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Forages

Beef Cattle Production, Nutritional Quality, and Economics of Windrowed Forage vs. Baled Hay During Winter

^a Dep. of Animal Science, Univ. of Wyoming, Laramie, WY 82071
^b Dep. of Plant Sciences, Univ. of Wyoming, Laramie, WY 82071
^c Dep. of Applied and Agricultural Economics, Univ. of Wyoming, Laramie, WY 82071

^* Corresponding author (brethess{at}uwyo.edu)

Received for publication January 28, 2006.

	ABSTRACT

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
Production expenses associated with harvesting and feeding hay account for a large proportion of annual production costs for ruminant livestock systems. A 2-yr experiment compared windrow grazing, as a potential method to reduce winter cost, with feeding baled hay to beef cows. Two irrigated meadows (16.2 and 10.1 ha) consisting of a mixture of ‘Garrison’ creeping foxtail (Alopecurus arundinaceus Poir.) and other introduced and native forage species were either baled and removed or windrowed and left in place 26 Aug. 1999 and 27 July 2000. Forage samples were collected from windrows and baled hay at harvest and then monthly until January. Beginning in November 1999 and 2000, 64 and 54 pregnant cows, respectively, were assigned to windrowed or baled forage for 42 d. Forage acid detergent fiber (ADF) was greater (P < 0.01) in 1999 and neutral detergent fiber (NDF) tended to be greater (P = 0.09) in 2000 for windrowed than baled forage. Crude protein (CP) tended to be greater in windrowed (100 g kg^–1) than baled (93 g kg^–1) forage in 2000 (P = 0.08), but was similar (windrows, 89 g kg^–1; bales, 90 g kg^–1) in 1999 (P = 0.11). In 1999, cows offered windrowed forage had greater average daily gain (ADG = 1 kg d^–1; P = 0.04) and body condition score (BCS = 5.5; P = 0.02) than cows fed baled forage [ADG = 0.66 kg^–d; BCS = 5.3]. In 2000, cattle offered windrows (–0.42 kg^–d) had lower (P = 0.03) ADG compared with cattle fed baled forage (0.1 kg^–d). Windrow grazing was less economical under the study and management conditions than bale feeding due to high cost of watering livestock and forage wastage.

Abbreviations: ADF, acid detergent fiber • ADG, average daily gain • BCS, body condition score • BW, body weight • CP, crude protein • DM, dry matter • EDP, estimated days pregnant • IVDMD, in vitro dry matter digestibility • NDF, neutral detergent fiber

	INTRODUCTION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
WINTER FEED makes up 60% or more of annual production expenses of cow–calf operations in the northern USA. Forty percent of annual production expenses are harvested and stored feeds (USDA, 1995). Grazing windrowed forage in the winter, rather than baling, storing, and feeding, might enable a livestock producer to lower some production costs.

Results from previous research on cooperating ranches near Laramie, WY, indicated that heifers grazing windrowed meadow hay during winter performed similarly to heifers fed baled meadow hay on adjacent pasture (Lux et al., 1999). Data from the University of Nebraska Gudmunsen Sandhills Laboratory (Behling, 1999; Volesky et al., 2002) indicated that calves grazing windrowed forage on subirrigated hay meadows gained more weight over the grazing period compared with calves fed hay in a drylot. Differences in animal performance were attributed to the availability and consumption of high-quality regrowth that occurred after haying. Forage wastage from the windrows was 26%, while bale wastage was 12%. The wastage from windrows was reduced to 18% by allowing mature cows to graze windrow residue after the calves.

Lux et al. (1999) concluded that while windrow-covered areas depressed forage yield the next year, there was a compensating gain in production adjacent to the windrows. This might be a function of nutrient recycling of urine and feces excreted by cows grazing windrows.

Using data of Turner and Angell (1987), Bates et al. (1990) indicated that winter grazing of rake-bunched hay was an economical alternative to feeding baled hay; returns were $48 greater per cow. L. Klein (1996, personal communication) suggested that costs of hauling manure from corrals back to fields, bedding, and watering would also be reduced or eliminated by windrow grazing practice. Volesky et al. (2002) suggested that total forage production costs for the bale-feeding strategy were about $63 ha^–1 higher than windrow grazing due to baling and bale moving costs. Furthermore, McCartney et al. (2004) reported that swath grazing required 38% less labor than traditional feeding and 21% less labor than alternate day winter feeding. Thus, windrow grazing can significantly reduce production costs by eliminating the costs of baling, transporting, and feeding forage.

The objectives of this experiment were to monitor the quality of windrowed and baled forage, determine the effects of grazing windrows vs. feeding baled forage on beef cow performance, and assess the economic viability of feeding methods.

	MATERIALS AND METHODS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
Experimental Site and Soil Fertility
Two flood-irrigated hay meadows [16.2 ha (Meadow A) and 10.1 ha (Meadow B)] that consisted of native species and ‘Garrison’ creeping foxtail (95% of the total forage mass), were selected for experimentation during the winters of 1999 and 2000 at the University of Wyoming Experimental Farm west of Laramie, WY. Included in the native species grouping were unimproved species such as meadow fescue (Festuca pratensis Huds.), Kentucky bluegrass (Poa pratensis L.), rush (Juncus balticus Willd.), sedge (Carex nebrascensis Dewey), dandelion (Taraxacum officinale F. H. Wigg. aggr.), fern (Potentilla anserina L.), lovegrass [Eragrostis cilianensis (All.) Vignolo ex Janch.], and foxtail barley (Hordeum jubatum L.), and the introduced species such as tall fescue (Festuca arundinacea Schreb.), red clover (Trifolium pratense L.), and reed canarygrass (Phalaris arundinacea L.). None of the native nor introduced species represented >1% of the total forage mass. Elevation is 2187 m and average annual precipitation is 29.2 cm. The average monthly temperature varied from 16.6°C to –8.5°C from August 1969 to January 2001, respectively. The average temperature from December 1999 to January 2000 and from November 2000 to December 2000 were 4.3°C and –9.1°C, respectively. Irrigation water for the meadows is traditionally applied from late May to late June. Experimental meadows are characterized by sandy loam soils. In the late winter of 1999–2000, Meadow A was fertilized with 90 kg N ha^–1 and 14 kg P₂O₅ ha^–1; only a small portion of Meadow B was fertilized because of soft, wet soil. In the late winter of 2000–2001, both meadows were fertilized with 71.6 kg N ha^–1 and 11.2 kg P₂O₅ ha^–1.

Hay Harvest and Forage Sampling
Yearling heifers grazed Meadow A and Meadow B from 27 May until 8 June 1999, and from 8 through 12 June 1999, respectively, to delay phenological development of forage and allow later harvest. Later hay harvest would reduce the time windrows were present on the meadows before grazing and, hopefully, produce forage higher in quality than hay normally harvested 1 mo earlier. Grazing began when forage was at least 5 cm in height and >1 Mg dry matter (DM) ha^–1 was available, as 1 Mg DM ha^–1 is the minimum amount of forage mass which must be available before intake is not limited (Black and Kenney, 1984). The stocking density was 5.4 animal unit (AU) ha^–1. Meadows were not grazed in June of 2000.

Meadows were swathed 26 Aug. 1999 and 27 July 2000. A 3.7-m swather was used, and adjacent swaths were combined to produce windrows averaging 1.2 m in width and spaced 14.8 m apart. Beginning 7 Sept. 1999 and 1 Aug. 2000, on one-half of each meadow, alternate windrows were baled (average bale weight = 23 kg) and stored uncovered outside for later feeding. On the remaining half, all windrows were baled (average bale weight = 454 kg) and completely removed, providing an area for winter hay feeding. Both meadows were divided by electric fence into swaths and hay-feeding halves. Each half of Meadow A was again divided in half by electric fence perpendicular to the dividing line between swaths and hay-feeding halves to limit cattle access to 21 d during the subsequent winter feeding period.

Six sampling areas in Meadow A and five in Meadow B were randomly chosen. At each sampling point, a 1.5-m² forage cage was placed over the windrow to determine forage quality throughout the experiment. Two steel t-posts were placed within the windrow, 9.1 m apart at each sampling location to monitor the effect of the windrows on forage production the following year. The bale closest to the forage cage sampling point was labeled and stored with the other square bales for later sampling. Both meadows were initially sampled on 7 and 12 Sept. 1999 and 5 and 13 Aug. 2000, respectively.

In the winters of 1999–2000 and 2000–2001, windrow and bale samples were also collected 13 Oct., 6 Nov., and 14 Jan. 2000 and 5 Sept., 13 Oct., 6 Nov., 21 Dec., and 2 Jan. 2001, respectively. Starting with the November sampling dates, regrowth underneath the windrows, regrowth between the windrows, and regrowth on the halves of the pastures where bales were to be fed were clipped from a 0.25-m² quadrat at the 2.5-cm height at each sampling area.

Laboratory Analyses
During 1999 and 2000, forage samples were dried in a forced-air oven at 55°C for 48 h, weighed, and ground in a Wiley mill (Arthur H. Thomas Co., Philadelphia, PA) to pass a 1-mm screen. Samples were analyzed in 1999 for DM and ash using standard methods (Association of Official Analytical Chemists, 1990). Nitrogen content was determined using Kjeltec 1026 distilling unit (Kjeltec System, Tecator, Hoganas, Sweden) and CP expressed as N x 6.25. In vitro dry matter digestibility (IVDMD) was determined using the technique by Tilley and Terry (1963). Neutral detergent fiber and ADF were determined by nonsequential methods (Goering and Van Soest, 1970), except that Whatman 541 hardened ashless filter paper (Hillsboro, OR) was used rather than fritted disc crucibles. In the winter of 2000–2001, forage samples were analyzed for DM and ash as described for the previous year, and further analyzed for N (LECO model FP-528; LECO Corp., St. Joseph, MI), ADF, and NDF (ANKOM²⁰⁰ fiber analyzer; ANKOM, Fairport, NY). Dry matter digestibility was estimated using an equation developed in our laboratory on forages comparable with forages used in this study (Nayigihugu et al., 2006).

Beef Cows
Sixty-four (winter of 1999–2000) and 54 (winter of 2000–2001) pregnant Angus x Gelbvieh rotationally crossbred cows were weighed on 30 Nov. and 1 Dec. 1999 and 6 and 7 Nov. 2000, respectively. Body condition scores (1-to-9-point scale; Wagner et al., 1989) were obtained by three independent evaluators on weighing dates. Animals were equally allotted to windrowed or baled forage treatment by body weight (BW), BCS, and estimated days pregnant (EDP) according to a randomized complete block design in which pastures were blocks. On the basis of estimated forage availability, 20 cows (winter of 1999–2000) and 13 cows (winter of 2000–2001) per treatment were allotted to the 16.2-ha pasture, while 12 cows (winter of 1999–2000) and 14 cows (winter of 2000–2001) were allotted to the 10.1-ha pasture.

During 1999, average EDP for both groups of cows allotted to Meadow A was 88; average EDP for cows allotted to Meadow B was 89 and 92 for windrow- and bale-fed cows, respectively. During 2000, average EDP for cows allotted to Meadow A was 153 and 144 for windrow- and bale-fed cows, respectively; average EDP for the cows allotted to Meadow B was 148 and 151 for windrow- and bale-fed cows, respectively. Estimated days pregnant at the time of ultrasound were confirmed with actual calving dates, and it was determined that ultrasound underestimated days pregnant by 21 d.

Cows were fed 12.4 kg (as-fed) per cow baled forage between 0800 and 0900 daily. Adjustments were made by weighing hay remaining from the previous day, and 5% was the target amount to remain. Free-choice water and loose mineral supplement were provided (Cu No. 1 A&C Mineral ML, Purina Mills, Inc., St. Louis, MO; guaranteed analysis [percentage of DM]: Ca, 8–10; P 15; NaCl, 8–10; Mg, 0.3; Cu, 2500 ppm; vitamin A, 2.2 x 10⁵ IU kg^–1). No other supplement was provided to cows during the experiment.

On 22 Dec. 1999 and 6 Dec. 2000, interim BW and BCS were determined for all experimental cows. Final BW and BCS were obtained on 12 and 13 Jan. 2000 and 19 and 20 Dec. 2000 for the winters of 1999–2000 and 2000–2001, respectively.

Based on the number of days and animals included in the experiment, and the total amount of forage available, cow-days of forage were calculated to estimate utilization during the 1999 grazing period. The grazing period was extended for 5 d during the latter year. During the 2000 grazing period, forage utilization was estimated only for 42 d because there was no cleanup period. The difference between the total amount of forage available and the estimated forage utilization provided the approximate amount of forage wastage.

Statistical Analysis
Forage and animal performance data were analyzed separately for each year because of vastly different environmental conditions between the 2 yr. Additionally, sampling dates and analytical protocols were not the same between the 2 yr. Forage data were analyzed as a split-block in a randomized complete block design (RCBD) with the GLM procedure of SAS (SAS Institute, Inc., Cary, NC). The block effect was meadow (Meadow A and Meadow B), and the treatment effect was forage type (windrowed and baled forage); pasture x treatment error (error a) was used to test treatment effects. Sampling date (split effect) and respective two- and three-way interactions were tested with residual error (error b). After a significant (P 0.05) preliminary F test, least-squared means were compared using the LSMEANS option of SAS.

Animal performance data were analyzed within each sampling period and year as a RCBD using the GLM procedure of SAS. The block effect was meadow and the treatment effect was forage type. Following significant (P 0.05) F tests, least-squared means were compared as previously mentioned.

Economical Analysis
Production data for 1999 and 2000 were utilized to determine the costs and savings associated with windrow grazing and feeding baled forage. Labor and fuel usage for each field operation (cutting, raking, combining windrows, baling, and bale transport and storage) were summarized, and costs were calculated for each operation. Costs also were calculated for fencing, watering/checking the animals, hay transport and feeding, and wasted forage. Costs of windrow grazing and feeding baled forage were compared using estimates from the University of Wyoming Experimental Farm, Doane Agricultural Services (2000), and information collected from hay producers by Agee (1975). Additionally, ownership and operating costs for the field operations, as summarized by Doane Agricultural Services (2000) and an unpublished survey of Albany County, Wyoming, ranches were averaged with University of Wyoming Experimental Farm data to provide a more conservative and reliable estimation of costs Mg^–1 of forage associated with the two feeding methods.

	RESULTS AND DISCUSSION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
Forage Quantity
Winter of 1999–2000
Total small square bale production was 24.9 Mg DM, on alternate windrows on one-half of each meadow (6.6 ha; Table 1). It was assumed that the amount of windrowed forage on adjacent windrows was the same, although there was most likely more in the unbaled rows since there is, on average, 8% loss with baling and transporting forage (Anderson and Mader, 1985). With 32 cows allotted to each treatment for 42 d, the experimental period included 1344 to 1664 cow-days. A cleanup period after the study was 320 cow-days on the windrowed treatment. Availability of windrowed forage including regrowth was 23.9 kg cow^–1 d^–1 including the cleanup period (Table 1). On the basis of this approximate availability, 25.4 Mg (Table 2) of windrowed forage, including the regrowth, were utilized during the experimental period. Regrowth beneath windrows (5.4% of area) yielded an average of 1.17 Mg ha^–1 and regrowth between windrows (94.6% of area) yielded an average of 1.01 Mg ha^–1 (Table 3). Total regrowth production was 14.83 Mg. Therefore, total available forage on the windrow grazing treatment was an estimated 39.69 Mg, providing 23.85 kg cow^–1 d^–1.

View this table: [in this window] [in a new window]   Table 2. Estimated forage utilization and wastage during 1999 and 2000 grazing periods.

Winter of 2000–2001
Small bale production was 15.31 Mg from alternate windrows on one half of each meadow. The quantity of forage available on the alternate windrows was assumed to be the same. Based on 27 cows allotted to each treatment for a period of 42 d, the experiment included 1134 cow-days on each treatment, and the availability of windrowed forage was estimated to be 13.5 kg cow^–1 d^–1 or 15.31 Mg of windrowed forage, excluding regrowth. Regrowth beneath and between windrows added 24.37 Mg of forage and boosted total available forage for windrow-grazing cows to 34.99 kg cow^–1 d^–1 (Table 1). Regrowth represented more forage than windrows. Bale-fed cows were offered 14.19 Mg of forage that was equivalent to 12.51 kg cow^–1 d^–1. An additional 19.73 Mg of forage regrowth was also available (Table 1). Therefore, bale-fed cows had 33.92 Mg or 29.91 kg cow^–1 d^–1 available.

Forage regrowth available to the animal, was greatest (P < 0.01) beneath windrows followed by regrowth between windrows and regrowth on the bale-fed site in 2000 (Table 4). Greater precipitation in September and October (Fig. 1 ), as well as earlier harvest (July) in 2000 than in 1999, led to forage regrowth amounts greater than the amount of forage baled and the amount left in windrows.

View larger version (15K): [in this window] [in a new window]   Fig. 1. Monthly 30-yr, 1999, and 2000 precipitation near Laramie, WY, from August 1999 and 2000 to January 2000 and 2001.

Forage NDF (Table 5) in windrows and bales decreased (P 0.01) from September to November sampling dates, and then increased for the January samples, most likely due to leaching of nutrients. This trend does not agree with Lux et al. (1999) or Munson et al. (1999), who reported an increase in NDF with progression of the feeding period. Forage IVDMD or CP did not vary with forage type (P = 0.60 or 0.11) or date (P = 0.94 or 0.61). There were no forage quality differences (P 0.12) with location of regrowth (Table 3). Green regrowth under windrows has been observed in production settings (May et al., 1999) and was suggested to increase the quality of available forage. However, results of this study suggest that forage regrowth under windrows is of comparable nutritional value to forage between windrows, and perhaps less nutritious than the windrowed forage or baled forage. Regrowth located between the windrows and on the halves of the meadows where cows were fed bales were exposed to the same environmental conditions and would be expected to be of similar quality during winter.

Winter of 2000–2001
Nutrient composition of windrowed and baled forage fed to beef cows during the winter of 2000–2001 is presented in Table 6. A forage type x sampling date interaction (P = 0.05) was noted for ADF. Windrowed forage tended to have greater ADF (P = 0.07) than baled hay from September through January. Greater ADF of forage left in windrows from September to January may be associated with greater exposure of windrow forage to the environment and weathering. Consequently, estimated IVDMD was greatest (P = 0.07) at harvest for both windrowed and baled forage, and declined as the grazing season progressed.

Forage CP tended to be greater (P = 0.08) for forage left in windrows compared with baled forage, but was not affected (P = 0.76) by sampling date. Lux et al. (1999) reported that perennial meadow forage harvested in August and left in windrows until grazing in December did not differ in CP compared with baled forage from the same meadow. Likewise, Nayigihugu et al. (2002) indicated no change in forage CP of windrows throughout the grazing season. The CP content of regrowth beneath windrows was greater (P = 0.03) than CP content of regrowth between windrows and regrowth on bale-fed sites (Table 4). Regrowth mass under windrows was greater (P < 0.01) than regrowth between windrows and on the bale-fed site, which may have occurred because cows had limited access to regrowth beneath windrows once an ice crust covered the windrows. Regrowth locations did not differ in ash and NDF (P = 0.11 and 0.29) (Table 4). Regrowth ADF tended to be less (P = 0.08) underneath than between windrows and on the bale-fed site. Consequently, forage regrowth underneath the windrows tended to be more digestible (P = 0.08) compared with regrowth between windrows.

Cow Performance
Winter of 1999
Windrow-fed cows were 10.1 kg heavier (P = 0.02) at the mid-weight period and 14.4 kg heavier (P = 0.04) at the final weighing date (Table 7). Difference in BW corresponded to greater ADG observed for the first 21-d period (P = 0.02) as well as overall (P = 0.04). Cow BCS was not different (P = 0.25) at the midpoint, but windrow-fed cows had greater (P = 0.02) BCS at the final measurement. In contrast, Lux et al. (1999) noted that bred heifers fed windrowed meadow forage for 73 d did not differ in BW or BCS compared with similar heifers fed baled forage from the same meadow. Likewise, Munson et al. (1999) also reported no differences in ADG or BCS for bred heifers grazing windrowed millet hay or fed baled millet hay. Similar to results from our study, cows grazing rake-bunched meadow forage in Oregon were 10 kg heavier than cows fed baled hay by the end of a 5-mo grazing period and 44 kg heavier than cows grazing standing forage (Turner and Angell, 1987). Furthermore, the BCS was lower for cows on standing forage but similar for hay-fed and windrow-grazed cows.

Several factors may have influenced the differences in cow performance on the two treatments. Cows grazing windrows grazed regrowth to a greater extent. Also, cows on the windrowed forage treatment had the opportunity to consume forage throughout the day, while cows fed bales were only offered enough feed for 1 d, and this feed was offered only one time each day. Greater intake and ADG have been observed in cattle offered full-feed versus restricted amounts of feed. Anderson and Mader (1985) state that dry pregnant cows eat 20 to 30% more than their needs when given free-choice access to hay.

Though temperatures were milder than usual during the grazing period, the bedding may have favored performance because cows grazing windrows would have lost less energy to the environment. Loss of heat due to conduction can be 30% of resting heat production (Stanier et al., 1984).

Winter of 2000–2001
Cows fed windrowed forage had similar (P = 0.85) BW as cows offered baled forage at the end of 21 d grazing period (Table 7). Cows offered windrowed forage tended to be lighter (P = 0.09) at final weighing compared with cows offered baled hay, resulting in less ADG (P = 0.03) during the 42-d study period, compared with cattle fed baled forage. Final BCS was not affected (P = 0.96) by forage type. Earlier reports have indicated that cattle fed windrowed forage had similar (Lux et al., 1999; Munson et al., 1999) ADG and BCS compared with cattle offered baled forage. Snow accumulation (41–43 cm) during the grazing period formed an icy crust on the top of the windrows, limiting access by cattle. The above phenomenon was also observed by Turner and Angell (1987). The observed reduction in forage intake due to inaccessible forage appeared to result in weight loss by cows grazing windrowed forage.

Unlike the winter of 1999–2000, cows offered windrowed forage consumed mostly regrowth between windrows because of ice accumulation on windrows. Cattle grazing windrows utilized 0.61 Mg ha^–1 (33%), while cows fed baled forage utilized 0.33 Mg ha^–1 (22%) of standing regrowth during the winter grazing period (Table 4). However, as noted previously, regrowth between windrows had greater fiber (ADF) and lower digestibility than regrowth underneath windrows (Table 4).

Economics
Averaged across 1999 and 2000, hay production in the form of large round bales was 3.12 Mg ha^–1 on the bale-fed halves of the two meadows. The cost per hectare for labor and fuel, based on hours and usage recorded for cutting, raking, combining windrows, baling, bale transport, bale storage, and bale feeding, as well as the cost of wastage of windrow grazing and bale feeding is presented in Table 8.

View this table: [in this window] [in a new window]   Table 9. Costs per megagram of forage for windrowed and feeding baled hay.

	CONCLUSIONS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

	REFERENCES

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 

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