Effects of silage from maize crops differing in maturity at harvest,grass silage feed value and concentrate feed level on performance of finishing lambs

The effects of (i) medium and high feed value (MFV and HFV) maize silages and (ii) MFV and HFV grass silages, each in combination with a range of concentrate feed levels, on the performance of finishing lambs were evaluated using 280 Suffolk-X lambs (initial live weight 36.1 kg). The MFV and HFV maize silages represented crops with dry matter (DM) concentrations of 185 and 250 g/kg, respectively, at harvest, and had starch and metabolisable energy (ME) concentrations of 33 and 277 g/kg DM and 9.6 and 11.0 MJ/kg, respectively. HFV and MFV grass silages had DM and ME concentrations of 216 and 294 g/kg and 11.0 and 11.5 MJ/kg DM, respectively. A total of 13 treatments were involved. The four silages were offered ad libitum with daily concentrate supplements of 0.2, 0.5 or 0.8 kg per lamb. A final treatment consisted of concentrate offered ad libitum with 0.5 kg of the HFV grass silage daily. Increasing the feed value of grass silage increased (P < 0.001) forage intake, daily carcass and live weight gains, final live weight and carcass weight. Increasing maize silage feed value tended to increase (P = 0.07) daily carcass gain. Increasing concentrate feed level increased total food and ME intakes, and live weight and carcass gains. There was a significant interaction between silage feed value and the response to concentrate feed level. Relative to the HFV grass silage, the positive linear response to increasing concentrate feed level was greater with lambs offered the MFV grass silage for daily live weight gain (P < 0.001), daily carcass gain (P < 0.01) and final carcass weight (P < 0.01). Relative to the HFV maize silage, there was a greater response to increasing concentrate feed level from lambs offered the MFV maize silage in terms of daily carcass gain (P < 0.05) and daily live weight gain (P = 0.06). Forage type had no significant effect on the response to increased concentrate feed level. Relative to the MFV grass silage supplemented with 0.2 kg concentrate, the potential concentrate-sparing effect of the HFV grass silage, and the MFV and HFV maize silages was 0.41, 0.09 and 0.25 kg daily per lamb, respectively. It is concluded that increasing forage feed value increased forage intake and animal performance, and maize silage can replace MFV grass silage in the diet of finishing lambs as performance was equal to or better (depending on maturity of maize at harvest) than that for MFV grass silage.     

The effects of grain treatment, grain feed level and grass silage feed value on the performance of and meat quality from, finishing beef cattle

A completely randomised design study involving 132 continental crossbred beef steers was undertaken to evaluate the effects of method of grain treatment and feed level, and grass silage feed value on animal performance, carcass characteristics and meat quality of beef cattle. Winter wheat was harvested and the grain was stored either ensiled crimped and treated with 4.5 l/t of a proprietary acid-based additive (crimped), ensiled whole and treated with 20 kg feed-grade urea per t (urea) or stored conventionally in an open bin treated with 3 l propionic acid per t. Two grass silages, of contrasting feed value (L and H) were ensiled. For the conventional, crimped and urea treatments, grain dry matter (DM) concentrations were 802, 658 and 640 g/kg, respectively. For the L- and H-feed value silages, DM concentrations were 192 and 240 g/kg and D values were 671 and 730 g/kg DM, respectively. The silages were offered as the sole forage supplemented with either conventional, crimped or urea-treated grain-based concentrate at either 3.5 or 6.0 kg DM per steer per day. The grain supplement consisted of 850 and 150 g/kg DM of grain and citrus pulp, respectively. For the conventional, urea and crimped treatments, DM intakes were 8.85, 9.43 and 9.04 kg/day (standard error (s.e.) = 0.129); estimated carcass gains were 0.60, 0.55 and 0.61 kg/day (s.e. = 0.020), respectively. For the low- and high- feed value grass silages, estimated carcass gains were 0.56 and 0.61 kg/day (s.e. = 0.014), respectively. For the low and high grain feed levels, estimated carcass gains were 0.56 and 0.61 kg/day, respectively. Grain treatment, grain feed level or silage feed value did not alter (P > 0.05) meat quality, lean colour or fat colour. There were significant silage feed value × grain feed level interactions (P < 0.05) for final live weight (LW) and daily live-weight gain (DLWG). Increasing grain feed level increased final LW and DLWG when offered with the low-feed value silage, however, grain feed level had no effect on final LW or DLWG when offered with the high-feed value silage. It is concluded that urea treatment of grain increased silage intake and feed conversion ratio (kg DM intake per kg carcass) and tended to decrease carcass gain. Crimping provides a biologically equally effective method to store grain as conventional methods. Improving grass silage feed value had a greater impact on animal performance than increasing grain feed level by 2.4 kg DM per day.     

Effects of replacing grass silage with either maize or whole-crop wheat silages on the performance and meat quality of beef cattle offered two levels of concentrates

A randomised design involving 66 continental cross beef steers (initial live weight 523 kg) was undertaken to evaluate the effects of the inclusion of maize or whole-crop wheat silages in grass silage-based diets on animal performance, carcass composition, and meat quality of beef cattle. Grass silage was offered either as the sole forage or in addition to either maize or whole-crop wheat silages at a ratio of 40:60, on a dry matter (DM) basis, alternative forage: grass silage. For the grass, maize, and whole-crop wheat silages, DM concentrations were 192, 276, and 319 g/kg, ammonia-nitrogen concentrations were 110, 90, and 150 g/kg nitrogen, starch concentrations were not determined, 225, and 209 g/kg DM and in vivo DM digestibilities were 0.69, 0.69, and 0.58; respectively. The forages were offered ad libitum following mixing in a paddle type complete diet mixer wagon once per day, supplemented with either 3 or 5 kg concentrates per steer per day, in two equal feeds, for 92 days. For the grass, grass plus maize and grass plus whole-crop wheat silage-based diets food intakes were 8.38, 9.08, and 9.14 kg DM per day, estimated carcass gains were 514, 602, and 496 g/day and carcass weights were 326, 334, and 325 kg; respectively. Altering the silage component of the diet did not influence carcass composition or meat eating quality. Increasing concentrate feed level tended ( P = 0.09) to increase estimated carcass fat concentration and increased sarcomere length ( P < 0.05), and lean a* ( P < 0.01), b* ( P < 0.05), and chroma ( P < 0.01). There were no significant silage type by concentrate feed level interactions for food intake, steer performance, carcass characteristics or meat eating quality. It is concluded that replacing grass silage with maize silage increased carcass gain, and weight due to higher intakes, and improved utilisation of metabolisable energy. Whilst replacing grass silage with whole-crop wheat silage increased live-weight gain, the reduced dressing proportion resulted in no beneficial effect on carcass gain, probably due to increased food intakes of lower digestible forage increasing gut fill. Meat quality or carcass composition were not altered by the inclusion of maize or whole-crop silages in grass silage based diets.     

Grass and lupin silage in rations for beef steers supplemented with barley or potatoes

Twenty-eight Simmental-cross steers weighing 200 (± 20.5) kg were used to evaluate grass and whole plant lupin silages in terms of growth rate, dry matter (DM) intake and carcass characteristics. The chemical composition of the silages was determined and Dacron bag procedures were used to estimate DM and protein degradability. The silages were supplemented with either rolled barley or crushed potato. The lupin silage had a lactic acid fermentation with lower DM, neutral detergent fiber (NDF) and protein nitrogen than the grass silage but higher crude protein. There were no statistically significant differences in gain, carcass weight, dressing percentage or backfat levels between steers fed lupin or grass silage. DM intake of the silages was not significantly different but there was a tendency for lower DM intake of lupin silage when supplemented with potatoes. There was no difference in DM degradability between lupin and grass silages. Lupin nitrogen degraded at a significantly faster rate (24.5% h⁻¹) compared with the grass (10.4% h⁻¹). The effective degradation of nitrogen at a ruminal fractional outflow rate of 0.05 h⁻¹ was 63.8% and 79.1% for grass and lupin silage, respectively. Ensiling whole plant lupin can produce a high quality silage for use in beef rations.     

Effects of replacing grass silage with maize silages differing in inclusion level and maturity on the performance,meat quality and concentrate-sparing effect of beef cattle

The effects of maturity of maize at harvest, level of inclusion and potential interactions on the performance, carcass composition, meat quality and potential concentrate-sparing effect when offered to finishing beef cattle were studied. Two maize silages were ensiled that had dry matter (DM) concentrations of 217 and 304 g/kg and starch concentrations of 55 and 258 g/kg DM, respectively. Grass silage was offered as the sole forage supplemented with either 4 or 8 kg concentrate/steer daily or in addition with one of the two maize silages at a ratio 0.5 : 0.5, on a DM basis, maize silage : grass silage supplemented with 4 kg concentrate daily. The two maize silages were also offered as the sole forage supplemented with 4 kg concentrate/steer daily. The forages were offered ad libitum. The six diets were offered to 72 steers (initial live weight 522 s.d. 23.5 kg) for 146 days. There were significant interactions (P < 0.05) between maize maturity and inclusion level for food intake, fibre digestibility and daily gain. For the grass silage supplemented with 4 or 8 kg concentrate, and the maize silages with DM concentrations of 217 and 304 g/kg offered as 0.5 or 1.0 of the forage component of the diet, total DM intakes were 8.3, 9.8, 8.9, 8.2, 9.2 and 9.8 kg DM/day (s.e. 0.27); live-weight gains were 0.74, 1.17, 0.86, 0.71, 0.88 and 1.03 kg/day (s.e. 0.057); and carcass gains were 0.48, 0.73, 0.56, 0.46, 0.56 and 0.63 kg/day (s.e. 0.037), respectively. Increasing the level of concentrate (offered with grass silage), maize maturity and level of maize inclusion reduced (P < 0.05) fat b* (yellowness). The potential daily concentrate-sparing effect, as determined by carcass gain, for the maize silages with DM concentrations of 217 and 304 g/kg offered as 0.5 and 1.0 of the forage component of the diet were 1.3, −0.3, 1.3 and 2.4 kg fresh weight, respectively. It is concluded that the response, in animal performance, including maize silage is dependent on the stage of maturity and level of inclusion in the diet. Maize silage with a DM of 304 g/kg offered ad libitum increased carcass gain by 31%, because of a combination of increased metabolizable energy (ME) intake and improved efficiency of utilization of ME, and produced carcasses with whiter fat.     

Effects of grass and maize silage feed value,offering soybean meal with maize silage,and concentrate feed level in late pregnancy,on ewe and lamb performance

In many countries, daily herbage accumulation on pasture declines towards zero during the winter period; thus, many pregnant ewes are housed and offered conserved forages supplemented with concentrate prior to parturition. The effects of forage type and feed value (FV), offering soybean meal with maize silage during mid and late pregnancy, and concentrate feed level in late pregnancy on the performance of ewes and their progeny (to slaughter) were evaluated. Ewes (n = 151) were assigned to one of nine treatments from mid-pregnancy until lambing. Medium FV and high FV grass silages (metabolisable energy concentrations of 10.7 and 12.0 MJ/kg DM) were offered ad libitum supplemented with either 15 or 25 kg concentrate/ewe during late pregnancy. Low and high DM maize silages (starch concentrations of 80 and 315 g/kg DM) were offered ad libitum either alone or with soybean meal (200 g/d) and supplemented with 15 kg concentrate during late pregnancy. A final treatment consisted of high FV grass silage supplemented with 5 kg soybean/ewe over the final 4 weeks of pregnancy. Ewes and lambs were put to pasture in a rotational-grazing system within 3 days of lambing. There were no interactions (P > 0.05) between grass silage FV and concentrate feed level for ewe or lamb traits. Increasing grass silage FV increased food intake (P < 0.001) during late pregnancy, ewe BW and body condition score (BCS) at lambing (P < 0.001), lamb BW at birth (P < 0.001) and weaning (P < 0.05), and reduced age at slaughter (P = 0.06). Increasing concentrate feed level increased metabolisable energy (P < 0.05) intake during late pregnancy but had no effect (P > 0.05) on ewe or lamb performance. Increasing maize DM at harvest and offering soybean meal with maize silage increased food intake (P < 0.001) and ewe BW and BCS at lambing (P < 0.05 or P < 0.01). Offering soybean meal with maize silage increased lamb BW at birth (P < 0.01) and reduced age at slaughter (P < 0.05). Reducing supplementation of high FV grass silage to 5 kg of soybean meal had no effect (P > 0.05) on animal performance. Replacing grass silage with maize silage did not affect (P > 0.05) BW gain of lambs. It is concluded that increasing the FV of the grass silage offered during pregnancy had the greatest positive impact on ewe and lamb performance.     

Examination of stability,and its effect on the nutritive value,of fish silage in diets for growing pigs

Fish silage was manufactured by the addition of formic acid (85% solution) to whole mackerel at a rate of 35 g kg⁻¹ [wet weight (ww)]. During 112 days of storage, the peroxide value of the silage declined from 164.3 meq O₂ kg⁻¹ oil on Day 1 to 55.0 meq O₂ kg⁻¹ oil by Day 42 and thereafter remained stable; microbial activity persisted at 10 colonies g⁻¹ silage ww. Four diets of similar crude protein, digestible energy and mineral concentrations were formulated with 0, 50, 100 or 150 g fish silage kg⁻¹ diet dry matter (DM). The diets were given to 72 Landrace × (Landrace × Large White) pigs (boars, gilts and castrated males) from 25 kg to slaughter at 55 kg.Animals on fish silage diets grew faster than those given no fish silage owing to an improved food conversion ratio (FCR); 100 g fish silage kg⁻¹ diet DM effected best performance (daily liveweight gain, 725 g; FCR, 1.96). Carcass measurements did not vary between dietary treatments. Soft, yellow fat was observed in carcasses from pigs given 150 g silage kg⁻¹ diet DM. Growth rates were similar between sexes; boars and gilts had less backfat than castrated males.     

The effect of silage additives containing formaldehyde on the fermentation of ryegrass ensiled at different dry matter levels and on the nutritive value of direct-cut silage

Ryegrass, harvested at the pre-ear emergence stage of growth, was ensiled in laboratory silos, either fresh (175 g dry matter kg^?1) or wilted to five DM levels ranging from 216–432 g DM kg^?1, with and without additive treatment. The additives used were “Sylade” containing sulphuric acid (15%) and formaldehyde (23%) applied at 4.6 l t^?1 and an “ADD-F” $\text{(85\%}\text{formic acid}\text{)}\text{formalin}$ mixture (7:3 by volume) applied at a similar rate (4.8 l t^?1). An additional treatment included application of the mixture at a constant rate related to the DM content of the ensiled crop (25 l t^?1 DM).In the untreated silages, the water-soluble carbohydrates (WSC) varied, respectively (over the DM range 175–432), from 0–32 g kg^?1 DM compared with 197-6 g kg^?1 DM for the “Sylade” treated silages and 256-50 g kg^?1 DM for the formic acid/formalin silages treated at an additive rate of 4.8 l t^?1. Corresponding ranges of protein N for the control and treatments (expressed as g kg^?1 total N) were 302–447, 624-502 and 620-505, respectively. When the formic acid/formalin additive was applied at a constant level related to the DM content of the crop, although the WSC content decreased with increasing DM (247-158 g kg^?1 DM), the protein N content (612 g kg^?1 total N) remained constant.Grass from the same field was ensiled fresh, treated with “ADD-F” at the rate of 3.4 l t^?1 fresh grass, $\text{“}\text{ADD-F}\text{”}\text{formalin}$ at the rate of 4.8 l t^?1 fresh grass and “Sylade” at the rate of 4.6 l t^?1 fresh grass. The silages were given to Suffolk-cross wether lambs in digestibility and intake trials. Digestibility coefficients of DM and energy of the silage treated with “Sylade” were significantly lower (P < 0.05) than those of the other three silages. The DM intakes of all the silages were high, ranging from 27.7 g kg^?1 live weight for the “Sylade” silage to 30.7 g kg^?1 live weight for the silage treated with $\text{“}\text{ADD-F}\text{”}\text{formalin}$. Live weight gains ranged from 200 g/day for the control silage to 267 g/day for the $\text{“}\text{ADD-F}\text{”}\text{formalin}$ silage.     

Evaluation of the factors affecting silage intake of dairy cows: a revision of the relative silage dry-matter intake index

An evaluation of the factors affecting silage dry-matter intake (SDMI) of dairy cows was conducted based on dietary treatment means. The data were divided into six subsets based on the silage treatments used in the experiments: concentration of digestible organic matter in dry matter (D-value) influenced by the maturity of grass ensiled (n = 81), fermentation quality influenced by silage additives (n = 240), dry matter (DM) concentration influenced by wilting of grass prior to ensiling (W; n = 85), comparison of silages made from primary growth or regrowth of grass (n = 46), and replacement of grass silage with legume (L; n = 53) or fermented whole-crop cereal (WC; n = 37) silages. The data were subjected to the mixed model regression analysis. Both silage D-value and fermentation quality significantly affected SDMI. The average effects of D-value and total acid (TA) concentration were 17.0 g and − 12.8 per 1 g/kg DM, respectively. At a given D-value, silage neutral-detergent fibre (NDF) concentration tended to decrease SDMI. Silage TA concentration was the best fermentation parameter predicting SDMI. Adding other parameters into the multivariate models did not improve the fit and the slopes of the other parameters remained insignificant. Total NDF intake was curvilinearly related to silage D-value the maximum intake being reached at a D-value of 640 g/kg DM. Results imply that physical fill is not limiting SDMI of highly digestible grass silages and that both physical and metabolic factors constrain total DM intake in an interactive manner. Silage DM concentration had an independent curvilinear effect on SDMI. Replacing primary growth silage with regrowth, L or WC silages affected SDMI significantly, the response to regrowth silage being linearly decreasing and to L and WC quadratically increasing. The outcome of factors affecting SDMI was used to update the relative SDMI index as follows: SDMI index = 100+10 × [(D-value − 680) × 0.0170 − (TA − 80) × 0.0128+(0.0198 ×  (DM − 250) − 0.00002364 × (DM² − 250 ²)) − 0.44 × a+4.13 × b − 2.58 × b²+5.90 × c − 6.14 × c² − 0.0023 × (550 − NDF)], where a, b and c represent the proportions (0–1) of regrowth, L or WC silages from total silage DM. For the whole data set, one index unit corresponded to the default value of 0.10 kg in SDMI. The SDMI index explained proportionally 0.852 of the variation in SDMI with 0.34 kg DM per day residual. The updated SDMI index provides improved basis for the practical dairy cow ration formulation and economic evaluation.     

Effects of shearing at housing, grass silage feed value and extended grazing herbage allowance on ewe and subsequent lamb performance

The study involved 120 crossbred ewes (sixty 1.5 years old animals and sixty 2.5 years old animals; initial liveweight 67.6 kg, condition score 3.7), that were mated in October. They were assigned to six treatments (two shearing treatments (shorn and unshorn) × two silage feed values (low and medium) and two extended grazed herbage allowances (1.0 and 1.8 kg dry matter (DM)/day)) designed to evaluate the effects of shearing at housing, grass silage feed value and extended-grazed herbage allowance on their performance and the performance of their progeny. Swards, which had silage harvested on 6 September, received fertiliser N (34 kg/ha) for extended (deferred) grazing between 19 December and lambing in mid-March. The herbage was allocated at DM allowances of 1.0 or 1.8 kg/ewe daily until 1 February. For the final 6 weeks of pregnancy, daily herbage DM allowances were 1.5, 1.6, 2.0, 2.0 and 2.0 kg for weeks 6, 5, 4, 3 and 2 to parturition, respectively. Two grass silages (low and medium feed value) were offered from housing on 19 December to lambing in mid-March. At housing, half the ewes were shorn whilst the remainder remained unshorn. Each ewe received 23.4 kg concentrate prior to lambing. For the extended-grazed herbage and the low and medium feed-value silages, DM concentrations were 132, 225 and 265 g/kg, and metabolisable energy (ME) concentrations were 10.0, 10.0 and 10.7 MJ/kg DM, respectively. Treatment did not alter (P > 0.05) litter size or number reared. Grass silage feed value did not significantly alter silage DM intake, or ewe and subsequent lamb performance. Increasing herbage allowance in mid-pregnancy decreased herbage utilisation (P < 0.05) and increased herbage intake (P < 0.05). Shearing increased silage intake (P < 0.05), lamb birth weight (P < 0.01) and tended to increase lamb weaning weight (P = 0.07). Relative to the housed shorn ewes, extended grazing did not alter (P > 0.05) ewe or subsequent lamb performance. It is concluded that shearing ewes at housing increased lamb birth weight due to increased silage intake probably associated with cold stress immediately post shearing and reduced heat stress in late pregnancy. Based on differences in lamb weight at weaning 0.8 kg of grass silage DM intake had the same feed value as a daily extended herbage DM allowance of 1.8 kg per ewe throughout the study. Neither silage feed value nor herbage allowance in mid-pregnancy affected lamb birth weight or subsequent growth rate.     

The effect of some pre-ensiling treatments on silage composition and nitrogen disappearance in the rumen

Ryegrass, harvested before ear emergence, was ensiled in triplicate in laboratory silos with and without pre-ensiling treatments. These were: 4.7 M sulphuric acid (39 and 79 g kg^?1 DM); formalin (28 and 58 g kg^?1 DM); ‘Add-F’ (22.5 M formic acid; 36 and 71 g kg^?1 DM); formalin (28 and 58 g kg^?1 DM); ‘Farmline’, a commercial additive containing acids and formalin (31 g kg^?1 DM); heat (30 and 60°C for 1 h); and Lactobacillus plantarum inoculum + glucose (4.6 g kg^?1 DM). The ensilage period was 120 days. Samples of each silage were incubated, in artificial fibre bags, in the rumens of four Hereford-cross steers fitted with permanent rumen cannulae. Total nitrogen (TN) disappearance was measured after incubation periods of 1, 2, 4, 7, 12 and 24 h.Hydrochloric acid and the heating pre-treatments had no significant effect (P > 0.05) on the pH, water-soluble carbohydrates and fermentation acid values compared with those of the control. Fermentation acid production was suppressed to an increasing extent by formalin (28 g kg^?1 DM), sulphuric acid (79 g kg^?1 DM), formic acid (36 g kg^?1 DM), formalin (58 g kg^?1 DM) and formic acid (71 g kg^?1 DM).The application of L. plantarum + glucose increased fermentation acids from 90.3 g kg^?1 DM in the control to 227 g kg^?1 DM, owing to a 10-fold increase in lactic acid content from 21.7 to 202 g kg^?1 DM.All treatments, with the exception of 30°C heating, produced silages with significantly (P < 0.001) more total nitrogen as protein than the control. This ranged from 334 g kg^?1 TN (60°C heating) to 748 g kg^?1 TN (formalin; 58 g kg^?1 DM).All treatments significantly (P < 0.05) reduced TN loss, compared with the control silage values, after a 7-h incubation period in the rumen. After 24 h, however, TN disappearance from the treated silages was not significantly different from that of the control with the exception of the two silages treated with formalin alone. With these silages, the proportion of TN disappearing was 55.0 and 40.0% for the low and high application rates, respectively, compared with a value of 74.0% for the control.     

Temperate forages ensiled with molasses or fresh cheese whey: Effects on conservation quality, effluent losses and ruminal degradation

Effects of ensiling and adding molasses or increasing levels of fresh cheese whey on the conservation and rumen degradability of temperate pasture silages were evaluated. Forage from three paddocks of mixed grass and legume pastures was used to make 45 silages (15 silages per paddock) with 5 treatments, including silage without additives (control), silage with 15 g/kg dehydrated molasses and silage with 20, 50 and 100 g/kg fresh cheese whey. The chemical composition and fermentation quality (i.e., pH, ammonia N, loss of dry matter (DM) and neutral detergent fibre (NDF), effluent production) of the silages were determined. Fresh and ensiled materials were evaluated for in situ rumen degradability. Ensiling reduced DM and NDF rumen degradability (P<0.01). When additives were employed, the reduction of DM degradability of the silages decreased (P≤0.03). Addition of molasses led to the lowest pH (P<0.01) and DM losses (P<0.01), and highest DM degradability (P<0.01). The conservation and DM degradation results of dried molasses silage was superior to those of fresh whey silages. In general, an increase in the level of whey increased DM degradability (P≤0.03), but linearly increased effluent production (P<0.01) and losses (P<0.01).     

The effect of inclusion of lupins/triticale whole crop silage in the diet of winter finishing beef cattle on their performance and meat quality at two levels of concentrates

This study investigated the performance and instrumental meat quality of finishing beef steers offered grass silage (GS), grass silage:maize silage (GS:MS) and grass silage:lupins/triticale silage (GS:LT). The lupins/triticale silage was grown as either two separate crops in the same field and harvested together (LT1) or grown and harvested as a mixture (LT2). The silages were offered to eighty continental cross beef steers, initial live weight 530 ± 47.7 kg and 18 ± 1.6 months of age and were supplemented with 3 or 6 kg concentrates fresh/head/d. Silage was fed ad libitum with the mixtures offered at a ratio of 60 GS:40 maize silage (MS), LT1 or LT2 on a dry matter (DM) basis and concentrates were offered once (3 kg) or twice (6 kg) daily on top of the silage. Animals were slaughtered in three batches after 100, 117 and 124 d on experiment. The LT1 and LT2 produced yields of 8.7 and 7.5 kg DM/ha and the silages were poorly fermented as demonstrated by high ammonia-N concentration (182 and 173 g/kg total N), low lactic acid (9 g/kg DM) and high pH (5.0 and 4.7). Silage type had no significant effect on slaughter live weight, liveweight gain, carcass gain, forage DM intake (DMI), total DMI or feed efficiency expressed as kg DMI/kg liveweight gain or kg DMI/kg carcass gain. Silage type had no effect on carcass characteristics or instrumental meat quality. The results of this study demonstrate that offering lupins/triticale silage in combination with high quality grass silage (D-value greater than 700) at a ratio of 60 grass silage:40 LT1 or LT2 on a DM basis had no effect on animal performance, carcass characteristics or meat quality parameters relative to high quality grass silage offered alone or in combination with maize silage.     

Viability of Cryptosporidium parvum during ensilage of perennial ryegrass

The survival of Cryptosporidium parvum during ensilage of perennial ryegrass was examined in laboratory silos with herbage prepared in one of three different ways; either untreated, inoculated with a strain of Lactobacillus plantarum or by direct acidification with formic acid. The pH values of all silages initially fell below 4.5, but only formic acid-treated silage remained stable at less than pH 4 after 106 d, with the pH of the untreated and inoculant-treated silages rising to above 6. The formic acid-treated silage had a high lactic acid concentration (109 g kg^-1 dry matter (DM)) and low concentrations of propionic and butyric acids after 106 d. However, the untreated and inoculant-treated silages showed an inverse relationship, with low lactic acid concentrations and high concentrations of acetic, propionic and butyric acids. These silages also contained ammonia-N concentrations in excess of 9 g kg^-1 DM. In terms of the viability of Cryptosporidium parvum oocysts very few differences were seen after 14 d of ensilage with ca 50% remaining viable, irrespective of treatment and total numbers had declined from the initial level of 5.9 × 10⁴ to 1 x 10⁴ g^-1 fresh matter. Total oocyst numbers remained approximately the same until the end of the ensiling period, with the percentage of viable oocysts declining to 46, 41 and 32% respectively for formic acid, inoculant and untreated silages. The results are discussed in terms of changes occurring during the silage fermentation, in particular the products which may influence the survival of Cryptosporidium and implications for agricultural practice and the health of silage fed livestock.     

The effects of concentrate energy source on feed intake and rumen fermentation parameters of dairy cows offered a range of grass silages

The effects of concentrate energy source on feed intake and rumen fermentation parameters of lactating dairy cattle, offered one of three grass silages differing in fermentation and intake characteristics, were evaluated in a partially balanced changeover design experiment involving four rumen fistulated dairy cows. Three silages were harvested using different management practices prior to and at ensiling. Silages A and C and silage B were harvested from primary or secondary regrowths either untreated or treated with a bacterial inoculant. For silages A, B and C, dry matter (DM) concentrations were 334, 197 and 183 g/kg (S.E. 3.1), pH values 4.00, 4.79 and 4.80 (S.E. 0.042) and ammonia nitrogen (N) concentrations were 123, 319 and 295 g/kg total N (S.E. 20.0), respectively. Two concentrates were formulated to contain similar crude protein, effective rumen degradable protein, digestible undegradable protein and metabolisable energy concentrations but using different carbohydrate sources to achieve a wide range of starch concentrations. For the low and high starch concentrates starch concentrations were 17 and 304 g/kg DM and acid detergent fibre concentrations were 170 and 80 g/kg DM, respectively. The silages were offered ad libitum, supplemented with 10 kg fresh concentrate daily. For silages A, B and C, DM intakes were 10.9, 7.2 and 8.6 kg/day and concentrate energy sources did not alter (P>0.05) intake. Increasing the level of starch in the concentrate decreased the molar concentration of acetate (P<0.05) and tended to increase the molar concentration of propionate (P<0.1). Silage type altered the molar concentration of acetate (P<0.01) and the acetate:propionate ratio (P<0.05). There were no silagetype×concentrate interactions (P>0.05) on silage intake or rumen fermentation parameters. It is concluded that when concentrate and silage form equal proportions of the diet, the composition of the silage has an over-riding influence on rumen fermentation parameters. Furthermore, the changes in milk fat concentration, observed in a concurrent production study, due to changes in silage and concentrate types can be accounted for by changes in the ratio of lipogenic to glucogenic precursors in the rumen fluid.     

Effects of ethyl ester supplementation to forage on short-term dry matter intake and preference by goats

In whole-crop maize silages with atypical smell and decreased acceptance by ruminants, high concentrations of the volatile organic compounds ethyl acetate (EA) and ethyl lactate (EL) were detected. The aim of this study was to evaluate the impact of different concentrations of ethyl esters added to forage on preference and short-term feed intake of goats. In the first of three trials, whole-crop maize silage was supplemented with different concentrations of EA and EL and then vacuum-stored before use. Forages sampled during the preference trial showed a good recovery of EL with a high accordance of target (naturally formed + supplemented) and analysed concentrations. Supplemented EA was not recovered, making transient storage of substrates before use in feeding trials equivocal. However, four treatments with different concentrations of EL (approximately 330, 560, 920 and 1300 mg/kg dry matter (DM)) were used for the preference trial. In Trials 2 and 3, EA and EL (with and without ethanol, respectively) were added to grass hay directly before offering the feed, each in concentrations of 0, 600 and 1200 mg/kg DM to have six treatments each. In all trials, each possible combination of treatments was offered to Saanen-type wethers (n = 10, Trial 1; n = 5, Trials 2 and 3) as free choice in preference trials. In Trial 1, there was only a weak impact of EL on preference behaviour as goats avoided medium EL concentrations, but did not avoid silages with higher concentrations. In Trials 2 and 3, there was no influence of added volatiles on short-term DM intake and preference at all. It can be concluded that it is unlikely that ethyl esters as single substance or in combination with ethanol affect preference behaviour and feed intake of ruminants. Possibly a combination or still unidentified fermentation products cause avoidance instead of a single compound.     

The effect of N-fertilisation rate or inclusion of red clover to timothy leys on fatty acid composition in milk of dairy cows fed a commercial silage : concentrate ratio

The aim of this experiment was to, under typical Swedish production conditions, evaluate the effects of grass silages subjected to different N-fertilisation regimes fed to dairy cows on the fatty acid (FA) composition of their milk, and to compare the grass silages in this respect to red clover-dominated silage. Grass silages made from first year Phleum pratense L. leys subjected to three N-fertilisation regimes (30, 90 and 120 kg N/ha, designated G-30, G-90 and G-120, respectively) and a mixed red clover–grass silage (Trifolium pratense L. and P. pratense L.; 60/40 on dry matter (DM) basis, designated RC–G) were produced. The experiment was conducted as a change-over design, including 24 primiparous and multiparous dairy cows of the Swedish Red breed, each of which was allocated to three of the four diets. The cows were offered 11 kg DM of silage and 7 kg concentrates. The silages had similar DM and energy concentrations. The CP concentration increased with increase in N-fertilisation level. There was a linear increase in DM intake of the different silages with increased N fertilisation. There were also differences in concentrations of both individual and total FAs amongst silages. The daily milk production (kg/day) did not significantly differ between treatments, but G-30 silage resulted in higher concentrations of 18:2n-6 in the milk compared with the other two grass silages. The highest concentrations of 18:3n-3 and cis-9, trans-11 18:2 were found in milk from cows offered the RC–G silage. The G-30 diet resulted in higher concentration of 18:2n-6 and the same concentration of 18:3n-3 in the milk as the other grass silages, despite lower intake levels of these FAs. The apparent recoveries of 18:3n-3 from feed to milk were 5.74%, 4.27%, 4.10% and 5.31% for G-30, G-90, G-120 and RC–G, respectively. A higher recovery when red clover is included in the diet confirms previous reports. The higher apparent recovery of 18:3n-3 on the G-30 treatment may be related to the lower silage DM intake, which led to a higher relative proportion of ingested FAs originating from concentrates compared with the G-90 and G-120 diets. With the rates and types of concentrates used in this study, the achieved differences in FA composition among the silages were not enough to influence the concentrations of unsaturated FAs in milk.     

Effect of fish oil on ruminal biohydrogenation of C18 unsaturated fatty acids in steers fed grass or red clover silages

Red clover and fish oil (FO) are known to alter ruminal lipid biohydrogenation leading to an increase in the polyunsaturated fatty acid (PUFA) and conjugated linoleic acid (CLA) content of ruminant-derived foods, respectively. The potential to exploit these beneficial effects were examined using eight Hereford × Friesian steers fitted with rumen and duodenal cannulae. Treatments consisted of grass silage or red clover silage fed at 90% of ad libitum intake and FO supplementation at 0, 10, 20 or 30 g/kg diet dry matter (DM). The experiment was conducted with two animals per FO level and treatments formed extra-period Latin squares. Flows of fatty acids at the duodenum were assessed using ytterbium acetate and chromium ethylene diamine tetra-acetic acid as indigestible markers. Intakes of DM were higher (P < 0.001) for red clover silage than grass silage (5.98 v. 5.09 kg/day). There was a linear interaction effect (P = 0.004) to FO with a reduction in DM intake in steers fed red clover silage supplemented with 30 g FO/kg diet DM. Apparent ruminal biohydrogenation of C18:2n-6 and C18:3n-3 were lower (P < 0.001) for red clover silage than grass silage (0.83 and 0.79 v. 0.87 and 0.87, respectively), whilst FO increased the extent of biohydrogenation on both diets. Ruminal biohydrogenation of C20:5n-3 and C22:6n-3 was extensive on both silage diets, averaging 0.94 and 0.97, respectively. Inclusion of FO in the diet enhanced the flow of total CLA leaving the rumen with an average across silages of 0.22, 0.31, 0.41 and 0.44 g/day for 0, 10, 20 or 30 g FO/kg, respectively, with a linear interaction effect between the two silages (P = 0.03). FO also showed a dose-dependent increase in the flow of trans-C18:1 intermediates at the duodenum from 4.6 to 15.0 g/day on grass silage and from 9.4 to 22.5 g/day for red clover silage. Concentrations of trans-C18:1 with double bonds from Δ4-16 in duodenal digesta were all elevated in response to FO in both diets, with trans-11 being the predominant isomer. FO inhibited the complete biohydrogenation of dietary PUFA on both diets, whilst red clover increased the flow of C18:2n-6 and C18:3n-3 compared with grass silage. In conclusion, supplementing red clover silage-based diets with FO represents a novel nutritional strategy for enhancing the concentrations of beneficial fatty acids in ruminant milk and meat.     

Effects of Agave salmiana Otto Ex Salm-Dyck silage as forage on ruminal fermentation and growth in goats

Ensiling of Agave salmiana Otto Ex Salm-Dyck, a widespread plant in Mexico, as a viable preservation method to create a potential animal feed resource for ruminants was investigated. Fresh A. salmiana with 205 g dry matter (DM)/kg and wilted alfalfa with 602 g DM/kg were ensiled in combinations (DM:DM) of 1000:0, 500:500 and 350:650, to evaluate feeding value of agave:alfalfa silages on ruminal fermentation and growth of goats. Chemical composition and in situ ruminal disappearance of three total mixed rations (TMRs), which included 240 g/kg DM of each silage (1000:0, 500:500 and 350:650) were determined. The TMR were used to assess ruminal fermentation and growth of 15 goats (20 ± 2.2 kg body weight (BW)). Silage pH (≤4), lactate (>25 g/kg DM) and ammonia (<50 g/kg total N) concentrations indicate that silage quality was good. Lactic acid was the main acid in all silages, acetic acid concentrations were relatively low, and butyrate was only detected in only the 1000:0 agave:alfalfa silage. Potential DM disappearance of the TMR increased quadratically as the amount of alfalfa included in the silage mixture increased. The BW gain and feed efficiency were not changed by treatment, even though DM intake decreased and aNDF intake increased linearly as the amount of alfalfa included in the silage mixture increased. Ruminal pH and butyrate increased, and ammonia N, lactate and propionate decreased linearly as alfalfa proportion of alfalfa in the silage mixture was increased. The TMR ingredient selectivity by the goats may have limited goat performance when alfalfa was included in agave silage mixtures. Because the agave:alfalfa blend improved nutritional quality, ruminal digestibility and intake of agave silage, alfalfa inclusion may improve nutritional characteristics of agave plants silages for ruminants.     

Feed consumption and performance of dairy cows with alternate feedings of grass silage and maize silage

A feeding experiment was conducted with 10 dairy cows of the Fleckvieh breed and the cross Red Holstein Friesian × Fleckvieh, to study whether feeding with grass silage at the morning meal and maize silage at the evening meal (treatment B: alternating forage allocation) affects forage intake and milk production, in comparison with combined feeding with these two silages at each meal (treatment A). In order to prevent a selective forage consumption in treatment A, the two silages were given as a homogeneous mixture of nearly equal portions (51.6% maize silage, 48.4% grass silage) of dry matter (DM). The experiment was of switch-back design, with the treatment sequences ABA and BAB, and three experimental periods of 6 weeks.The daily forage consumption averaged 12.3 kg DM when the silages were given as a mixture and was significantly higher than the total forage consumption of 11.8 kg DM (P < 0.05) during the alternating allocation of the silages. In treatment B, daily intake of maize silage (7.10 kg DM) was greater than that of grass silage (4.70 kg DM/day). Furthermore, variation between cows in forage intake was significantly higher in this treatment than in treatment A. Average daily milk yield for treatment A was 18.75 kg with 3.84% fat and 3.70% protein, and 18.10 kg with 3.76% fat and 3.68% protein for treatment B. Production was significantly higher (P < 0.05), by 0.65 kg milk or 0.90 kg FCM, for treatment A.