Timothy Silage Research Articles

Effects of grass species and harvest date on cell wall components and feed efficiency of dairy cows

There is a balance between DM yield and feed value when choosing types of grasses on a farm depending on the acreages of farmland and types of ruminants to be fed. Therefore, optimisation of the harvest strategy for grass silage is important for profitable dairy farming. Tall fescue has high DM yield and can replace traditional grasses, such as timothy, in Northern Europe in a changing climate as it has been shown to be more drought tolerant. As differences in climate responses previously have been related to differences in cell wall structure between grass species and, consequently, in digestibility, it is highly relevant to compare these species at similar maturity stages and to investigate if a very early harvest date will diminish potential differences between the species. This study evaluated the effects of harvest date and forage species on the concentration of hydroxycinnamic acids in silages and its relationship to feed efficiency of dairy cows. Tall fescue and timothy were harvested at very early date on May 25 or at early date on May 31 in the spring growth cycle. Forty lactating dairy cows were used in a block design. Cows received 1 of 4 treatments: (1) tall fescue harvested at very early date, (2) timothy harvested at very early date, (3) tall fescue harvested at early date, and (4) timothy harvested at early date. Diets were formulated to have the same forage-to-concentrate ratio (49:51 on DM basis). Tall fescue silages showed greater concentrations of DM, ash, and CP than timothy silages. Grasses harvested at early date showed greater concentrations of NDF, ADL, and cell wall than grasses harvested at very early date. Tall fescue silages showed greater concentration of p-coumaric acid and lower in vitro organic matter digestibility (IVOMD) compared to timothy silages. Milk production and composition were not affected by treatments but cows fed tall fescue-based diets showed lower milk protein yield and greater milk urea nitrogen than when timothy-based diets were fed. Furthermore, cows receiving timothy-based diets showed greater feed efficiency compared to cows receiving tall fescue-based diets. Thus, the lower concentration of p-coumaric acid and the higher IVOMD was associated with greater feed efficiency of cows fed timothy-based diets compared to tall fescue-based diets.

Intake, in vivo digestibility and protein utilization of wethers fed timothy or tall fescue when harvested at different dates in the first regrowth cycle

The objective of this study was to evaluate the effects of harvest date in the first regrowth cycle and grass species on intake, in vivo digestibility and its relation to protein utilization in wethers fed timothy or tall fescue silages. Timothy and tall fescue were harvested at regular (RTI and RTF, respectively) or late date (LTI and LTF, respectively) in the first regrowth, creating four experimental silages. Eight wethers were used in a duplicated 4 × 4 Latin square. Experimental periods lasted for 4 wk and wethers were fed ad libitum during the first 3 wk, with intake recorded during the third week. During the fourth week, wethers were fed 80% of ad libitum, and feces and urine were collected during the last 4 d. Wethers receiving RTI showed the greatest DM intake when expressed as kg/d or as percentage of body weight (BW) (P≤0.05). The intake of neutral detergent fiber (aNDFom) was affected by forage species only, where animals fed timothy silages had greater aNDFom intake than animals fed tall fescue silages (P<0.001). Intakes of CP and sum of the protein fractions A, B1 and B2 (AB1B2) were affected by the interaction between harvest date and forage species, where wethers fed RTI showed the greatest intakes of CP (P=0.001) and AB1B2 (P=0.02). Harvesting the forages at late date decreased the in vivo digestibility in wethers but only for timothy, where animals fed LTI silage showed the lowest DM (P<0.001), organic matter (OM) (P<0.001), aNDFom (P=0.02) and acid detergent fiber (P=0.004) digestibility, and a tendency for lower CP digestibility (P=0.07) compared with the other silages. Wethers fed RTI silage showed greater intake of nitrogen (N) (P=0.001) and digestible OM (P=0.003), greater allantoin (P=0.03) and hippuric acid (P=0.05) excretions, greater microbial N flow (P=0.03), and a tendency for greater excretion of fecal N (P=0.09) compared with the other silage-fed animals. In conclusion, delayed harvest decreased in vivo digestibility only in timothy, but even with lower in vivo digestibility wethers fed timothy silages showed a greater intake than wethers fed tall fescue silages, likely due to lower concentration of hydroxycinnamic acids observed in timothy compared with tall fescue as published previously.

Effect of Addition of Fermented Green Juice, Bacterial Inoculant, Enzyme or Effective Microorganisms on Fermentation Quality of Timothy Silage

Effect of Addition of Fermented Green Juice, Bacterial Inoculant, Enzyme or Effective Microorganisms on Fermentation Quality of Timothy Silage

Effects of Phenyllactic Acid, Lactic Acid Bacteria, and Their Mixture on Fermentation Characteristics and Microbial Community Composition of Timothy Silage.

This study investigated the effects of phenyllactic acid (PL), lactic acid bacteria (LAB), and their mixture on fermentation characteristics and microbial community composition of timothy silage. Timothy silages were treated without (CK) or with PL [10 mg/kg fresh matter (FM) basis], LAB inoculant (IN; a mixture of Lactobacillus plantarum and L.buchneri, 105 cfu/g FM), and their mixture (PI) and stored at ambient temperature (5°C∼15°C) in a dark room for 60 days. Compared with CK, all treated silages showed lower (P < 0.05) levels of butyric acid and ammonia-N. Treatment with PL enhanced (P < 0.05) the crude protein preservation of silage by favoring the growth of L. curvatus and Saccharomyces cerevisiae and inhibition of lactic acid–assimilating yeast belonging to Issatchenkia during ensiling. In particular, treatment with PL advanced (P < 0.05) the productions of lactic acid and volatile fatty acid in IN-treated silage. Therefore, PL used as a new additive exhibited potential for improving silage fermentation when it is combined with LAB IN during ensiling.

Effects of harvest date and grass species on silage cell wall components and lactation performance of dairy cows

This study evaluated the effect of harvest date and forage species on the concentration of hydroxycinnamic acids in silage and its relationship to dairy cow performance. Tall fescue and timothy were harvested at a regular date on June 27 and July 8, respectively, or at a late date on July 8 and 25, respectively, in the first regrowth. Forage was treated with a salt-based additive and ensiled in hard-pressed round bales. Forty-seven lactating dairy cows were used in a block design. Cows received 1 of 4 treatments: (1) tall fescue harvested at regular date (RTF), (2) timothy harvested at regular date (RTI), (3) tall fescue harvested at late date (LTF), and (4) timothy harvested at late date (LTI). Diets were formulated to have the same forage-to-concentrate ratio (46:54 on a dry matter basis). Harvesting at late date increased fiber components, but only for timothy, where LTI contained greater neutral detergent fiber, acid detergent fiber, and acid detergent lignin concentrations than the other silages. Concentrations of hydroxycinnamic acids were affected by forage species, where concentrations of esterified ferulic acid and p-coumaric acid were greater for tall fescue silages than for timothy silages. Cows fed the RTI diet showed the greatest intakes of dry matter, organic matter, and crude protein. Feeding diets containing timothy silages increased milk yield and energy-corrected milk yield compared with tall fescue diets when averaged over harvest dates. Cows fed the RTI diet had greater milk protein yield than cows fed the RTF and LTF diets, and milk lactose yield was greater for cows fed diets containing timothy silage compared with tall fescue silage when averaged over harvest dates. Cows fed the LTF diet showed greater urinary N excretion compared with the LTI diet, but RTI showed the lowest urinary N and urea N excretions when calculated as percent of N intake. Cows fed diets containing timothy silage excreted more uric acid than cows fed tall fescue diets. Allantoin excretion was greater for cows eating the RTI and LTI diets compared with cows eating the RTF diet. Cows fed the RTI diet had a greater estimated microbial N flow and a greater excretion of hippuric acid than the RTF and LTF groups. In conclusion, besides the effect of harvest date on increasing the fiber components of timothy, concentrations of hydroxycinnamic acids were mainly affected by forage species; consequently, milk production was only affected by forage species. This indicates that hydroxycinnamic acids, such as ferulic acid, which cross-links to glucuronoarabinoxylans, was a major factor regulating milk production of cows fed tall fescue- and timothy silage-based diets, where lower hydroxycinnamic acid concentrations were responsible for greater milk yield.

Tall fescue as an alternative to timothy fed with or without alfalfa to dairy cows

Tall fescue might be an alternative to timothy in northeastern North America because of its tolerance of recurring drought periods and its good summer regrowth, but is not always considered as an option in dairy rations because of its possible lack of palatability. The objective of this study was to evaluate the effects on the performance of lactating dairy cows of (1) replacing timothy silage by tall fescue silage, offered as sole forage in the diet or in combination with alfalfa silage, and (2) feeding tall fescue as silage (35% dry matter, DM) or haylage (55% DM). Experimental diets with a forage-to-concentrate ratio of 70:30 were (1) 100% timothy silage (TS); (2) 100% tall fescue silage (TFS); (3) 55:45 timothy:alfalfa silages (TS + AS); (4) 55:45 tall fescue:alfalfa silages (TFS + AS); and (5) 100% tall fescue haylage (TFH). Fifteen Holstein cows in mid-lactation (5 fitted with a rumen fistula) were randomly assigned to treatments in a triple 5 × 5 Latin square design with treatment periods of 21 d. Preplanned contrasts were timothy versus tall fescue silages, sole grass species versus grass-alfalfa, interaction between sole grass species and grass-alfalfa, and TFS versus TFH. Grass species did not affect dry matter intake (DMI) or milk yield and fat concentration. Milk protein concentration was not affected by grass species when offered in combination with alfalfa, but it was higher with the TS diet than the TFS diet when offered as sole forages. Adding alfalfa to either tall fescue or timothy silage resulted in greater DMI and milk yield, but lower milk fat concentration, than when the grass silages were the sole forage in the diet. The molar proportion of propionate in the rumen was greater when cows were fed diets with tall fescue silage compared with timothy silage, which resulted in a lower acetate-to-propionate ratio. Milk fat concentrations of fatty acids from microbial origin, namely branched-chain fatty acids, were greater when grass silage, and especially timothy silage, were fed as sole forages rather than with alfalfa silage. Feeding TFH rather than TFS caused a decrease in DMI and tended to lower milk protein concentration, but did not affect milk yield. A more fibrolytic fermentation profile was observed in rumen of cows fed TFH compared with TFS, as indicated by the increase in the molar proportion of acetate and the higher acetate-to-propionate ratio in rumen fluid, and a concomitant increase in branched-chain fatty acid concentration in milk fat. Tall fescue as silage or haylage is a valuable alternative to timothy silage for lactating dairy cows.

Effects of feeding early-harvested orchardgrass-perennial ryegrass mixed silage instead of heading stage harvested timothy silage on digestion and milk production in dairy cows.

We evaluated the effects of replacement of heading stage harvested timothy silage with early-harvested orchardgrass-perennial ryegrass mixed (OP) silage while maintaining or reducing concentrate input on dry matter intake (DMI), milk production, nutrient digestibility, and N balance in dairy cows. Nine multiparous Holstein cows were used in a replicated 3×3 Latin square design with three dietary treatments: TYL, a diet containing timothy silage where forage-to-concentrate ratio (FC) was 50:50; OPL, a diet containing OP silage where FC ratio was 50:50; and OPH, a diet containing OP silage where FC ratio was 60:40. We observed that an equal replacement of timothy with OP silage increased DMI, milk yield, milk protein production, and nutrient digestibility but decreased milk fat content (TYL versus OPL). We observed that replacing timothy with OP silage while reducing concentrate input increased milk fat and protein yield, nutrient digestibility, and feed efficiency and reduced urinary N loss with no effect on DMI or milk fat content (TYL versus OPH). These results show that replacing timothy with OP silage can be a good approach to improve milk production, feed efficiency, and N utilization and reduce concentrate input. However, milk fat depression should be considered when an equal substitution is performed.

Effects of silage additives on intake, live-weight gain and carcass traits of growing and finishing dairy bulls fed pre-wilted grass silage and barley grain-based ration

SUMMARYThe effects of silage additives on performance of dairy bulls were determined in a feeding trial using 45 Nordic Red and 45 Holstein bulls. Both breeds were allotted randomly to three treatments: (1) timothy silage (TS) without additives + barley (CON); (2) TS with sodium benzoate, potassium sorbate and sodium nitrate-based additive + barley (SALT); and (3) TS with a mixture of mostly formic acid and propionic acid-based additive + barley (ACID). The bulls were fed total mixed rationsad libitum. During the experimental period of 259 days, the average dry matter intake was 10·1 kg/d and there was no difference among the treatments. The average live-weight gain (LWG) and carcass gain was 1363 and 741 g/d, respectively. There were no treatment differences in the carcass gain but LWG of the CON bulls was 5% higher compared with the SALT and ACID bulls. Carcass conformation score of the SALT and ACID bulls was 6% higher compared with the CON bulls. The experiment demonstrated that there was only a slight benefit from silage additives in animal performance when silage dry matter was 350–400 g/kg and silage was ensiled in round bales.

A comparison of first-, second- and third-cut timothy silages in the diets of finishing beef bulls

The objective of the present experiment was to study the effects of the third-cut grass silage compared with the first- and second-cut silages on intake, performance and carcass characteristics of finishing bulls. A feeding experiment comprised 45 Simmental bulls which were fed a total mixed ration ad libitum. The three dietary treatments included either first-, second- or third-cut grass silage (550 g kg-1 dry matter), rolled barley (435 g kg-1 dry matter) and a mineral-vitamin mixture (15 g kg-1 dry matter). Dry matter and energy intakes and growth rates of the bulls increased when either first- or third-cut silages were used instead of the second-cut silage. This was probably due to differences in digestibility, which was the lowest in the second-cut silage. There were no differences in intake or growth between the first- and third-cut silage-based rations. No significant differences in carcass traits among the feeding treatments were observed.

Effects of replacing timothy silage by alsike clover silage on performance, carcass traits and meat quality of finishing Aberdeen Angus and Nordic Red bulls

AbstractThe objective of the study was to determine the effects of silage plant species and cattle breed on performance and meat quality of finishing bulls. A feeding experiment was conducted using thirty Aberdeen Angus (AA) and thirty Nordic Red (NR) bulls. Both breeds were randomly allotted to three experimental diets. The composition (g kg−1 dry matter) of the diets was as follows: (i) timothy silage (TS) (650) and barley (350); (ii) TS (325), alsike clover silage (AS) (325) and barley (350); and (iii) AS (650) and barley (350). The bulls were fed a total mixed ration ad libitum. Replacing TS by AS did not affect dry‐matter intake, growth, carcass conformation or meat quality traits of the bulls, but carcass fat score tended to decrease when replacing TS by AS (P = 0·07). The AA bulls grew faster and had better feed conversion and superior carcass conformation compared with the NR bulls (P &lt; 0·001). The loin of the AA bulls had lower shear force value and was given higher scores in sensory analyses compared with the NR bulls (P &lt; 0·01). The experiment demonstrated that replacing TS by AS in the diet of finishing bulls had minor effects on performance or meat quality.

Prediction of enteric methane emissions from Holstein dairy cows fed various forage sources

Milk fatty acid (FA) profile has been previously used as a predictor of enteric CH4output in dairy cows fed diets supplemented with plant oils, which can potentially impact ruminal fermentation. The objective of this study was to investigate the relationships between milk FA and enteric CH4 emissions in lactating dairy cows fed different types of forages in the context of commonly fed diets. A total of 81 observations from three separate 3×3 Latin square design (32-day periods) experiments including a total of 27 lactating cows (96±27 days in milk; mean±SD) were used. Dietary forages were included at 60% of ration dry matter and were as follows: (1) 100% corn silage, (2) 100% alfalfa silage, (3) 100% barley silage, (4) 100% timothy silage, (5) 50 : 50 mix of corn and alfalfa silages, (6) 50 : 50 mix of barley and corn silages and (7) 50 : 50 mix of timothy and alfalfa silages. Enteric CH4output was measured using respiration chambers during 3 consecutive days. Milk was sampled during the last 7 days of each period and analyzed for components and FA profile. Test variables included dry matter intake (DMI; kg/day), NDF (%), ether extract (%), milk yield (kg/day), milk components (%) and individual milk FA (% of total FA). Candidate multivariate models were obtained using the Least Absolute Shrinkage and Selection Operator and Least-Angle Regression methods based on the Schwarz Bayesian Criterion. Data were then fitted into a random regression using the MIXED procedure including the random effects of cow, period and study. A positive correlation was observed between CH4 and DMI (r=0.59,P<0.001), whereas negative associations were observed between CH4 and cis9-17:1 (r=−0.58, P<0.001), and trans8, cis13-18:2 (r=−0.51,P<0.001). Three different candidate models were selected and the best fit candidate model predicted CH4 with a coefficient of determination of 0.84 after correction for cow, period and study effects and was: CH4 (g/day)=319.7−57.4×15:0−13.8×cis9-17:1−39.5×trans10-18:1−59.9×cis11-18:1−253.1×trans8, cis12-18:2−642.7×trans8, cis13-18:2−195.7×trans11, cis15-18:2+16.5×DMI. Overall and linear prediction biases of all models were not significant (P>0.19). Milk FA profile and DMI can be used to predict CH4emissions in dairy cows across a wide range of dietary forage sources

Effects of forage silage species on yearling growth performance, carcass and meat quality, and nutrient composition in a forage based beef production system

Berthiaume, R., Lafrenière, C., Girard, C., Campbell, C. P., Pivotto, L. M. and Mandell, I. B. 2015. Effects of forage silage species on yearling growth performance, carcass and meat quality, and nutrient composition in a forage based beef production system. Can. J. Anim. Sci. 95: 173–187. Forty weaned, crossbred beef calves (predominantly Angus and Simmental) were forage-finished using all-silage diets (red clover–timothy versus tall fescue) to examine forage species’ effects on growth performance, carcass traits, meat quality, and nutrient composition. Weaned calves (257 d of age) were forage-finished using red clover–timothy or tall fescue silage and harvested at approximately 1 yr of age. During carcass processing, one side from each carcass was covered with a polyliner to examine if reducing rates of chilling could compensate for limited fat cover expected from low dietary energy contents fed, and limited time on feed. Longissimus thoracis, semimembranosus, and semitendinosus steaks were aged 10, 14, and 21 d to examine effects on Warner–Bratzler shear force values while fatty acid and vitamin B12 composition were determined on 10-d-aged steaks. Average daily gain, feed efficiency, hot carcass weights, and longissimus muscle area were greater (P&lt;0.03) when cattle were fed red clover–timothy versus tall fescue silage, most likely due to the higher protein content of red clover–timothy silage. Shear force was greater (P&lt;0.002) in steaks from all muscles evaluated from cattle fed tall fescue versus red clover–timothy silage. In comparison to 10-d-aged steaks, 14 d of ageing were needed to reduce (P&lt;0.001) shear force for longissimus steaks, while 21 d of ageing were needed to reduce (P&lt;0.001) shear force for semitendinosus steaks. Use of a polyliner decreased (P=0.0001) the rate of temperature decline at selected carcass sites, but did not reduce shear force values. The percent of n-3 fatty acids and polyunsaturated fatty acid/saturated fatty acid ratio were greater (P&lt;0.04) in longissimus from cattle fed red clover–timothy versus feeding tall fescue silage. Feeding red clover–timothy silage improved growth performance, carcass, shear force, and fatty acid composition traits versus feeding tall fescue silage.

Methane production, nutrient digestion, ruminal fermentation, N balance, and milk production of cows fed timothy silage- or alfalfa silage-based diets

The objective of this study was to investigate the effects of changing forage source in dairy cow diets from timothy silage (TS) to alfalfa silage (AS) on enteric CH4 emissions, ruminal fermentation characteristics, digestion, milk production, and N balance. Nine ruminally cannulated lactating cows were used in a replicated 3×3 Latin square design (32-d period) and fed (ad libitum) a total mixed ration (TMR; forage:concentrate ratio of 60:40, dry matter basis), with the forage portion consisting of either TS (0% AS; 0% AS and 54.4% TS in the TMR), a 50:50 mixture of both silages (50% AS; 27.2% AS and 27.2% TS in the TMR), or AS (100% AS; 54.4% AS and 0% TS in the TMR). Compared with TS, AS contained less (36.9 vs. 52.1%) neutral detergent fiber but more (20.5 vs. 13.6%) crude protein (CP). In sacco 24-h ruminal degradability of organic matter (OM) was higher for AS than for TS (73.5 vs. 66.9%). Replacement of TS with AS in the diet entailed increasing proportions of corn grain and bypass protein supplement at the expense of soybean meal. As the dietary proportion of AS increased, CP and starch concentrations increased, whereas fiber content declined in the TMR. Dry matter intake increased linearly with increasing AS proportions in the diet. Apparent total-tract digestibility of OM and gross energy remained unaffected, whereas CP digestibility increased linearly and that of fiber decreased linearly with increasing inclusion of AS in the diet. The acetate-to-propionate ratio was not affected, whereas ruminal concentration of ammonia (NH3) and molar proportion of branched-chain VFA increased as the proportion of AS in the diet increased. Daily CH4 emissions tended to increase (476, 483, and 491g/d for cows fed 0% AS, 50% AS, and 100% AS, respectively) linearly as cows were fed increasing proportions of AS. Methane production adjusted for dry matter intake (average=19.8g/kg) or gross energy intake (average=5.83%) was not affected by increasing AS inclusion in the diet. When expressed on a fat-corrected milk or energy-corrected milk yield basis, CH4 production increased linearly with increasing AS dietary proportion. Urinary N excretion (g/d) increased linearly when cows were fed increasing amounts of AS in the diet, suggesting a potential for higher nitrous oxide (N2O) and NH3 emissions. Efficiency of dietary N use for milk protein secretion (g of milk N/g of N intake) declined with the inclusion of AS in the diet. Despite marked differences in chemical composition and ruminal degradability, under the conditions of this study, replacing TS with AS in dairy cow diets was not effective in reducing CH4 energy losses.

Evaluation of fermentation parameters, microbiological composition and aerobic stability of grass and whole crop maize silages treated with microbial inoculants

experiments were conducted in 2011-2012 to evaluate the fermentation parameters, microbiological composition and aerobic stability of grass and whole crop maize silages treated with microbial inoculants, different blends of the selected bacterial strains and blend of the selected bacterial strains in combination with sodium benzoate. Wilted ryegrass:timothy and whole crop maize with 265 and 276 g kg -1 dry matter (DM) content were ensiled in 3 litre laboratory silos. The mean water soluble carbohydrate (WSC) concentration, buffer capacity and nitrate concentration in ryegrass:timothy and whole crop maize were 101.8 and 98.9 g kg -1 DM, 355 and 217 mEq kg -1 DM, and 153.2 and 841.1 mg kg -1 DM, respectively. Silages treated with the tested inoculants were characterized by higher concentrations of DM compared with the untreated silage. Ryegrass:timothy and maize herbage inoculant treatments before ensiling significantly decreased (P < 0.05) pH, significantly reduced butyric acid, ammonia-N concentrations and DM loss compared with control silage. Ryegrass:timothy and maize silages inoculated with homofermentative bacteria blends produce higher (P < 0.05) lactic acid compared with that of the control silage. Butyric acid, alcohols and N-NH 3 fraction concentrations were significantly (P < 0.05) decreased by inoculation. When compared with control silage, increased (P < 0.05) acetic acid concentration and decreased lactic acid concentration were observed in ryegrass:timothy silages and maize silages inoculated with heterofermentative lactic acid bacteria (LAB) strain Lactobacillus buchnery. The LAB blends used in our experiment significantly suppressed yeast and moulds growth reflected in the lower concentration of alcohols, generally correlated to yeast activity in silages. Inoculation increased the aerobic stability of ryegrass:timothy and maize silages, compared with control silage. The aerobic stability of inoculated ryegrass:timothy and maize silages was improved by 66-312 hours compared to control silage.

Effect of grain and forage fractions of corn silage on milk production and composition in dairy cows

Corn silage (CS) is associated with a reduction in milk fat content. The fact that CS is constituted of a grain and a forage fraction could explain this effect. This experiment evaluated the effect of grain fraction of CS on rumen fermentation, production performance and milk composition. Earless CS (ECS) was harvested after manually removing corn ears from the plant. Whole CS (WCS) was harvested from the same field on the same day. Eight (four ruminally fistulated) multiparous Holstein cows (84 days in milk) were utilized in a double 4 × 4 Latin square with 21-day periods. Treatments were (dry matter (DM) basis) (1) 23.0% WCS; (2) 12.4% ECS plus 10.6% high moisture corn (HMC) to obtain reconstituted CS (RCS); (3) 23.0% ECS; and (4) 23.0% timothy silage (TS). Diets were formulated to be isonitrogenous and were fed as total mixed ration once a day. DM intake (DMI), milk yield, 4.0% fat-corrected milk (FCM), as well as protein concentration and yield were higher for WCS than ECS. Compared with WCS, cows tended to eat less with RCS, and produced less milk and milk protein. However, yield of FCM was similar between WCS and RCS. Milk fat concentration and yield, as well as the specific ratio of t11 18:1 to t10 18:1 in milk fat did not differ among diets. Milk urea-N tended to be higher for ECS than WCS and TS, whereas ruminal NH3-N was higher with ECS than TS. Rumen pH decreased linearly with time after feeding but was not different between treatments. Higher acetate and lower propionate concentration resulted in greater acetate to propionate ratio with ECS compared with WCS. In conclusion, removing grain fraction from CS decreased milk production and modified rumen fermentation without affecting milk fat concentration and yield. Moreover, despite some differences in DMI and total ruminal volatile fatty acid concentration between WCS and RCS, the restoration of FCM yield, using HMC in RCS diets, to a level of production similar to WCS highlights the importance of energy and nutrients supplied by the grain fraction of CS to support milk yield.

The effects of hydrothermal conditioning, detergent and mechanical pressing on the isolation of the fibre-rich press-cake fraction from a range of grass silages

The initial stage of a Green Biorefinery involves the fractionation of plant biomass into a fibre-rich press-cake and a nutrient-rich press-juice that are subsequently used to provide energy, chemicals and materials. However, limited information has been published to date on the factors influencing the fractionation of green biomass. Perennial ryegrass and cocksfoot silages harvested at two stages of maturity were subjected to hydrothermal conditioning at three temperatures (20, 40 and 60 °C) with or without detergent. In a second experiment, Italian ryegrass and timothy silages harvested at three stages of maturity were subjected to three washing steps (30 min at 60 °C in a 3 water + detergent (30 g L −1 ): 1 silage ratio; undertaken 1, 2 or 3 times), before being mechanically pressed at three different pressures (1.5, 3.0 or 4.5 MPa). Overall, repeated washing (up to 2 washing steps) and mechanical pressing (3.0 MPa) proved the most effective treatments for the removal of solubles from a range of grass silages and in the isolation of a fibre-rich press-cake fraction. ► Fractionation is the crucial first step in a Green Biorefinery. ► Factors affecting fibre-rich press-cake isolation from grass silages were studied. ► Repeated washing and mechanical pressing were the most effective treatments. ► Changes in plant structure with advancing maturity negatively effects fractionation.

Methane Emissions from Dry Cows Fed Grass or Legume Silage

Using an open-circuit system, we compared the methane (CH 4 ) emission from dry cows fed first-cut Timothy silage (1 st TY), second-cut Timothy silage (2 nd TY), second-cut Italian ryegrass silage (2 nd IR), third-cut Italian ryegrass silage (3 rd IR), or second-cut red clover silage (2 nd RC) as the sole feed. The methane emission ranged from 258.2 L day -1 to 396.5 L day -1 . The methane emission from dry cows fed red clover silage was relatively lower than that from dry cows fed grass silage. However, the methane emission per unit digestible neutral detergent fiber (NDF) intake (dNDFI) did not differ significantly between the experimental silages. The methane emission was significantly correlated with the NDF intake and digestibility. Methane emission had a significant correlation with the quadratic function of dNDFI. The differences in the daily volume of methane emission from cows fed different forages can be explained by dNDFI.

Timothy silage with low dietary cation-anion difference fed to nonlactating cows

Decreasing the dietary cation-anion difference (DCAD) by using anion sources before calving reduces hypocalcemia in cows at calving. Reduced DCAD from CaCl2-fertilized timothy hay achieves similar results, but the effects of feeding low-DCAD forage as silage have not been determined. The objective of this study was to evaluate the effect of low-DCAD timothy silage on dry cows. Six nonlactating and nonpregnant Holstein cows were used in a replicated 3 × 3 Latin square. Treatments were 1) control diet (DCAD=232mEq/kg of dry matter, DM); 2) low-DCAD diet using a low-DCAD timothy silage (LDTS; DCAD=−21mEq/kg of DM); and 3) low-DCAD diet using a fermentation by-product (LDBP; DCAD=−32mEq/kg of DM). Differences between dietary treatments were considered statistically significant at P≤0.05 and tendencies were noted when 0.05<P<0.10. Compared with the control, feeding LDTS tended to decrease DM intake (10.6 vs. 12.5 kg/d) and decreased urinary pH (6.15 vs. 8.18) as well as apparent digestibility of DM (67 vs. 69%). Blood pH (7.37 vs. 7.42), HCO3− (25.3 vs. 27.5mM), and base excess (0.4 vs. 3.1mM) were decreased, and blood Cl− (29.6 vs. 29.1mg/dL) was increased. Apparently absorbed Na and Cl were higher and apparently absorbed K, P, and digested ADF were lower for LDTS compared with the control. Both LDTS and LDBP resulted in similar DM intake. Urinary pH tended to be higher (6.15 vs. 5.98) and percentage of digested DM was lower (67 vs. 70%) with LDTS compared with LDBP. Blood ionized Ca (5.3 vs. 5.4mg/dL) tended to be lower and blood Cl− (29.6 vs. 30.1mg/dL) was lower, whereas blood pH (7.37 vs. 7.33), HCO3− (25.3 vs. 21.5mM), and base excess (0.4 vs. −3.8mM) were higher with LDTS compared with LDBP. Apparent absorption of Na, Cl, S, and P, as well as apparent digestion of acid detergent fiber, neutral detergent fiber, and N were lower, and K, Cl, S, P, Mg, and N were less retained with LDTS compared with LDBP. Results confirm that low-DCAD timothy silage can be used to produce a compensated metabolic acidosis by decreasing the DCAD of rations served to nonlactating dairy cows.

Application of a Simulation Model for Dairy Cattle Production Systems Integrated with Forage Crop Production: the Effects of Whole Crop Rice Silage Utilization on Nutrient Balances and Profitability

In Japan, since rice consumption has been decreasing with the westernization of Japanese eating habits, surplus paddy fields have been increasing. If these surplus paddy fields can be utilized for forage rice production as feed for animal production and excretions (feces and urine) from animal production can be applied to the paddy fields as manure, then the problems of surplus paddy fields and excretions from animal production may be solved, and the environment kept sustainable. The objectives of the present study were to apply a bio-economic model to dairy and forage rice integration systems in Japan and to examine the merit of introducing whole crop rice silage (WCRS), as well as economic and environmental effects of various economic and management options in the systems. Five simulations were conducted using this model. The use of WCRS as a home-grown feed increased environmental loads and decreased economic benefit because of the higher amount of purchased feed, when compared to the use of typical crops such as maize, alfalfa and timothy silage (simulation 1). Higher economic benefits from higher forage rice yields and higher milk production of a dairy cow were obtained (simulations 2, 3). There were no economic and environmental incentives for utilizing crude protein (CP) rich WCRS, because an increase in the CP content in WCRS led to the use of more chemical fertilizers, resulting in high production costs and nitrogen outputs (simulation 4). When evaluated under the situation of a fixed herd size, increasing forage rice yields decreased the total benefit of the production, in spite of the fact that the amount of subsidies per unit of land increased (simulation 5). It was indicated that excess subsidy support may not promote yield of forage rice. It was, however, observed in most cases that dairy and forage rice integration systems could not be economically established without subsidies.

Methane production and energy partition in sheep fed timothy silage- or hay-based diets

SANTOSO, B., B. MWENYA, C. SAR and J. TAKAHASHI. 2007. Methane production and energy partition in sheep fed timothy silage- or hay-based diets. JITV 12(1): 27-33. Methane is produced as a result of anaerobic fermentation of the soluble and structural carbohydrates by methanogens in the rumen of ruminant animals. Removal of methane from rumen represents a loss of approximately 7.22% of gross energy intake. Four ruminally fistulated Cheviot wethers were used in a crossover design to determine methane production and energy partition in sheep fed timothy silage- or hay-based diets. The experimental diets consisted of either timothy silage or timothy hay and a commercial concentrate (85:15, on DM basis). Variables measured were nutrients digestibility, energy balance and methane production. Apparent digestibilities of DM, OM, CP, NDF, ADF, cellulose and hemicellulose were significantly higher (P<0.05) on sheep fed silage-based diet than those fed hay-based diet. Sheep fed silage-based diet had greater (P<0.01) urinary energy loss, methane and heat production, but lower (P<0.05) fecal energy loss. Methane production, either expressed as g kg -1 dry matter intake or g day -1 was markedly lower (P<0.05) in hay-based diet as compared to silage-based diet. There was a strong relationship between methane production (g day -1 ) and NDF digested (g day -1 ) (R 2 = 88.4%, P<0.001). Methane production expressed as g kg -1 NDF digested in silage-based diet was higher (P<0.05) than in hay-based diet (66.44 vs 62.70). These results