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Case Study : Effects of feeding fresh sugar beets to lactating dairy cows on milk production and milk composition
The Professional Animal Scientist 32 (2016):253–258; http://dx.doi.org/10.15232/pas.2015-01464 ©2016 American Registry of Professional Animal Scientists. All rights reserved.
C freshS sugar: Effects of feeding beets to lactating ase
tudy
dairy cows on milk production and milk composition Essi Evans,*1 Duane Bernhardson,† and Josh Lamont‡ *Essi Evans Technical Advisory Services Inc., Bowmanville, Ontario, Canada, L1C 3J1; †Betaseed Inc., Grand Forks, ND 58201; and ‡Atlantic Dairy and Forage Institute, Fredericton Junction, NB, Canada, E5L 1R1
ABSTRACT Sugar beets are a high-DM-yielding energy crop and offer the potential to replace grain in the rations of dairy cows. However, there is limited information regarding the amount of beets that can be included in the TMR. This study was conducted to evaluate the responses of mid-lactation Holstein cows to rations containing varying amounts fresh sugar beets. Sixteen multiparous mid-lactation Holstein cows were used in a 4 × 4 Latin square study, with feeding periods of 21 d. Rations contained 0, 8, 16, and 24% beets (DM basis), with beets replacing the grain portion of the diet, which was composed of corn and barley. Milk weights and DMI were evaluated for the last 7 d of each period. Milk components were determined on the final 2 d of each period. There were no differences (P > 0.05) in milk yield (26.6, 26.0, 26.4, and 26.4 kg), fat percentage (4.64, 4.66, 4.72, and 4.72%) and protein percentage (3.54, 3.44, 3.47, and 3.44%) for rations containing 0, 8, 16, and 24% beets, respectively. Likewise, there were
1 Corresponding author: essievans@ sympatico.ca
no differences (P > 0.05) in 3.5% FCM and energy-corrected milk that could be attributed to the treatments imposed. Efficiency values (FCM/DMI and energycorrected milk/DMI) were not different (P > 0.05) by treatment. These data indicate that sugar beets with sodium bicarbonate can be used to partially replace grain in the rations of lactating dairy cows, with concentrations of up to 24% of the TMR DM having no adverse effects on lactation performance. Key words: feed beets, sugar beets, sugar, NFC
INTRODUCTION Sugar beets are a well-established crop in North America. According to the USDA (2015) the United States plants 0.5 million ha (1.2 million acres) of sugar beets annually, with an average yield of 24.3 t/ha (27 tons/acre). Morrison (2008) determined that 20,000 ha of sugar beets were planted in Canada in 2006, with similar crop yields. With an average DM of 23%, yields are greater than many grain crops. Sugar beets, also referred to as “feed beets,” have a composition that
is similar to fodder beets on a DM basis but have a higher DM content (Hartnell et al., 2005), making them more suited to feed use. In addition, apparent DM digestibility and NDF digestibility of sugar beets have been determined to exceed 90 and 80%, respectively (Hartnell et al., 2005). Although considerable information is available regarding the feeding of sugar beet pulp, the feeding of sugar beets per se has been less well studied. Because of the fermentable sugar content, it has been suggested that this ingredient may pose an acidosis risk and that feeding may need to be restricted (Dulphy and Demarquilly, 2000). This study was conducted to evaluate the effects of feeding high concentrations of beets with sodium bicarbonate in diets for lactating dairy cows.
MATERIALS AND METHODS This study was conducted at the Atlantic Dairy and Forage Institute, located in Fredericton Junction, NB, Canada. Animals participating in the feeding trial were handled in accordance with guidelines as outlined by FASS (2010).
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Evans et al.
Table 1. Nutrient compositions of the sugar beets and forages Ingredient Nutrient (% of DM unless noted otherwise)
Sugar beets
Timothy brome hay
Timothy brome silage
Alfalfa timothy silage
23.6 2.31 8.36 11.58 71.20 0.39 6.20
88.2 8.08 40.45 61.73 6.07 1.53 11.22
34.3 16.60 36.31 47.00 3.19 2.26 6.31
50.1 15.11 32.92 51.10 6.48 3.61 5.88
DM (%) CP ADF NDF Sugar Ether extract Ash
Animals, Diets, and Experimental Design Sixteen postpeak, multiparous Holstein dairy cows were used in a replicated 4 × 4 Latin square study, with feeding periods of 21 d. The average DIM on the first day of the study was 148, with a range of 74 to 223 DIM. Animals were blocked by milk production as determined during the 14-d period before the start of this study and were randomly assigned to diets within blocks. The same treatment sequencing was applied in all 4 blocks to avoid confounding square design with block. Cows were milked twice daily at approximately 0700 and 1700 h. The first 14-d of each period was used for adaptation, followed by a 7-d data collection period. Animals were housed in tie stalls and were provided with ad libitum access to feed. Mangers were partitioned so that intakes by cow could be accurately determined. Cows were given freshly mixed feed twice daily at approximately 0600 and 1800 h and in sufficient quantities to ensure that 5 to 10% orts remained. Orts were collected and weighed before the a.m. feeding. Sugar beets, harvested in the Port Dover region of Ontario, Canada, in early November 2014, were used in the current study. Beets were tumbled to remove any loose soil before shipping and were trucked to the test facility in New Brunswick, Canada. The proximate analyses of the sugar beets and forages that were used in this trial are provided in Table 1. The in-
gredient compositions of the diets are shown in Table 2. Feed beets replaced corn and barley as sources of energy and were provided at 0 (control), 8.0 (LD), 16.0, (MD) and 24.0% (HD) of the total diet DM. Soybean meal was used to adjust ration protein to 16% of DM, and all diets contained sodium bicarbonate. Forages were kept constant across diets (Table 2). Dry matter was determined twice weekly for all high moisture ingredients. Diets were formulated to meet or exceed NRC (2001) requirements using the Spartan 3 software (Michigan State University, East Lansing, MI) with EAA and carbohydrate fractions verified using the AMTS software platform (Agricultural Modeling and Training Systems, Groton, NY). Fresh beets were stored in a wooden bin in the feed storage area for the duration of the feeding period. The beets were chopped just before adding to the TMR using a 2-horsepower electric turnip or beet chopper. The particles ranged from 2 to 4 cm in length and were approximately 1 cm in width. Because sugar beets have a low DM content, chopped hay was used in all rations to elevate the overall DM. The timothy-brome hay was obtained from a single field harvested on the same date, chopped using an International forage harvester (Lisle, IL) to approximately 5 cm, and stored in nylon sacks. Ingredients were mixed in a TMR mixer for 15 min to ensure a uniform mix. Water was added to the control and LD diets during mix-
ing so that the DM contents would be within a similar range for all diets (Table 3).
Data Collection and Chemical Analyses Milk samples were collected from both the morning and evening milkings on the last 2 d of each experimental period (4 samples per cow per period). Milk samples were submitted to the local DHI laboratory (Prince Edward Island Analytical Lab, Charlottetown, PE, Canada) for lactose, fat, and protein analysis using near infrared spectrometry. Samples were submitted within 24 h of collection, and no preservatives were added to the milk at the time of collection. Silages and beets were sampled twice weekly for the determination of DM; DM was determined when diets were formulated at the start of the trial for all dry ingredients. Dry matter concentration was determined after drying samples at 135°C for 2 h (AOAC International, 2000; method 930.15) Results were used to adjust the rations and ensure consistency for the duration of the trial. The TMR samples were collected daily (0.5 kg) and immediately frozen. Weekly pooled samples were submitted for analyses. Chemical analyses of ingredients and TMR were provided by Rock River Laboratory Inc. (Watertown, WI). Crude protein was determined by the Leco method (method 999.03; AOAC International, 2000). Acid
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Table 2. Ingredient compositions of diets1 used in the study (DM basis) % of total DM Ingredient Barley grain, ground Corn grain, ground Feed beets Soybean meal, solvent Ground limestone Salt Mineral-vitamin mix2 Sodium bicarbonate Levucell SC3 Megalac4 Timothy-brome hay Timothy-brome silage Alfalfa timothy silage Total
DM %
Control
LD
MD
HD
88.0 88.0 23.0 88.0 99.5 99.5 95.0 99.5 95.0 99.0 88.2 34.3 50.1
21.23 14.70 0.00 10.87 0.23 0.14 1.65 0.46 0.22 0.50 23.30 13.90 12.80 100
16.82 9.24 8.00 12.73 0.14 0.14 1.65 0.46 0.22 0.60 23.30 13.90 12.80 100
11.41 4.01 16.00 15.04 0.14 0.14 1.65 0.69 0.22 0.70 23.30 13.90 12.80 100
5.30 0.00 24.00 17.11 0.09 0.14 1.65 0.69 0.22 0.80 23.30 13.90 12.80 100
The control diet contained corn and barley. Diets LD, MD, and HD contained 8, 16 and 24% of TMR as sugar (feed) beets. Mineral-vitamin mix provided 13.2% Ca, 4.4% P, 9.45% Na, 4.8% Mg, 1.5% S, 1.2% K, 5,000 mg/kg Zn, 75 mg/kg I, 750 mg/kg Cu, 27 mg/kg Co, 2,500 mg/kg Mn, 338,333 IU/kg vitamin A, 75,000 IU/kg vitamin D, and 12,500 IU/kg vitamin E. 3 Registered trademark, Lallemand Animal Nutrition (Montreal, QC, Canada). 4 Registered trademark, Arm & Hammer Animal Nutrition (Princeton, NJ). 1 2
detergent fiber was determined according to AOAC International (2000; method 973.18), and NDF was assessed using the procedure of Van Soest et al. (1991). Sugar was determined as outlined by Hall et al.
(1999). Ingredient ash values were assessed as described by AOAC International (2000) method 942.05. Crude fat from ingredients was assessed using AOAC International (2000) method 945.16.
Table 3. Nutrient compositions of the diets1 Nutrient (% of DM unless noted otherwise) DM Water added Formulated composition CP RUP (% of CP) NEl (Mcal/kg) NDF ADF Sugar Determined composition CP NDF ADF Sugar
Diet Control
LD
MD
HD
53.7 20
51.8 10
47.7 0
44.3 0
16.0 32.5 1.58 37.4 21.8 4.3
16.0 32.5 1.58 37.1 22.1 9.9
16.0 32.3 1.57 36.8 22.3 15.4
16.0 32.2 1.56 36.5 22.5 20.7
15.67 39.25 22.14 4.61
15.68 37.87 20.07 10.51
15.71 37.02 22.66 15.35
15.85 38.20 23.03 19.12
The control diet contained corn and barley. Diets LD, MD, and HD contained 8, 16, and 24% of TMR as sugar (feed) beets.
1
Statistical Analyses The model used to assess the effects of treatment was as follows: Yijkl = μ + Bi + Pj + Ck + Tl + εijkl, where Yijkl = the dependent variable, μ = grand mean, Bi = effect of block i, Pj = effect of period j, Ck = effect of cow k, Tl effect of treatment l, and εijkl = residual error. Block, period, and treatment effects were considered to be fixed, and cow effects were considered to be random. The data were analyzed using Minitab 16 software (Minitab Inc., State College, PA).
RESULTS AND DISCUSSION The nutrient compositions of the diets are shown in Table 3. The chemical compositions of the TMR were similar to the levels formulated. Because the sugar beets contained only 23% DM, and the DM of the barley and corn were closer to 90%, exchanging grain for beets reduced the DM of the TMR. To maintain DM in a reasonably normal range for
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Table 4. Evaluation of sugar beets (feed beets) as a replacement for grain on lactation performances in Holstein dairy cows Diet2 Measurement1 Milk yield (kg/d) Fat (%) Protein (%) Lactose (%) Fat yield (kg) Protein yield (kg/d) 3.5% FCM (kg/d) ECM (kg/d) DMI (kg/d) FCM/DMI ECM/DMI 1 2
Control
LD
MD
HD
P-value
SEM
26.57 4.64 3.54 4.49 1.21 0.93 31.14 31.06 25.11 1.25 1.25
26.03 4.66 3.44 4.51 1.20 0.86 30.68 30.40 25.02 1.24 1.23
26.36 4.72 3.47 4.52 1.24 0.90 31.45 31.11 25.17 1.26 1.25
26.36 4.72 3.44 4.47 1.24 0.92 31.43 31.24 24.48 1.29 1.28
0.822 0.949 0.596 0.399 0.811 0.312 0.810 0.729 0.789 0.753 0.693
0.703 0.074 0.047 0.019 0.032 0.021 0.780 0.751 0.448 0.030 0.029
ECM = energy-corrected milk. The control diet contained corn and barley. Diets LD, MD, and HD contained 8, 16, and 24% of TMR as sugar (feed) beets.
the control and LD treatments, water was added to these diets. Feeding trial results are provided in Table 4. There were no differences (P > 0.05) in any of the parameters measured that could be associated with the amount of sugar beets provided. Intakes were similar with all treatments. This was a very high component herd, and fat and protein concentrations did not deviate when cows were presented with sugar beets. Sodium bicarbonate has been routinely added to all diets on this farm based on the belief that the additive contributes to maintenance of rumen pH, and there was no option for removal for the purposes of this trial. Furthermore, as Table 2 shows, the amounts of sodium bicarbonate added were greater (0.69% of DM) with the MD and HD diets than with the control and LD diets (0.46% of DM). Although nonstructural carbohydrate concentrations were formulated to be similar across treatments, the nonstructural carbohydrate-tobicarbonate ratio was greater for the control and LD treatments than for the MD and HD treatments. The current research needs to be interpreted with the understanding that not only was the source of nonstructural carbohydrates altered in these diets, there was also some confounding with
the addition of the rumen buffering agent. It was, however, not likely that buffering was needed to a greater extent with the sugar from beets than with the starch from corn and barley that the sugar replaced in these TMR. Chibisa et al. (2015) replaced starch from barley or corn with dried, whey permeate, increasing the sugar content of the diets by approximately 5% of DM. There were no differences between starch and sugar for either grain source with respect to daily mean rumen pH, or the amount of time pH was below 5.8. Penner (2015) recently summarized results from 9 studies in which up to 14% sugar was provided in rations for lactating dairy cows. When sugar replaced starch in the test diets, there were no differences in rumen pH in any of the studies. Similarly, Vallimont et al. (2004) evaluated diets where 0, 2.5., 5.0, and 7.5% sucrose replaced the same amounts of corn starch in a dual effluent continuous-culture system. There were no differences in pH in the culture systems. In contrast to this study and other studies (Chibisa et al., 2015; Penner, 2015) in which cows were given free access to feed throughout the day, Oba et al. (2015) ruminally dosed nonlactating cows consuming an aver-
age of 12.2 kg of DM with either 3 kg of sucrose, 3 kg of lactose, or 2.85 kg of corn starch. Rumen pH declined to a greater extent with sucrose than with lactose or corn starch at 120 to 180 min after the dose was administered. This finding indicates that sucrose may not be equivalent to starch in situations where animals do not have continued availability of feed, or when concentrate components of the diet are fed separately from forage. The diets contained different concentrations of added fat. Sugar beets contain very little ether extract relative to corn and barley, and the commercial fat source (Megalac, Arm & Hammer Animal Nutrition, Princeton, NJ) was used to ensure that ether extract levels of the final diets were similar across treatments. The use of the higher DM forages resulted in quite high DM with the control and LD treatments. An HD DM TMR may result in ingredient sorting. Leonardi et al. (2005) determined that the extent of sorting was greater with diets containing 80% DM than the same diet to which water was added to reduce DM to 64%. Fish and DeVries (2012) found that cows sorted for small particles to a lesser extent when water was used to reduce DM from 62 to 52%. However, in one study (Miller-Cushon and DeVries,
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2009), adding water to reduce TMR DM from 58 to 48% resulted in greater sorting. Therefore, water was added to the control and LD diets at levels calculated to provide final TMR with DM contents above 52% (Table 3). Care was taken during the mixing process to ensure that diets were homogeneous, and there was no obvious sorting with any of the dietary treatments. Other researchers have had less success with feeding beets as a replacement for grain, and the differences may revolve around methods of formulation. Mogensen and Kristensen (2003) replaced barley with beets in a TMR. Energy-corrected milk was 1.4 kg lower with the beet diet. The beets used in the study contained 21% ash, and this was not taken into account when the diets were formulated. The beets used in the current study were tumbled to remove excess soil and contained 6.2% ash, concentrations that are not unlike grains. The use of large amounts of grass or grass-legume silage in the ration may limit DMI when wet sugar beets are used as a concentrate source. Eriksson et al. (2004) provided cows with diets where the concentrate portion of the rations consisted of (DM basis) 80:20 mix of barley:raw potato, 80:20 beets:raw potato, or barley alone. Silage was available ad libitum in the study, with the concentrate ingredients provided at restricted levels. The energy-corrected milk with the 3 diets was 24.7, 23.0, and 25.3 kg, respectively. The DM contents of the rations consumed were 39, 28, and 42%. Intakes were lowest with the low DM diet. However, low DM alone may not be responsible for the decline in DMI. Phipps et al. (1995) provided cows with 6 kg of concentrate plus ad libitum grass silage, or mixtures of grass silage (67%) and either brewers grains, fodder beets, or corn silage. The DMI and milk yield were increased when the silage was mixed with other high moisture ingredients. This suggests that limitations in DMI of high moisture ingredients might occur when dairy cows are fed fresh
sugar beets in addition to high moisture forages. Unlike grains, where the primary carbohydrate is starch, the overwhelming component of carbohydrate in beets is sugar. The primary objection to feeding sugar is the perception that the sugar will ferment to acids quickly, lowering rumen pH and contributing to acidosis. To the contrary, in a recent review, Oba (2011) concluded that replacing starch in the diet with sugar did not alter rumen pH. In a more recent review, Penner (2015) likewise concluded that replacing starch with an equivalent amount of sugar does not decrease rumen pH. Gibbs (2011) suggested that, for dairy cows coming off pasture, beet feeding should be introduced gradually, but up to 8 kg of DM from beets was an acceptable feeding level with high forage diets. All changes from one diet to the next in this study were made abruptly, and no health issues were noted. Oba (2011) noted that there are conflicting results regarding the effects of sugar as a replacement for starch on the digestibility of NDF. Digestibility was not measured in this trial. The lack of differences in energy-corrected milk/DMI and FCM/ DMI suggests that NDF digestibility was not compromised by including sugar beets in place of grain in this study. However, the NDF in sugar beets has been shown to be highly digestible (Hartnell et al., 2005) and might have offset any reduction in digestibility of NDF from other ingredients. There may be economic advantages to growing sugar beets over traditional grains. This study demonstrated that fresh sugar beets can be incorporated in diets from cows in mid lactation at concentrations of up to 24% of DM to replace grains. More research is needed to further demonstrate the effects of feeding sugar beets to lactating dairy cattle on nutrient digestibility and rumen fermentation parameters and to determine whether rumen buffers are required when high concentrations of sucrose
replace starch in diets for lactating dairy cows.
IMPLICATIONS This study shows that sugar beets can be given to lactating dairy cows as a partial replacement for grain in the diet and can support milk production as well as grains. Because of high DM yields, sugar beets may provide economic advantages over traditional grains. The low DM content of beets may be the major drawback to feeding very high concentrations. Buffers were included in all treatment diets and may or may not be necessary.
ACKNOWLEDGMENTS This project was supported by the Dairy Farmers of New Brunswick (Sussex, NB, Canada). Beets were supplied by Betaseed Inc. (Bloomington, MN). Appreciation is extended to the dedicated staff at The Atlantic Dairy and Forage Institute.
LITERATURE CITED AOAC International. 2000. Official Methods of Analysis. 17th ed. AOAC Int., Gaithersburg, MD. Chibisa, G. E., P. Gorka, G. B. Penner, R. Berthiaume, and T. Mutsvangwa. 2015. Effects of partial replacement of dietary starch from barley or corn with lactose on ruminal function, short-chain fatty acid absorption, nitrogen utilization and production performance of dairy cows. J. Dairy Sci. 98:2627– 2640. Dulphy, J. P., and C. Demarquilly. 2000. Fodder beets in animal husbandry. Fourrages 163:307–314. Eriksson, T., M. Murphy, P. Ciszuk, and E. Burstedt. 2004. Nitrogen balance, microbial protein production, and milk production in dairy cows fed fodder beets and potatoes, or barley. J. Dairy Sci. 87:1057–1070. FASS. 2010. Guide for Care and Use of Agricultural Animals in Research and Teaching. 3rd ed. FASS, Champaign, IL. Fish, J. A., and T. J. DeVries. 2012. Short communication: Varying dietary dry matter concentration through water addition: Effect on nutrient intake and sorting of dairy cows in late lactation. J. Dairy Sci. 95:850–855.
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Gibbs, J. 2011. Wintering Dairy Cows on Fodder Beet. Challenge Your Future. Lincoln Univ., Canterbury, NZ, pp. 27–29.
or barley as supplements to silage ad libitum for high-yielding dairy cows on organic farms. Acta Agric. Scand. A 53:186–196.
Hall, M. B., W. H. Hoover, J. P. Jennings, and T. K. Miller Webster. 1999. A method for partitioning neutral detergent-soluble carbohydrates. J. Sci. Food Agric. 79:2079–2086.
Morrison, S. 2008. That Beet Is Sweet. Canadian Agriculture at a Glance. Catalogue no. 96-325-X. Stat. Canada, Ottawa, ON.
Hartnell, G. F., T. Hvelplund, and M. R. Weisbjerg. 2005. Nutrient digestibility in sheep fed diets containing Roundup Ready or conventional fodder beet, sugar beet, and beet pulp. J. Anim. Sci. 83:400–407. Leonardi, C., F. Giannico, and L. E. Armentano. 2005. Effect of water addition on selective consumption (sorting) of dry diets by dairy cattle. J. Dairy Sci. 88:1043–1049. Miller-Cushon, E. K., and T. J. DeVries. 2009. Effect of dietary dry matter concentration on the sorting behavior of lactating dairy cows fed a total mixed ration. J. Dairy Sci. 92:3292–3298. Mogensen, L., and T. Kristensen. 2003. Concentrate mixture, grass pellets, fodder beets,
NRC. 2001. Nutrient Requirements of Dairy Cattle. 7th rev. ed. Natl. Acad. Sci., Washington, DC. Oba, M. 2011. Review: Effects of feeding sugars on productivity of lactating dairy cows. Can. J. Anim. Sci. 91:37–46. Oba, M., J. L. Mewis, and Z. Zhining. 2015. Effects of ruminal doses of sucrose, lactose, and corn starch on ruminal fermentation and expression of genes in ruminal epithelial cells. J. Dairy Sci. 98:586–594. Penner, G. B. 2015. Optimal use of sugar in diets for dairy cattle. Proc. Cornell Nutr. Conf. 77:55–62. Phipps, R. H., J. D. Sutton, and B. A. Jones. 1995. Forage mixtures for dairy cows:
the effect on dry-matter intake and milk production of incorporating either fermented or urea-treated whole-crop wheat, brewers' grains, fodder beet or maize silage into diets based on grass silage. Anim. Sci. 61:491–496. USDA. 2015. Economic Research Service. Sugar and Sweeteners Yearbook Tables. Table 14. US sugarbeet crops: Area planted, acres harvested, yield per acre, and production, by state and region. Accessed Sep. 30, 2015. http://www.ers.usda.gov/data-products/ sugar-and-sweeteners-yearbook-tables.aspx. Vallimont, J. E., F. Bargo, T. W. Cassidy, N. D. Luchini, G. A. Broderick, and G. A. Varga. 2004. Effects of replacing dietary starch with sucrose on ruminal fermentation and nitrogen metabolism in continuous culture. J. Dairy Sci. 87:4221–4229. Van Soest, P. J., J. B. Robertson, and B. A. Lewis. 1991. Methods for dietary fiber, neutral detergent fiber and non-starch polysaccharides in relation to animal nutrition. J. Dairy Sci. 74:3583–3597.
C freshS sugar: Effects of feeding beets to lactating ase
tudy
dairy cows on milk production and milk composition Essi Evans,*1 Duane Bernhardson,† and Josh Lamont‡ *Essi Evans Technical Advisory Services Inc., Bowmanville, Ontario, Canada, L1C 3J1; †Betaseed Inc., Grand Forks, ND 58201; and ‡Atlantic Dairy and Forage Institute, Fredericton Junction, NB, Canada, E5L 1R1
ABSTRACT Sugar beets are a high-DM-yielding energy crop and offer the potential to replace grain in the rations of dairy cows. However, there is limited information regarding the amount of beets that can be included in the TMR. This study was conducted to evaluate the responses of mid-lactation Holstein cows to rations containing varying amounts fresh sugar beets. Sixteen multiparous mid-lactation Holstein cows were used in a 4 × 4 Latin square study, with feeding periods of 21 d. Rations contained 0, 8, 16, and 24% beets (DM basis), with beets replacing the grain portion of the diet, which was composed of corn and barley. Milk weights and DMI were evaluated for the last 7 d of each period. Milk components were determined on the final 2 d of each period. There were no differences (P > 0.05) in milk yield (26.6, 26.0, 26.4, and 26.4 kg), fat percentage (4.64, 4.66, 4.72, and 4.72%) and protein percentage (3.54, 3.44, 3.47, and 3.44%) for rations containing 0, 8, 16, and 24% beets, respectively. Likewise, there were
1 Corresponding author: essievans@ sympatico.ca
no differences (P > 0.05) in 3.5% FCM and energy-corrected milk that could be attributed to the treatments imposed. Efficiency values (FCM/DMI and energycorrected milk/DMI) were not different (P > 0.05) by treatment. These data indicate that sugar beets with sodium bicarbonate can be used to partially replace grain in the rations of lactating dairy cows, with concentrations of up to 24% of the TMR DM having no adverse effects on lactation performance. Key words: feed beets, sugar beets, sugar, NFC
INTRODUCTION Sugar beets are a well-established crop in North America. According to the USDA (2015) the United States plants 0.5 million ha (1.2 million acres) of sugar beets annually, with an average yield of 24.3 t/ha (27 tons/acre). Morrison (2008) determined that 20,000 ha of sugar beets were planted in Canada in 2006, with similar crop yields. With an average DM of 23%, yields are greater than many grain crops. Sugar beets, also referred to as “feed beets,” have a composition that
is similar to fodder beets on a DM basis but have a higher DM content (Hartnell et al., 2005), making them more suited to feed use. In addition, apparent DM digestibility and NDF digestibility of sugar beets have been determined to exceed 90 and 80%, respectively (Hartnell et al., 2005). Although considerable information is available regarding the feeding of sugar beet pulp, the feeding of sugar beets per se has been less well studied. Because of the fermentable sugar content, it has been suggested that this ingredient may pose an acidosis risk and that feeding may need to be restricted (Dulphy and Demarquilly, 2000). This study was conducted to evaluate the effects of feeding high concentrations of beets with sodium bicarbonate in diets for lactating dairy cows.
MATERIALS AND METHODS This study was conducted at the Atlantic Dairy and Forage Institute, located in Fredericton Junction, NB, Canada. Animals participating in the feeding trial were handled in accordance with guidelines as outlined by FASS (2010).
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Evans et al.
Table 1. Nutrient compositions of the sugar beets and forages Ingredient Nutrient (% of DM unless noted otherwise)
Sugar beets
Timothy brome hay
Timothy brome silage
Alfalfa timothy silage
23.6 2.31 8.36 11.58 71.20 0.39 6.20
88.2 8.08 40.45 61.73 6.07 1.53 11.22
34.3 16.60 36.31 47.00 3.19 2.26 6.31
50.1 15.11 32.92 51.10 6.48 3.61 5.88
DM (%) CP ADF NDF Sugar Ether extract Ash
Animals, Diets, and Experimental Design Sixteen postpeak, multiparous Holstein dairy cows were used in a replicated 4 × 4 Latin square study, with feeding periods of 21 d. The average DIM on the first day of the study was 148, with a range of 74 to 223 DIM. Animals were blocked by milk production as determined during the 14-d period before the start of this study and were randomly assigned to diets within blocks. The same treatment sequencing was applied in all 4 blocks to avoid confounding square design with block. Cows were milked twice daily at approximately 0700 and 1700 h. The first 14-d of each period was used for adaptation, followed by a 7-d data collection period. Animals were housed in tie stalls and were provided with ad libitum access to feed. Mangers were partitioned so that intakes by cow could be accurately determined. Cows were given freshly mixed feed twice daily at approximately 0600 and 1800 h and in sufficient quantities to ensure that 5 to 10% orts remained. Orts were collected and weighed before the a.m. feeding. Sugar beets, harvested in the Port Dover region of Ontario, Canada, in early November 2014, were used in the current study. Beets were tumbled to remove any loose soil before shipping and were trucked to the test facility in New Brunswick, Canada. The proximate analyses of the sugar beets and forages that were used in this trial are provided in Table 1. The in-
gredient compositions of the diets are shown in Table 2. Feed beets replaced corn and barley as sources of energy and were provided at 0 (control), 8.0 (LD), 16.0, (MD) and 24.0% (HD) of the total diet DM. Soybean meal was used to adjust ration protein to 16% of DM, and all diets contained sodium bicarbonate. Forages were kept constant across diets (Table 2). Dry matter was determined twice weekly for all high moisture ingredients. Diets were formulated to meet or exceed NRC (2001) requirements using the Spartan 3 software (Michigan State University, East Lansing, MI) with EAA and carbohydrate fractions verified using the AMTS software platform (Agricultural Modeling and Training Systems, Groton, NY). Fresh beets were stored in a wooden bin in the feed storage area for the duration of the feeding period. The beets were chopped just before adding to the TMR using a 2-horsepower electric turnip or beet chopper. The particles ranged from 2 to 4 cm in length and were approximately 1 cm in width. Because sugar beets have a low DM content, chopped hay was used in all rations to elevate the overall DM. The timothy-brome hay was obtained from a single field harvested on the same date, chopped using an International forage harvester (Lisle, IL) to approximately 5 cm, and stored in nylon sacks. Ingredients were mixed in a TMR mixer for 15 min to ensure a uniform mix. Water was added to the control and LD diets during mix-
ing so that the DM contents would be within a similar range for all diets (Table 3).
Data Collection and Chemical Analyses Milk samples were collected from both the morning and evening milkings on the last 2 d of each experimental period (4 samples per cow per period). Milk samples were submitted to the local DHI laboratory (Prince Edward Island Analytical Lab, Charlottetown, PE, Canada) for lactose, fat, and protein analysis using near infrared spectrometry. Samples were submitted within 24 h of collection, and no preservatives were added to the milk at the time of collection. Silages and beets were sampled twice weekly for the determination of DM; DM was determined when diets were formulated at the start of the trial for all dry ingredients. Dry matter concentration was determined after drying samples at 135°C for 2 h (AOAC International, 2000; method 930.15) Results were used to adjust the rations and ensure consistency for the duration of the trial. The TMR samples were collected daily (0.5 kg) and immediately frozen. Weekly pooled samples were submitted for analyses. Chemical analyses of ingredients and TMR were provided by Rock River Laboratory Inc. (Watertown, WI). Crude protein was determined by the Leco method (method 999.03; AOAC International, 2000). Acid
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Table 2. Ingredient compositions of diets1 used in the study (DM basis) % of total DM Ingredient Barley grain, ground Corn grain, ground Feed beets Soybean meal, solvent Ground limestone Salt Mineral-vitamin mix2 Sodium bicarbonate Levucell SC3 Megalac4 Timothy-brome hay Timothy-brome silage Alfalfa timothy silage Total
DM %
Control
LD
MD
HD
88.0 88.0 23.0 88.0 99.5 99.5 95.0 99.5 95.0 99.0 88.2 34.3 50.1
21.23 14.70 0.00 10.87 0.23 0.14 1.65 0.46 0.22 0.50 23.30 13.90 12.80 100
16.82 9.24 8.00 12.73 0.14 0.14 1.65 0.46 0.22 0.60 23.30 13.90 12.80 100
11.41 4.01 16.00 15.04 0.14 0.14 1.65 0.69 0.22 0.70 23.30 13.90 12.80 100
5.30 0.00 24.00 17.11 0.09 0.14 1.65 0.69 0.22 0.80 23.30 13.90 12.80 100
The control diet contained corn and barley. Diets LD, MD, and HD contained 8, 16 and 24% of TMR as sugar (feed) beets. Mineral-vitamin mix provided 13.2% Ca, 4.4% P, 9.45% Na, 4.8% Mg, 1.5% S, 1.2% K, 5,000 mg/kg Zn, 75 mg/kg I, 750 mg/kg Cu, 27 mg/kg Co, 2,500 mg/kg Mn, 338,333 IU/kg vitamin A, 75,000 IU/kg vitamin D, and 12,500 IU/kg vitamin E. 3 Registered trademark, Lallemand Animal Nutrition (Montreal, QC, Canada). 4 Registered trademark, Arm & Hammer Animal Nutrition (Princeton, NJ). 1 2
detergent fiber was determined according to AOAC International (2000; method 973.18), and NDF was assessed using the procedure of Van Soest et al. (1991). Sugar was determined as outlined by Hall et al.
(1999). Ingredient ash values were assessed as described by AOAC International (2000) method 942.05. Crude fat from ingredients was assessed using AOAC International (2000) method 945.16.
Table 3. Nutrient compositions of the diets1 Nutrient (% of DM unless noted otherwise) DM Water added Formulated composition CP RUP (% of CP) NEl (Mcal/kg) NDF ADF Sugar Determined composition CP NDF ADF Sugar
Diet Control
LD
MD
HD
53.7 20
51.8 10
47.7 0
44.3 0
16.0 32.5 1.58 37.4 21.8 4.3
16.0 32.5 1.58 37.1 22.1 9.9
16.0 32.3 1.57 36.8 22.3 15.4
16.0 32.2 1.56 36.5 22.5 20.7
15.67 39.25 22.14 4.61
15.68 37.87 20.07 10.51
15.71 37.02 22.66 15.35
15.85 38.20 23.03 19.12
The control diet contained corn and barley. Diets LD, MD, and HD contained 8, 16, and 24% of TMR as sugar (feed) beets.
1
Statistical Analyses The model used to assess the effects of treatment was as follows: Yijkl = μ + Bi + Pj + Ck + Tl + εijkl, where Yijkl = the dependent variable, μ = grand mean, Bi = effect of block i, Pj = effect of period j, Ck = effect of cow k, Tl effect of treatment l, and εijkl = residual error. Block, period, and treatment effects were considered to be fixed, and cow effects were considered to be random. The data were analyzed using Minitab 16 software (Minitab Inc., State College, PA).
RESULTS AND DISCUSSION The nutrient compositions of the diets are shown in Table 3. The chemical compositions of the TMR were similar to the levels formulated. Because the sugar beets contained only 23% DM, and the DM of the barley and corn were closer to 90%, exchanging grain for beets reduced the DM of the TMR. To maintain DM in a reasonably normal range for
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Table 4. Evaluation of sugar beets (feed beets) as a replacement for grain on lactation performances in Holstein dairy cows Diet2 Measurement1 Milk yield (kg/d) Fat (%) Protein (%) Lactose (%) Fat yield (kg) Protein yield (kg/d) 3.5% FCM (kg/d) ECM (kg/d) DMI (kg/d) FCM/DMI ECM/DMI 1 2
Control
LD
MD
HD
P-value
SEM
26.57 4.64 3.54 4.49 1.21 0.93 31.14 31.06 25.11 1.25 1.25
26.03 4.66 3.44 4.51 1.20 0.86 30.68 30.40 25.02 1.24 1.23
26.36 4.72 3.47 4.52 1.24 0.90 31.45 31.11 25.17 1.26 1.25
26.36 4.72 3.44 4.47 1.24 0.92 31.43 31.24 24.48 1.29 1.28
0.822 0.949 0.596 0.399 0.811 0.312 0.810 0.729 0.789 0.753 0.693
0.703 0.074 0.047 0.019 0.032 0.021 0.780 0.751 0.448 0.030 0.029
ECM = energy-corrected milk. The control diet contained corn and barley. Diets LD, MD, and HD contained 8, 16, and 24% of TMR as sugar (feed) beets.
the control and LD treatments, water was added to these diets. Feeding trial results are provided in Table 4. There were no differences (P > 0.05) in any of the parameters measured that could be associated with the amount of sugar beets provided. Intakes were similar with all treatments. This was a very high component herd, and fat and protein concentrations did not deviate when cows were presented with sugar beets. Sodium bicarbonate has been routinely added to all diets on this farm based on the belief that the additive contributes to maintenance of rumen pH, and there was no option for removal for the purposes of this trial. Furthermore, as Table 2 shows, the amounts of sodium bicarbonate added were greater (0.69% of DM) with the MD and HD diets than with the control and LD diets (0.46% of DM). Although nonstructural carbohydrate concentrations were formulated to be similar across treatments, the nonstructural carbohydrate-tobicarbonate ratio was greater for the control and LD treatments than for the MD and HD treatments. The current research needs to be interpreted with the understanding that not only was the source of nonstructural carbohydrates altered in these diets, there was also some confounding with
the addition of the rumen buffering agent. It was, however, not likely that buffering was needed to a greater extent with the sugar from beets than with the starch from corn and barley that the sugar replaced in these TMR. Chibisa et al. (2015) replaced starch from barley or corn with dried, whey permeate, increasing the sugar content of the diets by approximately 5% of DM. There were no differences between starch and sugar for either grain source with respect to daily mean rumen pH, or the amount of time pH was below 5.8. Penner (2015) recently summarized results from 9 studies in which up to 14% sugar was provided in rations for lactating dairy cows. When sugar replaced starch in the test diets, there were no differences in rumen pH in any of the studies. Similarly, Vallimont et al. (2004) evaluated diets where 0, 2.5., 5.0, and 7.5% sucrose replaced the same amounts of corn starch in a dual effluent continuous-culture system. There were no differences in pH in the culture systems. In contrast to this study and other studies (Chibisa et al., 2015; Penner, 2015) in which cows were given free access to feed throughout the day, Oba et al. (2015) ruminally dosed nonlactating cows consuming an aver-
age of 12.2 kg of DM with either 3 kg of sucrose, 3 kg of lactose, or 2.85 kg of corn starch. Rumen pH declined to a greater extent with sucrose than with lactose or corn starch at 120 to 180 min after the dose was administered. This finding indicates that sucrose may not be equivalent to starch in situations where animals do not have continued availability of feed, or when concentrate components of the diet are fed separately from forage. The diets contained different concentrations of added fat. Sugar beets contain very little ether extract relative to corn and barley, and the commercial fat source (Megalac, Arm & Hammer Animal Nutrition, Princeton, NJ) was used to ensure that ether extract levels of the final diets were similar across treatments. The use of the higher DM forages resulted in quite high DM with the control and LD treatments. An HD DM TMR may result in ingredient sorting. Leonardi et al. (2005) determined that the extent of sorting was greater with diets containing 80% DM than the same diet to which water was added to reduce DM to 64%. Fish and DeVries (2012) found that cows sorted for small particles to a lesser extent when water was used to reduce DM from 62 to 52%. However, in one study (Miller-Cushon and DeVries,
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2009), adding water to reduce TMR DM from 58 to 48% resulted in greater sorting. Therefore, water was added to the control and LD diets at levels calculated to provide final TMR with DM contents above 52% (Table 3). Care was taken during the mixing process to ensure that diets were homogeneous, and there was no obvious sorting with any of the dietary treatments. Other researchers have had less success with feeding beets as a replacement for grain, and the differences may revolve around methods of formulation. Mogensen and Kristensen (2003) replaced barley with beets in a TMR. Energy-corrected milk was 1.4 kg lower with the beet diet. The beets used in the study contained 21% ash, and this was not taken into account when the diets were formulated. The beets used in the current study were tumbled to remove excess soil and contained 6.2% ash, concentrations that are not unlike grains. The use of large amounts of grass or grass-legume silage in the ration may limit DMI when wet sugar beets are used as a concentrate source. Eriksson et al. (2004) provided cows with diets where the concentrate portion of the rations consisted of (DM basis) 80:20 mix of barley:raw potato, 80:20 beets:raw potato, or barley alone. Silage was available ad libitum in the study, with the concentrate ingredients provided at restricted levels. The energy-corrected milk with the 3 diets was 24.7, 23.0, and 25.3 kg, respectively. The DM contents of the rations consumed were 39, 28, and 42%. Intakes were lowest with the low DM diet. However, low DM alone may not be responsible for the decline in DMI. Phipps et al. (1995) provided cows with 6 kg of concentrate plus ad libitum grass silage, or mixtures of grass silage (67%) and either brewers grains, fodder beets, or corn silage. The DMI and milk yield were increased when the silage was mixed with other high moisture ingredients. This suggests that limitations in DMI of high moisture ingredients might occur when dairy cows are fed fresh
sugar beets in addition to high moisture forages. Unlike grains, where the primary carbohydrate is starch, the overwhelming component of carbohydrate in beets is sugar. The primary objection to feeding sugar is the perception that the sugar will ferment to acids quickly, lowering rumen pH and contributing to acidosis. To the contrary, in a recent review, Oba (2011) concluded that replacing starch in the diet with sugar did not alter rumen pH. In a more recent review, Penner (2015) likewise concluded that replacing starch with an equivalent amount of sugar does not decrease rumen pH. Gibbs (2011) suggested that, for dairy cows coming off pasture, beet feeding should be introduced gradually, but up to 8 kg of DM from beets was an acceptable feeding level with high forage diets. All changes from one diet to the next in this study were made abruptly, and no health issues were noted. Oba (2011) noted that there are conflicting results regarding the effects of sugar as a replacement for starch on the digestibility of NDF. Digestibility was not measured in this trial. The lack of differences in energy-corrected milk/DMI and FCM/ DMI suggests that NDF digestibility was not compromised by including sugar beets in place of grain in this study. However, the NDF in sugar beets has been shown to be highly digestible (Hartnell et al., 2005) and might have offset any reduction in digestibility of NDF from other ingredients. There may be economic advantages to growing sugar beets over traditional grains. This study demonstrated that fresh sugar beets can be incorporated in diets from cows in mid lactation at concentrations of up to 24% of DM to replace grains. More research is needed to further demonstrate the effects of feeding sugar beets to lactating dairy cattle on nutrient digestibility and rumen fermentation parameters and to determine whether rumen buffers are required when high concentrations of sucrose
replace starch in diets for lactating dairy cows.
IMPLICATIONS This study shows that sugar beets can be given to lactating dairy cows as a partial replacement for grain in the diet and can support milk production as well as grains. Because of high DM yields, sugar beets may provide economic advantages over traditional grains. The low DM content of beets may be the major drawback to feeding very high concentrations. Buffers were included in all treatment diets and may or may not be necessary.
ACKNOWLEDGMENTS This project was supported by the Dairy Farmers of New Brunswick (Sussex, NB, Canada). Beets were supplied by Betaseed Inc. (Bloomington, MN). Appreciation is extended to the dedicated staff at The Atlantic Dairy and Forage Institute.
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