Agricultural and Food Science, Vol. 18(2009): 234-256 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 234 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 235 © Agricultural and Food Science Manuscript received March 2009 Formic acid treated whole crop barley and wheat silages in dairy cow diets: effects of crop maturity, proportion in the diet, and level and type of concentrate supplementation Seija Jaakkola1, Eeva Saarisalo2,3 and Terttu Heikkilä2 1Department of Animal Science, PO Box 28, FI-00014 University of Helsinki, Finland e-mail: seija.jaakkola@helsinki.fi 2MTT Agrifood Research Finland, Animal Production Research, FI-31600 Jokioinen, Finland 3Currently: Ministry of Agriculture and Forestry, Department of Food and Health, PO Box 30, FI-00023 Valtioneuvosto, Finland Three trials in dairy cows were carried out to study the effects of replacing grass silage (GS) with whole- crop silage (WCS) made of barley (BS) or wheat (WS) harvested at dough stage with a dry matter (DM) concentration of 300−450 g kg-1. All silages were ensiled using a formic acid based additive 5 l t-1. Milk production responses to energy and protein supplementation of diets were studied. In Exp. 1, BS replaced GS at the rates of 0, 200, 400 or 600 g kg-1 forage DM. Also 10 kg of concentrate containing 0 or 2 kg of rape seed meal was fed. In Exp. 2, barley was harvested at three times (BS1, BS2, BS3) at one week inter- vals. Barley silages were fed as a mixture with GS (40:60) and in addition BS2 and GS alone. Silages were supplemented with a cereal based farm-made concentrate (FC) or a commercial compound having a lower concentration of starch than FC. In Exp. 3, barley and wheat were harvested at two week intervals, fed as a mixture with GS (40:60) and supplemented with low or high amount of concentrate. The fermentation quality of whole crop silages was good. Weather conditions and maturity affected the proportion of ear in the crop and subsequently the ratio of non-structural carbohydrates to NDF in the silage. The inclusion of WCS depressed diet OM digestibility depending on the digestibility of GS and the proportion of WCS in the diet. However, mixing GS and WCS did not depress intake. Subsequently the use of mixtures maintained or even increased milk yield as compared with GS diet in Exp. 2 and 3. In Exp. 1, higher proportions (400, 600 g kg-1) of BS decreased milk yield. Minor effects of growth stage on milk production were observed with barley whereas delaying wheat harvest increased milk yield. Different types and levels of concentrate induced mainly similar intake and milk yield responses with diets based on GS alone or on mixtures of GS and WCS. The synergistic effect of mixing GS and WCS was more positive in experiments where the protein concentration of concentrate was high (200 g kg-1 DM). Key-words: whole-crop, barley, wheat, grass, silage, dairy cow, milk A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 234 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 235 Introduction Agronomic and economic information indicates that inclusion of harvest of the whole crop (WC) cereals in the farming system has many advantages (Stark and Wilkinson 1995). Most of the literature on the use of whole crop silage (WCS) in dairy cow feeding is for wheat silage. Being suitable for the northern climate, barley and oats have been the dominant small grain cereals in Finland. Due to the lower fibre concentration and better feeding value (Kristensen 1992), barley is regarded as a better alternative than oats for high yielding dairy cows. Since harvesting as WCS does not require full maturity of cereals, higher yielding wheat varieties could be an option in areas where barley or oats has been used. The variation in the composition and feeding value of cereal crops is mainly associated with the differences in the proportion of grain and straw (Kristensen 1992, Südekum and Arndt 1998). Much of the variation is caused by variety and timing of harvest, in addition to environmental factors like location, weather and growth conditions. However, the effects of straw proportion are not clear since increased grain proportion, by advancing maturity or by elevated cutting heights does not necessarily affect intake of WC silage or animal performance (e.g. Sutton et al. 2002, Sinclair et al. 2003). There is ample evidence that feeding a mix- ture of grass silage and fermented or alkaline WC cereals in dairy cow feeding may increase silage intake (e.g. Leaver and Hill 1995, Phipps et al. 1995, Sutton et al. 1997). However, some negative effects like lack of positive milk yield responses, low energy value, low starch digestibility and potential pollution caused by nitrogen have been observed when using urea-treated WC wheat si- lage (Sutton et al. 2002). Successful preservation with alkalis, principally urea, requires a dry matter (DM) concentration of approximately 500 g kg-1. When immature low DM cereals are ensiled with NaOH or urea, butyric acid fermentation may oc- cur (Deschard et al. 1987, Tetlow 1992). In Fin- land, ensiling of untreated and urea-treated WC silage resulted in clostridial fermentation (Alaspää 1986) which, besides reducing the nutritive value of silage, poses a high risk for the quality of dairy products. In Nordic climatic conditions, the DM concentration of whole crop cereals is often low, even at late maturity of grain. Thus, ensiling of cereal crops should preferably be based on low pH generated by fermentation and/or additives, and the harvest should be done at the dough stage with a DM concentration of 300–400 g kg-1 (Vanhatalo et al. 1999). In the experiment by Vanhatalo et al. (1999) formic acid proved to be a potential pre- servative for whole crop cereals at dough stage by restricting in-silo fermentation and protein break- down as compared to untreated silage. The early harvested small grain cereal crops have been en- siled successfully (Edwards et al. 1968, Bergen et al. 1991, Südekum and Arndt 1998) and fermented whole crop silages do not necessarily present prob- lems with aerobic stability (Sutton et al. 2002) as observed in earlier works (Tetlow 1992). No previous studies were conducted on the use of WC silage in dairy cow feeding in Finland. Thus there was a need to identify the correct stage of harvest and appropriate concentrate supplemen- tation of formic acid treated barley silage. It was essential to understand the relationship between growth conditions and cereal crop development, and subsequently, how it affects the ensiling char- acteristics and nutritive value of whole crop cere- als. The present series of experiments were under- taken to evaluate the effects of inclusion of formic acid treated whole crop barley or wheat silages in a grass silage based diet on intake and milk pro- duction in dairy cows. The effects of advancing maturity of barley and wheat during dough stage, and the effects of protein supplementation, type of concentrate and concentrate level in dairy cow diet were studied. Material and methods Harvest Spring-sown barley (Hordeum vulgare L. cv. Inari, two-rowed) was used in three experiments and A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 236 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 237 spring-sown wheat (Triticum aestivum L. cv. Mahti) in one experiment. Both were harvested on the farm of Jokioinen Estates in MTT Agrifood Research Finland, Jokioinen (60o49’N, 23o28’ E). In the first experiment (Exp. 1) barley was harvested on 14th August 1996 at the early dough stage 27 days after the start of heading (Table 1). In the second experiment (Exp. 2), barley was harvested three times (BS1-BS3) at one week intervals (on 22nd July, 29th July and 4th August 1999) starting from the early dough stage 14 days after heading. In the third experiment (Exp. 3), whole crop barley and wheat were harvested at the early and soft/hard dough stages. Barley was harvested 23 (BS1) and 36 (BS2) days (on 3rd and 16th August 2000), and wheat 30 (WS1) and 44 (WS2) days after the onset of heading (on 10th and 24th August 2000). The harvest dates were determined by a combination of crop DM concentration and colour and grain DM and texture. Growing season was exceptionally warm and dry during Exp. 2. The mean temperature in June and July was 13.6, 17.5 and 14.6 oC, and precipitation 188, 79 and 165 mm in Exp. 1, 2 and 3, respectively. The whole crops were harvested direct-cut us- ing a flail harvester (Taarup 1500, Kerteminde, Denmark; Exp. 1) or a double chop harvester (Tup- la-Junkkari, Junkkari Oy, Finland; Exp. 2 and Exp. 3) at stubble height of about 10 cm. Silages were treated with a formic acid based additive applied at the rate of 5 l t-1 (Exp. 1: AIV-10 containing for- mic acid 775, orthophosphoric acid 20 and ethyl- benzoate 25 g kg-1, Kemira Chemicals Oyj; Exp. 2 and Exp. 3: AIV2000 containing formic acid 550, ammoniumformate 240, propionic acid 50, ben- zoic acid 10 and ethylbenzoate 10 g kg-1, Kemira Chemicals Oyj) and ensiled in bunker silos. Grass silage (GS) was harvested from a primary (24th June Exp. 1 and 15th-16th June Exp. 3) or second- ary growth (27th-29th September Exp. 2) of mixed timothy (Phleum pratense L.) and meadow fescue (Festuca pratensis Huds.) swards. The herbage was mown using a mower conditioner, harvested with a precision-chop forage harvester after a 4−6 h wilting period, treated with the same additives and application rates as the whole crop silages, and ensiled in bunker (Exp. 1 and 2) or tower (Exp. 3) silos. The additives were applied using a pump ap- plicator (Ylö HP-20, Ylöjärvi, Finland) attached to the forage harvester. Experimental design and diets Three feeding experiments were conducted using a cyclic change-over design (Davis and Hall 1969) with 16 (Exp. 1) or 20 (Exp. 2 and 3) cows. The duration of all the experiments was 84 days consist- ing of four 21-day experimental periods with an adaptation period from day 1 to 13 followed by a sampling period from day 14 to 21. Finnish Ayrshire cows were selected from the dairy herd of Jokioinen Estate. The cows were housed in individual stalls and had free access to silage allowing 5 to 10% refusals. Silages were grass silage or whole crop silage alone or a combination mixed using a mixer wagon. Daily concentrates were offered as three equal meals at 5.30, 12.30 and 16.30 h. Exp. 1 was conducted with eight dietary treat- ments and with two replicate blocks of eight mul- tiparous cows each. The cows were divided into blocks according to milk yield and feed intake, and allocated at random to the experimental treatments. At the beginning of the experiment, the cows had a mean (s.d.) live weight of 575 kg (47.5), a parity of 3.4 (1.55) and were 62 days (15.1) in lactation, pro- ducing 31.8 kg (2.93) milk per day. Dietary treat- ments in a 4 × 2 factorial arrangement consisted of four silage mixtures and two protein supplement rates (no supplement (−RSM) and rapeseed meal (+RSM)). Grass silage (GS) was gradually replaced by barley silage (BS) in the diet at the rates of 0 (BS0), 200 (BS20), 400 (BS40) or 600 (BS60) g kg-1 of silage DM. The basal concentrate mixture (Table 2) was formulated from barley (384 g kg-1) and oats (384 g kg-1) coarsely ground with a hammer mill, dry molassed sugar beet pulp (192 g kg-1) and mineral and vitamin supplement (40 g kg-1) (Ca 160, P 64, Na 90, Mg 80 g kg-1, vitamin A 150 000, vitamin D 100 000 IU kg-1, and vitamin E 500 mg kg-1; Viher-Hertta-Minera, Suomen Rehu Ltd, Helsinki, Finland). In protein-supplemented diets A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 236 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 237 Ta bl e 1. Y ie ld a nd c ha ra ct er is tic s of g ra ss (G S) , b ar le y (B S) a nd w he at (W S) h ar ve st ed a t d iff er en t g ro w th s ta ge s (1 , 2 , 3 ) b ef or e en si lin g an d re sp ec tiv e si la ge s (g k g- 1 d ry m at te r u nl es s ot he rw is e st at ed ) E xp er im en t E xp er im en t 1 E xp er im en t 2 E xp er im en t 3 Si la ge G S B S G S B S1 B S2 B S3 G S B S1 B S2 W S1 W S2 H ar ve st D ay s af te r s ow in g - 82 - 69 76 82 - 87 10 0 94 10 8 D ay s af te r h ea di ng - 27 - 14 21 27 - 23 36 30 44 D ry m at te r, g kg -1 , n =3 W ho le c ro p 24 6 30 8 24 2 31 8 39 1 44 1 24 9 28 2 34 3 28 8 37 8 E ar - 42 3 - 36 7 47 2 55 5 - 37 9 50 2 34 5 49 5 Y ie ld , t d ry m at te r h a- 1 - - - 5. 4 6. 7 6. 8 - 8. 4 9. 4 9. 2 10 .5 E ar p ro po rt io n - - - 51 0 59 0 66 0 - 46 0 56 0 43 0 58 0 Pl an t h ei gh t, cm - - - 56 60 57 - 82 81 90 91 Si la ge ra w m at er ia l, n= 2 or 3 C ru de p ro te in 13 8 10 0 11 1 11 8 12 0 10 4 13 1 11 6 10 2 11 8 11 2 N eu tr al -d et er ge nt fi br e 58 6 54 3 50 2 44 3 40 0 41 7 58 0 49 6 52 8 52 2 50 9 S ta rc h - 14 2 - 15 6 20 1 27 8 - 61 16 0 67 19 6 W at er s ol ub le c ar bo hy dr at es 10 4 19 6 18 9 20 6 17 6 11 8 13 9 14 4 88 14 4 52 Si la ge , n =4 D ry m at te r, g kg -1 25 1 31 1 22 1 35 6 39 0 41 8 26 4 28 2 33 4 30 0 34 0 A sh 82 75 85 63 62 66 64 73 77 89 85 C ru de p ro te in 13 8 10 0 11 0 11 3 11 3 11 3 12 9 10 7 10 7 12 6 12 2 N eu tr al -d et er ge nt fi br e (N D F) 56 2 48 8 51 9 41 7 36 0 33 9 54 2 50 2 46 0 49 4 45 1 A ci d- de te rg en t fi br e - - 26 5 19 8 17 1 15 3 30 5 26 6 23 9 28 2 24 0 L ig ni n - - 23 20 17 19 27 31 32 37 33 In di ge st ib le N D F 73 15 8 80 92 85 86 65 12 7 14 8 15 2 14 5 S ta rc h - 12 4 - 13 7 22 2 25 7 - 94 17 5 66 17 7 p H 4. 04 3. 78 3. 88 3. 86 3. 88 4. 07 4. 17 3. 98 4. 07 4. 00 4. 21 W at er s ol ub le c ar bo hy dr at es 53 27 67 44 40 96 82 35 84 42 96 L ac tic a ci d 50 53 53 46 41 29 53 41 33 55 24 A ce tic a ci d 19 22 16 24 21 13 14 20 7 24 9 B ut yr ic a ci d 1. 0 0. 2 0. 2 0. 3 0. 1 0. 2 0. 1 0. 3 0. 3 0. 1 0. 1 P ro pi on ic a ci d 1 0. 0 0. 0 1. 1 0. 6 0. 5 0. 4 0. 8 0. 8 0. 7 0. 9 0. 8 A m m on ia N , g k g- 1 N 2) 44 62 22 33 36 33 35 38 58 66 90 In v itr o O M d ig es tib ili ty 0. 73 2 0. 66 2 0. 70 9 0. 70 9 0. 72 2 0. 72 9 0. 72 7 0. 66 5 0. 66 9 0. 63 4 0. 66 0 M E , M J kg -1 d ry m at te r 3 ) 10 .8 9. 5 10 .4 10 .3 10 .5 10 .6 10 .9 9. 6 9. 6 9. 0 9. 4 A A T 4) 80 62 75 83 85 85 82 76 74 74 75 P B V 5) 2 –6 –1 8 –2 8 –3 2 –3 2 –1 2 –2 2 –1 9 –1 –8 1) I nc lu de s pr op io ni c ac id f ro m s ila ge a dd iti ve in E xp . 2 a nd E xp . 3 , 2 ) C or re ct ed f or N f ro m s ila ge a dd iti ve , 3 ) M E = M et ab ol is ab le e ne rg y, b as ed o n in v itr o m ea su re m en t o f or ga ni c m at te r (O M ) d ig es tib ili ty a nd c or re ct io n eq ua tio ns (H uh ta ne n et a l. 20 06 ), 4) A A T = A m in o ac id s ab so rb ed in th e sm al l i nt es tin e (M T T 20 06 ) 5 ) P B V = P ro te in b al an ce in th e ru m en (M T T 2 00 6) A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 238 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 239 solvent-extracted rapeseed meal (Raisio Feed Ltd, Raisio, Finland) replaced 2 kg of the basal mixture. Concentrate (110 or 164 g crude protein (CP) kg-1 DM) was offered at a rate of 10 kg per day. Exp. 2 was conducted with ten dietary treat- ments and with two replicate blocks (one for primi- parous, one for multiparous) of 10 cows each. The cows were selected so that each block involved group of cows which was as homogenous as pos- sible on the basis of milk yield and feed intake. Within the blocks the cows were allocated at ran- dom to the experimental treatments. The cows had a mean (s.d.) live weight of 580 kg (72.9), and were 75 days (29.2) in lactation, producing 30.6 kg (7.50) milk per day. Dietary treatments in a 5×2 factorial arrangement consisted of five silages and two types of concentrates. Silage treatments were GS, BS2, GS+BS1, GS+BS2, GS+BS3. The proportion of whole crop silage was 400 g kg-1 silage DM. A farm made concentrate mixture (FC) and a commercial com- pound (CC) having equal crude protein (197 g kg-1 DM) and ME (12.7 MJ ME kg-1 DM) concentra- tions were compared (Table 2). Concentrate was offered at 11.0 kg per day. The farm made mix- ture was formulated (g kg-1) from barley (470) and oats (250) coarsely ground with a hammer mill, rapeseed cake (Mildola, Helsinki, Finland) (250), mineral and vitamin supplement (18.2) (Ca 160, P 64, Na 90, Mg 80 g kg-1, A vitamin 150 000, D vitamin 100 000 IU kg-1, and E vitamin 500 mg kg-1; Viher-Hertta-Minera, Suomen Rehu Ltd, Hel- sinki, Finland), calcium carbonate (8.2) and sodi- um chloride (3.6). Pelleted CC (Raisio Feed Ltd, Raisio, Finland) consisted (g kg-1) of wheat (125), oats (125), barley (125), molassed sugar beet pulp (125), wheat middling (120), soybean meal (120), wheat molasses (60), rape seed meal (60), rape seed cake (60), vegetable oil (21), propylene glycol (10) and vitamin and trace element premix (49). Exp. 3 was conducted with ten dietary treat- ments and with two replicate blocks (one for primi- parous, one for multiparous) of 10 cows each. The cows were selected so that each block involved group of cows which was as homogenous as pos- sible on the basis of milk yield and feed intake. Within the blocks the cows were allocated at ran- dom to the experimental treatments. The cows had a mean (s.d.) live weight of 556 kg (39.9), and were 57 days (17.7) in lactation, producing 33.6 kg (6.70) milk per day. Dietary treatments in a 5×2 factorial arrangement consisted of five silage mix- tures and two amounts of concentrates. Silage treat- ments were as follows: GS, GS+BS1, GS+BS2, GS+WS1, and GS+WS2. The proportion of whole crop silage was 400 g kg-1 of silage DM. A pelleted commercial compound (Raisio Feed Ltd, Raisio, Finland) was offered at either 9 or 14 kg per day for the multiparous cows. The primiparous cows received proportionately 0.80 of concentrates (7.2 and 11.2 kg) fed to multiparous cows. Concentrate consisted of oats (154 g kg-1), barley (200 g kg-1), molassed sugar beet pulp (120 g kg-1), wheat mid- dling (120 g kg-1), rape seed meal (300 g kg-1), wheat molasses (70 g kg-1) and vitamin and trace element premix (36 g kg-1) (Table 2). Table 2. Mean chemical composition of concentrates (g kg-1 dry matter, unless otherwise stated) (n = 2 for each experiment). Experiment 1 Experiment 2 Experiment 3 –RSM 1) +RSM FC 2) CC 3) Dry matter, g kg-1 885 886 885 879 862 Ash 82 78 67 66 71 Crude protein 110 164 202 193 210 Ether extract - - 58 63 48 Neutral-detergent fibre 249 258 235 235 270 Starch - - 353 249 204 Metabolisable energy, MJ kg-1 dry matter 12.2 12.0 12.6 12.7 11.9 Amino acids absorbed in the small intestine 98 110 113 112 114 Protein balance in the rumen –36 0 10 20 16 1) RSM = rape seed meal, 2) FC = farm-made concentrate, 3) CC = commercial compound A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 238 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 239 Sampling and analyses Both barley and wheat fields were divided into three sub-areas. The yield of the whole crop was estimated before harvesting by taking plant samples from four replicates of 0.25 m2 on each sub-area. The height of the cereals was measured, the samples were cut at the height of 8 cm, pooled over the sub-areas resulting in three samples, weighed and analysed for DM concentration separately for whole crop and ears. Samples of whole crop cereals and grass were collected from every load at the time of ensiling and immediately stored at 4 oC. The samples were pooled over three loads resulting in two or three samples per treatment. Once ensiling was completed, samples were submitted for the determination of DM, total nitrogen (N), neutral detergent fibre (NDF) and water soluble carbohydrates (WSC), and whole crop cereal samples also for starch determination. Dur- ing the sampling period of the animal experiment, representative samples of silages were collected before mixing, and samples of silage mixtures and concentrates were collected daily. Concentrates were analysed for DM, ash, N, NDF, starch and acid insoluble ash (AIA). Silages were analysed for DM, ash, N, NDF, acid detergent fibre (ADF), lignin, starch, AIA, in vitro organic matter digest- ibility, indigestible NDF (iNDF), pH, lactic acid, VFA, WSC and ammonia N. Silage samples and DM concentration of concentrate were analysed separately for each period. For the determination of chemical composition, concentrate samples were pooled over two periods resulting in two separate determinations. Feed intake and milk yield were recorded daily. Cows were milked twice daily at 6.30 and 15.30 h. Milk samples were obtained from four consecutive milkings on day 18 to 20 and analysed by an infra- red milk analyser (Milko-Scan 133B, Foss Electric, Hillerød, Denmark) for fat, protein and lactose. A separate milk sample from two consecutive milk- ings on day 20 was taken for urea determination. Cows were weighed on two consecutive days at the beginning of the experiment and on days 20 and 21 of each experimental period at 10.00 h. Whole tract apparent digestibility was estimat- ed using AIA as an internal marker (van Keulen and Young 1977). During the last 5 days of each period spot faecal samples were collected at 06.30 and 15.30 h from 8, 10 and 10 cows assigned to the blocks of multiparous cows in Exp. 1, 2 and 3, respectively. At the end of each period, samples were pooled on an individual cow basis, thoroughly mixed, subsampled and stored at –20 ºC. Energy value for concentrates was calculated using published digestibility coefficients (MTT 2006) for each ingredient. Grass and whole crop silage ME values in the Table 1 are based on in vitro –measurement. Protein balance in the rumen (PBV) and amino acids absorbed in the small in- testine (AAT) were calculated according to a modi- fied Nordic AAT-PBV protein evaluation system adopted in Finland (MTT 2006). Forage AAT and PBV concentrations were calculated using the equations based on crude protein concentration and measured digestible organic matter (OM) in DM (MTT 2006). Concentrate AAT and PBV con- centrations were calculated using published values for individual concentrate ingredients (MTT 2006). Estimates of the efficiency of utilization of AAT for milk protein synthesis and milk production were calculated ignoring changes in live weight. The metabolisable energy (ME) concentration of the diets was calculated based on predicting ME intake from digestible OM measured in cows as- suming a ME concentration of 16 MJ kg-1 digestible OM (MAFF 1975). Calculations were conducted using AIA based digestibility measurements for in- dividual cows within block 1 and mean treatment values for block 2, since individual measurements of digestibility were not made for these animals. Milk energy concentration was estimated accord- ing to Sjaunja et al. (1990) and ME requirement for maintenance according to MAFF (1984). The effi- ciency of utilization of ME (kl) for milk production was calculated ignoring changes in live weight. Chemical analyses of the feed and faecal sam- ples, and milk urea measurement were made as reported previously by Huhtanen and Heikkilä (1996). Total N concentrations in fresh silage sam- ples were measured by the Kjeldahl method using Cu as a digestion catalyst and a Tecator 1028 Dis- A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 240 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 241 tilling Unit. In Exp. 1 starch concentrations in feed and faecal samples were measured as described by Bach Knudsen et al. (1987). In Exp. 2 and 3 starch concentrations were analysed by the method of McCleary et al. (1994) with assay format 2 with- out pullulanase/ß-amylase treatment. A modifica- tion of the pepsin-cellulase method (Friedel 1990) described by Nousiainen et al. (2003) was used to measure in vitro OM digestibility of the forages. The results were calculated with a correction equa- tion to convert pepsin-cellulase solubility values into in vivo digestibility by equations based on a data set consisting of Finnish in vivo digestibility trials (Huhtanen et al. 2006). The concentration of indigestible NDF in silages was measured as de- scribed by Ahvenjärvi et al. (2006). Statistical analysis Measurements collected during the sampling period were used when calculating the feed intake and milk production results. Experimental data was subjected to Analysis of Variance using the General Linear Model procedure (PROC GLM) of the Statistical Analysis Systems Institute (SAS, 1989). The sta- tistical model was yijkl = µ + Bi + C(B)ij + Pk + Tl + (B×P)ik + (B×T)il + eijkl, where B, C(B), P, and T are the effects of block, cow within block, period, and treatment, respectively, and eijkl is the error term. Treatment carry-over effect was included for milk production and feed consumption data, but no significant effects were found. Sums of squares for treatment effects were fur- ther separated using orthogonal contrasts into sin- gle degree of freedom comparisons. In Exp. 1 the comparisons for the main effects were the protein supplement (Prot) and the linear (L), quadratic (Q) and cubic (C) effect of the barley silage proportion in the silage mixture. The interactions were Prot × L, Prot × Q and Prot × C. In Exp. 2 the compari- sons for the main effects were the concentrate type (Conc), the L and Q effects of barley growth stage, and grass silage vs. BS2 silage. The interactions were Conc × L, Conc × Q and Conc × (grass silage vs. BS2). In Exp. 3 the comparisons for the main effects were the concentrate level (Conc), grass silage vs. cereal silages, barley silage vs. wheat silage, and the effect of growth stage of barley and wheat. The interactions were Conc × (grass vs. ce- real), Conc × (barley vs. wheat) and Conc × growth stage. The results of the main treatment effects of Exp. 2 and 3 are presented in the tables. Only a few significant interactions were observed and they are mentioned in the text. Results Silages The chemical composition of the barley, wheat and grass ensiled, and the respective silages are shown in Table 1 and that of the concentrates in Table 2. During harvesting at the dough stage the DM concentration of barley varied between 282 and 441 g kg-1, and that of wheat between 289 and 378 g kg-1. The proportion of ear increased with the advancing maturity of barley from 510 to 660 g kg-1 DM in Exp. 2 and from 460 to 560 g kg-1 DM in Exp. 3. In wheat the proportion of ear cor- responded to the values observed with barley (Exp. 3). The height of barley was in Exp. 2 much lower than that of barley and wheat in Exp. 3. The advancing maturity had a minor effect on cereal crude protein concentration, which was on average 110 g kg-1 DM in barley (Exp. 1-3) and 115 g kg-1 DM in wheat (Exp. 3) at harvest. The concentration of NDF in barley was much lower in Exp. 2 (mean 420 g kg-1 DM) than in Exp. 1 and 3 (522 g kg-1 DM) whereas the starch concen- tration was higher in Exp. 2 (mean 212 vs. 121 g kg-1 DM). The harvest time had only a minor ef- fect on the NDF concentration, whereas the starch concentration increased from 156 to 278 g kg-1 DM in Exp. 2, and from 61 to 160 g kg-1 DM in Exp. 3 in barley, and from 67 to 196 g kg-1 DM in wheat (Exp. 3). The change was reflected as a decrease in the concentration of water soluble carbohydrates. A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 240 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 241 The DM concentration of grass was similar in all experiments (mean 246 g kg-1). Compared to cereals, grass had higher concentration of crude protein (from 111 to138 g kg-1 DM) and NDF (from 502 to 586 g kg-1 DM). Indigestible NDF concentration was distinctly higher in cereal crop silages than in grass silages in Exp. 1 and 3. How- ever, in Exp. 2 no difference was observed be- tween the second cut grass silage and whole crop barley silages. Advanced maturity increased (Exp. 3 barley) or slightly decreased (Exp. 2 barley, Exp. 3 wheat) the iNDF concentration of silage. The starch concentrations of whole crop silag- es after the ensiling period were in some silages slightly lower than those of the parent material while NDF and WSC concentrations clearly de- creased during fermentation process. Exception was NDF concentration in BS1, and WSC con- centration in BS2 and WS2 (Exp. 3). The fermentation quality of whole crop silages was good in all experiments, as evidenced by low pH and concentrations of VFA (Table 1). Only traces of butyric acid were observed. Compared to whole crop silages, grass silages were of simi- lar good fermentation quality. In Exp. 2 harvest- ing barley at the late dough stage (BS3) resulted in higher pH and WSC concentration, and more restricted fermentation as compared with other barley silages. No effects of the harvest time on the proportion of ammonia N in the barley silage were observed. In wheat silages the ammonia-N proportion was higher than in barley silages and higher in WS2 than in WS1 (90 vs 66 g kg-1 N). In Exp. 1 the CP concentration of protein supplemented concentrate (+RSM) was 164 g kg-1 DM, clearly higher than that of the control concentrate (110 g kg-1 DM). In Exp. 2 and 3, concentrate CP concentration was higher (mean 202 g kg-1 DM) than in Exp. 1. In Exp. 2 the use of different ingredients resulted in lower starch concentration in CC than in FC concentrate. How- ever, there was no difference in the NDF concen- tration. Feeding experiment 1 The inclusion of barley silage in the diet tended (p<0.10) to change silage DM intake in a quadratic manner, such that the intake was highest with the BS20 and lowest with the BS60 diet (Table 3). Diet OM, NDF and CP digestibility decreased linearly (p <0.001) with the increasing proportion of barley si- lage. Protein supplementation increased significantly silage intake (p<0.001) and OM, NDF (p<0.01) and CP (p<0.001) digestibility. However, the increase in OM digestibility was different with different silage diets (interaction RSM × BS cubic). Due to the changes in intake and digestibility, inclusion of barley silage linearly decreased (p<0.001) and that of RSM increased (p<0.001) ME and AAT intake. Milk and milk constituent yields decreased lin- early (p<0.001) with the increasing proportion of barley silage in the diet, and increased (p<0.001, p<0.01) with the inclusion of RSM in the diet (Ta- ble 4). A significant interaction between BS cubic effect and RSM was observed in milk fat concentra- tion (p<0.05). Rape seed meal increased (p<0.001) milk protein and urea concentrations, while replac- ing grass silage with barley silage decreased lin- early (p<0.01) milk urea concentration. The efficiency of dietary N utilization, assessed as the ratio of milk N/N intake, decreased linearly with the increasing rate of barley silage in the diet (p<0.05) but no effect in AAT and ME utilization was observed. The use of RSM decreased the ratio of milk N/N intake (p<0.001) but increased AAT utilization (p<0.001). The efficiency of ME utiliza- tion decreased (p<0.05) with RSM supplementa- tion. Feed efficiency, assessed as the ratio of kg ECM kg-1 DM intake, decreased linearly with the increasing proportion of barley silage. Feeding experiment 2 Harvesting barley at one week intervals had no effect on silage DM intake (p>0.05) whereas the starch intake increased linearly (p<0.001) (Table 5). Cows fed the grass silage diet ate more NDF (p<0.001) and ME (p<0.05) but less starch (p<0.001) than those A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 242 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 243 Ta bl e 3. T he e ff ec t o f r ep la ci ng 0 , 2 00 , 4 00 o r 6 00 g k g- 1 g ra ss s ila ge d ry m at te r ( D M ) w ith w ho le c ro p ba rl ey s ila ge (B S) , a nd th e ef fe ct o f i nc lu di ng 0 (– ) o r 2 k g (+ ) r ap e se ed m ea l ( R SM ) i n co nc en tr at e m ix tu re o n D M a nd n ut ri en t i nt ak e an d di ge st ib ili ty (E xp er im en t 1 ). B ar le y si la ge p ro po rt io n 0 20 0 40 0 60 0 SE M St at is tic al s ig ni fic an ce s R ap e se ed m ea l – + – + – + – + R SM B S L in B S Q ua B S C ub I nt er ac tio n In ta ke N um be r o f o bs er va tio ns 8 8 8 8 8 8 8 8 Si la ge , k g D M d -1 11 .7 13 .0 12 .5 13 .3 12 .0 12 .5 11 .8 12 .5 0. 25 ** * C on ce nt ra te , k g D M d -1 9. 0 8. 7 8. 6 8. 8 8. 7 8. 9 9. 0 8. 8 0. 08 To ta l, kg D M d -1 20 .7 21 .7 21 .1 22 .1 20 .7 21 .4 20 .8 21 .3 0. 28 O rg an ic m at te r, k g d- 1 19 .0 20 .0 19 .4 20 .3 19 .1 19 .7 19 .1 19 .7 0. 26 ** N eu tr al -d et er ge nt fi br e, k g d- 1 8. 80 9. 51 8. 91 9. 53 8. 51 8. 92 8. 42 8. 81 0. 14 3 C ru de p ro te in , kg d -1 2. 55 3. 12 2. 39 3. 02 2. 41 2. 98 2. 37 2. 92 0. 04 8 M E , M J d- 1 1 ) 20 9 22 7 21 2 22 4 20 4 21 8 20 0 20 6 2. 7 ** * ** * A A T, g d -1 2 ) 18 07 19 88 17 94 19 72 17 20 18 82 16 86 18 29 21 .4 ** * ** * D ig es tib ili ty c oe ffi ci en ts N um be r o f o bs er va tio ns 4 4 4 4 4 4 4 4 O rg an ic m at te r 0. 68 6 0. 71 1 0. 68 4 0. 69 0 0. 66 8 0. 69 0 0. 65 3 0. 65 4 0. 00 47 ** ** * * R SM × B SC ub C ru de p ro te in 0. 59 6 0. 67 0 0. 57 9 0. 64 1 0. 55 8 0. 65 0 0. 54 2 0. 59 6 0. 00 94 ** * ** * N eu tr al -d et er ge nt fi br e 0. 60 0 0. 63 2 0. 56 7 0. 58 0 0. 53 3 0. 54 9 0. 46 2 0. 48 8 0. 00 92 ** ** * 1) M E = M et ab ol is ab le e ne rg y, c al cu la tio n ba se d on m ea su re d in v iv o or ga ni c m at te r d ig es tib ili ty in c ow s 2) A A T = A m in o ac id s ab so rb ed in th e sm al l i nt es tin e (M T T 20 06 ) SE M = S ta nd ar d er ro r o f t he m ea n, S E M h as b ee n gi ve n fo r t he in te ra ct io n ef fe ct (n =8 fo r i nt ak e da ta , a nd n =4 fo r d ig es tib ili ty d at a) R SM is th e ef fe ct o f r ap es ee d m ea l; B S L in , Q ua a nd C ub a re th e lin ea r, qu ad ra tic a nd c ub ic e ff ec t o f B S in cl us io n. In te ra ct io ns a re g iv en a s le tte r c om bi na tio ns . Si gn ifi ca nt d if fe re nc es a t p < 0 .0 5, p < 0 .0 1 an d p < 0. 00 1 le ve ls a re in di ca te d by * , * * an d ** *, re sp ec tiv el y. A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 242 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 243 Ta bl e 4. T he e ff ec t o f r ep la ci ng 0 , 2 00 , 4 00 o r 6 00 g k g- 1 g ra ss s ila ge d ry m at te r ( D M ) w ith w ho le c ro p ba rl ey s ila ge (B S) a nd th e ef fe ct o f i nc lu di ng 0 (– ) o r 2 k g (+ ) ra pe s ee d m ea l ( R SM ) i n co nc en tr at e m ix tu re o n m ilk p ro du ct io n, li ve w ei gh t a nd n ut ri en t u til iz at io n fo r m ilk p ro du ct io n (E xp er im en t 1 ). B ar le y si la ge 0 20 0 40 0 60 0 SE M St at is tic al s ig ni fic an ce s R ap e se ed m ea l – + – + – + – + R SM B S L in B S Q ua B S C ub In te ra ct io n N um be r o f o bs er va tio ns 8 8 8 8 8 8 8 8 Y ie ld M ilk , k g d- 1 29 .3 30 .7 28 .3 30 .2 27 .3 29 .1 26 .3 26 .9 0. 40 ** * ** * E C M , k g d- 1 1 ) 32 .3 33 .8 31 .1 33 .7 30 .2 31 .8 29 .1 30 .0 0. 46 ** * ** * Fa t, g d- 1 14 30 14 73 13 66 14 89 13 36 13 84 12 92 13 21 24 .4 ** ** * Pr ot ei n, g d -1 91 1 99 4 89 6 97 5 85 5 94 1 82 9 88 8 12 .3 ** * ** * L ac to se , g d -1 14 47 15 04 13 99 14 81 13 45 14 28 12 81 13 08 21 .4 ** ** * M ilk c om po si tio n Fa t, g kg -1 49 .3 48 .3 48 .5 49 .1 49 .9 48 .1 50 .0 49 .8 0. 46 * R SM × B SC ub Pr ot ei n, g k g- 1 31 .3 32 .5 31 .7 32 .2 31 .6 32 .5 31 .8 33 .4 0. 33 ** * L ac to se , g k g- 1 49 .6 49 .0 49 .4 49 .1 49 .3 49 .2 48 .9 48 .8 0. 28 U re a, m g 10 0 m l-1 13 .3 23 .3 11 .2 21 .5 10 .4 18 .3 11 .2 18 .6 0. 97 ** * * * L iv e w ei gh t, kg 56 5 57 4 57 0 58 1 57 0 57 5 57 0 58 3 2. 2 ** * * L iv e w ei gh t c ha ng e, k g d- 1 –0 .2 0 –0 .1 5 –0 .0 2 0. 42 0. 10 –0 .2 1 –0 .0 3 0. 70 0. 14 9 * * * R SM × B SC ub E ffi ci en cy o f u til iz at io n M ilk N / N in ta ke 0. 35 8 0. 32 0 0. 37 1 0. 32 3 0. 35 5 0. 31 6 0. 35 0 0. 30 6 0. 00 5 ** * * A A T u til iz at io n 2) 0. 62 3 0. 65 4 0. 63 5 0. 64 4 0. 62 5 0. 65 4 0. 62 5 0. 65 1 0. 00 58 ** * M E u til iz at io n 3) 0. 68 6 0. 63 9 0. 64 3 0. 64 8 0. 66 1 0. 63 8 0. 65 6 0. 65 4 0. 00 95 * E C M / dr y m at te r, kg k g- 1 1. 57 1. 56 1. 47 1. 52 1. 46 1. 49 1. 40 1. 41 0. 01 9 ** * 1) E C M = E ne rg y co rr ec te d m ilk 2) A A T = A m in o ac id s ab so rb ed in th e sm al l i nt es tin e (M T T 20 06 ) 3) M E = M et ab ol is ab le e ne rg y, c al cu la tio n ba se d on m ea su re d in v iv o or ga ni c m at te r d ig es tib ili ty in c ow s SE M = S ta nd ar d er ro r o f t he m ea n, S E M h as b ee n gi ve n fo r t he in te ra ct io n ef fe ct (n =8 ) R SM is th e ef fe ct o f r ap es ee d m ea l; B S L in , Q a nd C a re th e lin ea r, qu ad ra tic a nd c ub ic e ff ec t o f B S in cl us io n. In te ra ct io ns a re g iv en a s le tte r c om bi na tio ns . Si gn ifi ca nt d if fe re nc es a t p < 0 .0 5, p < 0 .0 1 an d p < 0. 00 1 le ve ls a re in di ca te d by * , * * an d ** *, re sp ec tiv el y. A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 244 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 245 Ta bl e 5. M ea n ef fe ct s of s ila ge (g ra ss (G S) o r b ar le y si la ge (B S) h ar ve st ed a t t hr ee s ta ge s of m at ur ity (B S1 , B S2 , B S3 )) a nd c on ce nt ra te (C ) t yp e (F C , f ar m - m ad e co nc en tr at e an d C C , c om m er ci al c om po un d) o n dr y m at te r ( D M ) a nd n ut ri en t i nt ak e an d di ge st ib ili ty in d ie ts b as ed o n gr as s si la ge , B S2 , a nd a m ix - tu re o f G S an d ba rl ey s ila ge s. In th e m ix tu re s, th e pr op or tio n of w ho le c ro p si la ge w as 4 00 g k g- 1 o f s ila ge D M (E xp er im en t 2 ). Si la ge C on ce nt ra te SE M St at is tic al s ig ni fic an ce s G ra ss B S2 G ra ss + B S1 G ra ss + B S2 G ra ss + B S3 FC C C C B S L in B S Q ua G ra ss v s B S2 In te ra ct io n In ta ke S ila ge , k g D M d -1 10 .7 10 .5 11 .9 12 .0 12 .2 11 .9 11 .0 0. 23 ** * C on ce nt ra te , k g D M d -1 9. 5 9. 2 9. 5 9. 2 9. 2 9. 3 9. 3 0. 13 T ot al , k g D M d -1 20 .2 19 .6 21 .4 21 .1 21 .4 21 .2 20 .3 0. 20 ** * O rg an ic m at te r, k g d- 1 18 .7 18 .3 19 .8 19 .6 19 .8 19 .7 18 .9 0. 19 ** * C ru de p ro te in , kg d -1 3. 01 3. 06 3. 15 3. 13 3. 16 3. 19 3. 01 0. 02 9 ** * N eu tr al -d et er ge nt fi br e, k g d- 1 7. 61 6. 24 7. 86 7. 77 8. 02 7. 70 7. 30 0. 11 8 ** ** * S ta rc h, k g d- 1 2. 84 4. 62 3. 52 3. 66 3. 92 4. 24 3. 18 0. 04 1 ** * ** * ** * M E , M J d- 1 1 ) 20 9 20 0 21 9 21 8 22 1 21 2 21 5 2. 1 * A A T, g d -1 2 ) 18 69 19 23 19 93 19 78 19 95 19 91 19 12 17 .7 ** * D ig es tib ili ty c oe ffi ci en ts O rg an ic m at te r 0. 69 9 0. 68 2 0. 69 5 0. 69 1 0. 69 1 0. 67 3 0. 71 0 0. 00 42 ** * * C ru de p ro te in 0. 63 8 0. 64 7 0. 64 4 0. 62 9 0. 63 3 0. 61 9 0. 65 7 0. 00 70 ** * N eu tr al -d et er ge nt fi br e 0. 58 1 0. 41 9 0. 54 1 0. 53 1 0. 54 0 0. 51 5 0. 52 9 0. 00 70 ** * S ta rc h 0. 93 8 0. 94 4 0. 94 7 0. 94 2 0. 95 2 0. 89 4 0. 99 5 0. 00 90 ** * 1) M E = m et ab ol is ab le e ne rg y, c al cu la tio n ba se d on m ea su re d in v iv o or ga ni c m at te r d ig es tib ili ty in c ow s 2) A A T = a m in o ac id s ab so rb ed in th e sm al l i nt es tin e (M T T 20 06 ) SE M = s ta nd ar d er ro r o f t he m ea n SE M h as b ee n gi ve n fo r t he m ai n ef fe ct o f s ila ge tr ea tm en ts w ith 1 6 ob se rv at io ns in in ta ke d at a an d 8 ob se rv at io ns in d ig es tib ili ty d at a. F or th e m ai n ef fe ct o f c on ce nt ra te tr ea tm en ts th e nu m be r of o bs er va tio n is 4 0 (i nt ak e) o r 2 0 (d ig es tib ili ty ), an d SE M s ho ul d be m ul tip lie d by 0 .6 32 . L in a nd Q ua a re th e lin ea r a nd q ua dr at ic e ff ec ts o f b ar le y m at ur ity . C is th e ef fe ct o f c on ce nt ra te ty pe . I nt er ac tio ns a re g iv en a s le tte r c om bi na tio ns . Si gn ifi ca nt d if fe re nc es a t p < 0 .0 5, p < 0 .0 1 an d p < 0. 00 1 le ve ls a re in di ca te d by * , * * an d ** *, re sp ec tiv el y. A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 244 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 245 fed the barley silage diet (BS2). The digestibilities of OM (p<0.05) and NDF (p<0.001) were lower on the BS2 diet than on the GS diet. Feeding of farm-made starch based concentrate resulted in higher silage and total DM intake and lower OM, CP and starch digestibility (p<0.001) compared with CC-concentrate. As a result, the in- takes of NDF (p<0.01), OM, CP, starch and AAT (p<0.001) were higher with the FC diet, but no dif- ference was observed in ME intake. The same milk, ECM, fat and lactose yield was obtained with GS and BS2 diets (Table 6). How- ever, feeding BS2 resulted in a higher milk protein concentration (p<0.001) and protein yield (p<0.05) than feeding GS. No difference was observed between the con- centrate types in milk or ECM yield (p>0.05). Milk protein concentration and yield increased with in- creasing maturity on the FC diet and decreased on the CC diet (interaction C × BSL p<0.05). On the FC diet milk protein concentration was 33.6, 34.1 and 34.3 g kg-1 on diets G+BS1, G+BS2, G+BS3, respectively. On the CC diet the values were 33.3, 34.0 and 32.6, respectively. Milk lactose concentra- tion was higher on the CC than FC diet (p<0.05). The cows gained more weight with FC than CC concentrate (p<0.05). Nitrogen and AAT utilization was more efficient with cows eating CC rather than FC concentrate (p<0.001, p<0.01). In ME utilization the cows hav- ing the FC diet were more efficient than those on the CC diet, although the value of kg ECM kg-1 DM intake was higher with CC (p<0.001). When com- paring GS and BS2 diets, the kl value was higher on the BS2 diet with CC concentrate whereas only a small difference was observed with the FC diet (interaction C × GS vs. BS2, p<0.05). The kl values were 0.620, 0.584, 0.631 and 0.642 on diets GS- FC, GS-CC, BS2-FC and BS2-CC, respectively. For kg ECM kg-1 DM intake the respective values were 1.39, 1.40, 1.38 and 1.50 (interaction C × GS vs. BS2, p<0.01). Feeding experiment 3 Compared to the grass silage diet, whole crop silage diets had, on average, lower digestibility of OM and NDF (p<0.001) (Table 7). However, lower digest- ibility was compensated by increased silage and total DM intake on mixed diets (p<0.001). Consequently, the intakes of OM and starch (p<0.001) and that of NDF (p<0.05) were higher with mixed diets than with the GS diet. The intakes of NDF (p<0.05) and ME (p<0.01) were higher with the BS diet than with the WS diet, the latter being related to the lower ME intake of the WS1 compared to the WS2 diet (p<0.01). The advancing maturity resulted in increased starch intake for both BS and WS diets (p<0.001). The digestibility of NDF was higher with the BS than the WS diet (p<0.05). An increase in concentrate feeding induced a higher (p<0.001) total DM intake, which was associated with a reduction in silage DM intake (p<0.001). Similarly, the intakes of OM, CP, starch, ME and AAT increased with the increasing con- centrate proportion (p<0.001). The use of higher concentrate amount resulted in decreased digest- ibility of diet NDF (p<0.05). The inclusion of whole crop silage in the grass silage diet had no effect on milk or milk compo- nents yields, or milk composition (Table 8). Nei- ther were there any differences between the BS and WS diets, or between growth stages of barley. With wheat silages, the WS2 diet increased ECM yield compared to the WS1 diet (p<0.05). Milk urea con- centration was lower with the GS diet than with mixed diets, which was explained by the higher CP concentration in the wheat silage diets as compared with barley silage diets (p<0.001). An increase in concentrate amount induced higher milk, ECM, milk fat, protein and lactose yields (p<0.001). In addition, high concentrate amount resulted in increased milk protein and urea (p<0.001) and lactose (p<0.05) concentrations. Further, higher live weight gain was observed with higher concentrate amount (p<0.01). Minor differences were observed between the silage diets in the efficiency of nitrogen and ME utilization. The only differences were between the A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 246 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 247 Ta bl e 6. M ea n ef fe ct s of s ila ge (g ra ss (G S) o r b ar le y si la ge (B S) h ar ve st ed a t t hr ee s ta ge s of m at ur ity (B S1 , B S2 , B S3 )) a nd c on ce nt ra te ty pe (F C , f ar m -m ad e co n- ce nt ra te a nd C C , c om m er ci al c om po un d) o n m ilk p ro du ct io n, li ve w ei gh t a nd n ut ri en t u til iz at io n in d ie ts b as ed o n gr as s si la ge , B S2 , a nd a m ix tu re o f G S an d ba r- le y si la ge s. In th e m ix tu re s, th e pr op or tio n of w ho le c ro p si la ge w as 4 00 g k g- 1 o f s ila ge D M (E xp er im en t 2 ). Si la ge C on ce nt ra te SE M St at is tic al s ig ni fic an ce s G ra ss B S2 G ra ss + B S1 G ra ss + B S2 G ra ss + B S3 FC C C C B S L in B S Q ua G ra ss v s B S2 In te ra ct io n Y ie ld M ilk , k g d- 1 27 .6 27 .5 29 .3 28 .7 28 .9 28 .2 28 .6 0. 24 E C M , k g d- 1 1 ) 28 .3 28 .2 30 .4 30 .2 29 .6 29 .4 29 .4 0. 31 Fa t, g d- 1 11 57 11 29 12 30 12 32 11 87 11 91 11 84 21 .1 Pr ot ei n, g d -1 88 2 91 6 96 8 96 8 95 5 94 3 93 3 8. 3 * * C × B SL in L ac to se , g d -1 13 73 13 72 14 67 14 36 14 42 14 04 14 32 12 .1 M ilk c om po si tio n Fa t, g kg -1 42 .8 41 .7 42 .6 43 .6 41 .7 42 .8 42 .1 0. 69 Pr ot ei n, g k g- 1 32 .5 33 .7 33 .5 34 .1 33 .6 33 .8 33 .1 0. 19 * * * * ** * C × B SL in L ac to se , g k g- 1 50 .0 50 .1 50 .3 50 .2 50 .3 50 .1 50 .3 0. 13 * U re a, m g 10 0 m l-1 21 .3 24 .1 21 .1 21 .2 22 .1 21 .7 22 .3 0. 48 L iv e w ei gh t, kg 58 8 58 3 59 1 58 9 59 7 59 2 58 8 2. 1 L iv e w ei gh t c ha ng e, k g d- 1 0. 28 –0 .2 0 0. 37 0. 22 0. 50 0. 40 0. 07 0. 12 7 * E ffi ci en cy o f u til iz at io n M ilk N / N in ta ke 0. 28 5 0. 29 4 0. 30 0 0. 30 1 0. 29 5 0. 28 8 0. 30 2 0. 00 31 * ** A A T u til iz at io n 2) 0. 59 3 0. 59 6 0. 60 2 0. 60 6 0. 59 4 0. 58 6 0. 61 0 0. 00 65 * * M E u til iz at io n 3) 0. 60 3 0. 63 7 0. 60 8 0. 60 9 0. 58 7 0. 61 5 0. 60 2 0. 00 53 * * ** * * C × G S vs B S2 E C M / dr y m at te r, kg k g- 1 1. 40 1. 44 1. 42 1. 43 1. 38 1. 38 1. 44 0. 01 0 * ** * * * C × G S vs B S2 1) E C M = e ne rg y co rr ec te d m ilk 2) A A T = a m in o ac id s ab so rb ed in th e sm al l i nt es tin e (M T T 20 06 ) 3) M E = m et ab ol is ab le e ne rg y, c al cu la tio n ba se d on m ea su re d in v iv o or ga ni c m at te r d ig es tib ili ty in c ow s SE M = s ta nd ar d er ro r o f t he m ea n SE M h as b ee n gi ve n fo r 16 o bs er va tio ns ( m ai n ef fe ct o f si la ge tr ea tm en ts ). W he n th e nu m be r of o bs er va tio ns is 4 0 (m ai n ef fe ct o f co nc en tr at e tr ea tm en ts ), SE M s ho ul d be m ul tip lie d by 0. 63 2. L in a nd Q ua a re th e lin ea r a nd q ua dr at ic e ff ec ts o f b ar le y m at ur ity . C is th e ef fe ct o f c on ce nt ra te ty pe . I nt er ac tio ns a re g iv en a s le tte r c om bi na tio ns . Si gn ifi ca nt d if fe re nc es a t p < 0 .0 5, p < 0 .0 1 an d p < 0. 00 1 le ve ls a re in di ca te d by * , * * an d ** *, re sp ec tiv el y. A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 246 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 247 Ta bl e 7. M ea n ef fe ct s of s ila ge ( gr as s (G S) , o r ba rl ey ( B S1 , B S2 ) an d w he at s ila ge ( W S1 , W S2 ) ha rv es te d at tw o st ag es o f m at ur ity ), an d co nc en tr at e (C ) le ve l ( L lo w , H h ig h) o n dr y m at te r (D M ) an d nu tr ie nt in ta ke a nd d ig es tib ili ty in d ie ts b as ed o n gr as s si la ge , a m ix tu re o f G S an d B S, a nd a m ix tu re o f G S an d W S. I n th e m ix tu re s, th e pr op or tio n of w ho le c ro p si la ge w as 4 00 g k g- 1 o f s ila ge D M . A m ou nt o f c on ce nt ra te (k g- 1 d ) w as 9 (L ) a nd 1 4 (H ) f or m ul tip ar ou s, a nd 7 .2 (L ) a nd 1 1. 2 (H ) f or p ri m ip ar ou s co w s (E xp er im en t 3 ). Si la ge C on ce nt ra te SE M St at is tic al s ig ni fic an ce s G ra ss G ra ss + B S1 G ra ss + B S2 G ra ss + W S1 G ra ss + W S2 L H C G ra ss vs W ho le c ro p B ar le y vs W he at B ar le y m at ur ity W he at m at ur ity In ta ke S ila ge , k g D M d -1 12 .2 13 .2 13 .2 12 .8 13 .2 13 .8 12 .0 0. 14 * ** ** * C on ce nt ra te , k g D M d -1 9. 0 8. 8 8. 8 8. 9 8. 8 7. 0 10 .7 0. 08 T ot al , k g D M d -1 21 .2 22 .0 22 .0 21 .7 21 .9 20 .8 22 .7 0. 12 * ** ** * O rg an ic m at te r, k g d- 1 19 .8 20 .5 20 .5 20 .2 20 .4 19 .4 21 .1 0. 11 * ** ** * C ru de p ro te in , kg d -1 3. 54 3. 53 3. 50 3. 55 3. 56 3. 27 3. 80 0. 01 9 * ** N eu tr al -d et er ge nt fi br e, k g d- 1 9. 04 9. 47 9. 35 9. 15 9. 15 9. 22 9. 24 0. 08 5 * * S ta rc h, k g d- 1 1. 83 2. 23 2. 60 2. 12 2. 70 1. 97 2. 63 0. 01 7 * ** ** * * ** * ** M E , M J d- 1 1 ) 22 7 23 1 22 7 22 0 22 7 21 6 23 7 1. 5 * ** ** * * A A T, g d -1 2 ) 20 30 20 56 20 43 20 28 20 49 19 04 21 78 9. 9 * ** D ig es tib ili ty c oe ffi ci en ts O rg an ic m at te r 0. 71 8 0. 70 4 0. 69 4 0. 68 0 0. 69 4 0. 69 6 0. 70 0 0. 00 62 ** C ru de p ro te in 0. 68 6 0. 67 6 0. 67 1 0. 66 4 0. 66 8 0. 67 2 0. 67 4 0. 00 71 N eu tr al -d et er ge nt fi br e 0. 56 6 0. 53 8 0. 51 0 0. 48 7 0. 50 9 0. 53 4 0. 51 0 0. 01 04 * ** * * St ar ch 0. 98 6 0. 98 9 0. 98 8 0. 98 7 0. 99 0 0. 98 8 0. 98 8 0. 00 07 * * 1) M E = m et ab ol is ab le e ne rg y, c al cu la tio n ba se d on m ea su re d in v iv o or ga ni c m at te r d ig es tib ili ty in c ow s 2 ) A A T = a m in o ac id s ab so rb ed in th e sm al l i nt es tin e (M T T 20 06 ) SE M = s ta nd ar d er ro r o f t he m ea n SE M h as b ee n gi ve n fo r t he m ai n ef fe ct o f s ila ge tr ea tm en ts w ith 1 6 ob se rv at io ns in in ta ke d at a an d 8 ob se rv at io ns in d ig es tib ili ty d at a. F or th e m ai n ef fe ct o f c on ce nt ra te tr ea tm en ts th e nu m be r of o bs er va tio n is 4 0 (i nt ak e) o r 2 0 (d ig es tib ili ty ), an d SE M s ho ul d be m ul tip lie d by 0 .6 32 . C is th e ef fe ct o f c on ce nt ra te le ve l. N o si gn ifi ca nt in te ra ct io ns w er e ob se rv ed . Si gn ifi ca nt d if fe re nc es a t p < 0 .0 5, p < 0 .0 1 an d p < 0. 00 1 le ve ls a re in di ca te d by * , * * an d ** *, re sp ec tiv el y. A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 248 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 249 Ta bl e 8. M ea n ef fe ct s of s ila ge (g ra ss ( G S) , o r ba rl ey (B S1 , B S2 ) an d w he at s ila ge (W S1 , W S2 ) ha rv es te d at tw o st ag es o f m at ur ity ), an d co nc en tr at e (C ) le ve l ( L lo w , H h ig h) o n m ilk p ro du ct io n, li ve w ei gh t a nd n ut ri en t u til iz at io n in d ie ts b as ed o n gr as s si la ge , a m ix tu re o f G S an d B S, a nd a m ix tu re o f G S an d W S. I n th e m ix tu re s, th e pr op or tio n of w ho le c ro p si la ge w as 4 00 g k g- 1 o f si la ge D M . A m ou nt o f co nc en tr at e (k g- 1 d ) w as 9 ( L ) an d 14 ( H ) fo r m ul tip ar ou s, a nd 7 .2 ( L ) an d 11 .2 (H ) f or p ri m ip ar ou s co w s (E xp er im en t 3 ). Si la ge C on ce nt ra te SE M St at is tic al s ig ni fic an ce s G ra ss G ra ss + B S1 G ra ss + B S2 G ra ss + W S1 G ra ss + W S2 H L C G ra ss vs W ho le c ro p B ar le y vs W he at B ar le y m at ur ity W he at m at ur ity Y ie ld M ilk , k g d- 1 31 .4 32 .1 31 .7 31 .1 31 .7 30 .0 33 .2 0. 24 * ** E C M , k g d- 1 1 ) 32 .0 32 .5 32 .2 31 .7 33 .2 30 .8 33 .9 0. 36 * ** * Fa t, g d- 1 12 96 12 96 12 94 12 79 13 80 12 59 13 59 22 .0 * ** * Pr ot ei n, g d -1 10 26 10 49 10 37 10 15 10 34 96 7 10 97 10 .4 * ** L ac to se , g d -1 15 37 15 87 15 61 15 24 15 64 14 72 16 38 13 .4 * ** M ilk c om po si tio n Fa t, g kg -1 41 .3 40 .5 40 .9 41 .3 43 .3 42 .0 40 .9 0. 61 Pr ot ei n, g k g- 1 32 .8 32 .9 32 .8 32 .8 32 .7 32 .3 33 .3 0. 17 * ** L ac to se , g k g- 1 49 .1 49 .6 49 .3 49 .1 49 .4 49 .1 49 .5 0. 14 * U re a, m g 10 0 m l-1 25 .2 26 .0 25 .5 28 .4 27 .6 24 .7 28 .3 0. 48 * ** * * ** L iv e w ei gh t, kg 57 1 57 6 57 7 57 7 57 8 57 3 57 9 1. 6 * * * L iv e w ei gh t c ha ng e, k g d- 1 0. 10 0. 14 0. 48 0. 30 0. 49 0. 16 0. 45 0. 10 0 * * E ffi ci en cy o f u til iz at io n M ilk N / N in ta ke 0. 28 8 0. 29 7 0. 29 6 0. 28 6 0. 28 9 0. 29 5 0. 28 8 0. 00 28 * * A A T u til iz at io n 2) 0. 62 1 0. 62 8 0. 62 5 0. 61 9 0. 62 0 0. 63 5 0. 61 0 0. 00 64 * ** M E u til iz at io n 3) 0. 60 3 0. 59 8 0. 60 9 0. 62 7 0. 62 7 0. 62 1 0. 60 5 0. 00 91 * E C M / dr y m at te r, kg k g- 1 1. 51 1. 47 1. 46 1. 46 1. 51 1. 47 1. 49 0. 01 93 1) E C M = e ne rg y co rr ec te d m ilk 2) A A T = a m in o ac id s ab so rb ed in th e sm al l i nt es tin e (M T T 20 06 ) 3) M E = m et ab ol is ab le e ne rg y, c al cu la te d ba se d on m ea su re d in v iv o or ga ni c m at te r d ig es tib ili ty SE M = s ta nd ar d er ro r o f t he m ea n. S E M h as b ee n gi ve n fo r 1 6 ob se rv at io ns (m ai n ef fe ct o f s ila ge tr ea tm en ts ). W he n th e nu m be r o f o bs er va tio ns is 4 0 (m ai n ef fe ct o f c on ce nt ra te tr ea tm en ts ), SE M s ho ul d be m ul tip lie d by 0 .6 32 . C is th e ef fe ct o f c on ce nt ra te le ve l. N o si gn ifi ca nt in te ra ct io ns w er e ob se rv ed . Si gn ifi ca nt d if fe re nc es a t p < 0 .0 5, p < 0 .0 1 an d p < 0. 00 1 le ve ls a re in di ca te d by * , * * an d ** *, re sp ec tiv el y. A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 248 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 249 cereal silages since the efficiency of dietary nitro- gen utilization (milk N/N intake) was higher with barley than with wheat silage, whereas ME utili- zation was higher with wheat silage (p<0.05). In- creasing concentrate amount resulted in decreased efficiency of N (p<0.05) and AAT (p<0.001) uti- lization. Discussion Chemical composition of crops at harvest and after ensiling Advancing crop maturity increased the proportion of ear and the concentration of starch in barley and wheat, while minor changes were observed in NDF and crude protein concentrations. Compared to some other studies, the decrease in NDF concentration of wheat was relatively small (Kristensen 1992, Sutton et al. 2002). The timing and interval of har- vests, and climatic factors, such as light intensity and temperature, affect the extent of compositional changes in cereals explaining the variation within the experiments. Chow et al. (2008) reported that delaying the planting day of barley altered barley’s growing environment (temperature, precipitation) and affected nutrient composition and in vitro NDF digestibility. The NDF concentration was much lower in whole crop cereals than in grass, whereas the con- centration of iNDF measured in WC silages in Exp. 1 and 3 was at least twice as high as in grass si- lage. In Exp. 2, the iNDF concentration of barley silage was exceptionally low, which can be due to the low straw proportion in dry and warm climatic conditions, and probably to the low lignification of straw in relation to grain development. The mean temperature of June and July during Exp. 2 was 2.9 and 3.9 oC higher than during Exp. 1 and Exp. 3, respectively. Further, the precipitation was 109 and 86 mm less, respectively. The increase in starch concentration of cereal crops with the advancing maturity was associated with a decrease in WSC concentration, which re- sulted in minor increases (from 34 to 43 g kg-1 DM, Exp. 2 and Exp. 3) in the concentration of total non- structural carbohydrates (NSC, starch + WSC). Hill and Leaver (1999a) reported lower concentrations of WSC in wheat at milk/early dough stages and the concentration appeared to decline faster than in the present experiment. A summary of the results of MacGregor and Edwards (1968) showed that the WSC concentration of barley reached a peak value (326 g kg-1 DM) at the milky ripe stage of growth when the DM concentration was 290 g kg-1. In spring wheat, WSC concentration remained high (140 to 250 g kg-1 DM) until 4 to 5 weeks after the start of heading, after which it fell sharply (Kris- tensen 1992). The variability of the starch concentration at the dough stage agrees with the results reported in the Nordic countries at the same growth stage (Kristensen 1992, Nadeau 2007, Wallsten et al. 2009). Comparison of different studies is, how- ever, challenging since the deposition of sugar to starch depends on many factors. Givens et al. (1993) suggested that the assessment of growth stage alone may not be a good guide to the com- position and digestibility of whole crop cereals. In the present experiment the ratio of NSC to NDF in barley seemed to be consistently more affected by the between-year differences in the climatic condi- tions than by the stage of maturity. The length and proportion of straw was exceptionally small and starch concentration high in Exp. 2. As a result the mean concentration of NSC was 150 g kg-1 DM higher and NDF concentration 95 g kg-1 DM lower in Exp. 2 than Exp. 3. Emphasizing the difficulties in controlling cereal development, the results of Sutton et al. (2002) showed that the crops may be physiologically at different maturity stages at the same DM concentration. Among other factors, the harvesting technique may affect the carbohydrate composition. Sinclair et al. (2003) reported that increasing cutting height (stubble heights 18 vs 38 cm) increased starch concentrations from 232 to 292 g kg-1 DM and reduced NDF from 433 to 384 g kg-1 DM. The changes in starch concentration during ensiling were inconsistent, reflecting mainly the A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 250 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 251 difficulties in taking representative samples rather than e.g. degradation of starch. Since the use of starch by lactic acid bacteria is limited the possible losses of starch may be due to the utilization by yeasts and fungi, plant respiration, and solubilisa- tion (McDonald et al. 1991). Fermentation quality of forages The fermentation quality of whole crop silages was good as evidenced by the low pH and small amounts of VFA. No problems were observed regarding the aerobic stability of silages but it should be noted that the experiments were conducted at winter time when low temperatures decrease the susceptibility to aerobic deterioration. The formic acid based additives restricted fermentation equally well in grass and whole crop silages. Based on the ratio of WSC to lactic acid, the fermentation was slightly more restricted in grass silage as compared to WC silages harvested at the early dough stage. Due to the increasing DM concentration with advancing maturity, the fermentation in later harvested cereal silages was less extensive than in grass silages. The DM losses and protein degradation caused by fer- mentation may be substantial in whole crop silages of low DM (Tetlow 1992). The results observed here suggest that the losses may be decreased by a formic acid based additive and/or postponing the harvest until the late dough stage. Formic acid is known to inhibit protein deg- radation and lactic acid fermentation during en- siling. The changes in the ratio of silage WSC to lactic acid affect the nutrient supply to the rumen microbes, and subsequently modify the microbial protein synthesis and molar proportions of VFA in the rumen (Jaakkola et al. 2006a) and affect milk production (Jaakkola et al. 2006b). With cereal si- lage, the intake of starch further complicates the nutrient supply and modifies the rumen fermenta- tion pattern. The total amount of NSC in whole crop silages varied between 108 and 353 g kg-1 DM being much higher than the typical values of restrictively fermented grass silages (53 – 82 g kg-1 DM). Growth stage and cereal type Lignin deposition characterizes the process of matu- ration of the straw of small grain cereals. In terms of whole crop digestibility, lignification is compensated by grain development and deposition of starch. This explains why within the two weeks interval no effects of barley or wheat maturity on diet digest- ibility were observed in Exp. 2 and 3. Inconsistent effects of wheat maturity on diet digestibility have been reported (Südekum and Arndt 1998, Sutton et al. 2002). Decreased or increased digestibility with advancing maturity may be attributed to the specific stage of growth and characteristics of the crops as well as to the method used in the digest- ibility measurement. In the early stages of a crop maturity from heading to early dough stage the OM digestibility has decreased in sheep offered wheat silage (Crovetto et al. 1998) and in dairy cow offered barley silage (Wallsten and Martinsson 2009). At that stage the starch formation is still limited while the digestibility of NDF decreases. With advancing maturity the increase in the concentration of starch results in a recovery of crop OM digestibility (Sut- ton et al. 2002). With high DM wheat the increases in OM digestibility have been attributed to urea treatment (Tetlow 1992) and decreases in starch digestibility to the hard cereal grains which are poorly digested by dairy cows (Sutton et al. 1997, Abdalla et al. 1999, Sutton et al. 2002). No differences were observed in silage DM intake with advancing maturity of barley or wheat (Exp. 2, Exp. 3) or between barley and wheat (Exp. 3). Sutton et al. (2002) noted increased intake with advancing wheat maturity, which might be attribut- ed to a much greater difference between the matu- rity stages (DM 300 vs 580 g kg-1) and the extent of silage fermentation than in the present experiment. However, they reported no effects of maturity on milk yield. In the present experiments, harvesting barley at one week (Exp. 2) or two week (Exp. 3) intervals had no significant effect on milk or milk component yields. The result indicates flexibility in the timing of harvest during dough stage of whole crop as timing is not as critical for the nutritive value as in case of grass. On the basis of the maxi- A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 250 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 251 mal crop yield the optimal harvest dates were at the soft/hard dough stage of barley. Higher ECM yield with WS2 than with WS1 diet was associated with a slightly higher diet OM digestibility (P=0.147) and milk fat concentration (41.3 vs 43.3 g kg). The result suggests that the later harvest time for wheat was more optimal in terms of both crop yield and ECM yield. This is in accordance with other studies showing increased crop yield of wheat with advancing maturity before stabilizing at DM concentrations of about 400 g DM per kg (Tetlow 1992, Kristensen 1992, Sutton et al. 2002). In barley the maximum yield is ob- tained at DM concentration of approximately 350 g kg-1 or 4−5 weeks after the initial ear emergency according to Kristensen (1992). Dietary inclusion rate of whole crop barley and wheat silages The large variation in the characteristics of whole crop silages suggests that the production responses can be attributed to the variable composition of ru- men fermentable carbohydrates of silages. Inclusion of whole crop silage in the silage mixture increased (Exp. 2 and 3) or had a minor effect (Exp. 1) on the intake of silage. Unlike with grass silage (Rinne et al. 1999), the intake responses could not be associ- ated with forage digestibility. Even when the diet digestibility clearly decreased (Exp. 1) with the increasing proportion of whole crop barley silage, no corresponding negative effects on silage intake were observed. Increased intakes with a mixture of grass and WC silage have been observed both with fermented and urea treated wheat silage (Sut- ton et al. 1997, Abdalla et al. 1999, Sinclair et al. 2003). In the experiment of Hameleers (1998), the response was achieved when WC silage was of later maturity and grass silage of higher ME value than in the present experiment. Also the response has been realized with grass silage of poorer fermentation quality (ammonia N 128 g kg-1 N) (Phipps et al. 1995). In a data analysis by Huhtanen et al. (2007), responses to replacing grass silage partially or to- tally with whole-crop silage could not be accurately predicted from differences in silage digestibility, DM concentration or fermentation quality, and the observed silage DM intake was generally higher than the predicted intake. Ahvenjärvi et al. (2006) examined the silages of Exp. 1 in a physiological study in cows equipped with rumen cannulas. They concluded that the characteristics of whole crop cereals allow cows more flexibility in regulating intake in relation to energy demand than grass silage. The lower NDF concentration of WC silage may be one reason for that (Huhtanen et al. 2007) since the animals were able to increase ruminal NDF pool at lower inclu- sion rates (0.2 and 0.4) (Ahvenjärvi et al. 2006). In Exp. 2, the NDF concentration of GS was 147 g kg DM-1 higher than the mean concentration in WC silages, which resulted in a higher silage-NDF concentration in the diets of GS alone than in the diets based on the mixtures of grass and whole crop silage (277 vs 210 g kg DM-1). The responses in intake to physical treatment of barley silage have also been studied. Soita et al. (2002, 2003) showed that reducing the chop length of barley silage increased feed intake in steers, while the effect depended on the concen- trate level of the diet. Despite changes in chemical composition, elevating the cutting height of wheat or barley did not improve or even decreased intake and animal performance in cows (Sinclair et al. 2003, Jackson et al. 2004) or in beef cattle (Walsh et al. 2009). Neither did the mechanical processing of barley silage affect its nutritive value in dairy cow diet (Eun et al. 2004). In the present study, the cutting height was the same in all experiments. The particle size of the silage was longer in Exp. 1 than in other experiments due to the different harvester (particle size not measured). Although the mechanical treatment of silage during harvest may have some effect, the assessment of the im- portance of the chop lengths/types is not possible in the present study. The use of a mixer wagon in all experiments further affected the particle size of the silages. The nutritive value of the control grass silage compared to the WC silage may partly explain the variation in the milk yield responses. The energy value of GS was higher in Exp. 1 (10.8 ME MJ A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 252 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 253 kg-1 DM) and Exp. 3 (10.9) than in Exp. 2 (10.4). Much of the poor milk yield response to whole crop silage inclusion in Exp. 1 can be ascribed to its low digestibility as compared with grass silage. Ahvenjärvi et al. (2006) noted that the decreases in OM and NDF digestibility were attributed to the higher iNDF concentration of barley silage com- pared to that of grass silage. Decreased microbial N flow from the rumen further explained the poor milk responses to barley silage. However, the iNDF concentration of WC silages in Exp. 3 was also twice as high as in GS (65 vs 143 g kg-1 DM) but the intake of grass and WC silage mixtures was significantly higher than that of GS, and milk yield unchanged. Thus, the response to WC silage might also be attributed to other factors than the fibre characteristics of GS and WCS. In the physiological study the daily averages of ruminal ammonia concentrations were lower (Ah- venjärvi et al. 2006) than the suggested minimum levels for optimum fibre digestion (Hoover 1986). It is possible that the rumen degradable N limited the microbial activity, especially with higher inclu- sion rates of WC. In Exp. 3, more positive milk yield response to feeding WC silage was observed, when the diet CP concentration was higher than in the protein supplemented diet in Exp. 1 (140 vs 162 g CP kg-1 DM). There was a substantial difference in CP concentration of concentrate (160 vs 210 g kg-1 DM) between the studies, which may explain the difference in milk yield response. The propor- tion of concentrate in diet DM was the same in both experiments (415 vs 407 g kg-1). The same milk yield with GS and BS2 in Exp. 2 suggests that the silages had similar energy value. This corresponds well with the same iNDF concen- tration of the forages but was associated with sig- nificantly lower OM and NDF digestibility of the BS2 diet than the GS diet. However, cows having a mixture of GS and BS2 produced on average 2.0 kg more ECM than those having only GS or BS2. The synergistic effect of feeding mixture suggests that the nutrient balance might be better than when silages were fed alone. Studies on rumen fermenta- tion have shown inconsistent results. The propor- tion of acetate was lower and that of propionate higher in cows consuming WC silages rather than alfalfa or grass silage (Khorasani et al. 1996, Ah- venjärvi et al. 2006) or rumen acetate or butyrate has increased after inclusion of WC in the diet (Ab- dalla et al. 1999, Owens et al. 2008). In Exp. 3, daily DM intake on mixed silage diets was 0.7 kg higher than that of the GS diet, compensating the decreased digestibility. This resulted in equal milk yield with the mixed and GS diets. Similarly, the increased feed intake of silage mixtures has not led to corresponding increases in milk yield in other experiments (Leaver and Hill 1995, Phipps et al. 1995, Hameleers 1998). Inclusion of WC silage in the diet had no ef- fect on milk composition except in Exp. 2 in which milk protein concentration was higher with BS2 than with GS. Also in some earlier experiments protein concentration was higher with mixtures of grass silage and urea-treated whole crop wheat than with grass silage alone (Abdalla et al. 1999, Sutton et al. 2002). Inclusion of barley silage in the diet decreased linearly N intake in Exp. 1 which explains the extremely low milk urea concentration. The high efficiency of N utilization in milk production is also attributed to the low N concentration of grass silage. In Exp. 2 and 3, due to the low N concentra- tion of both grass and WC silages, N utilization was also good despite the high protein concentration of the concentrate. Amount and type of concentrate supplementation Silage DM intake increased by an average of 0.7 kg per day when rape seed meal was included in the WC diets, being less than with grass silage (1.3 kg, Exp. 1). In milk production the mean response to rape seed meal supplementation of the WC diet was 0.94 kg ECM and 41.5 g milk protein per kg DM of RSM. With the GS diet the values were 0.83 kg and 46.1 g, respectively. The responses correspond well with the mean values in a literature review of rape seed meal studies in Finland (Huhtanen 1998) although the crude protein concentration of the control diets was exceptionally low (mean 117 g kg-1 DM). A vari- A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 252 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 253 ation was observed between the WC silages so that the highest responses in milk and protein yield were with BS20 silage (1.44 kg ECM) and BS40 (47.8 g protein), and the lowest with BS60 silage (0.50 kg and 32.8 g). Limited published data is available on the protein supplementation of barley silage. When urea treated whole-crop wheat was offered as a sole feed, additional protein supplement with fish meal but not with soya-bean meal increased milk yield (Hill and Leaver 1999b). The mean daily starch intake in Exp. 2 was 1.1 kg lower in the diets including commercial com- pound than cereal based FC concentrate. Further, for the GS diet the mean daily starch intake was 1.8 kg lower than with the BS2 diet. The absence of interaction between concentrate and silage type in- dicates no benefit by supplementing cereal silages with low starch concentrates. Kristensen (1992) compared rolled barley, fodderbeet and dried sugar beet pulp as supplement for whole crop barley si- lage, and observed only minor effects on the pro- duction of milk and milk components. The lack of interaction in the present study may be associated with the concentration of total NSC in the concen- trates, which was probably quite similar judging by the similar NDF concentration of concentrates (WSC not measured). In addition, there was no dif- ference between the FC and CC diets in the propor- tion of silage-NDF concentration of the diet (224 vs 216 g kg DM-1) which is considered to be an important criterion for optimal rumen function. The cows offered FC concentrate ate signifi- cantly more silage than those having CC concen- trate but there was no difference in milk yield due to the lower OM digestibility of the FC diet. The cows were able to compensate the lower digest- ibility of the FC diet by increasing silage intake. The low starch digestibility with the FC diet (0.89) suggests that some grain in the farm mixture re- mained intact after grinding. The reason for this is unlikely to be due to the WC starch digestibility since high starch digestibility with CC diet in Exp. 2, and with all diets in Exp. 3, indicates that starch of WC silages was completely digested. The effects of concentrate level in Exp. 3 agree with the results of Hill and Leaver (1999b) who of- fered dairy cows urea treated whole crop wheat as a sole feed. In the present experiment, increasing the amount of concentrate decreased silage intake but total DM intake increased by 1.9 kg DM per day. With the mixture of GS and whole crop silages the substitution rate was 0.45 kg silage DM per kg concentrate DM and 0.59 with GS. The values are in good agreement with the mean value observed in studies with grass silage (Huhtanen 1998). Similar- ly, with whole crop wheat silage as the sole forage the substitution rate of concentrate was 0.59 (Hill and Leaver 1999b). The mean response in milk yield was 0.65 and 0.90 kg ECM per kg concentrate DM with grass silage and grass-whole crop silage mixtures, respectively, being higher than 0.52 kg in the experiment of Hill and Leaver (1999b). The result of the present experiments suggests that the responses to increased concentrate amount in the diets of mixed grass and WC silage are similar with diets based on grass silage as the sole forage. Conclusions Successful preservation can be achieved by pre- serving whole-crop barley and wheat with a formic acid based additive at dough stage with dry matter concentration of 300–450 g kg-1. The results show that with barley, advancing maturity had no effect on milk yield, whereas with wheat silage harvest at soft/hard dough, rather than at early dough stage, increased milk yield. In terms of milk yield, the soft/hard dough stage is the optimal harvest time for both cereals. Whole-crop cereals did not accomplish as high digestibility as is possible with grass silage. How- ever, the results suggest that mixing grass silage and whole crop silage up to a whole crop silage proportion of 0.4 in forage DM may improve si- lage DM intake, and subsequently maintain or even increase milk yield. This can be explained by the good intake characteristics of whole crop silage and by the synergistic effect of combining grass and whole crop silages. The response in milk pro- duction may depend on the relative difference in the digestibility of grass and whole crop silage. A G R I C U L T U R A L A N D F O O D S C I E N C E Jaakkola, S. et al. Whole-crop silage for dairy cows 254 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 234–256. 255 Protein supplementation, different levels of concentrate and energy source of concentrate induced mainly similar intake and milk yield re- sponses with diets based on grass silage alone or on mixtures of grass and whole crop silages. However, the synergistic effect of mixing grass and whole crop silages was realized better in milk yield in the experiments where the protein concentration of concentrate was high (200 g kg-1 DM). Low N concentration of whole crop silage allows a use of a relatively high protein supplementation without excessively impaired efficiency of N utilization. Acknowledgements.The authors wish to acknowledge the technical assistance and cooperation of the staff in Lintupa- ju Experimental Farm, and other staff of Animal Nutrition and Jokioinen Estates, MTT Agrifood Research Finland. 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Ruokin- takokeissa tutkittiin säilörehujen lisäksi myös rehujen energia- ja valkuaistäydennystä. Kokeessa I nurmisäi- lörehua korvattiin ohrasäilörehulla eri ruokinnoissa 0, 200, 400 tai 600 g kg-1 kuiva-ainetta (KA). Säilörehun lisäksi lehmät saivat päivittäin 10 kg väkirehua, joka si- sälsi rypsirouhetta 0 tai 2 kg. Kokeessa II ohra korjattiin kolmena kertana (O1, O2, O3) viikon välein. Jokaista ohrasäilörehua syötettiin seoksena nurmisäilörehun kanssa ja ohrasäilörehun osuus karkearehusta oli 400 g kg-1 KA. Lisäksi O2-kokoviljasäilörehua ja nurmisäilö- rehua syötettiin ainoana karkearehuna. Väkirehuina (11 kg/pv) verrattiin viljapohjaista kotiseosta ja kaupallista täysrehua, jonka tärkkelyspitoisuus oli pienempi kuin kotiseoksen. Kokeessa III puolestaan sekä ohra että ke- vätvehnä korjattiin kahden viikon välein. Kokoviljasäi- lörehu syötettiin nurmisäilörehun kanssa seoksena, jossa kokoviljasäilörehun osuus oli 400 g kg-1 KA. Ruokintoja täydennettiin kahdella eri väkirehumäärällä (vanhemmat lehmät 9 tai 14 kg/pv, ensikot 7,2 ja 11,2 kg/pv). Sekä nurmisälörehujen että kokoviljasäilörehujen käymislaatu oli hyvä. Vuosien väliset erot sääolosuh- teissa sekä viljan kehitysaste vaikuttivat tähkän osuuteen kasvissa ja sen kautta sokerin, tärkkelyksen ja kuidun (NDF) pitoisuuksiin kokoviljasäilörehuissa. Kokovilja- säilörehun lisääminen ruokintaan huononsi rehuannoksen sulavuutta. Vaikutuksen voimakkuus riippui nurmirehun sulavuudesta ja kokoviljarehun osuudesta seoksessa. Kokovilja- ja nurmiseoksen syöttäminen ei kuitenkaan vähentänyt rehun syönnin kokonaismäärää. Tästä joh- tuen maitotuotos ei muuttunut tai tuotos jopa hieman lisääntyi kokeissa II ja III verrattuna nurmisäilörehu- ruokintaan. Sen sijaan kokeessa I maitotuotos väheni, kun kokoviljasäilörehun osuus karkearehusta oli 400 tai 600 g kg-1 KA. Tutkitut ohran kehitysasteet vaikut- tivat hyvin vähän maitotuotokseen, mutta kevätvehnän korjuun siirto taikinatuleentumisvaiheen loppupuolelle lisäsi tuotosta. Väkirehuvaihtoehtojen välillä ei ollut juuri eroa nurmisäilörehun ja nurmi-kokoviljaseoksen täydentäjinä. Nurmisäilörehun ja kokoviljasäilörehun seoksen positiivinen vaikutus maitotuotokseen oli suurin kokeissa II ja III, joissa väkirehun raakavalkuaispitoisuus oli melko suuri (200 g kg-1 KA). Kokoviljasäilörehun pieni raakavalkuaispitoisuus mahdollistaa suhteellisen runsaan valkuaistäydennyksen ilman, että typen hyväk- sikäyttö heikkenee oleellisesti. SELOSTUS Muurahaishapolla säilötty ohra- ja vehnäkokoviljasäilörehu lypsylehmän ruokinnassa: viljan kehitysasteen, kokoviljasäilörehun osuuden ja väkirehutäydennyksen määrän ja laadun vaikutus Seija Jaakkola, Eeva Saarisalo ja Terttu Heikkilä Helsingin yliopisto ja MTT Introduction Material and methods Harvest Experimental design and diets Sampling and analyses Statistical analysis Results Silages Feeding experiment 1 Feeding experiment 2 Feeding experiment 3 Discussion Chemical composition of crops at harvest and after ensiling Fermentation quality of forages Growth stage and cereal type Dietary inclusion rate of whole crop barley and wheat silages Amount and type of concentrate supplementation Conclusions References SELOSTUS