The effects of feeding fodder beet to dairy cows offered silage ad libitum

In a 16-week winter feeding experiment, 48 autumn calving cows and heifers were used to compare a control diet, with two diets including fodder beet at a low and a high level. The control diet was ad libitum silage and 6 kg d^-1 of concentrates (13.4 MJ (kg DM)^-1 of ME and 197 g (kg DM)^-1 of CP). The cows offered fodder beet were fed the control diet (C) plus fodder beet at either 2 (L) or 4 (H) kg DM d^-1. Soya bean meal was offered with the fodder beet at 0.5 or 1.0 kg d^-1 for diets L and H, respectively.
Total dry matter and metabolizable energy intakes were 15.2,16.4 and 17.3 kg DM d^-1; 177, 195 and 211 MJ d^-1 for treatments C, L and H, respectively. The mean milk yields were not significantly affected by the feeding of fodder beet. There was a significant improvement in the fat and protein content of the milk and yield of constituents. The milk composition and yield of solids were: fat content 42.3,44.2 and 45.9 (s.e.d. 1.25) g kg^-1; protein content 33.0, 34.5, 35.3 (s.e.d. 0.76) g kg^-1; fat yield 964,1027,1095(s.e.d. 63.2); protein yield 757, 801, 841 (s.e.d. 48.8) for treatments C, L and H, respectively. The treatments had no significant effect on live weight or condition score change.     

A comparison between barley and groundnut as supplements for dairy cows at pasture

In two 12-week grazing experiments using twelve and eighteen spring-calved cows in 1976 and 1977 respectively, the effects of feeding either a barley or a groundnut concentrate supplement were investigated. The mean yield of herbage DM on offer was 2330 and 2030 kg ha^-1, with crude protein concentrations of 192 and 193 g per kg DM in 1976 and 1977 respectively. Grazed herbage was the sole feed in the control treatment. In the other two treatments the herbage was supplemented with 3 kg per cow per d of a concentrate containing either 82·2% barley or groundnut with mean crude protein concentrations of 109 and 409 g per kg DM respectively. Similar results were obtained in both experiments with average daily milk yields of 18·3, 19·8 and 19·9 kg per cow on the control, barley and groundnut treatments respectively. The supplements had no significant effects on either milk composition or liveweight change. It is concluded, that with an ample supply of herbage of high crude protein concentration, a supplement of groundnut had no advantages over one of barley.     

Silage and milk production: a comparison between long, chopped and ground hays as supplements to silage of high digestibility

Grass silage made in May from S24 perennial ryegrass had a DM concentration of 262 g kg^-1 and an in vitro D-value of 0·698, and was given ad libitum to twelve Ayrshire cows in a 16-week feeding experiment. In addition supplements of hay with a mean in vitro D-value of 0·603 were offered in one of three forms—long, chopped (12·1 mm) or ground (0·80 modulus of fineness) and cubed—and of concentrates given at either 2 or 4 kg per 10 kg milk. Hay averaged 18·2% of total forage DM intake with mean daily intakes of 1·28, 1·22 and 2·26 kg DM per cow in the long, short and ground forms respectively. The highest daily intakes of forage, i.e. silage plus hay, occurred on the ground hay treatments, with values of 10·24 and 9·25 kg DM per cow on the 2 and 4 kg concentrate treatments respectively. The mean daily milk yields were 18·2,18·2 and 19·2 kg per cow on the long, short and ground hay treatments respectively but the increase in yield with the ground hay was only significant at the low level of concentrate intake. The hay treatments had small and non-significant effects on milk composition. It is concluded that ground hay was superior to either long or chopped hay as a supplement for silage, but the small advantages depended on the level of concentrate intake.     

Silage and milk production. A comparision between barley and groundnut cake as supplements to silage of high digestibility

Grass silage of hjgh digestibility made in late May from S23 perennial ryegrass was offered to twelve Ayrshire cows in a 16-week winter-feeding experiment. The silage had a DM content of 27.2% and contained 147% crude protein and 70.3% digestible organic matter in the DM. The silage was fed ad libitum and was the sole feed in the control treatment. In the other three treatments the silage was supplemented with barley, groundnut cake or a mixture of barley and groundnut supplying 4.7, 1.5 and 4.7 kg DM per cow per day respectively. The daily intakes of silage DM were 10.8 kg per cow in the control treatment and 8.6, 11.1 and 9.3 kg per cow in the barley, groundnut and barley plus groundnut treatments, respectively. The daily yields of milk were 14.6 kg per cow in the control, and 16.1, 17.6 and 17.9 kg per cow in the three supplement treatments, respectively. The fat content of the milk was highest in the barley treatment, whereas the SNF and CP contents were highest in the barley plus groundnut treatment. It is concluded that with a high digestibility silage, a supplement of groundnut cake was superior to barley for milk production.     

Silage and milk production: a comparison between concentrates containing different amounts of protected protein as supplements for silage of high digestibility

Grass silage made in late May from S24 perennial ryegrass was offered ad libitum to eight Ayshire cows in a 16-week feeding experiment. The silage had a DM concentration of 244 g kg⁻¹, contained 163 g crude protein (kg DM)⁻¹ with a ruminal degradability of 0.77 and had an in vitro DOMD concentration of 678 g kg⁻¹. In addition, four concentrates each containing 167 g soya-bean meal kg⁻¹ were consumed at a mean daily rate of 6.43 kg DM per cow. The soya-bean meal was either untreated, or 'protected' by formalin and mixed in the following proportions, 100:0; 66:34; 34:66; and 0:100 respectively, in the four concentrates. The daily intakes of silage DM were not significantly different on the four treatments and averaged 90 kg DM per cow, giving a mean total daily DM intake of 32.4 g kg⁻¹ live weight. The milk yields were not significantly different on the four treatments and averaged 23.9 kg ⁻¹ The treatments had small and non-significant effects on milk composition and live weight. It is concluded that with a high-digestibility, well-preserved grass silage of satisfactory protein content the inclusion of 'protected' protein in the supplementary concentrate had no beneficial effects on milk production.     

Silage and milk production: a comparison between supplements of barley and soybean meal offered with white clover silage

Silage made from Blanca white clover was offered ad libitum to four Friesian cows in a 12-week changeover experiment. The silage contained 990 g white clover DM (kg DM)⁻¹ with 254 g DM kg⁻¹ and 243 g CP (kg DM)⁻¹ The pH was 3.98 and the in vitro DOMD concentration 680 g kg⁻¹. The silage was the sole feed in the control treatment; in the other three treatments it was supplemented with barley, soybean meal, and a mixture of these feeds supplying 8.1, 2.7 and 7.8 kg DM per cow respectively. The daily intakes of silage DM were 19.3, 13.5, 17.5 and 13.5 kg per cow, and the daily milk yields were 26.3, 28.0, 28.6 and 27.6 kg per cow on the control, barley, soybean and barley plus soybean treatments respectively. It is concluded that the white clover silage had an excellent fermentation and a large potential for milk production.     

Silage and milk production: a comparison between additives for silage of high digestibility

Three grass silages made in early June from S23 perennial ryegrass were compared in a 16-week feeding experiment with twelve Ayrshire cows. The silages were made from uniform herbage which received either formic acid (‘Add-F’) at the rate of 201 t^?1, or a formalin-sulphuric acid mixture (‘Syiade’) at rates of 2.0 and 4.4 1 t^?1. The silages were offered ad libitum either alone or supplemented with a cube containing 38% CP in the DM at the rate of 1.4 kg per 10 kg milk. The daily intakes of silage DM were not significantly different on the three silage treatments, and averaged 10.7, 11.0 and 11.0 kg per cow on the formic acid and the 2.0 and 44 1 t^?1 formalin-acid treatments respectively. The mean daily yields of milk were 15.1, 13.3 and 13.7 kg per cow in the unsupplemented treatments, and 18.2, 18.1 and 18.0 kg per cow in the supplemented treatments on the formic acid and the 2.0 and 44 1 t^?1 formalin-acid treatments respectively. On the basis of total animal production expressed in terms of metabolizable energy requirements, it was concluded that the differences between the three silages were small.     

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.     

Effects of feeding fodder beet and concentrates with different protein contents on dairy cows offered silage ad libitum

In two changeover design experiments, fifteen early- and sixteen late-lactation cows were used to investigate the effects of offering food beet with ad libitum grass silage and concentrates with different CP content on milk yield and quality. In Experiment 1 (early lactation) cows were offered no fodder beet (0) or 4 kg DM d^?1 (4) in conjunction with one of three concentrates containing 159, 191 or 244g CP kg^?1 DM (L.M.H.). Treatments were therefore 1L/0, 1L/4, 1M/0, 1M/4, 1H/0 and 1H/4. In Experiment 2 (late lactation) cows were offered the same level of fodder beet in conjunction with two concentrates containing 129 and 229 (L,H) g CP kg^?1 DM. Treatments were therefore 2L/0, 2L/4, 2H/0 and 2H/4. In both experiments feeding fodder beet reduced silage DM intakes (P < 0·001) and increased total DM intake (P < 0·05 to P < 0·001). The substitution rate (r) ranged from 0·46 to 0·59kg of silage DM (kg^?1 fodder beet DM). In Experiment 1, fodder beet tended to increase milk yield, composition and yield of constituents, but the effect was statistically significant for milk protein content only (P < 0·01). In Experiment 2, milk yields for 2L/0, 2L/4, 2H/0 and 2H/4 were 11·3, 12·1, 11·7 and 12·5 kg d^?1 respectively (s.e.d. 0·43, non-significant), fat contents were 44·4, 47·3, 44·3 and 46·8g fat kg^?1 respectively (s.e.d. 0·73, P < 0·001), protein contents were 34·3, 35·6, 35·3 and 36·2 g protein kg^?1 respectively (s.e.d. 0·28, P < 0·001), fat yields were 494, 574, 512 and 579 g fat d^?1 respectively (s.e.d. 20, P < 0·001) and protein yields were 385, 426, 407 and 442 g protein d^?1 (s.e.d. 13, P < 0·01) respectively. Increasing CP in the concentrate significantly increased milk yield in Experiment 1 (23·9, 22·5, 23·5, 23·8, 26·2, 26·5kg d^?1 for 1L/0, 1L/4, 1M/0, 1M/4, 1H/0 and 1H/4 respectively, P < 0·05). Higher CP in concentrate also resulted in significantly increased milk protein yield in early-lactation (P < 0·001) and milk protein content in late-lactation (P < 0·01) cows. There was a significant interaction between fodder beet and concentrate CP content for milk protein yield (P < 0·001) in Experiment 1.     

Relationship between digestibility and faecal nitrogen in sheep and cows offered herbage ad libitum

A comparison was made of the digestibility, voluntary intake and concentration of N in faecal organic matter in castrated male sheep and non-lactating cows offered herbage ad libitum. The sheep ate 22% more herbage DM per kg liveweight than the cows. In general, the sheep and cows digested the organic matter of the herbage to the same extent, although on two occasions significantly higher digestibilities were observed in cows than in sheep. Similar concentrations of N in faecal organic matter in sheep and cows were matched by similar digestibilities of herbage organic matter. Regression equations relating herbage organic matter digestibility to faecal N concentration were not significantly different between sheep and cattle.     

Supplementary feeding of forage to grazing dairy cows, 3. The effect of three daytime stocking rates on the performance of cows offered grass silage overnight

Over a 24-week period, three groups of dairy cows were continuously stocked at 8, 10 or 12 cows ha^-1 between morning and afternoon milkings, and overnight were housed and offered grass silage ad libitum. Due to a prolonged drought, sward heights only averaged 4·1 cm.
The increase in daytime stocking rate led to a decline in herbage intake, and increases in silage intake. At the highest stocking rate (12 cows ha^-1), the silage intake failed to compensate for the reduced herbage intake. Consequently the total dry matter and estimated metabolizable energy intakes were lower than for the 8 and 10 cows ha^-1 treatments. Milk yields and milk composition were not significantly affected by treatment but the 12 cows ha^-1 stocking rate gave the lowest milk and milk solids yields.
The utilized metabolizable energy (UME) on the grazed swards was greatest for the 10 cows ha^-1 treatment. The sward cut to provide the silage had a UME level (GJ ha^-1) 32% greater on average than the grazed swards during the same growth period. The total areas utilized for grazing and silage production for 8, 10 and 12 cows ha^-1 were 0·240, 0·224 and 0·215 ha respectively. Fat and protein yields per unit area were greatest for the 10 cows ha^-1 group.     

Silage and milk production: a comparison between four rates of groundnut cake supplementation of silage of high digestibility

Grass silage made in late May from S24 perennial ryegrass was offered to twelve Ayrshire cows in a 16-week feeding experiment. The silage had a DM content of 25.3%, a pH of 3.91, and contained 16.8% CP and 68.4% digestible organic matter in the DM. The silage was fed ad libitum and was the sole feed in the control treatment. In the other three treatments the silage was supplemented with a cube offered at rates of 0.8, 1.4 and 2.0 kg per 10 kg milk. The cube contained 82.2% groundnut, plus molasses and minerals, and had 37.9% CP in the DM. The daily intake of silage DM was 11.4 kg per cow on average over the four treatments which did not differ significantly. The mean daily milk yields were 14.8 kg per cow in the control treatment, and 16.5, 18.2 and 18.4 kg in the 0.8, 1.4 and 2.0 kg supplement treatments respectively. The SNF, CP and lactose contents of the milk were Wghest on the 1.4 kg supplement treatment. It is concluded that with a high digestibility silage, there is little evidence to support the feeding of more than 1.4 kg of high-protein cubes per 10 kg milk in the declining phase of lactation.     

A comparison of two grassland-based systems for autumn-calving dairy cows of high genetic merit

A full lactation study compared the performance of autumn‐calving dairy cows of high genetic merit under two contrasting systems of milk production: high forage (HF) and high concentrate (HC). During the winter, animals on system HF were offered a silage with a high feeding value characteristics, supplemented with 5·5 kg of concentrate [crude protein content of 280 g kg^?1 dry matter (DM)] through an out‐of‐parlour feeding system. From 14 March, these animals were given increasing access to grazing, achieving 24‐h turnout on 15 April. Thereafter, until day 305 of lactation, these animals were offered a large daily herbage allowance (23·0 kg grass DM cow^?1, measured above a height of 4·0 cm), supplemented with 0·5 kg d^?1 of a ‘high‐magnesium’ concentrate. During the winter, animals on system HC were offered a silage of medium feeding value, mixed with ≈14·0 kg of concentrate d^?1 (crude protein content of 202 g kg^?1 DM) in the form of a complete diet. These animals commenced grazing on 9 April, achieving 24‐h turnout on 18 April. From 18 April until 9 June, daily herbage allowances and concentrate feed levels were 17·0 kg DM and 5·0 kg respectively; thereafter, and until day 305 of lactation, these daily allowances were reduced to 15·0 kg of herbage DM and 4·0 kg of concentrate. Animal performance during the first 305 days of lactation for systems HF and HC, respectively, were as follows: total concentrate DM inputs, 842 and 2456 kg; total silage DM intakes, 2205 and 1527 kg; total grass DM intakes, 3019 and 2044 kg; total feed DM intake, 6061 and 6032 kg and total milk output, 7854 and 8640 kg. Total milk output per cow with system HF was 786 kg lower than for system HC, despite similar total DM intakes, suggesting a greater total nutrient requirement with the former to support a given milk production. However, the study confirms that relatively similar levels of animal performance can be achieved from systems based on very different sources of nutrient supply.     

Silage and milk production: a comparison between barley and dried sugar-beet pulp as silage supplements

Two grass silages made from perennial ryegrass, and with D-values of 0·216 and 0·255, were offered ad libitum to 18 Ayrshire cows in two feeding experiments. On the control treatment the silages were supplemented with soybean meal only, and on the other two treatments with equal weights of DM from either barley or dried molassed sugar-beet pulp plus the same weight of soya as on the control treatment. The daily intakes of silage DM were not significantly different on the barley and beet-pulp treatments, and, on average, the intake of silage DM was reduced by 0·24 and 0·20 kg by feeding 1 kg barley and beet pulp DM respectively.
The daily milk yields were not significantly different on the barley and beet-pulp treatments with mean values of 19·2 and 19·2 kg per cow respectively compared with 17·2 kg on the control treatment. On the barley and beet-pulp treatments the fat, SNF, CP and lactose concentrations in the milk and the live weights of the cows were not significantly different. It is concluded that the barley and beet pulp had similar feeding values and replacement rates when used as supplements with grass silage, and that the two feeds were interchangeable on an equal DM basis.     

Nutritive value of barley/kale bi-crop silage for lactating dairy cows

Six mid‐lactation multiparous Holstein–Friesian dairy cows were used to examine the potential of a fermented whole‐crop barley (Hordeum vulgare)/kale (Brassica oleracea) bi‐crop as a feed compared with a first‐cut perennial ryegrass silage. The barley/kale bi‐crop was grown as a strip intercrop, and was harvested and ensiled as an intimate mixture [0·80 barley and 0·20 kale on a dry‐matter (DM) basis]. Animals were offered ad libitum access to one of three experimental diets in a duplicated Latin Square design experiment: (i) Bi‐crop (the barley/kale bi‐crop); (ii) Grass (the grass silage); and (iii) Mix (a 1:1 fresh mixture of Bi‐crop and Grass). All animals also received a standard dairy concentrate at a rate of 4 kg d^?1 in equal portions at each of two milkings. The Bi‐crop and Grass silages contained 346 and 293 g DM kg^?1, 108 and 168 g crude protein kg^?1 DM, 268 and 36 g starch kg^?1 DM, and had pH values of 3·87 and 3·80 respectively. Animals offered the two bi‐crop silage‐containing diets consumed more forage DM than those offered grass silage (14·6, 14·9 and 12·6 kg DM d^?1 for Bi‐crop, Mix and Grass respectively; s.e.d. 0·45, P < 0·01) and yielded more milk (24·0, 23·9, 22·6 kg d^?1 for Bi‐crop, Mix and Grass respectively; s.e.d. 0·26, P < 0·01). However, differences in the partitioning of dietary nitrogen towards milk protein and away from excretion in urine suggest a more efficient (rumen) utilization of feed protein by animals offered diets containing the bi‐crop silage. It is concluded that, despite having a low crude protein concentration, barley/kale bi‐crop silage offers excellent potential as a feed for lactating dairy cows.     

Silage and milk production: a comparison between soya, groundnut and single-cell protein as silage supplements

Grass silage made in May from S24 perennial ryegrass was offered ad libitum to twelve Ayrshire cows in a 12-week feeding experiment. The silage had a DM concentration of 217 g kg ^-1, contained 147 g crude protein per kg DM and had a D-value of 64·6. In addition each cow consumed 1 kg hay per d plus concentrate supplements of dried sugar-beet pulp with (A) soya bean meal, (B)‘Pruteen’, a single-cell protein (C) groundnut cake. The three concentrate supplements each contained 250 g crude protein per kg DM and were offered at the rate of 2·9 kg per 10 kg milk. The daily intakes of silage DM were 8·38, 7·94 and 7·49 kg on treatments A, B and C, respectively, with the extreme values being significantly different. The mean daily yields of milk on treatments A and B were both 16·2 kg per cow, and were significantly higher than the yield of 15·2 kg per cow on treatment C. The fat and lactose contents of the milk on the three treatments were not significantly different, but the CP content on treatment C was significantly lower than that on the other treatments. It is concluded that soya bean meal and‘Pruteen’were superior to groundnut cake as a protein supplement in a silage-based ration.     

Sodium fertilizer application to pasture. 10. A comparison of the responses of dairy cows with high and low milk yield potential

Current recommendations for the intake of sodium of lactating dairy cows are related to milk yield. A study was conducted to compare the responses of cows of high and low milk production potential to the application of sodium fertilizer to grazed perennial ryegrass pasture. The application of sodium fertilizer increased the intake of herbage dry matter (DM), the time that cows spent grazing and the biting rate. It also increased the concentration of sodium, magnesium and calcium in herbage and decreased the concentration of potassium. Applying sodium fertilizer increased milk yield and milk fat concentration and decreased somatic cell count in the milk of cows of low-production potential only, whereas it increased persistency of milk production in the cows of high-production potential. The concentration of lactose in milk increased in both groups after the application of sodium fertilizer. It is concluded that the optimum dietary sodium concentration for grazing cows does not increase with milk yield, and that most immediate advantage will be gained from increasing the sodium concentration in herbage for low-yielding cows.     

Comparison of the performance of dairy cows offered kale,swedes and perennial ryegrass herbage in situ and perennial ryegrass silage fed indoors in late pregnancy during winter in Ireland

The effects on the performance of dairy cows offered kale, swedes, and perennial ryegrass in situ and perennial ryegrass silage fed indoors to dairy cows pre‐partum during winter in Ireland was examined. Eighty‐eight spring‐calving dairy cows were randomly assigned to one of four offered treatments; (i) 8 kg of dry matter (DM) of kale leaf and stem + 4 kg DM of perennial ryegrass silage (treatment K), (ii) 8 kg DM of the root and leaf of swedes + 4 kg DM of perennial ryegrass silage (treatment S), (iii) 12 kg DM of perennial ryegrass herbage (treatment G) offered in situ and (iv) perennial ryegrass silage offered ad libitum indoors (treatment ID). Cows on treatments K, S and ID had a greater (P < 0·001) increase in body condition score (0·20, 0·14 and 0·50 units respectively) pre‐partum than cows on treatment G which lost 0·22 units. Pre‐partum treatment had no effect on variables of milk production in the following lactation. In the first 100 d of lactation, cows on treatment G pre‐partum had a lower milk fat concentration (35·6 g kg^?1) compared with cows on treatments S and ID (38·3 and 39·3 g kg^?1 respectively). There was no effect of treatment on the intervals between parturition and first insemination (mean 74·6 d) and conception (mean 96·1 d). The results suggest that offering kale and swedes to dairy cows pre‐partum resulted in a similar lactation performance to dairy cows grazing a perennial ryegrass sward or offered perennial ryegrass silage indoors.     

Mixing whole-crop pea–oat silage and grass–clover silage: positive effects on intake and milk production of dairy cows

Forty‐eight high‐yielding dairy cows of the Swedish Red breed were used to examine the effects of providing pea–oat silage (P), grass–clover silage (G) and a 0·50:0·50 mixture of the silages (M) ad libitum in diets with two concentrate levels (7 or 10 kg d^?1). A 9‐week experiment, including a 2‐week pre‐experimental period in which the cows were all fed the same diet, and an in vivo apparent digestibility study were conducted comparing the six dietary treatments (M7, M10, P7, P10, G7, G10). Intake and digestibility of the diets and milk production and live weight of the cows were measured. The G silage [11·3 MJ ME kg^?1 dry matter (DM)] was first‐cut grass herbage wilted for 24 h prior to addition of an additive, containing formic acid, propionic acid and ammonia, at 4 L t^?1 fresh matter (FM). The P forage was cut when the peas were at pod fill and ensiled directly with 6 L t^?1 FM of the same additive. The main hypothesis tested, that cows fed the M silage would produce more milk than the cows fed either the P or the G silages, was confirmed. The cows fed the M7 dietary treatment had similar milk yield and milk composition to cows offered the M10, G10 and P10 dietary treatments, and cows offered the G7 and P7 dietary treatments had lower milk and milk protein yields. This suggested that a mixed ration of pea–oat bi‐crop and grass–clover silage has a concentrate‐sparing effect, and that the use of pea–oat bi‐crop and grass–clover silage as a mixed ration for high‐yielding dairy cows can be recommended.     

A comparison of buffer and partial storage feeding of a straw/concentrate mixture to grazing dairy cows

A straw/concentrate mixture was offered to set-stocked dairy cows over a 24-week period. The cows were offered grazed herbage only (G), or grazed herbage with a straw/concentrate supplement offered either for 45 min after each milking (B), or overnight (P). The overnight treatment involved housing the cows between afternoon and morning milking. The straw/concentrate mixture contained 0·33 long barley straw, 0·28 barley, 0·12 soya bean meal, 0·25 molaferm and 0·02 minerals. During the first 8 weeks of the experiment an average of 2·25 kg of concentrate were fed, and from weeks 9–24, 2·0 kg of concentrate were fed.
The feeding of the straw/concentrate mixture led to a decrease in estimated herbage dry matter (DM) intake, particularly for treatment P. Estimated total DM intakes were increased throughout the experiment by offering the straw/concentrate mixture. However, total metabolizable energy (ME) intakes were only increased in mid-and late season.
Milk yield was higher in early season for treatment G; 28·1 kg d⁻¹ compared to 26·8 kg d⁻¹ and 25·5 kg d⁻¹ for treatments B and P respectively. In late season the cows in treatment G had lower milk yields; 13·3 kg d⁻¹ compared to 15·5 kg d⁻¹ and 16·8 kg d⁻¹ for treatments B and P respectively. Milk fat content was increased in early season in treatment P, and milk protein content tended to be reduced throughout the experiment for cows offered the straw/concentrate mixture overnight. Over the whole experiment there were no differences in yield of milk solids.