Cut Grass Silage Research Articles

Characterization of First Cut Alfalfa and Grass Silage Management Practices on Canadian Dairy Farms

Characterization of First Cut Alfalfa and Grass Silage Management Practices on Canadian Dairy Farms

Effects of primary growth compared to regrowth grass silage on feed intake, growth performance and carcass traits of growing bulls

The objective was to study the effects of primary growth vs. regrowth grass silage on intake, growth and carcass traits of growing bulls. In a feeding experiment, 30 bulls were offered a total mixed ration ad libitum. Two dietary treatments included either first or second cut grass silage (550 g kg-1 dry matter) supplemented with rolled barley (435 g kg-1 dry matter) and a mineral-vitamin mixture (15 g kg-1 dry matter). Feed and energy intake as well as the live weight gain of the bulls decreased when the second cut silage was used instead of the first cut silage. No differences in carcass conformation or carcass fat score between the treatments were observed. Analysed chemical, digestibility or fermentation parameters of the silage samples did not explain the differences in feed intake. However, some second cut silage samples were found to contain mycotoxins (zearalenone, roquefortine C, mycophenolic acid and HT-2), but it is difficult to estimate whether this was the factor that affected feed intake in the present study.

Comparison of rumen fluid inoculum vs. faecal inoculum on predicted methane production using a fully automated in vitro gas production system

The aim of the present study was to compare in vitro methane (CH4) production and other fermentation parameters from different substrates incubated either in rumen or faecal inoculum. Five different substrates were incubated in two different inocula and gas recordings were made using an automated in vitro gas production system. The substrates were: particulate matter obtained from reticulo-rumen (RR) digesta and faeces (FC) by wet sieving, timothy hay (H), first cut grass silage (S) and a mixture of grass silage and barley (50:50; SB). One gram of each substrate was incubated either in 60ml buffered rumen or faecal inoculum taken from Swedish lactating dairy cows for 48h. The results indicated that in vitro total gas production, predicted in vivo CH4 production and the ratio of CH4 production to total gas production were greater (P<0.01) for substrates incubated in rumen inoculum as compared to faecal inoculum. Mean of predicted in vivo CH4 production was greater for substrates incubated in rumen inoculum (23.5ml/g DM, 29.0ml/g OM) as compared to faecal inoculum (11.2ml/g DM, 14.3ml/g OM). Predicted CH4 production based on volatile fatty acids (VFA) stoichiometry equations (CH4VFA) showed no difference in CH4 per mol VFA (P=0.44) between the two sources of inoculum used for all substrates. Molar proportions of propionate were higher and that of butyrate were lower (P<0.01) for all substrates incubated in faecal inoculum compared to rumen inoculum. No difference (P=0.13) in molar proportions of acetate was observed. Digestibility of neutral detergent fibre (aNDFomD) and true organic matter digestibility (TOMD) were lower (P<0.01) for all substrates incubated in faecal inoculum compared to rumen inoculum. It can be concluded that using faecal inoculum tended to give lower values of predicted in vivo CH4 production as compared to rumen inoculum. The discrepancy between observed and stoichiometric CH4 production suggests an existence of acetogenesis in the hindgut.

Feces composition and manure derived methane yield from dairy cows: Influence of diet with focus on fat supplement and roughage type

The objective of the present study was to evaluate the effect of dairy cow diets on feces composition and methane (CH4) potential from manure with emphasis on fat level and roughage type and compare these results with the corresponding enteric CH4 emission. In experiment 1 six different diets, divided into two fat levels (low and high) and three different roughage types (early cut grass silage, late cut grass silage and maize silage), were used. The high fat level was achieved by adding crushed rapeseed. In experiment 2, the influence of increasing the fat level by using three different types of rapeseed: rapeseed cake, whole seed and rapeseed oil against a low fat ration with no rapeseed fat supplementation was studied. The diet and fat level had a significant influence on feces composition and CH4 yield. In general, ultimate CH4 yields (B0) were 8–9% higher than the present international default values for diets without extra fat and in feces from diets with extra fat supply the yield was 25–31% higher. It was possible to predict the B0 value from feed and feces characteristics; in fact, the best correlation was obtained by including both feed and feces characteristics. Addition of crude fat to diets to dairy cows reduced enteric CH4 emission but at the same time increased CH4 potential from feces both in terms of organic matter in feces and dry matter intake which might lead to increasing emissions unless proper manure handling such as anaerobic digestion is included. Without subsequent anaerobic digestion to produce energy the positive effect achieved at cow level could be counteracted by increasing manure emissions.

Enteric methane production, digestibility and rumen fermentation in dairy cows fed different forages with and without rapeseed fat supplementation

The purpose of this experiment was to study the effect of forage species (grass or maize) and the maturity stage of grass on enteric methane (CH4) production, nutrient digestibility and rumen fermentation, and to study possible interactions with cracked rapeseed as fat source. Six lactating, ruminal, duodenal and ileal cannulated Holstein dairy cows (206 days in milk, milk yield 25.1kg) were submitted to an incomplete Latin square design (6×4) with six diets and four periods. Two grass silages (early first cut, 361g aNDFom/kg DM and late first cut, 515g aNDFom/kg DM) and one maize silage were supplemented with either low fat concentrate or high fat concentrate. The dietary fat concentration in the high fat diets was approximately 60g/kg DM. Diurnal samples of duodenal and ileal digesta and feces were compiled. The CH4 production was measured for four days in open-circuit respiration chambers. Additional fat reduced the gross energy (GE) lost as CH4 from 6.3 to 5.8% of GE intake, independent of forage species and quality. Energy loss as CH4 constituted 6.1, 6.7 and 5.4% of GE intake for early grass silage, late grass silage and maize silage, respectively. However, there was no difference between early grass silage and maize silage when CH4 production was related to kg organic matter (OM) digested. Fat supplementation did not affect OM or aNDFom digestibility. Maize silage had a higher ruminal OM digestibility, but lower ruminal aNDFom digestibility than grass silage. Early cut grass silage had a higher total tract OM and aNDFom digestibility than late cut grass silage. The present study demonstrates that choice of forage species and harvest time affects CH4 emission from dairy cows, while the CH4 reducing ability of fat does not interact with forage characteristics.

Effect of Including Extruded, Rolled or Ground Corn in Dairy Cow Diets Based on Direct Cut Grass Silage

A study was conducted to determine the effect of corn (Zea mays L.) grain processing on intake, digestibility of nutrients and milk production and composition. The effect of extrusion on nutrient digestibility was evaluated in trial 1, using ground corn as a control. In trial 2, the effect of extrusion on intake was evaluated, comparing extruded corn of two densities (357 and 308 g L -1 ) with rolled corn (507 g L -1 ) as a control. In trial 3, the effects of extrusion on milk production, digestibility and intake were evaluated; using steam rolled corn and ground corn as controls. No effects on dry matter and metabolizable energy intakes due to differences in the extruded corn grains were

In vivo digestibility of different types of forages using sheep as a model of ruminants

Digestibility of a forage is very important as it contributes to the energy and protein values and intakepotential of the feed in ruminant production systems. The silages used in this digestibility trial present therange of variation encountered in practice of forages used within Finland: early cut grass (EG), late cutgrass (LG), red clover (Trifolium pratense, RC) and whole-crop barley (Hordeum vulgare, WCB). Grasssilages were a mixture of timothy (Phleum pretense) and meadow fescue (Festuca pratensis). EG, LG,RC and WCB were cut on 13 June (2006), 3 July (2006), 29 June (2006) and 2 August (2006),respectively. Grass and clover silages were wilted for 1 day and all silages were ensiled with AIV 2, andensiled in round bales. Four rams (Dorset and Finnsheep × Texel crossbred) were used to estimatedigestibility in a 4 × 4 Latin square experiment with four 3-week experimental periods. The totaldigestibility was determined using total collection method by measuring daily forage intake and theamount of faeces excreted over the last 7 days of each period.All silages were well preserved and had relatively high DM concentration, within 395 - 566 g/kg.The ash concentration in EG, LG, RC and WCB was 88, 70, 97 and 62 g/kg DM. The respective CPconcentrations were 180, 113, 163, 71 g/kg DM and NDF concentrations were 509, 623, 385and 548 (g/kgDM).The organic matter digestibility for EG, LG, RC and WCB was 0.751, 0.608, 0.645 and 0.618.There was a 20 day difference in the cutting dates of EG and LG resulting in 0.008 unit decrease inorganic matter digestibility per day. Neutral detergent fibre digestibility was highest for early cut grasssilage (0.74). and lowest for red clover (0.50) and whole-crop barley (0.51).Forages vary greatly in their digestibility depending on species and maturity as shown by theresults of the current study. The great variation emphasizes the importance of accurate routine digestibilityanalysis and need to analyze farm silages for ration formulation.

Passage kinetics of fibre in dairy cows obtained from duodenal and faecal ytterbium excretion: Effect of forage type

Passage kinetics of ytterbium labelled fibre was evaluated in four experiments with fistulated dairy cows. Eight forages (grass hay, early cut grass silage, late cut grass silage, whole crop barley silage, maize silage, lucerne hay, whole crop pea silage and clover-grass silage) were fed ad libitum as the sole feed or supplemented with 5.8 kg DM of concentrate. Rumen passage kinetics was determined algebraically and using age-dependent one compartment (G n) and two compartment (G nG1) models based on duodenal and faecal excretion of Yb. The G3 model provided the best fit of the one compartment models tested, whereas the G3G1 model was the overall superior model. The G4G1 model may be preferred for data sets based on faecal output, indicating an additional minor post-duodenal compartment. Using an algebraic approach total mean retention time averaged 39 h (duodenum) and 45 h (faeces), however the algebraic approach underestimated total mean retention time with on average 4 h compared to the G3G1 model. Mean retention time in the rumen compartments based on faecal sampling was on average only 1.2 h longer than based on duodenal sampling, and therefore a model combining duodenal and faecal samples is used for estimation of passage kinetics. Mean retention time in the rumen compartments varied from 32 h for supplemented pea silage to 48 h for unsupplemented late cut grass silage, but absolute values should be used with care, due to the risk for marker migration and uneven distribution of marker between particles. Retention time in the first non-escapable age-dependent compartment was always shorter than in the subsequent age-independent compartment. When forage was fed as the sole feed, the proportion of the mean retention time spent in the first compartment averaged 0.39, but varied from 0.32 (lucerne hay) to 0.47 (grass hay). When forage was supplemented, the proportion of the mean retention time spent in the first compartment averaged 0.33 but varied from 0.22 (whole crop barley silage) to 0.43 (early cut grass silage). Based on the present data, a fixed average distribution of mean retention time between the non-escapable and the escapable rumen compartments of 0.36:0.64 seems to be the best estimate for modelling purposes in future dynamic feed evaluation systems. On average 0.82 of the total tract retention time could be assigned to the pre-duodenal part of the GI-tract and 0.18 to the lower gut.

Effects of crop maturity and cutting height on the nutritive value of fermented whole crop wheat and milk production in dairy cows

Factors influencing the nutritive value of fermented whole crop wheat (WCW) and effects on milk production in dairy cows were investigated in three experiments. In experiment 1, WCW was harvested at one of two maturities: at a dry matter (DM) content of 296 g/kg, 52 g/kg DM starch (LS) or DM of 371 g/kg, 221 g/kg DM starch (HS). Ninety early lactation dairy cows were split into three groups and fed either LS, HS or a first cut grass silage (G). The WCW was mixed 2:1 on a DM basis with the grass silage. There was no significant effect of dietary treatment on milk production (kg/day) although cows fed the low starch WCW (LS) had the lowest milk protein concentration (mean values of 32.1, 30.7 and 31.6 g/kg for cows fed G, LS and HS, respectively, P<0.05). Plasma urea levels were significantly lower in cows fed the HS compared with the LS treatment ( P<0.05). In experiment 2, ninety early lactation dairy cows were fed one of three dietary treatments: WCW harvested at a long straw length and supplemented with either a starchy concentrate (LW) or a more fibrous concentrate (LF) or a short straw length and supplemented with a fibrous concentrate (SF). The WCW was mixed 1:1 on a DM basis with first cut grass silage. Increasing the cutting height increased starch concentrations from 232 to 292 g/kg DM and reduced neutral detergent fibre from 433 to 384 g/kg DM in the long and short straw WCW, respectively. There was no significant effect of dietary treatment on milk production, composition or body condition score over the experimental period. The lower plasma non-esterified fatty acid concentration in cows fed LW or SF during week 10 of lactation indicate a more positive energy balance in early lactation on these treatments. In experiment 3 the apparent digestibility of the grass silage, long straw whole crop wheat or short straw WCW fed at maintenance or the long straw WCW fed ad libitum was determined in growing lambs. Digestibility coefficients of the grass silage were significantly higher than those of any of the WCW forages, particularly for the fibre fractions. The digestibility of starch was high in all three WCW treatments and averaged 0.955 kg/kg but was not affected by straw length or feeding level. The improvement in metabolisable energy value (MJ/kg DM) by increasing the cutting height at harvest was small and not significant. Increasing the maturity at harvest and decreasing the length of straw at cutting was also observed to have a small but significant effect on decreasing the aerobic stability of the WCW forages. The results indicate that fermented whole crop wheat can provide a comparable milk production to a good quality grass silage and that harvesting at a later stage of maturity had little effect on milk production although milk protein levels tended to be higher in cows fed the higher starch material. There was little advantage to altering cutting height of fermented WCW on apparent digestibility or by altering supplement composition on milk production.

The effect of slurry application timing on grass silage fermentation and intake by dairy cattle

Many farmers apply slurry to grassland as a fertiliser or a means of waste disposal. There is evidence that winter slurry application leads to higher losses of nitrogen due to leaching subsequently reducing the efficiency of slurry N utilisation when compared with spring applications (Smith et al 1995). This suggests that slurry applications should be undertaken in spring, but the effect of timing on the extent of grass contamination is unknown. When grassland is used for silage production, contamination of the sward can lead to reduced silage fermentation and acceptability (Boxem and Remmelink 1987). A study was conducted to investigate the effect of timing of slurry application on fermentation and dry matter intake of first and second cut grass silage.

Influence of Maturity of Grass Silage and Flaked Corn Starch on the Production and Metabolism of Volatile Fatty Acids in Dairy Cows

An experiment employing a Latin square design was used to quantify the effects of two stages of maturity of grass silage (early cut and late cut) and three concentrations of flaked corn starch (0, 2, and 4kg) on the molar proportion of rumen volatile fatty acids (VFA), the production of rumen VFA, and the net fluxes of VFA in the splanchnic tissue of cows. The molar proportions of VFA in rumen fluid were similar for cows fed both silages. When the silage diets were supplemented with starch, the proportion of propionic acid increased for cows fed diets containing early cut grass silage, but no effects were found for cows fed diets containing late cut grass silage. Estimated gastrointestinal production of acetate, propionate, butyrate, and branched-chain fatty acids plus valerate was related to intake of metabolizable energy and organic matter fermented into VFA. The portal release of acetate was approximately 14% lower than the estimated production of acetate by cows fed diets containing early cut grass silage, but cows fed diets containing late cut grass silage showed a variable difference between estimated production and portal release (31, 24, and 15%, respectively) as starch supplementation increased. The portal release of butyrate plus β-hydroxybutyrate and the release of branched-chain fatty acids plus valerate were approximately 70 and 25%, respectively, of the estimated gastrointestinal production. Propionate production was similar to the portal release of propionate.Net flux measurements in splanchnic tissue in combination with gastrointestinal digestion and kinetics provide information that increases the knowledge of pathways and metabolism and quantifies the availability of individual nutrients for milk production in dairy cows.

Suckler cow colostrum yield and immunoglobulin concentrations and their calves' serum immunoglobulin concentrations

The objective of this experiment was to study colostrum yields and immunoglobulin (Ig) concentrations and subsequent calf serum Ig concentrations using mature suckler cows adequately fed pre-partum or severely feed restricted for the last 2 weeks of preganancy and 2 year old replacements heifers.Cows from a Limousin x Friesian spring calving suckler herd were used. There were 3 treatments 1) cows adequately fed pre-partum (second cut grass silage) (n=12) 2) , cows severely feed restricted for 2 weeks pre-partum (straw diet) (n=6) and, 3) two year old heifers calving for the first time and adequately fed (n=6). All animals were offered a suitable mineral/vitamin supplement. Colostrum yield was obtained by hand milking half the udder following an intramuscular oxytocin injection. Colostrum was then sampled. The objective was to feed the calf an allowance of 50g of colostrum /kg bodyweight via stomach tube. Actual colostrum intakes (g/kg bodyweight ± S.E.) were 47 ± 1.4, 48 ± 2.3 and 46 ± 1.9 for treatments 1, 2 and 3, respectively. Following an eight hour period when the calf was prevented from suckling (but left in the presence of the dam) a colostrum sample was obtained (2nd milking), the calf was blood sampled and then allowed to suckle as normal.

Suckler cow colostrum yield and immunoglobulin concentrations and their calves' serum immunoglobulin concentrations

The objective of this experiment was to study colostrum yields and immunoglobulin (Ig) concentrations and subsequent calf serum Ig concentrations using mature suckler cows adequately fed pre-partum or severely feed restricted for the last 2 weeks of preganancy and 2 year old replacements heifers.Cows from a Limousin x Friesian spring calving suckler herd were used. There were 3 treatments 1) cows adequately fed pre-partum (second cut grass silage) (n=12) 2) , cows severely feed restricted for 2 weeks pre-partum (straw diet) (n=6) and, 3) two year old heifers calving for the first time and adequately fed (n=6). All animals were offered a suitable mineral/vitamin supplement. Colostrum yield was obtained by hand milking half the udder following an intramuscular oxytocin injection. Colostrum was then sampled. The objective was to feed the calf an allowance of 50g of colostrum /kg bodyweight via stomach tube. Actual colostrum intakes (g/kg bodyweight ± S.E.) were 47 ± 1.4, 48 ± 2.3 and 46 ± 1.9 for treatments 1, 2 and 3, respectively. Following an eight hour period when the calf was prevented from suckling (but left in the presence of the dam) a colostrum sample was obtained (2nd milking), the calf was blood sampled and then allowed to suckle as normal.

Effects of rape-seed oil supplementation on digestion, microbial protein synthesis and duodenal microbial amino acid composition in ruminants

The effects of rape-seed oil supplementation on digestion and efficiency of microbial protein synthesis were estimated in four Friesian bulls fitted with rumen and simple-T duodenal fistula in 2 × 2 change-over design. The basal diet was 4.8 kg day −1 dry matter (DM) fresh cut grass silage and 2.6 kg day −1 DM rolled barley. The test feed (RSO) was formulated by supplementing the basal diet with 0.5 kg rape-seed oil. The bulls were fed at 07:00 and 19:00 h daily. Digestion in the rumen was measured by spot sampling of duodenal digesta, using the double marker method. Amino acid (AA) composition was determined from the microbial mass separated from duodenal digesta. A daily supplement of RSO showed no significant effect on rumen pH. Rumen total volatile fatty acids concentration decreased ( P = 0.09). Molar proportion of acetate and butyrate decreased ( P = 0.01) while propionate proportion increased ( P = 0.002). Rumen protozoal population decreased from 4.2 × 10 5 to 2.9 × 10 51 −1. Whole tract and ruminal digestion of organic matter was lower for RSO compared with basal diet. The mean N intake was 160 g day −1 for basal and 153 g day −1 for RSO and the corresponding duodenal flow was 140 g day −1 and 146 g day −1 with microbial N flow of 78 g day −1 and 86 g day −1, respectively. Duodenal microbial AA N (g per 100 g microbial N) was 85.0 for basal and 64.6 for RSO with decreased ( P = 0.02) lysine and methionine content of microbial AA. The rate of passage ( K p) was reduced with extended fibre retention time.

The effect of drying method on the degradation characteristics of grass silage

The metabolisable protein system (AFRC, 1992) requires the measurement of the dynamics of the degradation of protein in the rumen. However many drying techniques used during sample preparation cause protein damage and denaturation which may affect the subsequent assessment. The objective of this work was to compare the dry matter and nitrogen degradation profiles of samples of grass silage dried using a range of techniques.One kilogram samples of first cut grass (Lolium perenne) silage (156 g CP/kg DM) were air dried (AD), freeze dried (FD), dried at 50 (OD50) or 100°C (OD100) in a still air oven or dried in a microwave oven (MD) on the ‘defrost’ setting. In sacco degradability was assessed in fistulated yearling wether sheep, using a 5x5 Latin square and incubation times of 3,6,12,24 and 48 hours. Bags size was nn x nn cm with a sample size of 3 g. Bags were rinsed and frozen upon removal, mechanically washed and dried at 60°C before analysis. Dry matter and nitrogen disappearance data for each sheep was fitted to the model y = a + b(1-e-ct) using non-linear regression.

Effects of rapeseed oil on rumen enzyme activity and in sacco degradation of grass silage

The effects of rapeseed oil (double zero variety, 00) supplement (RSO) on rumen protozoal, microbial carboxylmethylcellulase (CMCase) and xylanase activity was studied on four rumen-fistulated Friesian bulls in a 2×2 changeover design. Each experimental period lasted 21 days. The basal diet was 4.8 kg day −1 dry matter (DM) fresh cut grass silage and 2.6 kg day −1 DM rolled barley. The test feed (RSO) was formulated by supplementing the basal diet with 0.5 kg crude rapeseed oil. Crude RSO contained 98.2% fatty acids and was mixed daily with rolled barley manually. Feeding took place twice a day at 07:00 and 19:00 h. Drinking water was available at all times. In sacco rumen degradability of RSO-treated (RSOT) and untreated (UTS) fresh cut grass silage was determined on both basal and RSO diets during both periods. A daily supplement of 0.5 kg RSO had no effect ( P = 0.53) on rumen pH but decreased ( P = 0.01) protozoal mass (gl −1). It also depressed ( P = 0.07) rumen digesta CMCase and xylanase ( P = 0.01) activities. Carboxylmethylcellulase and xylanase activities from rumen-incubated grass silage fibre was depressed by both dietary RSO and RSO treatment of grass silage prior to incubation. In sacco degradability of grass silage DM, neutral detergent fibre (NDF) and acid detergent fibre (ADF) was lowered both by dietary RSO and RSO treatment of grass silage prior to rumen incubation. However, RSO treatment of grass silage was not as effective in fibre degradation as dietary RSO. The value for the soluble fraction ( a) of RSOT silage NDF and ADF was negative on both diets, whereas the value for the insoluble, potentially degradable material ( b), was high for RSOT silage. Lag time was extended by both dietary RSO and RSO treatment of silage prior to rumen incubation. The relationship of rumen CMCase and xylanase activity levels to in sacco NDF degradation of both RSOT and UTS on both diets was linear ( r = 0.97).