Winter Grazing System Research Articles

Forage species and summer management impacts on soil carbon and nitrogen in winter stockpiled grazing systems

AbstractSoil organic matter (SOM) in managed grasslands have economic and environmental benefits. This experiment evaluated a stockpiled winter grazing system with two summer management treatments (grazing or hay harvest) and three forage species treatments: tall fescue (TF, Schedonorus arundinaceus Schreb.), switchgrass (SG, Panicum virgatum L.), and mixed big bluestem–Indiangrass [BBIG, Andropogon gerardii Vitman–Sorghastrum nutans (L.) Nash]. Soil was sampled on 18 dates (January 2016–July 2017) at two depths (0–5 and 5–15 cm) in 15 paddocks in central Tennessee. Total organic carbon and total nitrogen concentrations in 0–5‐cm samples were greater in grazed paddocks relative to hay harvest, and greater in TF relative to BBIG and SG. Summer grazing also resulted in greater 0–5‐cm permanganate‐oxidizable carbon (POXC) and 5–15 cm hot‐water extract ultraviolet absorbance at 254 nm (A254). Hot‐water extractable carbon, A254, and POXC concentrations were reduced in SG soils compared with TF and BBIG. Summer hay harvests, compared with grazing, reduced hot‐water extractable C/N in both soil horizons in TF. The interactions between management and plant species suggests contrasting nutrient cycling associated with TF and the morphologically different native grasses BBIG and SG. This study represents the first observations of soil impacts within stockpiled grazing systems and the first observations of grazed native grass species in the southeastern United States.

Impact of cool‐season legume interseedings or timed nitrogen applications on yield and nutritive value of annual ryegrass

AbstractAnnual ryegrass (Lolium multiflorum Lam.) is an essential part of winter grazing systems in the southern United States. Because of an increase in nitrogen (N) cost, producers are considering decreasing fertilizer application rates while incorporating forage‐type legumes as part of their grazing management system. The objectives of this study were to determine optimum management practices including N fertilizer application rate and timing and the incorporation of legume species and to assess changes in yield and nutritive value. ‘Marshall’ ryegrass was planted in a prepared seedbed at a rate of 25 lb pure live seed acre–1 in the fall of 2008, 2009, and 2010. The experiment included nine N fertilization regimes such as the fall and spring application of ammonium nitrate (34‐0‐0). Along with an untreated check (UC), N applications (lb N acre−1 in fall, spring, or both) included the following: 25F‐0S, 0F‐25S, 25F‐25S, 50F‐0S, 0F‐50S, 50F‐25S, 25F‐50S, and 50F‐50S lb N acre–1. Along with fertilization treatments, annual and perennial clover (Trifolium spp.) and hairy vetch (Vicia villosa Roth subsp. villosa) were included in the study. Yields were significantly lower during the 2009–2010 season. Higher yields were observed in the 2010–2011 season when warmer temperatures occurred in the spring. Nitrogen applications produced a slight yield advantage than the clover species. The 75 lb N acre–1 (25F‐50S) application produced the highest forage mean yield. Clover treatments had a higher yield than the UC.

Potential of catch crops to reduce nitrogen leaching in New Zealand winter grazing systems

Winter grazing of fodder beet and kale is common practice in many regions of New Zealand. However, large quantities of urine-nitrogen (N) is returned by livestock onto bare soil during grazing at a period when the risk of drainage is high. Results from recent field trials in the Canterbury region show that sowing a catch crop directly after winter forage grazing can reduce N leaching losses by up to 49% compared with fallow soil, as well as offer significant gains in feed production, via additional annual production from the catch crop. However, the magnitude of effectiveness varies in response to crop management, catch crop genotype, soil type and seasonal weather conditions. For example, early-sown cereal genotypes adapted to lower temperatures provide the greatest potential to reduce leaching. This summary also highlights three important areas for future research: (i) overcoming the practical challenges of establishing catch crops in unfavourable conditions, (ii) development of biophysical models that can predict outcomes over a wide range of production systems and conditions, and (iii) quantification of other processes in the N cycle causing changes in N leaching, e.g. microbial immobilisation of N.

Winter Grazing and Rainfall Synergistically Affect Soil Seed Bank in Semiarid Area

The soil seed bank is an important ecological component of grassland restoration and renewal. In semiarid regions, grassland restoration and renewal are highly affected by annual variations in precipitation and grazing activity because these variations can affect the composition, density, richness, and diversity of seeds in the soil. This study aimed to characterize and compare these parameters of the germinable seed bank under different stocking rates in a winter grazing system in a semiarid area of China in 2015 and 2016 (dry and near-average rainfall condition, respectively). The composition, density, richness, and diversity of seeds were determined by the method of seedling emergence. The results showed that a total of 18 species belonging to nine families germinated from the soil. Drought significantly reduced the density, richness, and diversity of the soil seed bank, but grazing was able to significantly increase the richness and diversity of the soil seed bank by increasing the richness and diversity of the aboveground vegetation. The similarity between the soil seed bank and aboveground vegetation was influenced by the rainfall conditions: in the dry year, it was higher at the lower stocking rates (0 and 0.4 animal unit months [AUM] ha–1), and in the near-average rainfall condition year, it was higher at the higher stocking rates (0.8 and 1.3 AUM ha–1).

Daily Gain of Japanese Shorthorn Raising Cattle in a Winter Grazing System Utilizing a Spring-Autumn Meadow in Northern Tohoku, Japan(Activation of Public Pasture)

Daily Gain of Japanese Shorthorn Raising Cattle in a Winter Grazing System Utilizing a Spring-Autumn Meadow in Northern Tohoku, Japan(Activation of Public Pasture)

Heifer development systems: Dry-lot feeding compared with grazing dormant winter forage1

Two hundred ninety-nine Angus-based, nulliparous heifers (253 ± 2 kg initial BW) from 3 production years were utilized to compare traditional postweaning dry lot (DL) development with a more extensive winter grazing system utilizing a combination of corn residue and winter range (EXT). Heifers developed in the DL were offered a common diet after the weaning period for 208 d in yr 1, 194 d in yr 2, and 150 d in yr 3 until breeding. Heifers developed in EXT grazed corn residue for 135 d in yr 1, 106 d in yr 2, and 91 d in yr 3, and then fed in the DL until breeding (yr 1) or grazed dormant winter grass for approximately 60 d before being fed in the DL (yr 2 and 3). All 3 years, heifers were estrus synchronized, with timed AI performed in yr 1. In yr 2 and 3, estrus was detected and those detected in estrus were artificially inseminated approximately 12 h later. Heifers were exposed to bulls 10 d after the last AI for 60 d while grazing summer pasture. During the winter grazing period, EXT heifers gained less (P = 0.01) BW than DL heifers and EXT heifers had lighter (P = 0.02) BW at breeding. Fewer (P < 0.01) EXT heifers reached puberty before breeding. Conception to AI was not different (P = 0.23); however, AI pregnancy rate tended (P = 0.08) to be less in EXT heifers. Final pregnancy rates were not different (P = 0.38) between treatment groups. Although EXT heifers had lighter (P = 0.02) BW at pregnancy diagnosis; however, they did compensate with greater (P = 0.05) ADG after breeding, resulting in similar (P = 0.22) precalving BW. Winter development system did not influence (P > 0.10) percentage of calving in the first 21 d, calf birth date, and calf birth BW, or dystocia score. Pregnancy rate after the second breeding season was not different (P = 0.56) between treatments. Heifer development using extended winter grazing reduced (P < 0.01) the cost of producing a pregnant heifer by $45 compared with DL.

Winter grazing system and supplementation of beef cows during late gestation influence heifer progeny1

A 2 × 2 factorial arrangement of treatments was used to evaluate effects of dam winter grazing system and supplementation in the last third of gestation on subsequent BW gain, feed efficiency, and reproduction in heifer progeny. Crossbred cows (yr 1, n = 109; yr 2, n = 114; yr 3, n = 116) grazed range (WR) or corn residue (CR) during winter and within grazing treatment received 0.40 kg/d of 31% CP (DM basis) cubes (PS) or no supplement (NS). Heifer calves (yr 1, n = 56; yr 2, n = 56; yr 3, n = 54) grazed dormant pasture for 114 d postweaning and were individually fed for 87 d before a 45-d natural service breeding. Dam PS reduced (P = 0.04) heifer birth date and CR tended to increase (P = 0.07) heifer birth BW. Both PS and CR increased (P ≤ 0.05) heifer weaning BW; however, adjusted 205-d weaning BW was only lighter (P = 0.03) if the dam grazed WR with NS. Heifers from PS dams tended to be younger (P = 0.09) at puberty than NS, and there was a trend (P = 0.11) for more heifers to be pubertal by breeding if the dam grazed WR with PS compared with other treatment groups. Heifers from WR-NS dams tended to weigh less (P ≤ 0.09) at breeding and at pregnancy diagnosis than WR PS. There was a trend (P = 0.13) for pregnancy rate to be greater for heifers born to PS dams. Individually fed heifer DMI was not affected (P = 0.25) by treatment; however, heifers from dams that grazed CR with PS gained the least BW (P = 0.04) during individual feeding and had the smallest (P = 0.03) G:F. In contrast, there were no differences (P > 0.15) in feed efficiency when expressed as residual feed intake. The first calf birth and weaning BW of the heifer was unaffected (P > 0.15) by dam treatment. Heifers from dams that grazed WR with NS tended to have lighter (P = 0.09) BW before the second breeding season but similar (P = 0.97) pregnancy rates. Cows grazing CR with NS produced the most valuable heifer calf at weaning; however, heifers from cows that grazed WR with NS cost the least to develop per pregnant heifer. Winter grazing system and late gestation supplementation affected heifer progeny BW, feed efficiency, and fertility.

Selection of Residence and Feeding Sites by Cattle in a Winter Grazing System Utilizing a Spring-Autumn Meadow in Northern Tohoku, Japan

Selection of Residence and Feeding Sites by Cattle in a Winter Grazing System Utilizing a Spring-Autumn Meadow in Northern Tohoku, Japan

Winter grazing system and supplementation during late gestation influence performance of beef cows and steer progeny1

ABSTRACTA 2 × 2 factorial study evaluated effects of cow wintering system and last trimester CP supplementation on performance of beef cows and steer progeny over a 3-yr period. Pregnant composite cows (Red Angus × Simmental) grazed winter range (WR; n = 4/yr) or corn residue (CR; n = 4/yr) during winter and within grazing treatment received 0.45 kg/d (DM) 28% CP cubes (PS; n = 4/yr) or no supplement (NS; n = 4/yr). Offspring steer calves entered the feedlot 14 d postweaning and were slaughtered 222 d later. Precalving BW was greater (P = 0.02) for PS than NS cows grazing WR, whereas precalving BCS was greater (P < 0.001) for cows grazing CR compared with WR. Calf birth BW was greater (P = 0.02) for CR than WR and tended to be greater (P = 0.11) for PS than NS cows. Prebreeding BW and BCS were greater (P ≤ 0.001) for CR than WR cows and PS than NS (P = 0.006) cows. At weaning, CR cows were heavier (P < 0.001) than WR cows but had similar BCS (P = 0.74). Cow weaning BW and BCS were not affected (P > 0.32) by PS. Calf weaning BW was less (P = 0.01) for calves from NS cows grazing WR compared with all other treatments. Pregnancy rate was unaffected by treatment (P > 0.39). Steer ADG, 12th-rib fat, yield grade, and LM area (P > 0.10) were similar among all treatments. However, final BW and HCW (P = 0.02) were greater for steers from PS-WR than NS-WR cows. Compared with steers from NS cows, steers from PS cows had greater marbling scores (P = 0.004) and a greater (P = 0.04) proportion graded USDA Choice or greater. Protein supplementation of dams increased the value of calves at weaning (P = 0.03) and of steers at slaughter regardless of winter grazing treatment (P = 0.005). Calf birth and weaning BW were increased by grazing CR during the winter. Calf weaning BW was increased by PS of the dam if the dam grazed WR. Compared with steers from NS cows, steer progeny from PS cows had a greater quality grade with no (P = 0.26) effect on yield grade. These data support a late gestation dam nutrition effect on calf production via fetal programming.

The suitability of cool- and warm-season annual cereal species for winter grazing in Saskatchewan

Winter grazing is a practice that can reduce feeding cost for cattle production. Current production has been utilizing traditional cool-season cereals for winter grazing. Warm season (C4) cereals also have the potential to be adapted to winter grazing in Saskatchewan. The objective of this study was to evaluate cool and warm season annual cereal species for adaptation, quality, and dry matter production in annual fall and winter grazing systems. Two seeding dates, nine treatments and two harvest times were used at sites across Saskatchewan over 3 yr. The crops in this trial have significant differences in maturity and dry matter yield. Seeding date did not consistently affect dry matter yield. Pearl millet [Pennisetum glaucum (L.) R. Br.] and sorghum-sudangrass [Sorghum bicolor (L.) × S. arundinaceum (Desv.) Stapf var. sudanense (Stapf) Hitchc.] had low dry matter yields and were poorly adapted to Saskatchewan. The proso millet (Panicum miliaceum) cultivar, Crown, and the foxtail millet (Setaria italica L.) cultivars, Red Siberian and Golden German, hadyields similar to oat (Avena sativa L.) and barley (Hordeum vulgare L.), but lower than high-input corn (Zea mays L.). Corn haddry matter yield that was similar to barley and oat but yield variability across sites and years was higher for corn. Delaying the harvest lowered the protein concentration of all the crops except pearl millet and sorghum-sudangrass. There were significant changes in acid detergent fibre (ADF), neutral detergent fibre (NDF), calcium (Ca) and phosphorus (P) due to a cultivar ×harvest timing interaction. Weathering in the windrow until December did not significantly reduce the quality of the forage. Golden German foxtail millet is well adapted for swath grazing in eastern Saskatchewan. More data are required to determine its adaptability in central and western Saskatchewan and the adaptability of corn in all of Saskatchewan. Key words: Avena sativa L., Hordeum vulgare L., Setaria italica L., Panicum miliaceum, Zea mays L., swath grazing

Yield and Forage Quality of Different ×Festulolium Cultivars in Winter

Abstract×Festulolium ssp. are of particular interest as autumn‐saved herbage in the winter grazing system, but information concerning their performance in this low‐input system is not available. To this end, we examined dry matter (DM) yield and forage quality in winter of four different cultivars of ×Festulolium ssp. (×Festulolium pabulare, Festulolium braunii), either with festucoid or loloid attributes, compared with Festuca arundinacea Schreb. Furthermore, pre‐utilization (accumulation since June or July) and date of winter harvest (December or January) were varied examining the influence of different sward management. DM yield, crude protein, metabolizable energy (ME) (in vitro rumen fermentation technique), acid detergent fibre (ADF) and ergosterol concentration were determined. Within all years, the festucoid cultivars (mean 3.4 t ha−1) attained significant higher yields during winter than the loloid cultivars (mean 1.6 t ha−1), but their yields were comparable with F. arundinacea (mean 3.0 t ha−1). Crude protein was decisively influenced by the different yield levels of the cultivars resulting in higher values for the loloid cultivars. Energy concentrations decreased with later winter harvest, whereas ADF as well as ergosterol concentrations frequently increased from December to January. The greatest differences between festucoid and loloid cultivars were generally observed during severe winters. Obviously, the festucoid cultivars were better adapted to a utilization as autumn‐saved herbage than the cultivars with rather loloid attributes. However, the hybrids did not surpass F. arundinacea regarding yield and quality.

Potential of stockpiled perennial forages in winter grazing systems for pregnant beef cows.

We conducted a 3-yr study to measure herbage masses and chemical compositions of stockpiled perennial forages and corn crop residues and compare performance of cows grazing these forages or maintained in a drylot during winter. Midgestation, mature, medium-framed crossbred beef cows (mean BW, 506 kg; mean condition score, 5.3) 1) strip-grazed replicated fields containing stockpiled tall fescue-alfalfa, 2) strip-grazed stockpiled smooth bromegrass without (yr 1) and with (yr 2 and 3) red clover, 3) strip-grazed corn crop residues at 1.2 cows/ha, or 4) they were confined in a drylot for 129 to 141 d. All cows were offered grass-legume hay as large round bales to maintain a condition score of 5 on a 9-point scale. Mean initial amounts (P < .05) and daily changes (P < .01) of OM mass were greater in corn crop residues than in stockpiled perennial forages during the winter grazing seasons. Initial in vitro organic matter disappearance (IVOMD) and CP concentrations were greater (P < .05) and initial NDF, ADF, and ADIN concentrations in stockpiled forages were lower (P < .01) than those in corn crop residues. Mean changes in IVOMD, CP, NDF, and ADF concentrations during the grazing season were -.09, -.004, .10, and .11 percentage units OM/d, and they did not differ (P > .05) among forage species or grazed and nongrazed areas. Cows grazing stockpiled tall fescue-alfalfa had greater (P < .05) BW gains than those in other systems and greater (P < .05) body condition score increases than cows grazing corn crop residues. Because cows grazed stockpiled tall fescue-alfalfa, smooth bromegrass-red clover, and corn crop residues for 85, 83, and 57 d before beginning hay supplementation, cows grazing these forages required 1,069, 1,031, and 627 kg/cow less hay DM to maintain body condition than cows confined in a drylot.

Semi-Arid Warm-Season Grass Yield and Nutritive Value in Argentina

The use of standing dead biomass, during the winter that was produced by warm-season grasses in the previous growing season by pregnant beef cows may be an alternative to grazing systems in the semi-arid Pampean Region of Argentina. This study, conducted over 2 years, 1990 and 1991, compared the winter forage quality produced during the previous growing season for 4 warm-season grasses; switchgrass (Panicum virgatum L. cv. Pathfinder), kleingrass (Panicum coloratum L.), tetrachne (Tetrachne dregei Nees) and weeping lovegrass (Eragrostis curvula (Schrad), Nees cv. Tanganyka). Five harvests of the summer growth started after the first frost, and were spaced evenly throughout the winter period. Changes in the standing crop of dry matter were measured and subsamples of forage were divided into leaf and stem fractions. Forage quality analyses included: crude protein (CP), in vitro dry matter digestibility (IVDMD), effective rumen degradability (ED), neutral (NDF) and acid (ADF) detergent fiber and lignin. Tetrachne dregei produced forage with a higher leaf:stem ratio and of generally higher quality, than the other species, although the differences were not always significant. Its CP content was marginally below the maintenance requirements of cows. Dry matter yield of tetrachne was lower than that of weeping lovegrass, but differences were only significant in 1990. Kleingrass generally was high in quality and dry matter yield, although it was the lowest in percentage of leaves of the 4 species evaluated. Switchgrass was the least productive; the nutritive value of its forage was low, comparable or lower than that of weeping lovegrass. The first harvest date was higher in nutritive value. Although the nutritive value of leaves and stems were not compared statistically, the leaves tended to be higher than the stems. Tetrachne dregei, the best of the species evaluated in this study, is a very promising warm-season grass, which could provide nutritious forage for winter grazing systems in the semiarid Pampean Region of Argentina.

IMPROVING PASTURE BY WINTER MANAGEMENT

DURING the last few seasons many dairy farmers in Taranaki have noted that winter-grazed paddocks have grown more feed, and of a better quality, than paddocks-not grazed in the winter. These farmers were part of the high proportion which has adopted the winter grazing system commonly known as "block" or "long rotation" wintering.