AT HARVEST EFFECTS ON YIELD AND QUALITY OF WINTER CEREALS FOR SILAGE

MATURITY AT HARVEST EFFECTS ON YIELD AND QUALITY OF WINTER CEREALS FOR SILAGE Carol Colla';, Allan Fulton2 and Marsha Campbe/f, Fann Advisors Winter forages are an important component in feeding programs on California dairies. In the San Joaquin Valley, approximately 500,000 acres of winter cereals are grown each year.the majority is put up as silage, although oats are sometimes harvested as hay, particularly in the northern and central San Joaquin Valley. Exact figures on acreage are hard to come by since not all counties report these crops in the same way. Winter forages for silage or hay are well suited to double-crop with corn. The cereal forages are typically planted November through December and harvested at the soft dough stage of maturity in April or May. Corn for silage is planted in May and June and harvested as silage August through September. Many dairy producers and nutritionists consider winter forage a dry cow or heifer feed, reserving corn silage for lactating cows. Cereal silages are generally lower in energy concentration than corn silage. One reason for the poor feeding value of winter forages for lactating cows relates to the stage at which the crop is harvested. Maturity has important effects on the quality of cereal forages. Four stages of growth or maturity are generally recognized in small grains for forage. Following are descriptions of each stage: 1. Boot stage- Head remains in the stem, sheath of flag leaf separates and awns begin to emerge. Nutrient content is highest at this stage. Begins late March or early April depending on planting date. Lasts about a week to ten days. 2. Flower stage- Pollination and initial development of grain occur. Head elongated out of flag leaf. Pollen often seen in awns. Plant is green, but lower leaves may begin to die. Typically occurs mid to late April, depending on planting date and lasts five to seven days. 3. Milk stage- White, milk-like fluid occupies kernel, made up of water and starch. Embryo develops fully. This stage is least palatable to livestock. Research has shown slower and less efficient gains in beef cattle and Iambs compared to dough stage. Lasts about ten days. 4. Dough stage- Water content of the kernel decreases to dough consistency, changing from soft to hard dough in a week to ten days. Lowest forage protein content and fiber digestibility, but highest forage yields. I Dairy, Forage and Livestock Farm Advisor, Kings County, University of California Cooperative Extension 680 Campus Drive, Hanford, CA 93230 2 Soils, Water and Cereal Crops Farm Advisor, Kings County, University of California Cooperative Extension 680 Campus Drive, Hanford, CA 93230 3 Field Crops and Weed Control Fann Advisor, University of California Cooperative Extension. Stanislaus County, 733 County Center 3 Ct., Modesto, CA 95355 174

The majority of growers and dairy producers harvest winter forages for silage at the soft dough stage to achieve the highest dry matter yields per acre. Unfortunately, this is also the stage at which fiber digestibility is lowest. Dairy producers are well aware of the tremendous difference in feeding value between alfalfa harvested at bud stage compared with a mid- or full bloom stage harvest. Quality testing programs for alfalfa have been in place in California for over 30 years, based on research at UC Davis that has shown greater digestibility, faster weight gains, and higher milk production from cattle fed alfalfa harvested at an immature stage. Maturity of alfalfa is closely related to- its fiber content; as stage of maturity increases, so does its fiber content, and digestibility of the plant decreases. Laboratories that test alfalfa hay predict TDN (total digestible nutrients) and energy values for an alfalfa sample based on its fiber content. These values in turn are used in establishing relative economic values of different lots of alfalfa hay. Are the same principles true for winter cereals grown for silage or hay? There is limited information available on the feeding value of winter forages for dairy cattle, particularly as it relates to stage of maturity at harvest. Following is a review of research on this subject conducted in California. Published reports from other locations (which in general support the studies in California) are listed at the end of this paper as additional references for those who want to do more reading on the subject. An early study in California was conducted at UC Davis over 35 years ago (1). Feeding and digestion trials (with sheep) were used to evaluate the feeding value of seven different growth stages of Kanota oats. Selected data from this study are presented in Table I. Table I. Composition of forage in oat maturity feeding trials, UC Davis, 1958. (100% dry matter basis) Comparisons 21% boot 1 % flower 18% flower 44% milk Lignin, % 4.9 5.8 6.4 9.0 8.4 42% dough Crude fiber, % 21.0 24.0 27.0 29.0 27.0 Crude protein, % 18.0 16.0 14.0 12.0 12.0 Digest. protein, % 1.0 10.5 8.5 6.4 7.0 TDN, % 65.0 64.0 60.0 50.0 53.0 Crude fiber increased with advancing maturity to milk stage and then decreased at dough stage. Protein decreased with advancing maturity to milk stage. Crude protein was more digestible at the younger plant growth stages. TDN (based on the digestion trial) was 65% at boot stage, but decreased to 50% in the milk stage. The formation of grain caused an increase in TDN to 53% at dough stage. Daily weight gains of sheep fed the milk and dough stages were significantly lower than gains for sheep fed the other stages. Feed consumption was lower for 175

the immature stages and higher for the milk and dough stages. When the data were expressed on a per acre basis, yield of TDN per acre was not greater after 18% flower stage, although total dry matter yield had increased. Lamb production (Ibs. of Iamb per acre -an indication of how well the nutrients are utilized after digestion) increased until 18% flower stage, and then decreased at milk stage. When the forage entered the dough stage, lamb production/acre increased again, although not to the level at 18% flower stage. Based on the results of this study, the researchers concluded that there were two critical times for harvest of oats- early flower and dough stage. Two more recent feeding studies, a lactation and a digestion trial, were funded by the California Milk Advisory Board and conducted at UC Davis in 1986. These studies evaluated the nutritional value of mixed winter cereals with vetch when used as silage or hay (2). In the lactation study, a winter forage mixture containing oats, wheat, barley and vetch was harvested at the flower stage of maturity for the oats and preserved as silage. Feeping value for dairy cows in terms of dry matter intake and milk production was determined. Fifty lactating Holstein cows were assigned to one of three treatments in the lactation study. Treatments involved replacing a portion of the chopped alfalfa hay in the diet with cereal silage. All the forage in the control diet was chopped alfalfa hay and this was referred to as the looa diet. The 66A diet contained 66% of its forage from alfalfa and 34% from cereal silage, while the 34A diet contained 34% alfalfa and 66% cereal silage. Data for the lactation study are in Table 2. Table 2. Perfonnance of lactating cows at three levels of cereal silage, UC Davis, 1986 f Item 100 A (no silage) 66 A (34% silage) 34 A (66% silage) DM Intake, Ibs/day 45.0 44.5 41.2 Milk, Ibs/day 71.9 71.9 71.4 4% FCM, Ibs/day 67.7 69.9 68.4 Fat, % 3.68 3.86 3.74 Fat, Ibs/day 2.60 2.76 2.65 Protein, % 3.06 3.06 2.90 Protein, Ibs/day 2.18 2.18 2.05 Total Solids, % 12.62 12.73 12.30 Total Solids, Ibs/day 9.00 9.08 8.75 Dry matter intake was lower for cows receiving the high cereal silage diet, but yields of milk and 4% fat-corrected milk were not affected by diet. Milk protein was lower for cows fed the high cereal silage diet (34A), probably due to lower energy intake by cows fed this diet. The authors concluded from the lactation study that cereal silage harvested at flower stage could be

fed to dairy cows in early lactation. However, they cautioned that cereal silage harvested at later maturity could result in reduced feed intake (as a consequence of rumen fill) and result in reduced milk production. -0 In the digestion study, the same forage mix was harvested as hay at the flower, milk, soft dough and hard dough stages of maturity and fed to sheep to determine forage digestibility during a 21 day digestion trial. Composition of the cereal forage at the different maturities is shown in Table 3. Table 3. Chemical composition of cereal hays, UC Davis, 1986. (100% dry matter basis) Item Flower Milk Soft Hard Crude protein, % 9.5 9.2 dough dough 8.5 7.6 Acid detergent fiber, % 41.2 40.1 39.3 37.2 Neutral detergent fiber, % 65.6 64.3 63.6 62.1 Lignin, % 4.6 4.4 4.7 5.3 As the forage matured, crude protein, ADF (acid detergent fiber) and NDF (neutral detergent fiber) decreased. Lignin content increased with advancing maturity. Lignin is a chemical component of plants that is associated with decreasing plant digestibility. Maturity at harvest dramatically affected the hay's digestibility by the sheep, shown in Table 4. Table 4. Apparent nutrient digestibility and mn Davis, 1986. (% digestibility) of cereal forage at four maturities, UC Item: Flower Milk Soft dough Hard dough DM 55.4 54.6 51.6 48.9 ADF 47.5 44.0 39.5 34.6 NDF 52.4 49.5 45.2 39.3 mn 48.0 47.0 45.4 43.8 As the forage maturity increased, the digestibility of dry matter, energy, ADF and NDF decreased. Consequently, the mn content of the forage decreased with maturity. Relationships between chemical constituents and TDN were determined by regression analysis. Correlation coefficients for TDN with lignin, crude protein, ADF and NDF were r = -0.75, +0.75, +0.72 and +0.69. The negative correlation for lignin indicates that as the lignin content of the forage increased with advancing maturity, the TDN content decreased. Likewise, the positive correlation of +0.72 for ADF indicates that TDN content increased as the ADF increased, 177

which is opposite to the ADF and TDN relationships seen with alfalfa. The authors pointed out that erroneous results will be obtained when trying to predict the energy content of cereal forages if prediction equations derived from research with legumes are used. Other stage of harvest studies with winter cereals have been conducted by UC farm advisors during 1983-1985, and in 1993. In 1983, Tulare County farm advisors evaluated several winter forage blends and a few individual components for yield and quality at boot, flowering, milk and soft dough stages of growth (3). Crude protein was highest at boot stage and decreased with each harvest. All treatments had lower yields at boot stage. No yield differences were observed between treatments at boot stage, but significant differences between several treatments were noted at the other growth stages. Table 5. Yield or winter forages harvested at four stages of growth, UCCE Tulare County, 1983. (tons/acre at 70% moisture) Treatments containing legumes had lower yields than those containing only cereals, except for a blend with horsebeans. Digestible dry matter (DDM) was estimated from in vitro rumen digestion. DDM/acre was highest for cereals harvested at the flower stage, Table 6. Table 6. Digestible dry matter (DDM) yield of forages at four growth stages, UCCE Tulare County, 1983. (100% DM basis) Similar tests were conducted in Tulare County in 1984, with similar results (4). No yield advantage was noted by adding legumes to barley or triticale. Treatments with legumes tended to have higher crude protein percentage, but protein/acre was not greater since total yield was 178

slightly reduced by including legumes. Crude protein was generally lowest at the soft dough stage and highest at the flowering stage due to the cereal grains filling with starch. TDN per acre in both years increased with advancing maturity, but caution should be used in interpreting this information. TDN was estimated from a prediction equation that most likely did not account for the ADF and TDN relationships for winter forages described in the 1986 UC Davis study. Thus, TDN values for soft dough stage of maturity may have been overestimated in this trial. In 1985, UC farm advisors in Merced and Stanislaus Counties conducted a stage of harvest trial with six cereals, two mixes and five legumes (5). The cereals were harvested at boot. flower, milk and soft dough stages. There was a 15% increase in yield from flower to soft dough in oats, while the crude protein decreased by 19% during the same period. Highest protein per acre for oats was achieved when harvested at flower stage. All cereals had increased yields with advancing maturity. In all treatments, protein decreased with advancing maturity. Percent ADF tended to follow a curvilinear pattern, increasing from boot to flower stage, leveling out at milk stage and decreasing at dough stage. The farm advisors noted that optimum harvest depended on whether quality or yield was more important to the user. If the forage would be fed to dry cows or heifers, quality was not as important as yield. On the other hand, the value of harvesting early increased if high producing cows were fed the winter forage. Some dairy producers have recently found that certain winter forages can successfully substitute for corn silage in diets for lactating cows. Wheat, in particular a public variety named Yecora Rojo, has become the winter forage of choice in the South San Joaquin Valley because of its high yields, relatively low fiber and high protein compared to other small grains for forage harvested at the soft dough stage. This development prompted UC farm advisors in Kings County to conduct the most recent stage of harvest trials in Kings County in 1993 (6). The prolonged California drought made the project even more intriguing. With limited water, early harvest of winter cereals could become important. Winter rains supply part of the water required for cereal crops in the South Valley, but even in a normal rainfall year, growers have to irrigate cereals once or twice to reach soft dough stage. In addition to potential water savings, early harvest could also allow earlier planting of corn or cotton. Varieties traditionally used for soft dough stage harvest may not be those best suited for early harvest. In this trial, six cereals were harvested at boot and at soft dough stage. Attempts were made to select an early and a late maturing cultivar each of wheat, barley and triticale. Yield data were collected and nutrient analyses were made of each cereal at each harvest stage. Apparent dry matter digestibiljty was determined by the nylon bag method. This measurement is made by suspending nylon bags filled with a known quantity of the feed being tested in the rumen of a fistulated steer (a steer with a hole in his side). After 48 hours, the bags are removed, washed and dried and the amount of feed digested is determined. The forage trial was planted on November 20. All varieties were planted in replicated small plots within a 30 acre field of Yecora Rojo wheat. Winter rains supplied approximately 11" of water and the field was irrigated on March 23 and Apri113. Each variety was harvested when it reached boot and soft dough stages of maturity. Results for boot stage harvest are in Table 7 and for soft dough stage harvest in Table 8. Yield in tons/acre is corrected to 70% moisture 179

(30% dry matter) Nutrient analyses are reported on a 100% dry matter basis. TABLE 7. Wheat, Barleyand UCCE Kings County, 1993. Triticale: Yield and Feeding Value at Boot Stage Harvest, BARLEY WHEAT TRITICALE Solum SB 458 Yecora Rojo Dirkwin 301 303 Harvest date 3/12 3/22 3112 4/7 3122 3/18 Plant height, " 42.25 35.25 24.50 32.00 34.50 35.75 Dry matter at harvest, % 15.33 13.86 19.46 18.26 16.37 17.69 Yield, tons/acre 12.95 11.94 8.23 16.53 13.68 11.70 Protein, % 13.48 16.18 16.23 12.65 13.21 12.37 ADF, % 36.16 35.93 30.85 34.07 36.47 35.90 NDF, % 58.67 57.33 52.83 55.18 59.75 59.76 Lignin, % 3.29 3.33 2.82 3.27 3.29 3.52 Cellulose, % 30.49 30.58 24.23 28.70 31.07 30.37 Ash, % 10.48 11.86 11.55.34 10.59 9.38 Digestibility, % 75.00 78.67 79.67 79.08 77.67 75.92 Dirkwin wheat had the highest yield at boot stage harvest, 16.53 tons/acre. Yield for Dirkwin was double the yield of Yecora Rojo, which had the lowest yield at boot stage, 8.23 tons/acre. The barleys and triticales had yields that fell between the yields of the two wheats. Feeding value was best at boot stage harvest for Yecora Rojo. Protein was highest for Yecora (16.23%) followed closely by SB 458 with 16.18% protein. Fiber levels were lowest and dry matter digestibility was highest for Yecora at boot stage. Based on the results of harvest at boot stage, Dirkwin wheat had highest yield with good feeding value. Other studies with Dirkwin at boot stage have reported higher protein percentage than the 12.7% in this trial. Feeding value was best for Yecora Rojo, but its yield was only half that of Dirkwin. Since it is later maturing, Dirkwin reaches boot stage during a time when weather conditions are better for field drying. But it also requires more inputs to get to boot stage than the earlier varieties. Dirkwin was the only variety in this trial that required an irrigation to get to boot stage of maturity. Cotton growers could consider Solum barley harvested at boot stage as a winter crop. Solum has been used successfully in dryland grain conditions. It is very tall, vigorous and will tolerate saline soil conditions as well as anything else. However, it will lodge severely if irrigated more than once, so it should not be considered for later harvest. In a 180

normal rainfall year Solum should not need irrigation to reach boot stage T ABLE 8. Wheat, Barley and Triticale: Harvest, UCCE Kings County, 1993.. Yield and Feeding Value at Soft Dough Stage BARLEY WHEAT TRmCALE SoIum SB 458 Yecara Raja Dirkwin 301 303 Harvest date 4/12 4116 4/23 5/7 5/7 4/30 Plant height, " 48.25 42.25 36.50 48.00 52.50 51.25 Dry matter, % at harvest 30.72 27.32 35.1 33.65 37.28 34.66 Yield, tons/acre 24.24 20.10 25.47 31.31 35.84 34.01 Protein, % 8.68 9.68 10.21 9.28 8.36 8.02 ADF, % 32.20 33.87 28.27 36.22 31 1 32.31 NDF, % 57.54 56.38 50.11 57.94 55.47 55.27 Lignin, % 4.41 4.41 4.12 4.77 4.16 4.47 Cellulose, % 26.31 28.57 21.40 29.04 25.20 26.18 Ash, % 7.00 8.92 7.65 9.24 6.78 6.69 Digestibility, % 66.08 67.42 69.50 65.75 68.33 65.42 At soft dough stage harvest the triticales (Resource Seeds) had highest yields. Triticale is a cross between wheat and rye that has always yielded well in University forage tests, but quality has been a problem. Quality improvements have been made and as can be seen in Table 8, the 301 triticale variety has quality parameters that approach those of Yecora Rojo. Dirkwin wheat yielded more than Yecora Rojo, but less than the triticales. Quality appears poorest for Dirkwin, in part because it was not allowed to go all the way to soft dough stage of maturity. Dirkwin is a late maturing wheat-- about a month later than Yecora Rojo (notice harvest dates in Table 8). To reach soft dough stage, Dirkwin needed another 7-10 days, which would have put harvest on May 14-17. Dirkwin is popular in the northern San Joaquin Valley as a forage crop. It is leafy and fine stemmed, so it can be used as silage or hay. Yecora Rojo produced 25.47 tons/acre, comparable to yields measured on local farms. It had lower levels of fiber components (ADF, NDF, cellulose and lignin) and higher % protein than the other varieties. The superior feeding value based on lab analyses is backed up by the apparent digestibility which is highest for Yecora Rojo. The two barleys in the test yielded less than Yecora Rojo and feeding value was lower. Solum barley lodged badly when taken to soft dough harvest. SB 458 is a Northrup King barley that 181

has yielded competitively in grain trials. Based on the results of harvest at soft dough stage of maturity, as well as results from other forage trials and five years of experience on local farms, Yecora Rojo wheat combines the attributes of high yields with excellent feeding value. One drawback of Yecora Rojo is its susceptibility to leaf rust and barley yellow dwarf virus. These diseases can be a problem during wet, cool growing seasons. Resource Seeds 301 triticale produced considerably higher yields than Yecora Rojo with slightly lower quality in this trial. This triticale variety will be an attractive option to Yecora Rojo wheat when it becomes commercially available. r SUMMARY... Winter forages produce lower dry matter yields at boot compared to more advanced growth stages where data were reported. Boot stage yields of cereals in the 1993 Kings County trial ranged from 33 to 60% of soft dough yields, depending on cultivar and species. Nutritive value as determined by animal performance studies and chemical analyses is highest at boot or flower stages when compared to later stages. Digestibility of nutrients declines with advanced maturity. The fiber content of cereal forages is not a good predictor of maturity. As the fiber content of the stem increases with advanced maturity and becomes less digestible, the grain kernels are developing at the same time. The grain, being very low in fiber, dilutes the increasing fiber of the stem, resulting in little change in total plant fiber as the plant matures. Total fiber content actually declines as the cereal plant develops to the dough stage, resulting in a curvilinear relationship between fiber and maturity. Laboratory tests for fiber that are used to predict maturity and feeding value of alfalfa are inappropriate for cereal forages. At the present time, there is no laboratory test that can accurately estimate the feeding value of cereal forages. The varied success met by dairy producers feeding winter cereal silage to lactating cows may be related to several factors, including maturity at harvest, variety or cultivar quality differences, silage moisture levels and erroneous laboratory energy estimates. Winter forages can be used successfully in the rations for high producing cows. Research is needed to develop equations for use with cereal forages that represent and can accurately predict feeding value at different growth stages when harvested. f Few studies have focused on the nutrients/acre aspect of winter forages. How much more is the lower yielding, yet more nutritious, less mature forage worth? Can early harvest be justified when total tons/acre is so much lower? A dairy ration formulation program developed at UC Davis (PC Dairy) was used to determine the relative economic value of varying qualities of cereal forages based on their palatability, consumption and nutritional values. Use of this program illustrates the point that increased value of early harvested forage depends on the level of milk production of cows consuming it. If the forage is fed to high producing cows (who need high quality forages in addition to liberal amounts of grain-concentrates to maintain high milk yields), then the economics may favor early harvest. If the intended use for the forage is feed for low producing cows, dry cows or growing heifers, then the higher nutritional value may be negated by low yields. Regardless of what the computer predicts, if growers are not monetarily compensated for lower yielding, high quality silage, the market will always favor 182

harvest when total yields are highest- at soft dough stage Other considerations need mentioning. Less mature forages are much wetter at harvest than soft dough stage. Moisture levels of 80 to 85% for boot stage are typical compared to 65 to 70% for soft dough stage. Boot stage forage can not be properly ensiled at these moistures. Consequently, boot or flower stage harvested forages must be swathed and field wilted for a day or two (depending on weather). Soft dough stage forages can be direct chopped. Field wilting in the early spring adds an element of risk, since the weather is somewhat unpredictable in March and April. Boot (or early flower) and soft dough stage cereal forages are two very different products, each with distinct good and bad points. Growers, dairy producers and nutritionists should recognize this and try to take advantage of the attributes of each type of forage by targeting it to the best end use. REFERENCES 1. Meyer, J.H., W.C. Weir, L.G. Jones, and J.L. Hull. 1957. The influence of stage of maturityon the feeding value of oat hay. J. Anim. Sci. 16:623. 2. DePeters, E.J., J.F. Medrano, and D.L. Bath..1989. A nutritional evaluation of mixed winter cereals with vetch utilized as silage or hay. J. Dairy Sci. 72:3247. 3. Wright, S. and T. Shultz. publication. 4. Wright, S. and T. Shultz publication. 1983 Winter forage variety and harvest stage trial. County 1984 Winter forage type and harvest stage trial County 5. Feyler, M. and D. Gisi, 1985. report of 1986 winter forage trials. Winter cereal stage of harvest trial Published in regional 6. Collar, C. and A. Fulton stages. In progress. 1993. Yield and quality of winter cereal forages at two growth ADDITIONAL REFERENCES 7. Chemey, J.H. and G.C. Marten. 1982. Small grain crop forage determinants of quality and yield. Crop. Sci. 22:227. Biological and chemical 8 Christiansen, D.A., B.D. Owen, G Steacy, W.L Crowle, and J.P. Mtimuni 1977 183

Nutritive 57:537. value of whole crop silage made from seven cereal cultivars. Can. J. Anim. Sci.,r 9. Fisher, L.I., and D.B. Fowler. 1975. Predicted forage value of whole plant cereals. Can. I. Plant Sci. 55:975. 10. Fisher, L.I., I.R. Lessard, and G.A. Lodge. 1972. Whole crop barley as conserved forage for lactating cows. Can I. Anim. Sci. 52:497. 11. Helsel, Z.R. and I.W. Thomas. 1987. Small grains for forage. I. Dairy Sci. 70:2330. 12. MacGregor, A. W., and R.A. Edwards. 1968. Ensilage of whole crop barley II. Composition of barley and barley silage at different stages of growth. I. Sci. Food Agric. 19:661. 13. Marx, G.D. 1980. Use of small grain for cattle. Minneapolis, MN. Proc. Minnesota Nutr. Co~f. 14. -Polan, C.E:, T.M. Starling, I.T. Huber, C.N.Miller, and R.A. Sandy. 1968. Yields, compositions, and nutritive evaluation of barley silages at three stages of maturity for lactating cows. I. Dairy Sci. 51:1801. 15. Snyder, T.J., C.E. Polan, and C.N. Miller. 1979. Effects of dry matter content of barley silage on nutrient preservation and animal response. J. Dairy Sci. 62:297. ~ 184