. kg/d), but both management strategies produced weight gains within reasonable proximity to normal targets for heifers in this weight range. Fall-grown oat should be managed as stockpiled forage for deferred grazing, and good utilization of fall-oat forage can be accomplished by a one-time removal of standing forage, facilitated by a single lead wire advanced daily to prevent waste. © 2014 American Dairy Science Association.


Coblentz W.K.,U.S. Department of Agriculture | Bertram M.G.,University of Wisconsin Marshfield Agricultural Research Station
Journal of Dairy Science | Year: 2012

During 2009 and 2010, alfalfa (Medicago sativa L.) hays from 2 cuttings harvested from the same field site were used to evaluate the effects of a propionic acid-based preservative on the storage characteristics and nutritive value of hays stored as large round bales. A total of 87 large round bales (diameter = 1.5m) were included in the study; of these, 45 bales served as controls, whereas 42 were treated with a commercial propionic acid-based preservative at mean application rates of 0.5±0.14 and 0.7±0.19% of bale weight, expressed on a wet (as is) or dry matter basis, respectively. Initial bale moisture concentrations ranged from 10.2 to 40.4%. Internal bale temperatures were monitored daily during an outdoor storage period, and heating characteristics were summarized for each bale as heating degree days (HDD) >30°C. For acid-treated bales, the regression relationship between HDD and initial bale moisture was best fitted to a quadratic model in which the linear term was dropped to improve fit (Y=2.02x 2 - 401; R 2=0.77); control hays were best fitted to a nonlinear model in which the independent variable was squared [Y=4,112 - (4,549×e -0.000559x*x); R 2=0.77]. Based on these regressions, acid-treated bales accumulated more HDD than control hays when the initial bale moisture was >27.7%; this occurred largely because acid treatment tended to prolong active heating relative to control hays. Linear regressions of recoveries of dry matter on HDD did not differ on the basis of treatment, yielding a common linear relationship of Y=-0.0066x+96.3 (R 2=0.75). Regressions relating changes (post-storage - pre-storage) in concentrations of several nutritional components (neutral detergent fiber, lignin, ash, crude protein, and total digestible nutrients) with HDD for acid-treated hays typically exhibited more inflection points or were higher-ordered polynomial regressions than those of control hays. These more complex responses probably reflected the perturbation of normal heating patterns following acid treatment; however, overall effects on post-storage nutritive value were relatively limited in scope. The potential to improve nutritive value relative to cost for these large round bales was not especially favorable, and hay producers may find that diligence to achieve adequate field desiccation before baling, or use of oxygen-exclusion methods, such as wrapping in plastic, may be better alternatives for preserving moist hays. © 2012 American Dairy Science Association.


Coblentz W.K.,U.S. Department of Agriculture | Jokela W.E.,U.S. Department of Agriculture | Hoffman P.C.,University of Wisconsin - Madison | Bertram M.G.,University of Wisconsin Marshfield Agricultural Research Station
Agronomy Journal | Year: 2010

Replacement dairy heifers (Bos taurus) off ered diets comprised largely of corn (Zea mays L.) silage or other high-energy forages oft en become overconditioned, which may damage their future performance as lactating cows. Our objective was to assess the yield potential of a perennial C4 grass, eastern gamagrass [Tripsacum dactyloides (L.) L.], for incorporation into fiber-demanding, dairy-heifer or dry-cow diets. Replicated field plots of 'Pete' eastern gamagrass were evaluated within nine harvest systems and four N fertilization regimes. For single-harvest systems, dry matter (DM) yields increased across harvest dates, reaching numerical maximums of 7192, 9764, and 7554 kg ha -1 by mid-August of 2007, 2008, and 2009, respectively. During each year, there was a strong linear (P < 0.001) effect of harvest date; however, higher-ordered effects varied within year. Relatively large yield increases (≥1812 kg ha -1) between early and mid-August during 2008 and 2009 suggest that better yields could be achieved by delaying single harvests of eastern gamagrass beyond mid-August. Yields of DM from double-harvest systems were not competitive with single-harvest systems timed in mid-August. Nitrogen fertilization increased (P < 0.001) DM yields, exhibiting both linear (P < 0.001) and quadratic (P = 0.027) effects of application rate. However, efficiency of N usage was reduced as fertilization rates increased. © 2010 by the American Society of Agronomy.


Coblentz W.K.,U.S. Department of Agriculture | Nellis S.E.,University of Wisconsin - Madison | Hoffman P.C.,University of Wisconsin - Madison | Hall M.B.,U.S. Department of Agriculture | And 3 more authors.
Journal of Dairy Science | Year: 2013

Sixty samples of 'ForagePlus' oat were selected from a previous plot study for analysis of in vitro gas production (IVGP) on the basis of 2 factors: (1) high (n=29) or low (n=31) neutral detergent fiber (NDF; 62.7±2.61 and 45.1±3.91%, respectively); and (2) the range of water-soluble carbohydrates (WSC) within the high- and low-NDF groups. For the WSC selection factor, concentrations ranged from 4.7 to 13.4% (mean=7.9±2.06%) and from 3.5 to 19.4% (mean=9.7±4.57%) within high- and low-NDF forages, respectively. Our objectives were to assess the relationships between IVGP and various agronomic or nutritional characteristics for high- and low-NDF fall-oat forages. Cumulative IVGP was fitted to a single-pool nonlinear regression model: Y=MAX × (1 - e [-K × (t - lag)]), where Y=cumulative gas produced (mL), MAX=maximum cumulative gas produced with infinite incubation time (mL), K=rate constant, t=incubation time (h), and lag=discrete lag time (h). Generally, cumulative IVGP after 12, 24, 36, or 48h within high-NDF fall-oat forages was negatively correlated with NDF, hemicellulose, lignin, and ash, but positively correlated with WSC, nonfiber carbohydrate (NFC), and total digestible nutrients (TDN). For low-NDF fall-grown oat forages, IVGP was positively correlated with growth stage, canopy height, WSC, NFC, and TDN; negative correlations were observed with ash and crude protein (CP) but not generally with fiber components. These responses were also reflected in multiple regression analysis for high- and low-NDF forages. After 12, 24, or 36h of incubation, cumulative IVGP within high-NDF fall-oat forages was explained by complex regression equations utilizing (lignin:NDF)2, lignin:NDF, hemicellulose, lignin, and TDN2 as independent variables (R2≥0.43). Within low-NDF fall-grown oat forages, cumulative IVGP at these incubation intervals was explained by positive linear relationships with NFC that also exhibited high coefficients of determination (R2≥0.75). Gas production was accelerated at early incubation times within low-NDF forages, specifically in response to large pools of WSC that were most likely to be present as forages approached boot stage by late-fall. © 2013 American Dairy Science Association.


Coblentz W.K.,U.S. Department of Agriculture | Esser N.M.,University of Wisconsin Marshfield Agricultural Research Station | Hoffman P.C.,University of Wisconsin - Madison | Akins M.S.,University of Wisconsin - Madison
Journal of Dairy Science | Year: 2015

Gravid heifers consuming high-quality forage diets are susceptible to excessive weight gains and overconditioning. One approach for controlling this problem is to dilute diets with low-energy forages, such as straw, that reduce the caloric density and dry matter intake (DMI) of that diet by heifers. These diluting agents are often sortable by dairy heifers, but previous visual evidence has suggested that eastern gamagrass haylage may be a nonsortable alternative. Our objectives were (1) to compare the growth performance of dairy heifers offered a high-quality forage diet (control) with diets containing 1 of 3 diluting agents [eastern gamagrass haylage (EGH), chopped wheat straw (WS), or chopped corn fodder (CF)]; and (2) evaluate sorting behaviors of heifers offered these forage diets. Holstein heifers (n = 128) were stratified (32 heifers/block) on the basis of initial body weight (heavy, 560 ± 27.7 kg; medium-heavy, 481 ± 17.7 kg; medium-light, 441 ± 22.0 kg; and light, 399 ± 14.4 kg), and then assigned to 1 of 16 identical research pens (4 pens/block; 8 heifers/pen), where each of the 4 research diets were assigned to 1 pen within each block. Diets were offered in a 118-d feeding trial with heifers crowded to 133% of capacity at the feed bunk. Inclusion of low-energy forages was effective in reducing both diet energy density and DMI. Concentrations of physically effective fiber (pef) particles did not change during the 24-h period following feeding for either the control or EGH diets; however, this response for pef particles masked the competing (and cancelling) responses for individual large and medium particles, which heifers sorted with discrimination and preference, respectively. Sorting against pef particles was detected for WS, and much more severely for the CF diet. Sorting of forage particles by heifers could not be related to heifer performance. Compared with control (1.16 kg/d), average daily gains (ADG) were reduced by dilution in all cases, but were virtually identical between EGH (0.98 kg/d) and CF (0.97 kg/d), which exhibited no sorting and extensive sorting of pef, respectively. Furthermore, ADG for WS was approximately 0.2 kg/d less than EGH or CF, despite exhibiting sorting characteristics intermediate between EGH and CF. Diets diluted with low-energy forages were formulated to be isonitrogenous and isocaloric; within that context, WS was most effective in reducing DMI and maintaining ADG within typical recommendations for Holstein heifers. © 2015 American Dairy Science Association.


Coblentz W.K.,U.S. Department of Agriculture | Bertram M.G.,University of Wisconsin Marshfield Agricultural Research Station | Martin N.P.,U.S. Department of Agriculture
Agronomy Journal | Year: 2011

Previous research has shown that cereal-grains, such as oat (Avena sativa L.), that undergo stem elongation following late-summer establishment will likely exhibit a 2:1 advantage in forage dry matter (DM) yield before winter compared to other cereals that remain vegetative until spring. Our objectives for this project were to assess the effects of planting date on the fall forage growth of one forage- and three grain-type oat cultivars. Over a 3-yr trial, oat cultivars were planted on three target dates (15 July, 1 August, and 15 August), and subsequently evaluated over fi ve harvest dates (15 September, 1 October, 15 October, 1 November, and 15 November) each year. For the 15 July planting date, a late-maturing forage cultivar (ForagePlus) produced maximum annual yields ranging from 4501 to 8100 kg ha-1, and these responses were explained generally by linear (P < 0.01) and quadratic (P ≤ 0.03) effects of time. Accumulation of DM was superior to grain-type cultivars because ForagePlus matured slowly, and was better able to respond to sometimes erratic late-summer precipitation. With a 1 August planting date, maximum forage yields generally were similar to those observed with a mid-July planting date, but peak yield oft en was delayed by approximately 2 wk. For the 15 August planting date, maximum yields of forage DM were only 42.3, 79.9, and 20.5% of those observed following planting dates on 1 August of 2007, 2008, and 2009, respectively. Under these circumstances, the late-maturity characteristics of Forage Plus were less advantageous, oft en resulting in poorer yields throughout early harvest dates compared to grain-type cultivars. © 2011 by the American Society of Agronomy.


Coblentz W.K.,U.S. Department of Agriculture | Brink G.E.,U.S. Department of Agriculture | Esser N.M.,University of Wisconsin Marshfield Agricultural Research Station | Cavadini J.S.,University of Wisconsin Marshfield Agricultural Research Station
Journal of Dairy Science | Year: 2015

Fall-grown oat has shown promise for extending the grazing season in Wisconsin, but the optimum date for initiating grazing has not been evaluated. Our objectives for this project were (1) to assess the pasture productivity and nutritive value of 2 oat cultivars [Ogle and ForagePlus (OG and FP, respectively)] with late-September (EG) or mid-October (LG) grazing initiation dates; and (2) to evaluate growth performance by heifers grazing these oat forages compared with heifers reared in confinement (CON). A total of 160 gravid Holstein heifers (80 heifers/yr) were assigned to 10 research groups (8 heifers/group). Mean initial body weight was 509. ±. 40.5 kg in 2013 and 517. ±. 30.2 kg in 2014. Heifer groups were assigned to specific pastures arranged as a 2. ×. 2 factorial of oat cultivars and grazing initiation dates. Grazing heifer groups were allowed to strip-graze oat pastures for 6 h daily before returning to the barn, where they were offered a forage-based basal total mixed ration. Main effects of oat cultivar and sampling date interacted for forage characteristics in 2013, but not in 2014. During 2013, oat forage mass increased until early November before declining in response to freezing weather conditions, thereby exhibiting linear and quadratic effects of sampling date, regardless of oat cultivar. Similar trends over time were observed in 2014. For 2013, the maximum forage mass was 5,329 and 5,046 kg/ha for FP and OG, respectively, whereas the mean maximum forage mass for 2014 was 4,806 kg/ha. ForagePlus did not reach the boot stage of growth during either year of the trial; OG matured more rapidly, reaching the late-heading stage during 2013, but exhibited only minor maturity differences from FP in 2014. For 2013, average daily gain for CON did not differ from grazing heifer groups (overall mean. =. 0.63 kg/d); however, average daily gain from FP was greater than OG (0.68 vs. 0.57 kg/d), and greater from EG compared with LG (0.82 vs. 0.43 kg/d). For 2013, advantages in average daily gain for heifers grazing FP pastures were likely related to the greater energy density of FP oat throughout the fall that reached a maximum of 68.8% total digestible nutrients on November 27 compared with only 63.7% for OG on October 10. During 2014, average daily gain from CON exceeded all grazing heifer groups (0.81 vs. 0.57 kg/d), and average daily gain from EG again exceeded LG (0.70 vs. 0.44 kg/d). These results suggest that delaying grazing until mid-October will consistently suppress heifer growth performance, particularly if rapidly maturing cultivars are used. © 2015 American Dairy Science Association.


PubMed | University of Wisconsin Marshfield Agricultural Research Station, University of Wisconsin - Madison and U.S. Department of Agriculture
Type: Journal Article | Journal: Journal of dairy science | Year: 2015

Gravid heifers consuming high-quality forage diets are susceptible to excessive weight gains and overconditioning. One approach for controlling this problem is to dilute diets with low-energy forages, such as straw, that reduce the caloric density and dry matter intake (DMI) of that diet by heifers. These diluting agents are often sortable by dairy heifers, but previous visual evidence has suggested that eastern gamagrass haylage may be a nonsortable alternative. Our objectives were (1) to compare the growth performance of dairy heifers offered a high-quality forage diet (control) with diets containing 1 of 3 diluting agents [eastern gamagrass haylage (EGH), chopped wheat straw (WS), or chopped corn fodder (CF)]; and (2) evaluate sorting behaviors of heifers offered these forage diets. Holstein heifers (n=128) were stratified (32 heifers/block) on the basis of initial body weight (heavy, 560 27.7 kg; medium-heavy, 481 17.7 kg; medium-light, 441 22.0 kg; and light, 399 14.4 kg), and then assigned to 1 of 16 identical research pens (4 pens/block; 8 heifers/pen), where each of the 4 research diets were assigned to 1 pen within each block. Diets were offered in a 118-d feeding trial with heifers crowded to 133% of capacity at the feed bunk. Inclusion of low-energy forages was effective in reducing both diet energy density and DMI. Concentrations of physically effective fiber (pef) particles did not change during the 24-h period following feeding for either the control or EGH diets; however, this response for pef particles masked the competing (and cancelling) responses for individual large and medium particles, which heifers sorted with discrimination and preference, respectively. Sorting against pef particles was detected for WS, and much more severely for the CF diet. Sorting of forage particles by heifers could not be related to heifer performance. Compared with control (1.16 kg/d), average daily gains (ADG) were reduced by dilution in all cases, but were virtually identical between EGH (0.98 kg/d) and CF (0.97 kg/d), which exhibited no sorting and extensive sorting of pef, respectively. Furthermore, ADG for WS was approximately 0.2 kg/d less than EGH or CF, despite exhibiting sorting characteristics intermediate between EGH and CF. Diets diluted with low-energy forages were formulated to be isonitrogenous and isocaloric; within that context, WS was most effective in reducing DMI and maintaining ADG within typical recommendations for Holstein heifers.

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