Effects of feeding clover silages on feed intake, milk production and digestion in dairy cows

Silages were made from pure crops of perennial ryegrass, red clover and white clover over 2 years. In all but one case the silage was stored as bales. A silage additive specially adapted for bales (Kofasil Ultra^TM) was used for all silages and they were all of good hygienic quality. The additive contained sodium nitrite, hexamethylene, tetraamine sodium bensoate and sodium propionate. The silages were offered ad libitum, either pure or mixed [grass/clover 0·50/0·50 on a dry‐matter (DM) basis] with a fixed amount (8 kg) of concentrate. Two experiments, one in each year, were performed with high‐yielding multiparous dairy cows in mid‐lactation, and both rumen‐cannulated and intact cows were used. The experiments were carried out using an incomplete changeover design with fifteen cows and five treatments each year. The cows consumed large quantities of these silages (12·7–16·3 kg DM per cow per day). The highest intakes were obtained when the red clover and the 0·50 red clover:0·50 perennial ryegrass silage diets were offered. However, there was a difference between years. In year 1, 0·50 red clover:0·50 perennial ryegrass and 0·50 white clover:0·50 perennial ryegrass silage diets showed the highest intakes while pure perennial ryegrass and white clover silage diets gave lower intakes. In year 2 the highest intake of silage was obtained when the diet containing silage from red clover from a second cut was offered, while the silage from red clover from a first cut gave the lowest intake. The voluntary intakes of silages from white clover and perennial ryegrass were intermediate. No cases of bloat or other digestive disturbances were observed. Milk yield was significantly lower for the perennial ryegrass silage diet compared with all other diets in year 1. In year 2 milk yield was highest for the white clover silage diets and lowest for the red clover silage diets from both cuts. In year 1 there were relatively small differences in milk composition while in year 2 milk fat content was significantly lower with white clover silage diet and milk protein content was significantly higher with the perennial ryegrass diet. The overall conclusion from these experiments was that cows were able to consume large quantities of pure legume silage without serious disturbance to their metabolism. Differences in measurements of rumen metabolism were found between diets and especially between years. Milk production differences appears to be coupled to both differences in rumen physical characteristics, such as passage rate and particle size as well as differences in volatile fatty acid production in the rumen.     

THE EFFECT OF FEEDING RED CLOVER CONSERVED BY DRYING OR ENSILING ON REPRODUCTION IN THE EWE

Forage diets were prepared from ryegrass (non oestrogenic control) and from red clover as pellets or as unwilted silage. Each diet was fed to separate groups of 20 Border Leicester × Cheviot ewes for three weeks prior to the introduction of the ram, and for two cycles after mating. Subsequently, all three groups of ewes were fed in a similar manner until lambing and the reproductive performance of the ewes was measured. The control diet was prepared by barn drying a primary growth crop of perennial ryegrass, Lolium perenne cv S23. Tetraploid red clover, Trifolium pratense cv. Hungarpoly, was harvested as a first regrowth crop and the pelleted diet prepared by high temperature drying, grinding (2 mm screen) and pelleting. The silage was prepared without wilting. The level of formononetin in the red-clover silage was three times that in the dried red-clover pellets. Compared with the control grass diet, the feeding of red clover in either form significantly reduced (P<0·001) the number of lambs born. The incidence of barrenness was higher (P<0·001) for ewes fed red-clover silage compared with red-clover pellets and the control diet. The rate of twinning was significantly (P<0·001) higher for the ewes fed the control grass diet than for either of the red-clover diets. The resultant lambing percentages were 190,165, and 100% for the control grass, red-clover pellet and red-clover silage treatments. In flock management, both the grazing of red clover and the feeding of red-clover pellets or silage, prior to and during mating, should be avoided.     

Digestion in the stomach and intestines of sheep receiving diets of red clover silage with various supplements

Three castrated male sheep fitted with rumen and duodenal re-entrant cannulae were used in a 3×3 Latin Square experiment to investigate the digestion of three diets of red clover silage with supplementary concentrates containing barley or barley and groundnut meal or barley and urea. The supplements were designed to be isocaloric and the groundnut meal and barley-urea mixtures to be isonitrogenous. There were no significant (P >0.05) differences between treatments in the digestibility of organic matter (mean value 71.2%) or in the percentage of dietary organic matter digested in the stomach (mean value 53.6%) and diiferences between treatments in the concentrations of total and individual short-chain fatty acids in the rumen were small. The nitrogen intake for the barley treatment was 19.41 g/d and that for the groundnut meal and barley-urea treatments were 23.36 g/d and 23.05 g/d respectively. Corresponding figures for the duodenal flows of nitrogen were 21.97 g/d, 21.48 g/d and 21.14 g/d and for the faecal losses of nitrogen were 7.09 g/d, 6.98 g/d and 6.92 g/d. As a consequence, although the diets supplied quite different amounts of digestible crude protein they supplied similar amounts of crude protein digested in the intestines.     

Rumen degradation and intestinal digestion of grass and clover at two maturity levels during the season in dairy cows

A comparison was made of the effect of season and maturity on the in situ ruminal breakdown and intestinal protein digestion in dairy cows between intensively N-fertilized grass (whole sward) and moderately N-fertilized ryegrass and clover from a mixed sward. From May to September 1990, eight consecutive cuts were made, representing alternate harvests of late and early swards. Limited effects of fertilizer-N on chemical and ruminal degradation characteristics and intestinal digestion of grasses were observed. Clover had higher ash, crude protein (CP) and lignin and lower hemicellulose, cellulose and sugar contents than grass. Moreover, soluble fractions of organic matter (OM) and CP were higher, and rumen-undegradable OM and CP fractions were lower. Soluble fractions of grasses and clover decreased and undegradable fractions increased during the season. More mature swards showed increased undegradable fractions. Degradation rates of OM and CP in clover were, respectively, higher than or similar to those of grass. Seasonal effects on degradation rates differed between grass and clover. Effectively rumendegradable (g kg⁻¹ DM) carbohydrates and CP, escaped protein and intestinal digestion of escaped protein were higher in clover than in grasses. Inclusion of clover in swards may result in higher post-rumen protein supply. Supplementation of clover-based diets is suggested to compensate for an increased loss of N in the rumen.     

The effects of forage preservation method and proportion of concentrate on digestion of cell wall carbohydrates and rumen digesta pool size in cattle

Six bulls with ruminal and duodenal cannulae were used in a 6 × 6 Latin square design with a 2 × 3 factorial arrangement of treatments. Barn-dried grass (G) and direct-cut silage (S) from the same sward were fed together with 250 (L), 500 (M) and 750 (H) g kg^-1 total dry matter (DM) of a barley-based concentrate (barley 875 and rape-seed meal 125 g kg^-1) at the level of 80 g DM kg^-1 live weight^0·75. Rumen and total digestibility of cell wall constituents were measured by a double marker and total collection method. Rumen pool sizes of dietary constituents were estimated by emptying the rumen. Particle-associated enzyme activities were measured from rumen particulate material and feed particles incubated in nylon bags in the rumen. Neutral detergent fibre (NDF) and hemicellulose digestibility were higher (P<0·05) for G diets than for S diets while no differences were observed between the forages in acid detergent fibre (ADF) and cellulose digestibility. Both rumen and total digestibility of cell wall constituents decreased with increasing level of concentrate. The proportion of total cell wall digestion in the rumen was unaffected by the forage preservation method and the proportion of concentrate. NDF, and especially cellulose digestibility, declined quadratically with increasing level of concentrate. Dietary effects on particle-associated carboxymethylcellulase and xylanase activity were consistent with those observed in cell wall digestion. There were no differences between the forages in rumen pool size of total ingesta or any dietary constituent. Rumen pool size of total ingesta decreased with increasing level of concentrate. On the other hand, DM content of ingesta increased with the level of concentrate, while the pool size of DM, NDF and ADF declined quadratically reaching a minimum on M level of concentrate. The differences in rumen NDF pool size were mainly in the digestible fraction. Calculation of digestion kinetic parameters showed that both the rate of passage and especially the rate of digestion were markedly depressed in animals fed on the highest level of concentrate. The results suggest that a reduced fate of digestion of NDF with high concentrate diets can be partially compensated for by an increased NDF retention time in the rumen of animals fed at a restricted level of feeding.     

海南黑山羊生长期的能量与蛋白质需要量

试验选用12只海南黑山羊断奶羔羊（约4月龄）,采用饲养试验和消化代谢试验,研究生长期海南黑山羊的能量和蛋白质需要量及其代谢规律。试验羊分成4组,采用4&#215;4拉丁方设计。按照Keral（1982）适宜于发展中国家的山羊饲养标准为参考设计了高能高氮、低能高氮、高能低氮、低能低氮4种能氮比的日粮。结果表明：舍饲海南黑山羊生长期干物质采食量与代谢体重和日增重的关系为DMI（g/d）=27.18W^0.75＋0.83△W＋210.76（r=0.8916）;总能、消化能、粗蛋白质和可消化蛋白质需要量的估测模型分别为GEI（MJ/d）=0.82W0.75＋0.028△W＋3.76（r=0.7804）,DEI（MJ/d）=0.59W^0.75＋0.021△W-0.24（r=0.6651）,CPI（g/d）=2.45W^0.75＋0.26△W＋22.14（r=0.5712）,DCP（g/d）=2.69W^0.75＋0.03△W-0.38（r=0.6605）;生长期海南黑山羊日粮总能代谢率平均为58.88%,粗蛋白的消化率平均为57.08%,净蛋白利用率平均为35.25%,每增重1g体沉积蛋白质需要量为0.37g。     

Nutritive Value of Wheat Bran Diets Supplemented With Fresh Carrots and Wet Brewers’ Grains in Yellow Mealworm

We evaluated the effect of supplementation of a wheat bran (WB) diet with fresh carrots (FC) or wet brewer’s grains (WBG) on the growth performance and chemical composition of Tenebrio molitor larvae. Additionally, a digestibility trial was performed to determine the nutritional value of the raw materials used. The control diet was based on WB-only. Two other diets were formulated in which WB was supplemented with FC (FC diet) or with WBG (WBG diet). The experiment was conducted in trays (12 per treatment) and lasted 90 d. Larval weight, feed intake, and excreted feces were controlled in each tray the experiment. The digestibility trial was performed from 48 to 62 d post-hatch. Results showed digestibility coefficients of ashes, crude protein, and gross energy were significantly higher in FC diet compared with the other diets. Consequently, both digestible energy (DE) and digestible protein (DP) contents of FC were also significantly higher than those obtained for WB and WBG diets (on av. +1.12 megajoule [MJ] DE and +9.15 g DP per kg dry matter [DM]; P < 0.003). Mealworms fed FC diet showed significantly higher final weight and average daily gain than those fed the WBG diet (+12.4%), being higher in WBG than in WB diet (+3.5%). Dietary treatment did not affect DM, ashes, ether extract, and crude protein content of mealworms obtained. Some dietary effects on amino acid and fatty acid composition were observed. This study provides novel data and a unique experimental approach to assess the nutritional value of raw materials in mealworms.     

饲料用稻谷和糙米的营养特性

 对18个饲料用水稻样品的稻谷和糙米的常规营养成分、氨基酸组成和有效能值进行了分析和测定。稻谷和糙米含蛋白质分别为(8.85±1.23)%, (10.35±1.33)%,含总能分别为(15.83±0.28) MJ/kg, (15.95±0.20) MJ/kg, 含消化能10.28 MJ/kg 和 13.48 MJ/kg。稻谷的养分消化率明显低于糙米的相应值。主要是由于稻谷含粗纤维8.94%,而糙米的相应值为1.19%。稻谷和糙米分别含赖氨酸0.29%和0.44%,蛋氨酸0.10%和0.18%,苏氨酸0.26%和0.30%。用作猪饲料时,赖氨酸是第一限制性氨基酸,苏氨酸是第二限制性氨基酸,异亮氨酸是第三限制性氨基酸。     

Determination of the best level of dietary energy with two diet formulation methods based on total and digestible amino acid on broiler diet

In order to evaluate the effects of different levels of energy and methods of formulation of Amino Acid (AA) requirements of diets, this experiment was conducted using 392 broiler chicks. The experiment was carried out using a complete randomize block design with 7 levels of energy 3175, 3075, 2975, 2875, 2775, 2675 and 2575 kcal kg(-1) for grower diet and 3225, 3125, 3025, 2925, 2825, 2725 and 2625 kcal kg(-1) for finisher diet and two methods of formulation of diets AA requirements (total and digestible) as a factorial arrangement. Results showed that by increasing level of energy feed intake, body weight and FCR were promoted in grower diet (p<0.05). Effect of decreasing level of energy up to 2725 and 2825 kcal kg(-1) was not significant on body weight and FCR in finisher diet, respectively. Formulating of diet based on total or digestible AA affected feed intake and FCR in finisher diet (p<0.05). Interaction effect of independent factors affected on body weight in grower diet (p<0.05). Decreasing level of energy increased gastrointestinal tract percentage weight (p<0.05). Formulation of diet based on digestible AA decreased gastrointestinal tract percentage weight (p<0.05). Abdominal fat decreased significantly as ME content of diets decreased. Results showed that it's possible to reduce the level of energy up to 3175 kcal kg(-1) in grower and 2725 kcal kg(-1) in finisher diet for giving the best and economical performance response. Formulation of diet based on digestible AA in finisher diet resulted in promotion of performance.     

The rate of addition of formic acid to grass at ensilage and the subsequent digestion of the silage in the rumen and intestines of sheep

The main object of the experiment was to assess the effect of the relative proportion of non-protein nitrogen (NPN) to total nitrogen in silage on digestion in the sheep. Four unwilted perennial ryegrass silages were made with the addition of formic acid at 0, 2·2, 4·2 and 5·2 litres t^-1 to provide foods with NPN proportions reducing from 0·26 to 0·20 of the total N. The digestion of the silages was studied in a 4 × 4 Latin Square experiment with sheep cannulated in the rumen, proximal duodenum and terminal ileum.
Results for organic matter (OM), cellulose and N showed no major difference between silages in their digestion in the rumen, small intestine and caecum and colon, though small differences ( P <0·25) in rumen fermentation pattern and in the proportion of digestible OM disappearing in the small intestine were observed. Concentrations of ammonia N in the rumen and rates of rumen bacterial protein synthesis did not differ significantly between silages and there were no treatment effects on the passage of individual amino acids to the small intestine. The results indicate that the proportions of NPN to total N in the silages examined had little influence on the efficiency of silage N utilization in the rumen or on the passage of undegraded dietary protein to the small intestine.     

Effects of variation in herbage sodium levels and salt supplementation on the nutritive value of perennial ryegrass for sheep

Six groups of five 18-month-old wether sheep received a diet of dried grass ad libitum with a pelleted ground barley/oat supplement containing various levels of salt for 30 d. The first group received grass of high Na concentration (7·3 g per kg DM) with no added salt in the supplement, a second group received low sodium grass (4·2 g per kg DM) with no salt additions, and the other four groups received the low sodium grass with varying levels of salt added to the supplement to provide a final dietary Na concentration ranging from 7·0 to 18·0 g per kg DM.
Dry matter (DM) and organic matter (OM) intakes were significantly reduced for groups receiving salt supplementation. The digestibilities of DM and OM were reduced for all groups on the low sodium grass diets compared with the high sodium grass diet, but were not affected by salt supplementation.
No consistent changes were observed in the molar proportions of volatile fatty acids in rumen fluid, but N availability and retention were higher for the animals on the high sodium grass diet.
The high sodium grass diet gave a better apparent availability and retention of minerals than the low sodium grass diets and, while addition of salt tended to improve the availability of minerals, the urinary loss of minerals increased with salt addition to the diet.
There were no changes in plasma Na levels, and plasma K changes were inconsistent. However, plasma Ca concentration was reduced significantly for salt-supplemented diets with a Na concentration above 7·0 g per kg DM, and plasma Mg was significantly depressed at dietary Na concentrations above 15·0 g per kg DM.     

Utilization of silage nitrogen in sheep and cows: amino acid composition of duodenal digesta and rumen microbes

Two experiments are reported. In the first experiment the amino acid compositions of rumen bacteria and protozoa isolated from sheep given a diet of grass silage were compared with those taken from sheep given a diet of hay and barley; four sheep were assigned to each diet. There were no significant differences (P<0·05) between diets in the amino acid compositions of the microbial fractions and bacterial contents of α-ɛ-diaminopimelic acid were also similar for both diets.
In the second experiment the digestion of a grass silage and barley diet (65:35; 135 g CP (kg DM)^-1) was studied using four non-lactating Ayrshire cows fitted with cannulae in the rumen and in the proximal duodenum. The mean N intake was 154 g d^-1 and the corresponding duodenal flow was 126 ± 10 g d^-1 indicating that 0·21±0·07 of the N intake was absorbed between the mouth and the duodenum. The mean rumen NH₃-N concentration was high, 297 g litre^-1, and the mean rate of microbial protein synthesis in the rumen was low, 17 g microbial N (kg OM apparently digested in the rumen)^-1. There was a low content of bacterial N in the non-ammonia N at the duodenum (mean proportion 0·52±005) and low concentrations of methionine and lysine in the duodenal digesta protein. The results are discussed in relation to previously published data on the digestion of silage diets in sheep and to the utilization of silage diets for milk production in the cow.
It is concluded that with silage diets the supply of methionine and lysine to the duodenum is likely to be low because of the low rates of microbial protein synthesis in the rumen and that in cows those two amino acids may be limiting for milk production.     

Digestion in vitro of Italian and perennial ryegrasses, red clover, white clover and lucerne

Herbage at various stages of growth from three field experiments, one with Italian ryegrass, one with perennial ryegrass and one with white clover, red clover and lucerne, was incubated for 0, 24 or 48 h in rumen liquor followed by 48 h in acid-pepsin. The proportion of cell content OM in herbage (measured by pepsin) declined with advancing stage of growth more quickly in the legumes than in Italian ryegrass. At a high level of digestibility the legumes had a higher proportion of cell content OM than Italian ryegrass, but the position tended to be reversed at a low level of digestibility. Decline in proportion of cell content and decline in digestibility of cell wall were both major contributors to the decline in digestibility of Italian ryegrass with advancing maturity, whereas in white clover the decline in proportion of cell content was entirely responsible for the decline in digestibility. Lucerne and red clover occupied intermediate positions. At an early vegetative stage rate of digestion appeared to be higher in Italian than in perennial ryegrass. Rate of digestion was higher in the legumes than in the ryegrasses, the difference being largest at an advanced stage of growth.     

Nitrogen and Italian ryegrass.

The regrowth of Italian ryegrass was studied at weekly intervals from 2 to 14 weeks after a cut in late April when 140 kg ha^-1 N was applied. Reduction in digestibility with delay in date of harvest was due to both an increase in the proportion of cell wall and a reduction in the digestibility of the cell wall, particularly the former from week 2 to about week 5 and particularly the latter after week 5. The reduction in the digestibility of the cell wall was about equally attributable to reduction in digestibility of cellulose and to reduction in digestibility of hemicellulose. The proportion of lignin in cell wall was highly correlated with both digestibility of cellulose and digestibility of hemicellulose. The proportion of digestible cell wall in dry matter was not as constant as has sometimes been noted, increasing by about 5 percentage units from week 2 to week 5 and decreasing by about 10 percentage units from week 5 to week 13. During the latter period the decline in digestible cell wall in dry matter accounted for nearly half the decline in true digestibility of dry matter. The ratio of cellulose:hemicellulose averaged 1:0.89 and hemicellulose was more digestible than cellulose. Rate of increase in yield of cell contents appeared to diminish from about the third week of regrowth onwards, whereas the rate of increase in yield of dry matter did not begin to diminish until about the seventh week. In vitro dry matter digestibility was not increased by adding extra N to the digestion tubes, even with samples containing only 1% N in dry matter.     

Effect of concentrate, dried grass and dried white clover ratios on intake, digestibility and liveweight gain by early-weaned lambs

Early-weaned lambs were offered rations of conventional concentrate, dried grass and dried white clover pellets ad libitum for 52 days. In vivo OM digestibility coefficients of concentrate, grass and clover were 80.0, 53.4 and 66.6% respectively. Dry matter intake of dried grass was similar to that of concentrates but supported significantly lower (P < 0.001) daily gains (0.18 kg). Supplementation of dried grass with an equal proportion of dried clover significantly increased (P <0.05) DM and DOM intake and daily gains. Daily gains by lambs offered the 1:1 grass:clover diet (0.29 kg) were similar to gains by lambs offered either dried clover (0.30 kg) or concentrates (0.30 kg).     

The fertility of heifers consuming red clover silage

The fertility of forty-two heifers offered either red clover silage or grass silage prior to and during the period of insemination was compared. Pregnancy rate to first service was significantly higher ( P < 0·25) on red clover silage at 76% compared with 43% on grass silage. Pregnancy rates from a mating period covering three oestrus cycles were similar on the two silage diets. The ratio of services to pregnancies was lower on red clover silage (1·2) than on grass silage (2·2). In a subsidiary trial with twenty-three heifers, pregnancy rate to first service on red clover silage was 78%.
There was no evidence to indicate that herd fertility is depressed by red clover silage.     

THE UTILIZATION OF DRIED GRASS BY EARLY WEANED LAMBS

Three groups of 8 Polled Dorset Iambs were weaned at 8 weeks of age and were fed dried grass, a 50–50 mixture of dried grass and protein-supplemented barley and protein-supplemented barley. All rations were completed. Digestibility trials were also conducted and the effect of level of feed intake on nutrient digestibility investigated. The dried grass resulted in rates of gain comparable to those produced by the pelleted barley ration. Feed conversion efficiency was lowest for the grass and highest for the barley ration. An interaction between the dried grass and barley was observed in nutrient digestibility. Increasing the level of feeding from approximately maintenance to appetite tended to result in slight depressions in the digestibility of energy and protein of all rations. The results suggest that dried grass can be used successfully for intensive feeding of early weaned lambs and little nutritional advantage appears to be gained from combining dried grass with barley.     

Red clover varieties of Mattenklee type have higher production,protein yield and persistence than Ackerklee types in grass–clover mixtures

Dairy farmers have increased interest in multiyear red clover–ryegrass ley pasture swards because of their high productivity and protein concentration but the adoption of such mixtures has been restricted because of poor persistency of many red clover cultivars currently used. We aimed (i) to assess dry‐matter yield (DMY), persistence and nutritive value of four Mattenklee and four Ackerklee cultivars and (ii) to investigate the underlying plant morphological traits. We conducted a 4‐year field experiment with red clover–ryegrass mixtures, in combination with a short‐term pot experiment in which the red clover cultivars were grown both in monoculture and in mixture with Lolium perenne L. In the field, Mattenklees showed higher production (on average 42% higher) and clover content (on average 34% higher) in the third and fourth year of production compared to Ackerklees. In the fourth year, Mattenklees had slightly lower digestibility and lower protein concentration compared to Ackerklees cultivars; however, the digestible DMY and the protein yield were higher for Mattenklees. Both persistence and nutritive value of the different red clover cultivars were closely correlated with plant morphological traits. For stem length, there was close correlation (r > .77) between the results from the pot experiment and the field experiment, suggesting that stem length may be an important trait for plant breeding.     

A comparison of grass/white clover and grass silages offered to dairy cows as the sole feed

Two diets were compared: perennial ryegrass ( Lolium perenne L.) silage and perennial ryegrass/white clover ( Trifolium repens L.) silage, in each case fed ad libitum , without supplementation, to lactating dairy cows. The comparison was made with silages cut on each of four dates. The crops were wilted to a dry matter content of at least 256g kg^-1 and no additives were used.
The grass/clover silages were well preserved at all four cuts. The grass was well preserved at three cuts, but, at a May cut, the grass silage was less well preserved and less digestible than the grass/clover silage. When the May silages were fed, milk yield was higher with grass/clover than with grass. Taking the experiment as a whole, however, milk yield and composition were similar on the two diets. The grass/clover silages had a lower proportion of cell wall and their intake by dairy cows was consistently higher than that of the grass silages.
It is concluded that perennial ryegrass/white clover crops can be ensiled successfully and fed successfully, with high intake, to lactating dairy cows, but it should not be assumed that cows will give more milk than when fed equivalent all-grass silage.     

Effect of seed rate of red clover and of companion timothy or tall fescue on herbage production

Tetraploid red clover (cv. Hungaropoly) was sown at seed rates of 6,12 or 18 kg ha^?1 alone and in mixture with timothy (cv. Scots) at 2, 4 or 6 kg ha^?1 or with tall fescue (cv. S170) at 6,12 or 18 kg ha^?1. Two ‘silage’ crops and an ‘aftermath grazing’ crop were harvested in 2 successive years. In harvest years 1 and 2, total herbage production levels of 11.12 and 7.47 t dry matter (DM) ha^?1 respectively were obtained from pure-sown red clover compared with 11.84 and 8.78 t DM ha^?1 for red clover-timothy and 12.23 and 9.64 t DM ha^?1 for red clover-tall fescue. Corresponding red clover production levels were 10.93 and 5.30 t DM ha^?1 (red clover swards), 8.04 and 3.131 ha^?1 (red clover-timothy), and 6.42 and 109 t ha^?1 (red clover-tall fescue). Total herbage organic matter digestibility was improved by the timothy companion grass but not consistently by the tall fescue, whereas crude protein (CP) concentration was decreased by the addition of either grass. Increased seed rate intensified these effects, as well as the general effect of the companion grass in depressing red clover DM, digestible organic matter (DOM) and CP production. Total herbage DM, DOM and CP were not markedly affected by increasing red clover seed rate but red clover DM, DOM and CP were increased as red clover seed rate was raised, due to increases in the red clover component. The potential for silage cropping of red clover swards was confirmed but there was advantage in sowing a companion grass. Taking yield and quality parameters into consideration, timothy proved a better companion than tall fescue. A seed rate of 2 or 4 kg ha^?1 timothy and 12 kg ha^?1 red clover proved the most satisfactory.